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PRIME SEAL ISLAND Scientific Expedition

2008

The Hamish Saunder s Memor ial Island Sur vey Progr am HAMISH SAUNDERS MEMORIAL TRUST, NEW ZEALAND

Biodiversity Conservation Branch Department of Primary Industries, Parks, Water and Environment


Prime Seal Island Scientific Expedition 2008 A partnership program between the Hamish Saunders Memorial Trust, New Zealand and Biodiversity Conservation Branch, DPIPWE, Tasmania. Š Department of Primary Industries, Parks, Water and Environment Book ISBN 13 978-07246-6510-5 Web ISBN 13 978-0-7246-6511-2 Cite as: Harris, S., Driessen, M. and Bell, P. (2009). Prime Seal Island Scientific Expedition 2008. Hamish Saunders Memorial Trust, New Zealand and Biodiversity Conservation Branch, DPIPWE, Hobart, Nature Conservation Report Series 09/3 This work is copyright. It may be reproduced for study, research or training purposes subject to an acknowledgement of the sources and no commercial use or sale. Requests and enquiries concerning reproduction and rights should be addressed to the Branch Manager, Biodiversity Conservation Branch DPIPWE or the Hamish Saunders Memorial Trust, Auckland, New Zealand.


PRIME SEAL ISLAND Scientific Expedition

2008 A partnership program between the Hamish Saunders Memorial Trust, New Zealand and Biodiversity Conservation Branch, DPIPWE, Tasmania.

Editors: Stephen Harris Michael Driessen assisted by Phil Bell.


C ONTENTS

2


Photo by Rolan Eberhard.

FOREWORD

4

Hamish Saunders

6

Acknowledgements

6

Summary of Results

7

INTRODUCTION

8

GEODIVERSITY

10

VEGETATION

26

A REVISED FLORA

40

THE MAMMALS

60

THE REPTILES

66

THE DISTRIBUTION AND MANAGEMENT OF ENVIRONMENTAL WEEDS

76

INVERTEBRATE SURVEY

84

PRELIMINARY OBSERVATIONS OF THE SPIDERS

102

THE MOTHS

110

OBSERVATIONS ON ORTHOPTERA

114

BIRDS

120

NOTES ON NEARSHORE FISHES

128

BRIDGETTE MOFFAT Report of Hamish Saunders Memorial Trust Award Recipient 2008

132

DYLAN VAN WINKEL Report of Hamish Saunders Memorial Trust Award Recipient 2008

134

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F OREWORD

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Photo by Rolan Eberhard.

The Hamish Saunders Memorial Island Survey Program was established in 2005 as the result of a partnership agreement between the Tasmanian Government and the Hamish Saunders Memorial Trust. The program arose from the tragic loss of this young New Zealand scientist while he was assisting in Tasmanian Government research on remote Pedra Branca Rock in south western Tasmania.

The program aims to collect scientific information on Tasmanian and New Zealand islands as a contribution to the long term management and conservation of their natural values. Islands not only hold a special romantic and scenic attraction but are also regarded as scientifically important repositories of biodiversity including biogeographically significant species. Islands are also valuable areas that can be used as benchmarks against which wider threats and changes can be measured. They can also be considered in some cases as playing a role in quarantining insurance populations of threatened species. Since the partnership agreement was signed in 2005 each of the expeditions has resulted in a report which the department has published in the Hamish Saunders Memorial Island Survey Program series.

In this volume the results of the third expedition are reported. Prime Seal Island is one of the largest of the Outer Furneaux Islands and the twelve papers in this volume cover diverse aspects of its natural values. This will assist in the long-term management of the island by the government and the lessees who currently occupy much of the island. The island survey program was recently reviewed and both the Tasmanian Government and the Trust have re-affirmed their commitment to building on the work so far in both Tasmania and New Zealand. Apart from all the practical benefits, the professional and personal interaction that this program generates between scientists on both sides of the Tasman will be one of the legacies of Hamish Saunders.

Kim Evans Secretary Department of Primary Industries, Parks, Water and Environment Tasmania

David Saunders Hamish Saunders Memorial Trust New Zealand

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Hamish Saunders Hamish Saunders was a New Zealand volunteer who died tragically in 2003 while conducting survey work on a Tasmanian endangered species program. Hamish graduated from Waikato University with a First Class Honours and Masters degree in marine geology. He later completed a postgraduate GIS course with distinction. He also achieved qualifications as a scuba dive instructor, was a good sportsman and was talented, not solely academically, but as an all round individual. As an explorer, Hamish achieved in his 26 years much of which most only dream. From Antarctica to the Galapagos, Central America, South America, South-East Asia, Europe and Australia, he combined his passion for the natural world and conservation with that of an interest

in local cultures and people. Not only did he travel to these places, but he also took a great interest in the people around him. He touched many lives. Hamish was a remarkable and talented young man. The passion and enthusiasm he engendered in those whom he met and the gentle leadership he embodied is his legacy. This island survey program is dedicated to the memory of Hamish Saunders and intended as a platform for emerging leaders in marine conservation. The Tasmanian Government’s commitment and long-term support for the program was endorsed by the then Minister for Environment and Planning, The Hon. Judy Jackson MHA, on 8 July 2005.

Acknowledgements We especially thank once again, the Hamish Saunders Memorial Trust for participating in the program, particularly Alan and David Saunders, and the Trust’s travel award recipients Bridgette Moffat and Dylan van Winkel. Sincere thanks to George Jennings of Shaw and Sons Pty Ltd. and John Cooper of Flinders Island who were supportive of the study and provided background information as needed. James Luddington provided transport between Flinders Island and Prime Seal Island and we are grateful for his logistical support in this regard. Penny Wells and Mike Pemberton provided Agency support. We also thank Wayne Dick, the Parks and Wildlife Service Ranger on Flinders Island for taking a keen interest in the study and for visiting the party in the field. Wayne Warren of Parks and Wildlife Service, Lois Ireland and Noel Whittaker of Flinders Island were helpful to the party. We thank the many people who provided their time and expertise, some in a volunteer capacity, across the range of specialties dealt with in this report – they are acknowledged separately in the individual reports herein. Thanks to Brett Littleton of the ILS Design Unit in the Department of Primary Industries, Parks, Water and Environment for his design and layout of the report.

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Summary of Results 1. Prime Seal Island comprises a granite basement overlain by alkaline dunesands which accumulated prior to the Last Glacial Maximum. Some dunes are still mobile. 2. There are a number of significant geomorphic features, especially around the coast. These have been added to the Tasmanian Conservation Database. 3. The vegetation comprises 13 vegetation communities, including 3 listed as threatened: Eucalyptus ovata forest and woodland (DOV), Heathland on calcarenite (SHC) and Seabird rookery complex (SRC). 4. The native vegetation cover has expanded over the last few decades. 5. An additional 40 species of plants have been added to those known for the island, taking the total to 193. 6. The island has populations of 10 threatened plant species. Where population estimates were carried out these demonstrated much larger populations than previously thought.

7. Prime Seal Island supports one of the greatest diversities of reptile species of all the Outer Furneaux Islands. The presence of cats and house mice could potentially have an effect on the reptile fauna. 8. The introduced flora was assessed for problem species. Seven of these were mapped and prioritized for action, 5 of which are high priority. 9. The current occupants of the island have undertaken extensive control of boxthorn, with evidence of manual removal across much of the island. 10. The mammal survey revealed five wild mammal species, one of which was the Tasmanian pademelon, common on the island. Evidence of Brushtail Possum was detected but sightings not made. The most common introduced mammals were house mice and feral cats. 11. The first collection of spiders yielded 75 species, including Tasmania’s largest wolf spider Tasmanicosa godeffroyi with a body length of 26 mm. 12. A species of cave cricket previously known only from Flinders, Babel and Little Dog Island was found in Manalargenna Cave.

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13. The survey resulted in the first record of the spur-throated locust from eastern Tasmania and the first record of a raspy cricket from the eastern Bass Strait islands. 14. Several new species of invertebrates were discovered including a new species of centipede, and a possible new species of bristletail. Over 7 000 specimens were collected from the island. 15. The invertebrate fauna of the island is quite diverse and likely to be relatively intact with fewer exotic species than expected. 16. The invertebrate fauna of the island is likely to be best conserved by maintaining the island in its present condition. 17. An undescribed geometrid moth is a new record for Tasmania. 18. Forty-seven bird species were recorded for the island including wedge-tailed eagles. Although no presently used nest of the species was found, a disused nest was observed. Birds would be favoured by eradication of cats, better fencing in some areas, and careful fire management. 19. Fifty-one fish species were recorded inshore on a small portion of the east coast of Prime Seal Island. The species are typical of what could be expected in this locality.


I NTRODUCTION FLINDERS ISLAND Whitemark PRIME SEAL ISLAND

LOCATION CAPE BARREN IS

BASS

STRAIT

Launceston

Hobart

8


Prime Seal Island. Basemap: 1:25000 map Wybalenna 5656 (reproduced courtesy of TASMAP, DPIPWE).

Prime Seal Island, at 1221 hectares, is one of the largest of the approximately one hundred outer islands in the Furneaux Group in eastern Bass Strait. The island occurs at 40°03’45’’ latitude, 147°45’31’’longitude about ten kilometres to the west of Flinders Island itself and is about ten times longer than it is wide. The island has a north-south orientation. Flinders, Cape Barren and Clarke Islands are the three main islands in the Furneaux Group. Together with their outer islands and those of the Kent, Hogan and Curtis Groups further north, they form an archipelago between Wilsons Promontory in Victoria and the Tasmanian mainland. These islands have variously been part of a land bridge at times of lower sea level such as during the Last Ice Age prior to about 8 thousand years ago, or separated as they are now by higher sea level. The island is varied in topography and looks imposing with its three rounded elevated hummocks visible from a considerable distance. Like most of the islands in the group, it is composed mainly of granite with a mantle of calcarenite, alkaline sandy soils, and acid soils formed directly over the granite exposures. Islands in the Furneaux Group with

limey sands were considered fairly fertile compared with the granite islands and their infertile siliceous soils. Consequently the more fertile islands were settled from the early nineteenth century as farming and fishing took on more importance following the demise of the sealing period in about the 1820s. Much of the island is still operated as a wool growing operation under leasehold by the Crown to Shaw and Sons Pty Ltd. In the 2008 shearing season 43 bales of medium to fine merino wool was taken off the island. The lessees also carry out infrastructure maintenance, weed control, game management and burning. There is a network of vehicle tracks on the island, an airstrip, shearing, machinery and generator sheds, accommodation, water tanks and fencing. Islands are significant for biological conservation and there have been many practical examples of the role played by islands in being refuges for scientifically important biota, sometimes free from feral or problem animals and as potential sites for translocations or reintroductions of endangered species that might otherwise be under pressure in the rest of their range. There had been very little focussed scientific exploration on Prime Seal Island. Books on the flora and fauna of the Furneaux Islands by Stephen Harris and Nigel Brothers and colleagues assembled most of the

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information on which this expedition has been able to build. There were still many gaps in our knowledge of the island. The size, and geographic location of the island, together with government’s joint management responsibility (a small part of the island is outside the leasehold) with a private lessee, were amongst the factors that made this island an ideal target of the Hamish Saunders Memorial Island Survey Program. The expedition party landed on Flinders Island on 13 October 2008 thence to Prime Seal Island the following day. The team departed Prime Seal Island on the 19 October 2008 and then Flinders Island on 20 October. The expedition party leader was Stephen Harris, joined by Michael Driessen (mammals, reptiles), Nick Mooney (wildlife), Clare Hawkins (mammals), Rolan Eberhard (geomorphology), Emma Betts (geomorphology), Abbey Throssel (invertebrates), Kevin Bonham (invertebrates), Sarah Munks (mammals), Dylan van Winkel (Hamish Saunders Memorial Trust Travel Award Recipient 2008, wildlife), Bridgette Moffat (Hamish Saunders Memorial Trust Travel Award Recipient 2008, natural history), Micah Visoiu (vegetation/ flora) and Oliver Strutt (weeds).


G EODIVERSITY

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Plate 1 Quaternary sands exposed by erosion on the southwest coast. Photo by Rolan Eberhard.

By Rolan Eberhard Geologically, Prime Seal Island comprises a granite basement overlain by Quaternary sediments, principally dunesands. Weathering of the granite combined with aeolian and coastal processes have strongly influenced the geomorphology. Thermoluminescence dates for dunesands indicate an extended period of aeolian sedimentation in the period leading up to the Last Glacial Maximum. Sandy alkaline soils and calcrete duricrusts reflect the role of calcareous sand as the dominant soil parent material. Prime Seal Island was episodically connected to, and isolated from, adjacent land masses, due to oscillating sea levels during Quaternary glacial-interglacial cycles. The most recent period of isolation may have commenced around 8 000 years ago. The 2008 Prime Seal Island expedition provided information that will be used to update the Tasmanian Shoreline Geomorphic Types Digital Line Map Version and the Tasmanian Geoconservation Database. It highlighted the importance of avoiding land management practices with potential to exacerbate soil erosion hazards on Prime Seal Island.

INTRODUCTION The geodiversity (geology, geomorphology and soils) of Prime Seal Island is poorly documented. The scale of available geological

mapping is limited to the 1:250 000 Flinders Island sheet (Jennings and Cox 1978). Geomorphological aspects are touched on in reports concerning Mannalargenna Cave, the cultural significance of which was recognised in the late 1980s (Harris 1988; Brown 1991). The island was visited briefly during a reconnaissance inventory of the geoconservation values of Tasmania’s islands in the mid 1990s. Some unusual karst features were noted at this time (Dixon 1996) and later listed in the Tasmanian Geoconservation Database as the Prime Seal Island Karst and Concretions site (http:// www.dpiw.tas.gov.au/inter.nsf/ WebPages/LBUN-6TY32G?open). The soils have been described only insofar as their agricultural capability is considered in unpublished documents relating to the leasehold arrangement for the island. The Hamish Saunders Memorial trip was an opportunity for additional observations on aspects of the geodiversity of Prime Seal Island.

METHODS and RESULTS This overview of the geodiversity of Prime Seal Island is based on an examination of recent and historical air photos and 3 field days, during which time the main parts of the island, including most of the coast, major sandblows and features of interest reported previously, such as Mannalargenna Cave and karst on

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the northwest coast, were covered. Sand samples were collected for thermoluminescence (TL) dating by David Price (University of Wollongong). This paper alludes to the dating results, although this work will be described in detail elsewhere.

Geology Prime Seal Island is essentially a single large outcrop of granitic basement rock, probably granodiorite but referred to here as granite for simplicity. Although locally obscured by Quaternary sediments, the granite crops out extensively on all parts of the island. The rock is most likely a member of the Wybaleena suite of granitoids, which are widespread along the western side of the Furneaux Group (Reid 1987). Granitoids account for approximately 70% of the Palaeozoic basement of the Furneaux Islands (ibid), part of a broader northsouth oriented granitoid mass that underlies much of eastern Tasmania. These rocks are Devonian in age and were emplaced as a series of large magmatic intrusions into older sedimentary strata (Mathinna beds) between 395 and 368 million years ago (Seymour and Calver 1995). Uplift and erosion over an extended period of geological time has exposed the granite at the surface. The Quaternary sediments are dominated by unconsolidated dunesands of variable thickness. These sediments are well exposed in sandblows and erosion gullies on the western side of the island (Plate 1).


Plate 2 Sandrock cropping out on the coast near Target Hilll. Photo by Rolan Eberhard.

A second specimen from the same general locality was a mixture of shell fragments up to 20 mm and poorly sorted subangular to angular siliceous grit ranging in diameter from about 0.25 to 7 mm. In this case the matrix, creamy amorphous material, was estimated to constitute about 50% of the rock.

Older lithified sands are associated with aeolianite that crops out on or near the coast at many sites (Plate 2). The aeolianite is thinly bedded with dips of 0-30° and frequent cross bedding. The presence of numerous shell macrofossils in strata at one or two sites on the east coast implies a marine or beach origin for some coquina-like facies, but the grain and bedding characteristics are clearly aeolian in the majority of cases. Examination of hand specimens under low power optical microscope

1

indicate a high siliceous content for some aeolianite units. A sample from near Mannalargenna Cave was found to consist mainly of subangular to rounded siliceous grains typically about 1 mm in diameter and, to a lesser extent, platey shell fragments of similar size. These materials were cemented by a meagre (<10%) whitish matrix of presumed carbonate. A sample of pinkish sandrock from Peacock Bay comprised well sorted subangular to rounded siliceous grains about 0.25-0.5 mm in diameter. About 30% of the rock was whitish matrix.

Sandrock is a field term for sandstone that is not firmly cemented (Jackson 1997)

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These observations suggest that some rocks which have been referred to as limestone, such as the strata in which Mannalargenna Cave has formed, may be better described as calcareous sandstones or â&#x20AC;&#x2DC;sandrockâ&#x20AC;&#x2122; 1. Secondary carbonate deposits on the cliff containing the cave, and within the cave itself, are potentially accounted for by leaching from overlying shell-rich sands (Plate 3). On the other hand, the degree of karstification at certain other locations indicates the presence of limestone sensu stricto (ie. >50% calcium carbonate). The parent material implies a form of limestone known as aeolian calcarenite ie. lithified calcareous dunes. Aeolian calcarenite referred to as Palana Limestone (Sutherland and Kershaw 1971) crops out extensively on the eastern parts of Flinders Island. Palana Limestone at Settlement Point, 6 km from Prime Seal Island and the closest point to it on mainland Finders Island, contains a moderate to high calcium carbonate content of 61-95% (Hughes 1957). The formation is evidently somewhat heterogeneous, with some facies


Plate 3 Secondary carbonate coatings on the cliffline containing Mannalargenna Cave. Photo by Rolan Eberhard.

reported to contain considerable amounts of angular to rounded quartz grit (Sutherland and Kershaw 1971), suggesting possible parallels with sandrock units on Prime Seal Island. Sutherland and Kershaw (1971) argue that the Palana Limestone developed from late Tertiary to early Pleistocene calcareous dunes, suggesting â&#x20AC;&#x2DC;a Lower Pleistocene, pre-Riss/Wurm age for most of itâ&#x20AC;&#x2122; on the basis that the limestone is cut by what they regard as a Last Interglacial sea level. Kiernan (1992) supports a pre Last Interglacial age for aeolian calcarenite at Fotheringate Bay on Flinders Island, also on the evidence that it too was planed off by Last Interglacial marine erosion. A pre Last Interglacial age

is potentially consistent with the degree of lithification of at least some aeolian formations on Prime Seal Island, although evidence of truncation by a Last Interglacial sea level is debateable. However, a thermoluminescence date of 56 ka for cavernous sandrock on the west coast implies a post Last Interglacial age in this case (Eberhard in prep.). Thermoluminscence dates for unconsolidated dunesands interbedded with slope deposits from a site on the southwest coast of Prime Seal Island suggest that the sediment accumulated between about 38 and 7 ka, with a strong aeolian contribution prior to the Last Glacial Maximum (Eberhard in prep.). A buried soil horizon near Target Hill was dated to 3-4 ka,

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implying more stable conditions by the mid-late Holocene. These results contrast with dates for dunesands in northwest Tasmania of 24-22 ka (Duller and Augustinas 2006) and 29-14 ka (McIntosh et al. 2009). Tasmania-wide data indicates a significant increase in landscape instability from 35 ka onwards, although a number of older dates for aeolian sediments have been reported (McIntosh et al. 2005). The Prime Seal Island dates imply that the period of increased aeolian activity recorded after 35 ka elsewhere in Tasmania may have commenced at about the same time or somewhat earlier on the Furneaux Group.


Plate 4 Granite tor near Sealers Cove. Photo by Rolan Eberhard.

Plate 5 Limestone shore platform, north of Peacock Bay. Photo by Rolan Eberhard.

swells reaching western Tasmania being refracted eastwards through Bass Strait. Accordingly, the western side of the island is considerably more exposed than the east. This is reflected in the character of coast on the respective sides of the island.

Geomorphology Prime Seal Island is approximately 10 km long on the north-south axis and typically about 1 km wide on the eastwest axis. Four principal hills, rising to a maximum elevation of 155 m and separated by more-or-less equally spaced wind gaps, give the island its characteristic humped profile, with some older publications referring to it as Hummock Island. The bold domed form of the hills is typical of granitic terrains with widely spaced joint fractures. Little evidence was seen of solutional features which often develop on granitic rocks, such as runnels and gnammas. However, some small but spectacular isolated tors

and bluffs, another landform typical of granitic terrain, are present along the mid and upper slopes on the western side of the island (Plate 4). Prime Seal Islandâ&#x20AC;&#x2122;s coast is approximately 29.2 km long. Although its location within the low-moderate wave energy zone of Daviesâ&#x20AC;&#x2122; (1978) qualitative classification of wave energy for Tasmania suggests a relatively quiet coastal environment, mariners attest to Bass Strait as a stormy seaway not lacking in wave energy. This is due to a combination of frequent strong winds associated with passage of low pressure weather systems across the region and south-westerly

The western coast comprises a virtually continuous rocky shore dominated by broad shore platforms up to 100 m or more in width, with offshore reefs and occasional deeply indented coves and gulches. Strong structural control of the coastline is clearly evident in air photos, which highlight the results of vigorous mechanical erosion along frequent intersecting linear features such as conjugate joint sets. A few short sandy beaches account for less than 4% of the coast on this side of the island. Some of these are developed on the landward side of rocky shore platforms. Minor boulder beaches are present. In contrast, about 20% of the relatively sheltered eastern side is sandy beaches, which tend to be broader than those of the west. Shore platforms are common, but rarely exceed 30 m in width 2.

2 A number of discrepancies were noted for shoreline geomorphic types attributed to Prime Seal Island on the Tasmanian Shoreline Geomorphic Types Digital Line Map Version 4.0 (Sharples 2006). For example: (1) shorelines mapped as upper intertidal cliffs between Spit Point and Peacock Bay, and at South Bay, are steeply inclined in places but rarely vertical, and better described as rocky (bedrock) shorelines; (2) a shoreline east of Target Hill is mapped as upper intertidal cliffs with no distinctly different lower intertidal shoreline element, whereas the shoreline actually comprises a well-developed lower intertidal shore platform in limestone below a rocky upper intertidal shore; (3) shorelines east of North Hill, and at Wolff Bay, mapped as upper intertidal shell, pebble cobble or boulder beaches or shorelines, are in fact sandy beaches; and (4) a shoreline south of Sealers Cove mapped as upper intertidal cliffs, is actually a shore platform backed by a steep slope formed in Quaternary sands. The Tasmanian shoreline geomorphic types map is based generally on a combination of published and unpublished sources, air photos and field verification in some places. Older unpublished maps based on air photo interpretation by Revel Munro, with no field verification, were the source in the case of Prime Seal Island (C. Sharples, pers. comm.). By convention, the geomorphic types map A number of discrepancies were noted for shoreline geomorphic types attributed to Prime Seal Island on the Tasmanian Shoreline Geomorphic Types Digital Line Map Version 4.0 (Sharples 2006). For example: (1) shorelines mapped as upper intertidal cliffs between Spit Point and Peacock Bay, and at South Bay, are steeply inclined in places but rarely vertical, and better described as rocky (bedrock) shorelines; (2) a shoreline east of Target Hill is mapped as upper intertidal cliffs with no distinctly different lower intertidal shoreline element, whereas the shoreline actually comprises a well-developed lower intertidal shore platform in limestone below a rocky upper intertidal shore; (3) shorelines east of North Hill, and at Wolff Bay, mapped as upper intertidal shell, pebble cobble or boulder beaches or shorelines, are in fact sandy beaches; and (4) a shoreline south of Sealers Cove mapped as upper intertidal cliffs, is actually a shore platform backed by a steep slope formed in Quaternary sands. The Tasmanian shoreline geomorphic types map is based generally on a combination of published and unpublished sources, air photos and field verification in some places. Older unpublished maps based on air photo interpretation by Revel Munro, with no field verification, were the source in the case of Prime Seal Island (C. Sharples, pers. comm.). By convention, the geomorphic types map records all rocky shore platforms as lower intertidal landforms, despite the fact that such features often extend into the upper intertidal zone. This is true of the majority of shore platforms on Prime Seal Island.

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Plate 6 Limestone pinnacles on beach, Peacock Bay. Photo by Rolan Eberhard.


An exception to the generally modest shore platforms of the eastern side of the island is a feature developed in aeolian calcarenite about 1 km south of Mannalargenna Cave. This shore platform is in the order of 50 m wide, strikingly level and covered by a dense mat of the seaweed Hormosira sp. (Plate 5). It bears comparison with the extensive limestone shore platforms of the western coast of Flinders Island (Kiernan 1992). A combination of solutional lowering and mechanical abrasion are considered to account for the formation of broad, flat shore platforms that characterise many

limestone coasts (Trudgill 1985), implying that these features are partially karstic in origin. Karst has also developed on thin (ca. 2 m thick) case hardened limestone that crops out at South Bay and intermittently between Sealers Cove and the northern tip of the island. A variety of karren forms are present including pans, pits, rills and runnels. Pointy karst pinnacles (spitzkarren) protrude through sand on the beach north of the camp on Peacock Bay (Plate 6). Small caves, generally shelterlike cavities and arches, extend

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beneath the case hardened caprock (kankar) at several locations (Plate 7). The presence of an indurated capping layer provides the structural integrity necessary to support the cave roof, a phenomenon that has been noted in other aeolian calcarenite karsts (White 1994). The entrances of larger examples tend to face west into the prevailing weather, suggesting that they may be less a product of solution than physical and/or chemical weathering, under conditions of more or less continuous assault by salt-laden wind and spray. A mantle of loose fine sediment on the cave floors would


Plate 7 Cave developed in case-hardened aeolian calcarenite.

Plate 8 Tufa terraces on coast near Target Hill.

Photo by Rolan Eberhard.

Photo by Rolan Eberhard.

Plate 9 Relict aeolian sands deposited on the windward (western) side of the island. Note evidence of recent burning. Photo by Rolan Eberhard.

be consistent with the disintegration of the parent rock through a process such as salt wedging. On the other hand, the deposition of speleothems such as stalactites and columns implies either solutional erosion of the limestone above the caves or leaching of carbonates from overlying shell-rich sands. This does not necessarily contradict a nonkarstic mode of cave formation. The sandrock in which it has developed and domed internal form of Mannalargenna Cave, the only cave of significance on the eastern side of the island, suggests that it too is not primarily a karst feature, despite the presence within it of presumed carbonate speleothems. First reported by Harris (1988), this cave comprises a 6 m wide entrance leading to a small inner chamber (Figure 1). No part of the accessible cave is more than about 6 m from the dripline. The full extent of the original cavity is more spacious than

it appears, as archaeologists dug through 4 m of sediment before encountering the sloping bedrock floor of the inner chamber (Sim 1991). Mannalargenna Cave is about 50 m above present sea level and faces southeast. The site was occupied by Pleistocene humans between about 8 and 20 ka (Brown 1991). The â&#x20AC;&#x2DC;knobbly concretionsâ&#x20AC;&#x2122; associated with the karst reported by Dixon (1996) are typically about 30 mm in diameter, near spherical in form with a rough botryoidal texture on the surface. They appear to be restricted to several square metres of limestone pavement a few metres above sea level at one site on the northwest coast. The mode of formation is unclear. Concentrically banded concretions in caves known as cave pearls develop in shallow pools where a mineral coating develops on a nucleus such as a sand grain. The detached spherical form

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of cave pearls requires cave drips to agitate the particles, preventing them from becoming cemented to other surfaces (Hill and Forti 1997). A similar process can be ruled out for the Prime Seal Island concretions, as the size of the particles precludes agitation by wind or rain and the context is not a pool. An alternative explanation is that the concretions are a calcrete duricrust deposited as a lag following deflation of the carbonate-rich sands in which they formed. This explanation does not account for the consistent size of the concretions or their absence from other sites. Irrespective of their origin, the concretions are an unusual feature of which Prime Seal Island is the only recorded Tasmanian example. Springs are common where the contact between the granite basement and overlying calcarenite and/or Quaternary sands is exposed along the high water mark. Seventeen springs or


clusters of springs were counted in October 2008. Rapid infiltration of precipitation and the seaward deflection of groundwater along the geological contact account for both the abundance of coastal springs and the paucity of surface runoff and fluvial landforms. There is little evidence of the latter barring some gully erosion on the southern part of the island. Many of the springs have precipitated carbonate in the form of tufa. A major example occurs at the head of a small bay west of Target Hill. Here, an impressive series of tufa terraces has developed

(Plate 8). Water samples obtained from two springs on the southern coast were high in dissolved salts, with sodium and chloride levels that suggest a significant contribution from windblown spray off the sea (Appendix 1). Calcium levels are towards the upper end of the range reported for karst waters in Tasmania (Eberhard and Houshold 2002). Despite the salinity, the quality of water would not necessarily be considered unsuitable for stock to drink. Aeolian landforms characterise those parts of Prime Seal Island which are mantled by Quaternary sands.

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These include linear transgressive dunes several hundred metres long and oriented east-west across the wind gaps between Sealers Bay and Peacock Bay and between North Hill and Target Hill. As on Flinders Island (Kershaw and Sutherland 1972), the dunes are relict features, being vegetated and no longer mobile, despite localised sandblows. Aeolian sands interbedded with slope deposits crop out on the western flanks of Prime Seal Islandâ&#x20AC;&#x2122;s main southern hill. The sands are incised by a few deep gullies of recent origin and truncated by marine erosion near present sea level (Plate 9). Thermoluminescence


Figure 1. Extent of sand erosion on north Prime Seal Island in 1951 and 2003. Basemap: November 2003 air photo (reproduced courtesy of TASMAP, DPIPWE).

dates indicate that the sediment accumulated between about 38 ka and 7 ka (Eberhard in prep.). The age of the top of the sequence is close in time to the culmination of the Holocene marine transgression at 6 ka. The absence of buried soil horizons within the profile suggests a high level of landscape instability

and harsh environmental conditions, particularly prior to the Last Glacial Maximum, when the bulk of the sediment accumulated. Active sandblows are present several locations on Prime Seal Island, mostly but not exclusively on the more exposed western side (Figure 1). These include a notable

pair of parallel sandblows which extend for ca. 0.5 km from near sea level to an elevation of ca. 70 m on Target Hill. To estimate the extent and trajectory over time of actively eroding sand country on Prime Seal Island, areas interpreted as bare or mobile sand (excluding beaches) were digitised from scanned and

Table 1: Approximate extent in hectares of bare or actively eroding sand on Prime Seal Island, as interpreted from air photos between 1951 and 2003. Refer to Figures 1 and 2 for locations. Note that air photo coverage was not available for South Bay or the Lower South-west in 1986. 1951

1973

1974

1982

1986

1998

2003

North Hill

1.33

2.36

1.78

1.59

1.18

0.03

0.12

Target Hill

2.33

7.44

6.24

6.16

4.44

3.74

3.80

Sealers Cove

5.92

7.37

3.15

1.41

0.28

0.18

0.06

Lower South-west

2.12

0.92

3.39

3.86

-

1.53

5.39

South Bay

0.00

0.26

2.19

0.59

-

0.21

0.37

TOTAL

11.70

18.35

14.79

13.61

(>5.90)

5.71

9.74

18


Figure 2. Extent of sand erosion on south Prime Seal Island in 1951 and 2003. Basemap: November 2003 air photo (reproduced courtesy of TASMAP, DPIPWE).

orthorectified air photo mosaics in a GIS (Figures 1 and 2). The methodology is subject to variations in the quality of the images and the light conditions at the time the images were captured, both of which affect the ability to accurately assess erosion status. The area totals should therefore be considered indicative only (Table 1). About 11.7 ha of the island appear to have been actively eroding at the time of the first air photos in 1951. This increased by 6.7 ha (57%) between 1951 and 1973, but then retreated between 1973 and 1998. By 1998 the total eroded area had contracted by 12.6 ha, reducing it to about half what it had been in 1951. Results in the latter part of this period are skewed in

favour of a lower result because air photo coverage for the two more southerly sites was not available for 1986. This trend was reversed between 1998 and 2003 when the total eroded area is seen to expand again, gaining 4.0 ha (71%) but still remaining lower than results for 1982 and earlier runs. The pattern is not consistent across the island as a whole. For example, the eroded area in the lower south-west shrunk by 1.2 ha (57%) between 1951 and 1973 when eroded areas elsewhere on the island were expanding, although it later increased to gain 3.3 ha (154%) by 2003. Only the sandblow at South Bay is not present to some degree over the entire air photo record. This feature developed between 1951 and 1973, expanding rapidly to its maximum extent

19

between 1973 and 1974. These results should not be interpreted simply as evidence that land management practices over the last 30+ years have reduced the scale of erosion on Prime Seal Island. In fact, the apparent increase in erosion post 1998, especially in the southern parts of the island, and field observations concerning active sandblows and deep gullying on seaward slopes that had recently been burnt, suggest a more complex scenario.

Soils The soils of Prime Seal Island are dominantly well-drained loamy sands or light sandy loams of weak to moderate structure. Soil pH ranges from 8-9 (Poole et al.


Plate 11 Calcified tree roots in sandblow at Target Hill.

Plate 10 Calcrete duricrust. Photo by Rolan Eberhard.

Photo by Rolan Eberhard.

Plate 12 Residual pedestal formed by loss of soil around knobby clubsedge root ball. Photo by Rolan Eberhard.

2002), which is consistent with the alkaline soil parent material â&#x20AC;&#x201C; calcareous Quaternary sand. A calcrete duricrust is widespread in the form of hardpans and rounded whitish clasts, often exposed by erosion or brought to the surface by anthropogenic disturbance (Plate 10). The calcrete results in stony soils on some parts of the island. The soils and sand units on which they are formed are highly erodible, as demonstrated by sandblows and erosion gullies described elsewhere in this paper. Some of these sandblows contain lags of calcareous pipes formed around plant roots (Plate 11), reminiscent of King Islandâ&#x20AC;&#x2122;s Calcified Forest. Burrowing seabirds are a source of intense local bioturbation of soils on

the southwestern coast, exacerbating erosion hazards in areas that have been burnt. Up to 1 m of sediment has been lost from some sites, as indicated by the height of pedestals formed where soil has been retained around knobby clubsedge root balls (Plate 12). Numerous bones from seabird and small mammals litter the surface of some deflated areas.

GENERAL DISCUSSION and CONCLUSION Crustal deformation associated with the separation of Australia and Antarctica produced the Bass Basin, into which the sea began to intrude early in the Tertiary Period. This process culminated in the separation

20

of Tasmania from mainland Australia about 38 million years ago. Since that time, eustatic fluctuations in sea level have periodically exposed the land bridge, notably during Quaternary ice ages, or flooded it (Jennings 1959). Prime Seal Island would have first come into existence as an island in its own right, as opposed to a range of hills on the eastern margin of the Bassian Plain, during one of these sea level highs. Cainozoic marine sediments up to 18 m above present sea level on Flinders Island (Sutherland and Kershaw 1971) imply that, on one or more occasions, the wind gaps between the hills of Prime Seal Island would have been submerged, creating a minor archipelago of three or four smaller islands.


The timing and duration of isolation events (islands) versus connectivity events (land bridges) can be modelled using bathymetry data and Quaternary sea level curves. An important caveat on this is that it cannot necessarily be assumed that submerged Quaternary land surfaces have been preserved following post glacial rises in sea

level, due to sediment movement in the marine environment. This is particularly pertinent around Flinders Island, where strong currents have both scoured deep trenches and deposited extensive sandy shoals (Jennings 1959). Nor can it be assumed that the elevation of the land relative to the sea is affected only by fluctuations in sea

21

level, as land can be pushed up or down through tectonic movement or isostatic pressure. However, although there is evidence that many parts of the Tasmanian coast have experienced Quaternary uplift, this does not appear to be the case on Flinders Island in the latter part of the Pleistocene (Murray-Wallace and Goede 1995).


Other factors being equal, the depth of water overlying a former land bridge is a threshold that determines whether a change in sea level has potential to expose the land bridge or drown it. In the case of Prime Seal Island, the channel between it and Flinders Island is shallow, being about 10-15 m deep (Australian Hydrographic Service 2002). This would require only a modest fall in sea level to create a land bridge. Within 1-2 km west of Prime Seal Island, the sea bed drops fairly rapidly to a depth of about 40 m, due to the presence of a linear submarine feature interpreted as a probable fault (Jennings 1959). Further west, the gradient of the sea bed moderates, and the 60 m depth contour â&#x20AC;&#x201C; the approximate average depth of the Bassian Rise,

the presumed former land bridge between Tasmania and mainland Australia â&#x20AC;&#x201C; is some 30 km offshore. Consequently, below the 40 m depth contour, a small change in relative sea level would result in a major shift in the position of the coastline. The 40 m depth contour is also the approximate depth of the presumed former land bridge between Flinders Island and Tasmania, now Banks Strait. A post-glacial sea level curve based on dated marine sediments from the eastern Australian region (Hopley 1987) suggests that the most recent major sea level transgression, which commenced after 20 ka, would have overtopped the Bassian Rise around 12-13 ka. The same sea level curve suggests that the Flinders-Tasmania land bridge would have disappeared

Figure 3. Sketch plan of Mannalargenna Cave (from Harris 1988).

22

at about 10-11 ka, while Prime Seal Island would have ceased to be joined to Flinders Island at 8-9 ka. This potentially corroborates the age of the youngest dated cultural horizon in Mannalargenna Cave, as it is plausible that humans ceased to make use of the cave when it became isolated by sea. Sea level curves based on more recent reviews of data from eastern Australia suggest that Prime Seal Island became separate from Flinders Island around 8.5-10 ka (Sloss et al. 2007). Differences between these and other sea level curves reflect the field data from which they are derived, which in turn are affected by many local factors. Blom (1988) argues that the Bassian Rise was not overtopped until as late as 8 ka, based on a date for


the first appearance of an oceanic facies in a sediment core from Bass Strait. Thus, at present, the timing of the most recent inundation of the presumed former land bridges can only be constrained to within several thousand years. A sea level curve based on dates from uplifted coral terraces on the Huon Peninsula, Papua New Guinea, is available from 260 ka onwards (Aharon and Chappell 1986). Inferences made on the basis of this curve would suggest that Prime Seal Island was rarely cut off from Flinders Island prior to the most recent marine transgression. It was probably isolated for a period between about 118-135 ka and possibly briefly at around 106, 220 and 240 ka. The same sea level curve suggests that the Bassian Rise was exposed on various occasions: prior to 250 ka, around 190 ka, between about 170-140 ka, possibly briefly at 110 ka, intermittently between 80-30 ka and then again at around 29-12 ka. The Flinders-Tasmania land bridge would have been dry for longer periods and may have escaped inundation for most of the period 10-80+ ka. Although earlier sea level curves are available, these are more speculative still and their applicability to Prime Seal Island, where a mere 10 m rise or fall in sea level is critical, is questionable. However, the general pattern of episodic isolation and connectivity events can be assumed to have applied during earlier Pleistocene glacial-interglacial cycles. 3

Conclusions Whereas a 6.4 km wide seaway currently separates Prime Seal Island from Flinders Island, which in turn lies about 50 km off the coast of northeast Tasmania, Prime Seal Island existed for extended periods only as an outlying cluster of hills on the windy Bassian Plain, overshadowed by the higher ranges to the east on present-day Flinders Island. The physiographic context at this time was continental rather than maritime. Consistent with this is the presence on the island of relict sandsheets and longitudinal dunes, a legacy of the once extensive aeolian landscape that extended south to Tasmania across the Bassian Plain. Despite strong similarities with other parts of the Furneaux Group, the geodiversity of Prime Seal Island includes features which are particularly well developed or otherwise of considerable interest for science and conservation. These include aeolianite karst phenomena, which are common in parts of Bass Strait but poorly represented in Tasmania generally. Additionally, eroded sections through Quaternary sands provide access to sedimentary sequences spanning a period of major environmental change during the late Pleistocene and Holocene. These features warrant consideration for listing 3 in the Tasmanian Geoconservation Database, which currently contains only one reference to PrimeSeal

These have now been listed.

23

Island, the Prime Seal Island Karst and Concretions site. While sand erosion has facilitated access to valuable scientific evidence, the same process is depleting the overall scientific resource while creating a potentially serious source of land degradation. Evidence of recent or ongoing sand movement can be observed on many parts of Prime Seal Island today, particularly where the land management practices include grazing and burning on steep and/or exposed slopes. In the interest of avoiding further anthropogenic modification to relict aeolian landforms and compromising important sedimentary records, these practices should be avoided.

ACKNOWLEDGEMENTS Thanks to the organisers and other participants of the Hamish Saunders Memorial trip to Prime Seal Island and to Emma Betts for assistance in the field. Air photos used in this study were made available by Tasmap (DPIPWE) and orthorectified by Bronwyn Tilyard (DPIPWE). Stephen Harris gave permission to use the map of Mannalargenna Cave. Thermoluminescence dating of sand samples was carried out by David Price at the University of Wollongong. Water samples were analysed by Analytical Services Tasmania, a NATA accredited laboratory.


REFERENCES Australian Hydrographic Service. (2002) Furneaux Group 1:150,000, Chart Aus 800, Australian Hydrographic Service, Wollongong. Aharon, P. and Chappell, J. (1986) Oxygen isotopes, sea level changes and the temperature history of a coral reef environment in New Guinea over the last 105 years, Palaeogeography, Palaeoclimatology, Palaeoecology, 56: 337-379. Blom, W.M. (1988) Late Quaternary sediments and sea-levels in Bass Basin, southeastern Australia â&#x20AC;&#x201C; a preliminary report, Search 19(2): 94-96. Bowden, A.R. (1983) Relict terrestrial dunes: legacies of a former climate in coastal northeastern Tasmania, Z. Geomorph. N.F. 45: 153-174. Brown, S. (1991) Mannalargenna Cave: a Pleistocene site in Bass Strait, pp. 258-271 in Smith, M.A., Spriggs, M. And Frankauser, B. (eds.) Sahul in Review, Department of Prehistory, ANU. Davies, J.L.(1978) Beach sand and wave energy in Tasmania, in: Davies, J.L. and Williams, M.A.J., (eds), Landform Evolution in Australasia, ANU Press, Canberra. Dixon, G. (1996) A Reconnaissance Inventory of Sites of Geoconservation Significance on Tasmanian Islands, Parks and Wildlife Service Tasmania. Duller, G.A.T. and Augustinas, P. (2006) Reassessment of the record

of linear dune activity in Tasmania using optical dating, Quaternary Science Reviews 25: 2608-2618. Eberhard, R. and Household, I. (2002) Water quality in karstlands at Mole Creek, Tasmania, Pap. Proc. Roy. Soc. Tasm., 136: 159-172. Harris, S. (1988) A Catalogue of Some Cultural Relics in the Outer Furneaux Islands, Report to the Australian National Parks and Wildlife Service. Hill, C. and Forti, P. (1997) Cave Minerals of the World, National Speleological Society Inc., Huntsville. Hopley, D. (1987) Holocene sealevel changes in Australasia and the south Pacific, pp. 375-408 in Devoy, R.J.N. (ed.) Sea Surface Studies, Croom Helm, London. Hughes, T.D. (1957) Limestones in Tasmania, Tasmania Department of Mines, Geological Survey Mineral Resources No. 10. Jackson, J.A. (1997) Glossary of Geology, 4th edition, American Geological Institute, Virginia. Jennings, D.J., and Cox, S.F. (1978) King Island â&#x20AC;&#x201C; Flinders Island 1:250,000 Scale Geological Map, Geological Survey of Tasmania, Department of Mines, Hobart. Jennings, J.N. (1959) The submarine topography of Bass Strait, Proc. Roy. Soc. Vict. 71: 49-72. Kershaw, R.C. and Sutherland, F.L. (1972) Quaternary Geomorphology of Flinders Island, Rec. Q. Vic. Museum 43: 1-28.

24

Kiernan, K. (1992) Some coastal landforms in aeolian calcarenite, Flinders Island, Bass Strait, Helictite 30(1): 11-19. McIntosh, P.D., Price, D.M., Eberhard, R. and Slee, A.J. (2009) Late Quaternary erosion events in lowland and mid-altitude Tasmania in relation to climate change and first human arrival, Quaternary Science Reviews 28: 850-872. Murray-Wallace, C.V., and Goede, A. (1995) Aminostratigraphy and electron spin resonance dating of Quaternary coastal neotectonism in Tasmania and the Bass Strait Islands, Australian Journal of Earth Sciences 42: 51-67. Poole, L., Harris, S., North, J., P. Stafford and Bayley, S. (2002) Prime Seal Island Management Report, unpublished. Reid, E.J. (1987) Furneaux Islands, pp. 261-266 in C.F. Burrett and E.L. Martin (eds.) Geology and Mineral Resources of Tasmania, Geological Society of Australia Inc. Special Publication 15. Sim, R. (1991) Archaeological Excavations on Prime Seal Island and Badger Islands in the Furneaux Group, Bass Strait, report to the Tasmanian Aboriginal Land Council, the Flinders Island Aboriginal Association and the Tasmanian Aboriginal Centre. Seymour, D.B. and Calver, C.R. (1995) Explanatory Notes for the TimeSpace Diagram and Stratotectonic Elements Map of Tasmania, Tasmanian Geological Survey Record 1995/01.


Sharples, C. (2006) Data Dictionary for the Tasmanian Shoreline Geomorphic Types Digital Line Map Version 4.0 (2006) (Tascoastgeo_ v4gda), report to the Department of Primary Industries and Water, Tasmania. Sloss, C.R., Murray-Wallace, C.V. and Jones, B.G. (2007) Holocene sea-level change on the southeastern coast of Australia: a review, The Holocene 17:999-1014. Sutherland, F.L. and Kershaw, R.C. (1971) The Cainozoic geology of Flinders Island, Bass Strait, Pap. Proc. Roy. Soc. Tasm., 105; 151-175. Trudgill, S. (1985) Limestone Geomorphology, Longman, London. White, S. (1994) Speleogenesis in aeolian calcarenite: a case study in western Victoria, Environmental Geology 23: 248-255.

Appendix 1. Physico-chemical characteristics of two Prime Seal Island springs Spring 1

Spring 2

Easting (GDA)

562760

563630

Northing (GDA)

5560890

5561210

Temperature (°C)

14.8

13.7

pH

8.70

-

Conductivity (mS/cm)

2.54

-

Bromide (mg/L)

2.9

3.1

Chloride (mg/L)

513

631

Fluoride (mg/L)

1.09

0.98

Sulphate (mg/L)

179

342

0.018

0.016

Location

Field measurements

Analyte

Ammonia (mg-N/L) Nitrate (mg-N/L)

10.1

7.82

Nitrite (mg-N/L)

0.029

0.005

11

8.4

0.237

0.362

<1

<1

Aluminium (µg/L)

2500

1880

Calcium (mg/L)

56.2

98.1

Cadmium (µg/L)

Nitrogen (mg-N/L) Phosphorus (mg-P/L) Silver (µg/L)

<1

<1

Cobalt (µg/L)

1

<1

Chromium (µg/L)

6

6

Copper (µg/L)

1

3

Iron (µg/L)

2030

2030

Magnesium (mg/L)

37.4

42.4

Manganese (µg/L)

39

49

Sodium (mg/L)

445

611

Nickel (µg/L)

<10

<10

Lead (µg/L)

<7

<7

Zinc (µg/L)

5

6

25


V EGETATION

26


Photo by Micah Visoiu

By Micah Visoiu A survey of Prime Seal Island in October 2008 resulted in identification, description and mapping of 13 TASVEG mapping units (Harris & Kitchener 2005). The mapping units identified are ‘Allocasuarina verticillata forest (NAV)’, ‘Eucalyptus ovata forest and woodland (DOV)’, ‘Coastal scrub on alkaline sands (SCA)’, ‘Heathland on Calcarenite (SHC)’, ‘Coastal Grass and Herbfield (GHC)’, ‘Seabird rookery complex (SRC)’, ‘Saline sedgeland/rushland (ARS)’, ‘Lowland grassland complex (GLC)’, ‘Sand Mud (OSM)’, ‘Pteridium esculentum fernland (FPF)’, ‘Agricultural Land (FAG)’, ‘Weed Infestation (FWU)’ and ‘Regenerating cleared land (FRG)’. Distinct facies within these communities have been described and related to previous literature descriptions.

INTRODUCTION The first signs of human occupation of Prime Seal Island has been dated at 18 500 years BP, through archaeological work undertaken at Mannalargenna Cave on the island’s north east coast. The use of this site continued until at least 15 000 years BP. However after this date it is thought that rising sea levels reduced and finally eliminated human influence from these islands until the arrival of Europeans in the late 18th and early 19th centuries. From this time onwards the human impacts

on the majority of Furneaux Islands including Prime Seal Island was very significant (Harris et al. 2001). Since the arrival of sealers on the island in these early years, fire has been a significant shaping influence on the vegetation. Clearing through burning and then the grazing of livestock has been a use of the island for well over a century (Whinray 1971). Aerial photographs taken in the early 1950’s show that woody vegetation at that time covered probably less than 20% of the island, this is a significant change to the observations made by Campbell in 1828 who stated the island to be ‘lofty and covered in trees’ (in Harris et al. 2001). More recent Aerial photographs show that the cover of woody vegetation on the island has increased markedly in the last 50 years. It would appear from the available aerial photographs (1951, 1974, 1982, 1998, and 2004) that the vegetation is very dynamic. The development from grassland then heathland, scrub and forest is rapid, whilst fire is an ever present stochastic factor that can halt this succession at any time. The first vegetation map of Prime Seal Island was published in 2001 (Harris et al. 2001) as part of a volume that described and mapped the vegetation of islands within the outer Furneaux Group in Bass Strait. Nineteen mapping communities were identified during several visits to the island in the early late 1980s and early 1990s. The extent of these mapping units on the ground

27

was then mapped using 1998, 1:24 000 aerial photography, along with field notes. This map and associated vegetation descriptions of Harris et al. (2001) together with some new aerial photographic interpretation (using 2003 1: 42 000, air photos) were used to classify and map the island’s vegetation within the 1:25 000 statewide Tasmanian Vegetation map ‘TASVEG 2.0’ in 2008 (TVMMP 2009). The process of converting the original units into TASVEG mapping units described in Harris & Kitchener (2005), is not straightforward and may have resulted in some translation errors. The extensive ground survey work on the island during the 2008 expedition provided an invaluable opportunity to ground truth the current vegetation mosaic, update the mapping and determine the most appropriate TASVEG mapping units in which to place the vegetation communities present. This paper therefore provides an updated vegetation map of Prime Seal Island, along with detailed descriptions of the vegetation communities on the island. Extent and occurrence of threatened species and species of biogeographic significance are dealt with elsewhere in this report, as is the occurrence and extent of exotic species on the island.


28


METHODS The island was comprehensively traversed on foot. Composition of floristic communities was noted in areas that were determined to be representative of the vegetation on the island. Vegetation extent and community boundaries were subsequently mapped using a variety of remotely sensed imagery. The most recent aerial photography was at 1: 42 000 scale and dated from 2003, the only 1:24 000 coverage was 1998 black and white imagery. Examination of these two photo runs suggested that the vegetation on the island was very dynamic, with changes in vegetation extent in this 5 year period obvious in several areas. Google Earth (www.earth. google.com 2009) was found to use 2009, 2.5 metre resolution SPOT 5 imagery, which indicated further changes in vegetation community extents since 2003. The 2009 SPOT 5 imagery was deemed to be of high enough quality to map the vegetation when used in conjunction with the 1998 and 2003 aerial photography, ground observations and landscape photographs taken during the field trip. Mapping was carried out on transparency overlays over ~1:15 000 sized SPOT 5 printouts from Google Earth. The vegetation mapping units used are from Harris & Kitchener (2005). Some of the floristic communities (facies) within these mapping units were also described.

Species nomenclature follows Buchanan (2005). Structural classification follows the National Vegetation Information System (NVIS) structural formations rule set (Thackway et al., in Mackenzie et al. 2008).

RESULTS On-ground observations on Prime Seal Island over the course of the six day field trip provided a good insight into the vegetation associations present. A number of these associations would seem to be unique within Tasmania, primarily due to Lasiopetalum discolor which is extensively distributed over the island and is dominant or subdominant in several communities. This species, within Tasmania, is confined to this island. Examination of aerial photographs and satellite imagery, combined with extensive field observations suggest that the vegetation is very dynamic. An apparent reduction in the extent of grazing of the island in recent years along with an associated reduction in burning of some areas has resulted in a significant increase in the cover of scrub communities, whilst some areas of Allocasuarina verticillata forest also seem to be expanding. No vegetation was seen on the island that did not show signs of fire in the past. The floristic communities have been described in Community descriptions and biogeographic notes.

29

Vegetation Map Community descriptions and biogeographic notes The vegetation on Prime Seal has been categorised here into 13 TASVEG mapping units (Harris & Kitchener 2005). Within several of these mapping units there is more than one facies. The vegetation mapping units present are listed in Table 1, along with the different floristic/structural associations where present. Floristic communities described elsewhere from statewide surveys which are related to those seen on Prime Seal Island are also indicated. All the defined vegetation associations which were noted on the Island are described below.


Table 1: List of Mapping units and floristic associations observed on Prime Seal Island (2008) TASVEG mapping Unit Name

Code

Floristic/structural associations distinguished

Similar described floristic Communities

Allocasuarina verticillata forest

NAV

Allocasuarina verticillata short open forest

2. Allocasuarina verticillata forest (Harris et al. 2001) Coastal Allocasuarina low forest (Duncan & Brown 1985)

Allocasuarina verticillata, Myoporum 2. Allocasuarina verticillata forest insulare, Bursaria spinosa short (Harris et al. 2001) closed forest Island Allocasuarina low forest (Duncan & Brown 1985) Eucalyptus ovata forest and woodland

DOV

Eucalyptus ovata, Allocasuarina verticillata short closed forest

Coastal scrub on alkaline sands

SCA

Beyeria lechenaultii, Myoporum insulare closed shrubland

17. Leptospermum laevigatum scrub (+/Leucopogon parviflorus, Bursaria spinosa, Dodonaea viscosa, Melaleuca ericifolia, (Melaleuca armillaris â&#x20AC;&#x201C;Long Island only), Correa alba) (Harris et al. 2001)

Leptospermum laevigatum, Allocasuarina verticillata, Pomaderris paniculosa subsp. paralias, Dodonaea viscosa, Leucopogon parviflorus, Bursaria spinosa, Olearia ramulosa closed shrubland

17. Leptospermum laevigatum scrub (+/Leucopogon parviflorus, Bursaria spinosa, Dodonaea viscosa, Melaleuca ericifolia, (Melaleuca armillaris â&#x20AC;&#x201C;Long Island only), Correa alba) (Harris et al. 2001)

Myoporum insulare tall closed shrubland

24. Myoporum insulare closed Scrub (Harris et al. 2001)

Dominance community 19. Leptospermum laevigatum scrub (Kirkpatrick & Harris 1995)

Dominance community 24. Myoporum insulare shrubland (Kirkpatrick & Harris 1995) Heathland on Calcarenite

SHC

Beyeria lechenaultii, Pimelea serpyllifolia heathland

11. Heathland on calcarenite (Harris et al. 2001)

Lasiopetalum discolor heathland

11. Heathland on calcarenite (Harris et al. 2001)

Acrotriche cordata, Lasiopetalum discolor open heathland

11. Heathland on calcarenite (Harris et al. 2001) Floristic community 34. Spyridium vexilliferumAcrotriche cordata heath (Kirkpatrick & Harris 1995)

30


TASVEG mapping Unit Name

Code

Floristic/structural associations distinguished

Similar described floristic Communities

Coastal Grass and Herbfield

GHC

Fire disclimax Austrostipa stipoides closed tussock grassland

4. Austrostipa stipoides tussock grassland (Harris et al. 2001) Dominance community 30. Austrostipa stipoides tussock grassland (Kirkpatrick & Harris 1995)

Austrostipa stipoides, Disphyma 32. Succulent herbfield (Tetragonia implexicoma crassifolium, Tetragonia implexicoma, / Disphyma crassifolia / Sarcocornia quinqueflora T. tetragonoides open tussock succulent herbfield) (Harris et al. 2001) grassland Floristic community 15. Austrostipa stipoidesDisphyma crassifolium tussock grassland (Kirkpatrick & Harris 1995) Seabird rookery complex

SRC

Leucophyta brownii, Tetragonia implexicoma sparse shrubland

18. Leucophyta brownii heathland (Harris et al. 2001) Dominance community 7. Leucophyta brownii shrubland (Kirkpatrick & Harris 1995)

Saline sedgeland/ rushland

ARS

Juncus kraussii rushland

14. Juncus kraussii rushland (Harris et al. 2001)

Lowland grassland complex

GCL

Sand Mud

OSM

Pteridium esculentum fernland

FPF

Pteridium esculentum closed fernland

28. Pteridium esculentum fernfield (Harris et al. 2001)

Agricultural Land

FAG

Improved pasture

9. Exotic grassland and improved pasture (Harris et al. 2001)

Weed Infestation

FWU

Mesembryanthemum crystallinum closed forbland

Regenerating cleared land (FRG)

FRG

Slashed scrub on alkaline sands

Dominance community 16. Juncus kraussii rushland (Kirkpatrick & Harris 1995) Austrostipa flavescens Austrodanthonia spp. Poa labillardierei closed grassland

31

10. Exotic grassland and improved pasture dominated by Ficinia nodosa (Harris et al. 2001)


Allocasuar ina ver ticillata forest (NAV) The high fire frequency on the island since European discovery has contributed to reduced tree cover. Harris et al. (2001) cites an early account by Campbell, who in 1828 described the island as lofty and covered in trees. This general reduction in tree cover is well illustrated by a 1951 aerial photo which clearly shows the Allocasuarina verticillata forest extent on the island (presumably A. verticillata was the only widespread tree species on the island at this time), to be confined to two small patches and a number of other areas of scattered trees. This forest type has since this time expanded considerably as shown by more recent aerial photos. In several stands large mature and often senescing trees were located at the centre with younger individuals found towards the outside. A. verticillata forest currently occurs in stands on the more rocky areas on the summits of the hills extending down slope on the northern sides. Patches also persist on well drained sandy rises, presumably in areas that have escaped high intensity burning regimes. These site characteristics are typical for the vegetation mapping units in north eastern Tasmania (Harris & Kitchener 2005). In long undisturbed areas on the island A. verticillata forest is characterised by complete dominance by A. verticillata underlain by a thick cover of leaf litter on the ground. Individual Pimelea serpyllifolia are occasional in

the understorey. In gaps caused by the breaking down of “old growth” A. verticillata; Lasiopetalum discolour and Myoporum insulare occur, as do the short lived shrubs Apalochlamys spectabilis and Zygophyllum billardierei. These disturbance gaps would appear to be short lived as regeneration of A. verticillata was also apparent in many of the canopy gaps in which senescing trees were observed. This facies of the community best matches the structure and habitat of “Coastal Allocasuarina low forest” as described by Duncan and Brown (1985); however the associated species are different from the common associates seen on mainland Tasmania. This is due to the flora of Prime Seal Island lacking many of these species, and including many species that do not occur commonly on the Tasmanian mainland. In some areas, primarily on the large hill to the south of Peacock Bay, a second facies of A. verticillata forest has developed that is far more species rich than the typical form elsewhere on the island. Contributory factors to this might include more recent fire disturbance as indicated in this area by the presence of fire scars on several larger trees and a single cohort regeneration of several species including A. verticillata, two to three metres in height. The overstorey incorporates Myoporum insulare, and occasionally Bursaria spinosa. A quite dense shrub layer is developed that includes Pomaderris paniculosa subsp. paralius, Bursaria spinosa, Dodonaea

32

viscosa, Leucopogon parviflora and Lasiopetalum discolour. The ground layer is quite dense with a cover of grasses; predominantly Poa labillardierei and Austrodanthonia sp., and herbs such as Wahlenbergia gracilenta, Daucus glochidiatus and Ajuga australis. Several orchid species are also present; most commonly Caladenia latifolia and Microtis uniflora however Cyrtostylis robusta and a large stout fruiting specimen of a Pterostylis sp. were also encountered. The facies of Allocasuarina verticillata forest fits the floristic community “Island Allocasuarina low forest” (Duncan & Brown 1985). In the description of this community it is stated that this type of vegetation was probably extensive on Prime Seal Island (amongst others) prior to European use of the Island.

Eucalyptus ovata forest and woodland (DOV) There is a small area of Eucalyptus ovata forest and woodland (DOW) present on the large hill to the south of Peacock Bay. It occurs on north easterly slope on deep limey sands overlain by a +/- 10 cm thick layer of gray brown sandy loam. This vegetation is floristically very similar to the higher diversity facies of Allocasuarina verticillata forest, however a sparse population of Eucalyptus ovata is also scattered throughout forming a sub-dominant layer amongst the slightly taller A. verticillata. This situation is quite unusual and the resulting floristic community could be interpreted as a facies of A. verticillata forest


(NAV), however the significance of the occurrence of E. ovata at this site warrants its separate mapping unit (see other paper by Visoiu this volume). The E. ovata at this site are low spreading +/- mallee form trees and are 1-2 metres shorter than the surrounding overstorey and often have no shrub layer beneath, with a lush thick herbaceous ground layer. This community is floristically distinct from E. ovata described elsewhere in Tasmania (Duncan & Brown 1985). It has similarities with “Island Allocasuarina low forest” (Duncan & Brown 1985); however E. ovata is not named as an associate in this community elsewhere, although E. globulus occurs commonly with it on Flinders Island. In the early 1950s, the site of the E. ovata population was located in a small forested remnant situated in an extensively cleared landscape, as shown in aerial photographs taken early 1951. Since that time much of the surrounding pasture has been invaded by native vegetation with significant areas of A. verticillata forest and scrub on alkaline sands now surrounding this original remnant. Despite the significant expansion of this woody vegetation, the E. ovata does not appear to have spread from the original wooded patch visible in 1951. Harris et al. (2001) suggested the confinement of this species to this site (only one individual was encountered at that time) suggested a paucity of eucalypts on the island prior to European use.

Coastal scrub on alkaline sands (SC A) This mapping unit incorporates much of the vegetation on Prime Seal Island, however the vegetation it covers is quite heterogeneous. The areas mapped as Coastal scrub on alkaline sands (SCA) are a fine scale mosaic of scrub communities delineated mainly by period since last fire. They are however all similar in that they all occur on limey and sometimes cemented sands with characteristic species including Beyeria lechenaultii, Myoporum insulare and Leptospermum laevigatum present in varying combinations. This scrub complex fits loosely into mapping unit 17 “Leptospermum laevigatum scrub (+/- Leucopogon parviflorus, Bursaria spinosa, Dodonaea viscosa, Melaleuca ericifolia, (Melaleuca armillaris –Long Island only), Correa alba)” described by Harris et al. (2001). In its simplest form the CS community on the island is dominated by Beyeria lechenaultii and/or Myoporum insulare, the dominance of which is determined by the substrate, with B. lechenaultii most prevalent on calcarenite and consolidated sands whilst M. insulare dominates on deeper limey sands. Pimelea serpyllifolia, Lasiopetalum discolor and Pomaderris paniculosa subsp. paralia are usually also present as scattered midstorey shrubs. The dense nature of this closed scrub usually prevents the development of a ground layer; instead leaf litter and detritus cover the ground along with

33

areas of exposed sand. In many areas this facies occurs in association with granite outcrops. However, the soil in these areas remains calcareous, often with calcarenite sheets developed on the outcropping granite bedrock where it meets the ground. Occasionally at the centre of these outcrops there are areas where the calcium carbonate has been leached out. In these areas other species associations occur and would be mapped as Dry scrub (SDU) if they were sufficiently extensive to map, but their rarity and small extent precluded them from being distinguished in the mapping. Species that occur in these areas are rare on the island and include Leptecophylla juniperina subsp. oxycedrus, Pultenaea daphnoides var. obcordata and Kunzea ambigua. A second more complex facies of scrub on alkaline sands is found on some areas of deeper sands. At these sites Allocasuarina verticillata, Leptospermum laevigatum, Pomaderris paniculosa subsp. paralia, Dodonaea viscosa, Leucopogon parviflora, Bursaria spinosa and Olearia ramulosa also occur. Myoporum insulare is usually present, but Beyeria lechenaultii is often absent. There is often no obvious dominant; instead there is a mixture of +/- even height individuals of a selection of the above species or a fine scale mosaic of small patches of those species. The cover of any one of these species rarely exceeds 20%. Poa labillardierei, Austrostipa flavescens and Austrodanthonia sp. often form


Photo by Rolan Eberhard.

a grassy ground cover. The shrubs Apalochlamys spectabilis, Zygophyllum billardierei, and herbs Parietaria debilis, Dichondra repens, Senecio biserratus and Urtica incisa are all commonly present amongst the grass tussocks or in relatively bare areas. No systematic survey and classification of scrub communities has been undertaken in Tasmania, however areas of this facies may fit into the dominance community “19. Leptospermum laevigatum scrub” (Kirkpatrick & Harris 1995). A third floristic community that has been mapped in the SCA mapping unit occurs in areas that have remained undisturbed for a long time. This facies is predominantly located on easterly facing slopes. In such areas Myoporum insulare forms a more or less closed scrub often with occasional Allocasuarina verticillata. The vegetation ranges from 3 to 6 metres in height with a +/- open understorey with a well developed ground layer of herbs, grasses and orchids. The best examples of this M. insulare closed scrub are present on the eastern slopes of the large hill to the south of Peacock Bay. This vegetation type has been identified by Harris et al. (2001) as mapping unit 24 “Myoporum insulare closed Scrub” and occurs on a number of the Furneaux Islands. It has however not been floristically described elsewhere.

Heathland on Calcarenite (SHC) There is a reasonably large extent of heathland on calcarenite on Prime Seal Island. Patches are primarily located on westerly to north-westerly facing slopes and are found on most of the hills along the length of the island. The substrate in all these areas is granite overlain by a cap of calcarenite which is in places exposed as a sheet or as beds of broken and angular rubble, calcareous sands form the subsoil with a thin (5 cm thick) layer of dark brown organically enriched top soil. There are three distinct facies of this heathland on the island which seem to be determined by soil type. All three facies are included in mapping unit 11 “Heath on calcarenite” (Harris et al. 2001). The first facies is characterised by deeper limey sands with little organic matter, there is little or no exposed limestone, however fragments are scattered on the surface. This soil type is generally found on the lower slopes and flats below hills. The dominant species is generally short Beyeria lechenaultii var. latifolia 0.5-1 metres high with 25-75% cover. Pimelea serpyllifolia forms a 25-50% cover with bare ground often prevalent (10-50% cover). Other species that are often present with lower covers are Pomaderris paniculosa subsp. paralia, Zygophyllum billardierei and stunted Myoporum insulare. This floristic community has not been specifically described elsewhere.

34

The second facies is generally found on the steeper slopes in areas where outcropping rock is limited. The soil is comprised of a higher organic content in the top 5cm, with limey sands, mixed with granite gravels below this; fragments of calcarenite are also common. The overwhelming dominant is Lasiopetalum discolor 50-80cm high and with 25-75% cover. Beyeria lechenaultii var. latifolia and Pimelea serpyllifolia are both also prevalent with 10-30% cover each. Hibbertia sericea is also present as is Zygophyllum billardierei. There are few herbs and ground covers and bare ground is common. This floristic community has not been described specifically elsewhere. The dominance of L. discolor would make this community unique to Prime Seal Island. The third facies is associated with outcropping and broken surface calcarenite rubble with a matrix of calcareous sand and low levels of organic matter. In these areas Acrotriche cordata commonly dominates with 10-50% cover. Lasiopetalum discolor and Beyeria lechenaultii are always present, with Hibbertia sericea also usually present. Spyridium vexilliferum and or Eutaxia microphylla are also occasionally present in these areas. This floristic community has affinities with “Floristic community 34. Spyridium vexilliferum-Acrotriche cordata heath” described by Kirkpatrick & Harris (1995), from north eastern Flinders Island. It differs from this community in that L. discolor makes


up a substantial proportion of the cover. A. cordata and E. microphylla have been seen to have similar environmental preferences on Flinders Island, where they occur together in the few sites they are known from (Underwood 1998).

Seabird rooker y complex (SRC) There are small areas of sea bird rookery in the south western corner of the island which are occupied by a relatively small breeding colony of less than 3000 pairs of short tailed shear waters (Puffinus tenuirostris) (Brothers et al. 2001). These areas differ from the normal sea bird rookery vegetation in the Furneaux islands in that the dominant species is Leucophyta brownii, with interspersed Tetragonia implexicoma. There are also large scattered individuals of South African boxthorn (Lycium ferocissimum). The L. brownii individuals are very large, some being up to 1.5 metres in height and 2 metres in canopy width. The colonies are located on flats and steep slopes which are composed of consolidated

calcareous sands that are rich in sub-fossil bird and marsupial remains. Bare sand with scattered sub fossil remains comprises 30-60% of the ground cover. This community is described as mapping unit 18 “Leucophyta brownii heathland” by Harris et al. (2001); however it has not been floristically distinguished beyond this. It would however fit into the dominance community “7. Leucophyta brownii shrubland” (Kirkpatrick & Harris 1995).

Saline sedgeland/rushland (ARS) There are small patches of this vegetation in the saddle to the south of North Hill. At this site wind is funnelled inland bringing salt spray during onshore westerly weather. The facies is very species poor, being dominated by Juncus kraussii of around 50% cover, with bare red/orange soil exposed over much of the remaining area, often with a visible salt crust. Occasional herbs are Gnaphalium indutum, Vellereophyton dealbatum and Disphyma crassifolium. This is similar

35

to areas of saline sedgeland/rushland in other coastal areas of Tasmania (Harris & Kitchener 2005) and the Furneaux Islands (Harris et al. 2001).

Lowland grassland complex (GCL) There are several small patches of native grassland on the island that have developed in areas of previously improved pasture. These are generally openings in regenerating scrub and are dominated by Austrodanthonia racemosa, Austrostipa flavescens and Poa labillardierei. Annual weed grasses are relatively common in these areas however the native grasses are the dominant. This vegetation mapping unit is rare on the Outer Islands of the Furneaux Group and may only occur on the biggest islands. The site characteristics and floristics are typical of the vegetation types throughout the drier areas of the Tasmanian mainland (Harris & Kitchener 2005). The one slightly unusual aspect of the community on Prime Seal Island is the presence of Austrostipa flavescens as one of the


dominants. This species is uncommon away from coastal areas, with other Austrostipa species more common in Lowland grassland complex (GCL) within its primary occurrences’, which is in the northern and southern midlands.

Coastal Grass and Herbfield (GHC) Coastal grassland and herbfield is widespread along the western and southern coast of Prime Seal Island where it is primarily located on alkaline sands which are in varying stages of calcarenite formation. There are two main facies represented in this mapping unit, both of which fit into mapping unit 4 “Austrostipa stipoides tussock grassland” described by Harris et al. (2001) for the Furneaux Islands. The first and most widespread facies is a fire disclimax community, being characterised by large tussocks of Austrostipa stipoides with few other species present. These areas are

maintained by patch burning, with fires set as soon as the vegetation will hold a fire which is usually every three to four years (J. Cooper pers comm). This type of grassland is common and extends several hundred metres inland in many areas. In some places there is an obvious succession between this community and the SCA community. Where the fire frequency is lower, Myoporum insulare and Beyeria lechenaultii begin to overtop the grass tussocks and the conversion to scrub is rapid. Examination of historical aerial photos (1951, 1974, 1982, 1998) indicates the boundaries between these two communities are quite dynamic and are often represented by wide ecotones. Just to the south east of Sealers Cove on a steep dune face an interesting example of the fire disclimax community occurs with Pultenaea tenuifolius and Eutaxia microphylla common amongst the A. stipoides tussocks in otherwise bare sand.

36

The second facies of Coastal grass and herbfield (GHC) appears to be the more natural of the two. It is less fire dependent gaining disturbance instead from salt spray and coastal processes. This facies has higher species diversity. Typically there is a 25-50% cover of A. stipoides, with inter-tussock spaces covered by mats of Tetragonia implexicoma and to a lesser extent T. tetragonoides, Disphyma crassifolium, and short spreading Myoporum insulare. Poa poiformis is scattered and occasional throughout the grassland and herbfield. The best examples of this herbaceous community are located in the north western eastern tip of the Island, where extensive beds of Disphyma crassifolium occur. This vegetation fits floristic community 15 “Austrostipa stipoides-Disphyma crassifolium tussock grassland” as described by Kirkpatrick and Harris (1995). Areas of it are mapped as unit 32 “Succulent herbfield (Tetragonia implexicoma / Disphyma crassifolia / Sarcocornia quinqueflora


Zygophyllum billardieri in flower on a limestone cliff, western side of Prime Seal Island. Photo by Micah Visoiu

succulent herbfield)â&#x20AC;? by Harris et al. (2001).

Sand Mud (OSM) There are a number of areas along the western coast of the island where sand blows have occurred. The cemented and semi-cemented nature of the sands has caused several of these blows to form vertical sides, exposing a multitude of bird and marsupial sub-fossil remains some of which are from species no-longer present on the island. Occasional shrubs of Leucophyta brownii, Ozothamnus turbinatus and Olearia axillaris are present in stabilising areas.

Pter idium esculentum fernland (FPF) On the south eastern slopes of the large unnamed hill to the south of Peacock Bay there are several large patches of Pteridium esculentum. These have apparently invaded areas previously cleared and converted for agricultural use and are on deep alkaline sands. Pteridium esculentum dominates with close to 100% cover; there are occasional pasture species present. This is a typical community of disturbed sandy areas throughout Tasmania (Harris et al. 2001, Harris and Kitchener 2005).

Agricultural Land (FAG) Agricultural land of varying levels of improvement covers much of the Island. The largest patches occur along the east coast and cover the majority of the large unnamed hill

to the south of Sealers Cove and Peacock Bay. The majority of the area that has been converted to this land use is underlain by deep alkaline sands with occasional limestone and granite outcrops. The floristic makeup of the pasture varies depending on the level of improvement. Common pasture grasses are Lolium perenne and Bromus diandrus. A number of Trifolium species are also widespread and dominant in places. Annual weed grasses including Parapholis incurva, Lagurus ovatus and Catapodium rigidum are common and widespread as are herbaceous species Geranium molle, Cerastium glomeratus and Arctotheca calendula. In many less improved areas native species persist or continue to invade. These include Apalochlamys spectabilis, Bulbine semibarbata, Lasiopetalum discolor, Ficinia nodosa, Austrostipa stipoides and Pimelea serpyllifolia.

Weed Infestation (FWU) There are scattered weeds present in various places on Prime Seal Island. The weed issues and mapping of these species are dealt with by Strutt (this volume). The only infestation large enough to be mapped as a distinct patch is located on the south western tip of the island. At this site the succulent halophyte Mesembryanthemum crystallinum is dominant over an area of between one and two hectares. The species is annual to biennial and forms a dense mat in the area. M. crystallinum accumulates salt. The salt is released once the plant dies,

37

increasing the salinity of the soil (Vivrette & Muller 1977). This makes the habitat unsuitable for all but the most salt tolerant species and allows a new generation of M. crystallinum seeds to germinate with little competition (Bohnert & Cushman 2000). M. crystallinum is a rare weed in Tasmania (Harris et al. 2001, NVA 2009), and is not known to have formed any other infestations of a mappable size anywhere else in the state.

Regenerating cleared land (FRG) The vegetation on Prime Seal Island shows signs of having undergone significant changes in land use in the past. Aerial photos taken in 1951 show that substantially more of the island was cleared at that point than now. Slashed regrowth scrub in areas that have reverted to native vegetation occur in the southern part of the island. There are several large areas around the shearing shed where this has recently occurred. The resulting vegetation is rapidly re-sprouting and numerous seedlings of native shrubs are quickly growing. These areas have been mapped as regenerating cleared land, although it is unclear whether they will regenerate fully to scrub or be further improved and converted back to improved pasture.


GENERAL DISCUSSION & MANANGEMENT RECOMMENDATIONS There is incomplete correspondence of the mapping units from Harris et al. (2001) with TASVEG mapping units (Harris & Kitchener 2005) resulting in the allocation of the scrub communities on the island to “Acacia longifolia coastal scrub (SAC)” and “Heathland scrub mosaic on Flinders Island (SHF)” in TASVEG 2.0. In the vegetation mapping presented in this paper the areas mapped as these two mapping units have been incorporated under “Coastal scrub on alkaline sands (SCA)”, which was deemed to be warranted by the floristics and substrate on which they occurred. The fast rate of vegetation progression on the island has also meant that the TASVEG 2.0 mapping of vegetation extent was already out of date when it was previously mapped due to the lack of contemporary aerial photographs. Acacia longifolia coastal scrub (SAC) is a distinct vegetation assemblage of A. longifolia and Leucopogon parviflorus. However, A. longifolia was found to be extremely rare on the island, only being seen at one site with less than 5 individuals. Heathland scrub mosaic on Flinders Island (SHF) is a mosaic of scrub and heath that is characterised by a group of species that are not present on Prime Seal Island. These include Eucalyptus nitida, Xanthorrhoea australis, Banksia

marginata, Leptospermum scoparium, and Leptospermum glaucescens. This species list would suggest that the vegetation type is situated on less fertile substrates with a lower pH than those that are typical of Prime Seal Island. The two other mapping units used in TASVEG 2.0 have been reallocated. Succulent saline herbfield (ASS) on the island has been absorbed into “Coastal grass and herbfield (GHC)”. The Coastal heathland (SCH) has been reallocated to Coastal scrub on alkaline sands (SCA). The rapid development of the vegetation, combined with the removal of African boxthorn (Lycium ferocissimum) infestations by the land manager and some small amounts of scrub clearance, have all contributed to changes in vegetation boundaries since the TASVEG 2.0 mapping (based on 1998 1:24 000 aerial photos and 2003 1:42 000 photos). In general the Lycium ferocissimum is no longer mappable as weed infestations in the north eastern part of the island, scrub communities have expanded significantly, Allocasuarina verticillata forest has expanded noticeably and a small amount of scrub in the centre of the island has been slashed. The extent of Heathland on calcarenite (SHC) is not as extensive as was thought in the south of the island, due probably to over-mapping of it previously rather than clearance. This vegetation type was however found to be under mapped in the central and northern part of the island.

38

It would be beneficial if fire was excluded from the reserve in the north of the island, and the vegetation in this area was allowed to continue to grow older. Likewise it would be a priority to keep fire out of the scrub and forest communities on the large hill to the south of Peacock Bay. The Eucalyptus ovata in this area is of high conservation significance within the outer islands and it would benefit greatly from being left unburnt. The Allocasuarina verticillata forest on the hills through the centre of the island should also be left unburnt. The dynamic nature of the vegetation on Prime Seal Island mean that this description is a snapshot in time. It will continue to change and develop, and burn, and start again.

ACKNOWLEDGEMENTS Stephen Harrris provided advice in the field and in the preparation of this paper. Winston Smith kindly prepared the vegetation map.


Photo by Emma Betts

REFERENCES Bohnert, H.J. & Cushman, J.C. (2000) The Ice Plant Cometh: Lessons in Abiotic Stress Tolerance. Journal of Plant Growth Regulation 19, 334-346. Brothers, N., Pemberton, D., Pryor, H. & Halley, V. (2001) Tasmaniaâ&#x20AC;&#x2122;s Offshore Islands: Seabirds and Other Natural Features. Tasmanian Museum and Art Gallery, Hobart, Tasmania. Buchanan, A.M. (2005) A Census of the Vascular Plants of Tasmania, Fourth Edition. Tasmanian Herbarium Occasional Publication No. 7. Tasmanian Museum and Art Gallery. Hobart Duncan, F. & Brown, M.J. (1985) Dry sclerophyll vegetation in Tasmania, extent and conservation status of the communities, Wildlife Division Technical Report 85/1. National Parks and Wildlife Service, Tasmania

Harden G.J. (Ed) (1990) Flora of New South Wales, volume 1, UNSW Press. Sydney Harris, S. & Kitchener, A. (2005) From Forest to Fjaeldmark: Descriptions of Tasmaniaâ&#x20AC;&#x2122;s Vegetation. Department of Primary Industries, Water and Environment. Printing Authority of Tasmania. Hobart. Harris, S., Buchanan, A. & Connolly, A. (2001) One Hundred Islands: The Flora of the Outer Furneaux, DPIWE, Hobart. Kirkpatrick, J.K. & Harris, S. (1995) The conservation of Tasmanian dry coastal vascular plant communities. Wildlife Scientific Report 95/1. Parks and Wildlife Service. DELM, Hobart.

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Thackway, R., Neldner, V.J. & Bolton, M.P. (2008) Vegetation, In: Mackenzie, N.J., Grundy, M.J., Webster, R. & Ringrose-Voase (eds) (2008) Guidelines for Surveying Soil and Land Resources, Second Edition. CSIRO publishing, Victoria. Underwood, S 1998, Synecology & Conservation of Vegetation on Aeolian Calcarenite, Flinders Island, Bass Strait, BSc thesis, University of Tasmania. Vivrette, N.J. & Muller, C.H. (1977) Mechanism of Invasion and Dominance of Coastal Grassland by Mesembryanthemum crystallinum. Ecological Monographs 47, 301-318. Whinray, J.S. (1971) A note on Prime Seal Island, The Tasmanian Naturalist, No. 27, Hobart


A REVISED FLORA

40


Photo by Micah Visoiu

By Micah Visoiu

INTRODUCTION

A survey of Prime Seal Island in October 2008 resulted in 40 species of vascular plant being added to those previously recorded. These comprise 13 exotic species and 27 species that are native to Tasmania. This takes the known flora of the island to 193 taxa. The island provides habitat for populations of the threatened taxa Lasiopetalum discolor, Pomaderris paniculosa subsp. paralia, Eutaxia microphylla var. microphylla, Spyridium vexilliferum var. vexilliferum, Zygophyllum billardierei, Acrotriche cordata, Parietaria debilis, Stellaria multiflora, Cyrtostylis robusta, and Leucopogon lanceolatus. Biogeographically significant taxa encountered were: Threlkeldia diffusa, Eucalyptus ovata, Convolvulus erubescens and Asplenium trichomanes. An exotic species, Orobanche minor sensu lato, is included in this section as its presence on this island intriguing. Callitris rhomboidea was previously recorded but was not encountered in this survey. The population size and extent of each threatened or otherwise significant taxa were described on the basis of the 2008 and previous surveys.

Prime Seal Island has been known for some time to have an interesting and in some ways unique flora when compared to the other Furneaux Islands and mainland Tasmanian. In the first half of the 19th century the island was visited by at least two well known Tasmanian naturalists, those being R.C. Gunn and J. Milligan both of whom recorded the presence of Lasiopetalum discolour, amongst other things (Tas. Herbarium data, Whinray 1971). The first vascular plant species list for the island was published J. Whinray in 1971 and contained 66 taxa. A second, more comprehensive list was published in 2001 (Harris et al.) and contained 143 taxa. Both of these lists were based on the authors’ ground surveys; with the exception of one historical record of Taraxacum cygnorum (J. Milligan 1844) included by Harris et al. (2001). Combining the lists provided a total known flora of 155 taxa, including 50 exotic species and two endemics. Harris et al. (2001) produced a vegetation map of the island, descriptions of the vegetation and preliminary estimates of some populations of threatened taxa. At that time eight species listed under the Tasmanian Threatened Species Protection Act 1995 (TSPA 1995) were known from the Island, (Acrotriche cordata, Eutaxia microphylla var. microphylla, Lasiopetalum discolor, Leucopogon lanceolatus, Pomaderris paniculosa subsp. paralia, Parietaria debilis,

41

Spyridium vexilliferum var. vexilliferum and Zygophyllum billardierei). Taraxacum cygnorum which is listed under the Environment Protection and Biodiversity Conservation Act 1999 (EPBCA 1999) has also been recorded there in the past. The Hamish Saunders Memorial expedition to Prime Seal Island in October 2008 provided the opportunity to complete a more thorough examination of the island’s vegetation and flora, and improve population estimates for threatened or biogeographically interesting plant taxa on the island. It is hoped that the information presented here will be of value for future conservation management planning on this and other Bass Strait Islands, as well as being relevant to future assessment and monitoring for threatened flora inhabiting Prime Seal Island. The information provided here also adds to the understanding of biogeographic relationships in the flora of Bass Strait

METHODS The island’s vegetation was sampled by means of traversing along a number of routes over the six day period. The island was only sampled and this incomplete coverage of the island is a limitation of the survey. Data were recorded during the survey of all plant species and vegetation formations observed. Data on the habitat preferences and distributions of particular target taxa were used to estimate the area


of occupancy for these taxa on the Island. Vegetation maps (Visoiu this volume) also assisted in determining habitat availability. Population counts/densities of target species were estimated by counting or estimating the number of individuals within a small sample area and extrapolating average densities to the total area of occupancy. In some instances belt transects were used to determine population densities. Error ranges were included in assessments; these were subjective and based on the confidence in the population estimate. This was deemed to be a more reliable and accurate representation of the true population given the limitations of the survey than would an arbitrary error percentage. The species records from the 2008 survey of the island were compared with the two previous published lists for the Island (Whinray 1977, Harris et al. 2001) as well as records held by the Tasmanian Herbarium, and data available online on the Natural Values Atlas (NVA July 2009) and Australia’s Virtual Herbarium (AVH July 2009). This information was used to create the most comprehensive list so far prepared for Prime Seal Island (Appendix 1). Taxonomic nomenclature for plant taxa follows Buchanan (2005). The nomenclature adopted here for vegetation communities follows Harris and Kitchener (2005).

RESULTS An updated species list for Prime Seal Island is located in Appendix one. It contains 193 taxa which include 66 introduced species and 127 native taxa of which two are endemic to Tasmania. Forty species were observed for the first time on Prime Seal Island during the 2008 survey, 27 of these were indigenous Tasmanian taxa, while 13 were exotics that have become naturalised in Tasmania (Buchanan 2005). Populations of nine threatened species were located during the 2008 survey; two other species have been recorded from the island in the past but were not located during the 2008 survey. Six species of biogeographic interest within the Furneaux Islands were also observed. The species for which population information is described are summarised in Table 1.

Threatened taxa Acrotr ic he cordata Acrotriche cordata is a small heath (up to 50cm tall and 80cm broad) in the family ERICACEAE, and is listed as Vulnerable in Tasmania (TSPA 1995). It has a disjunct distribution, its western most populations occurring around the south west coast of Western Australia where it is considered relatively common. It is also considered common in the south east of South Australia. It occurs sporadically in Victoria near

42

the South Australian border and is listed as Rare under the Advisory List of Rare or Threatened Plants in Victoria 2005 (ALRTPV 2005). The population in Tasmania is confined to a localized area in the Furneaux Islands approximately 800 km from the South Australian and Victorian populations. Within the islands it is known only with certainty from Flinders and Prime Seal Island (NVA July 2009). There is also one specimen held in the Australian National Herbarium (Canberra) which may have been collected on one of the Sisters Islands which are off the north coast of Flinders Island. The grid accuracy and location notes of this specimen are, however, inconclusive (Unit ID 668889, ANHSIR July 2009). Acrotriche cordata is one of a group of taxa, the populations of which in Tasmania are regarded as southern outliers of the Australian mainland core distributions (Underwood 1998). On Prime Seal Island Acrotriche cordata was first collected in the mid 1960’s and has been collected several times since however no population data has been provided until now. During the 2008 survey A. cordata was determined to be locally common on westerly to north westerly facing slopes in ‘Heathland on calcarenite’. The species is known to occur on the same substrate on Flinders Island (Underwood 1998). On Prime Seal Island the species tends to be concentrated in the rockier facies of the heathland where plant cover is lower and sandy


Table 1: Plant taxa for which population distributions and estimates were determined. Threatened taxa

Common name

Family

Distribution

Status

First Recorded

Acrotriche cordata#

coast groundberry

EPACRIDACEAE

WA, SA, VIC, TAS

Vulnerable

1966

Cyrtostylis robusta

large gnat-orchid

ORCHIDACEAE

WA, SA, VIC, TAS

Rare

2008

Eutaxia microphylla

spiny bushpea

FABACEAE

WA, SA, VIC, NSW,

Rare

1986

coast velvetbush

STERCULIACEAE

Rare

Mid 19th century

lance beardheath

EPACRIDACEAE

var. microphylla# Lasiopetalum

TAS WA, SA, TAS

discolor# Leucopogon

SA, VIC, NSW, QLD, Rare

lanceolatus* Pomaderris

Early 1990’s

TAS shining dogwood

RHAMNACEAE

WA, SA, VIC, TAS

Rare

1966

shade pellitory

URTICACEAE

All states

Rare

1966

RHAMNACEAE

SA, VIC, TAS

Rare

Mid 19th century

CARYOPHYLACEAE

WA, SA, VIC, NSW,

Rare

2008

Vulnerable (EPBCA

Mid 19th century

paniculosa subsp. paralia Parietaria debilis

Spyridium vexilliferum helicopter bush var. vexilliferum Stellaria multiflora

rayless starwort

TAS Taraxacum

coast dandelion

ASTERACEAE

WA, VIC, TAS

cygnorum*# Zygophyllum

1999) coast twinleaf

ZYGOPHYLACEAE

WA, SA, VIC, TAS

Rare

Asplenium

maidenhair

ASPLENIACEAE

WA, VIC, NSW, TAS

2008

trichomanes

spleenwort

Callitris rhomboidea

oyster bay pine

SA, VIC, NSW, QLD,

1965

billardierei# Taxa of biogeographic significance

CUPRESSACEAE

TAS Convolvulus

blushing bindweed

CONVOVULACEAE

angustissimus subsp.

WA, SA, VIC, NSW,

1965

QLD, TAS

angustissimus Eucalyptus ovata

black gum

MYRTACEAE

SA, VIC, NSW, TAS

Mid 1980’s

Orobanche minor

lesser broomrape

OROBANCHACEAE

WA, SA, VIC, NSW,

Mid 1980’s

coast bonefruit

CHENOPODIACEAE

WA, SA, VIC, TAS

sensu lato Threlkeldia diffusa#

QLD, TAS

* Taxa that were not observed during the survey # Taxa with highly restricted distributions within Tasmania

43

Mid 1980’s


coloured broken limestone covers the ground. A. cordata dominates these heaths providing 10-50% of the vegetation cover. Lasiopetalum discolor and Beyeria lechenaultii always co-occur with A. cordata in this community. There are three locations on the island where Acrotriche cordata was found to be densely populated. At North Hill there are a number of small patches of A. cordata dominated vegetation, which are occupied by 750 mature plants (plus or minus 250). Similarly on the small hill to the south of Target Hill where three distinctive patches were observed to include 750 mature plants (plus or minus 250). The largest population was observed on the unnamed large hill south of Peacock Bay. In this area there are 2300 mature plants (plus or minus 700). Therefore the total estimated population of A. cordata on Prime Seal Island is 3800 mature plants (plus or minus 1200).

Cyr tostylis robusta Cyrtostylis robusta in the family ORCHIDACEAE is a geophytic colony forming terrestrial orchid. It has a single ground hugging reniform leaf and a six to 25cm high scape with up to seven insignificant brownish red flowers (Jones et al. 1999). It is regarded as common and widespread in the south west of Western Australia, Likewise on the south east coast of South Australia. It is scattered in Victoria where it is regarded as not threatened. In Tasmania it is distributed

around the east and northern coastal areas of Tasmania and it is listed as Rare (TSPA 1995). On the Furneaux islands C. robusta is known from Flinders, Babel, Badger and Vansittart islands (Harris et al. 2001, NVA July 2009). It has also been collected from Inner Sister Island and the Kent Group of Islands (National Herbarium of Victoria, AVH July 2009). Cyrtostylis robusta was first recorded on Prime Seal Island during the 2008 survey. It was found in the grassy herbaceous understorey of Allocasuarina verticillata and Myoporum insulare open forest (‘Allocasuarina verticillata forest’). It was located in free draining site on a substrate of calcareous sands with a layer of organically enriched top soil. The site had a north easterly aspect and gentle (four degree) slope. The colony occupied an area of one square metre and was composed of about 15 leaves. No plants were in flower at the time however several individuals had maturing fruit present. The habitat and leaf morphology combined with residual floral features present on the maturing fruit were sufficient to identify the taxa. Time constraints prevented further extensions surveys for the species in the immediate vicinity. There were at least several hectares of similar habitat in the local area that may support further colonies.

Eutaxia microphylla var. microphylla Eutaxia microphylla in Tasmania is a spiney prostrate shrub in the family

44

FABACEAE. It generally grows to 5-10cm high and can get up to one metre in diameter, although some Australian mainland populations grow as small upright shrubs. Eutaxia microphylla is widespread and locally common in the southwest of Western Australia, it is also common in southern South Australia, throughout Victoria and in the southern half of New South Wales. It is listed as Rare in Tasmania (TSPA 1995). Within Tasmania the Eutaxia microphylla is usually associated with Tertiary limestone and limey sands in close proximity to the coast. It is known from a number of sites on the west coast of Flinders Island, and on Cape Portland. Two populations are known from the South East, one on the Forestier Peninsula and one near Midway Point (Lynch 1993). When Lynch (1993) surveyed the majority of known populations in the early 1990s, all populations contained less than 100 individuals each with the exception of the Forestier Peninsula population which was estimated at 200 while a loose estimate of 1000 individuals was given for Prime Seal Island (Lynch 1993). During the recent trip to Prime Seal Island Eutaxia microphylla was surveyed more extensively. Akin to the Flinders Island populations, it was found to occur in areas mapped as ‘Heathlands on calcarenite’, and also in calcareous sand dunes. It was noted as being present just inland of Wolff Bay on the west coast, at this site there were only a handful of plants seen. In dunes just to the


Lasiopetalum discolor in flower. Photo by Micah Visoiu

southeast of Sealers Cove 300 (plus or minus 100) smallish plants were encountered growing with Austrostipa stipoides and Pultenaea tenuifolia in an area that appears to have a high fire frequency (in the vicinity of five to ten year fire intervals). Several hundred metres south of this site there is a large patch of ‘Heathland on calcarenite’ growing on the western slope of a large un-named hill. At this site Acrotriche cordata, Lasiopetalum discolour and Beyeria lechenaultii co-dominate on broken limestone and shallow soil, 1500 (plus or minus 500) Eutaxia microphylla were estimated to be present. At this site plants were large and well established with some reaching a metre in diameter. The total estimated Prime Seal Island population of Eutaxia microphylla is therefore 1800 (plus or minus 600) mature plants more than double the population estimate (500 plants) for the rest of Tasmania (Lynch 1993).

Lasiopetalum discolor Lasiopetalum discolor is a medium sized multi-stemmed shrub (one metre by one metre) in the family STERCULIACEAE. It is common along the south coast of Western Australia and in coastal areas of South Australia where is extends nearly as a far as the Victorian Border. The only known extant population in Tasmania occurs on Prime Seal Island which is around 800km east and 200km south of the nearest South Australian population.

While there are several historical records from north western Tasmania there is some doubt about the accuracy of the locality descriptions for these collections (see discussion below). Lasiopetalum discolor is listed as Rare in Tasmania (TSPA 1995). On Prime Seal Island this species is the dominant in most areas of ‘Heathland on calcarenite’ (Harris & Kitchener 2005). In particular those areas on the steeper slopes which have lower amounts of limestone outcropping and incorporate some granite gravels and dark coloured organic matter is more prevalent in the soils. In such areas Lasiopetalum discolor reaches up to 75% total cover. It often dominates in the rockier facies of the heathland where plant cover is lower and sandy coloured broken limestone covers

45

the ground. In these areas it grows with Acrotriche cordata. At one site on North Hill plants were counted in a transect measuring135 metre long and ten metres wide through a patch of heathland dominated by Lasiopetalum discolour. A total of 674 plants were counted. The heathland extent at this site was 4.5 ha and was likely to contain a population of about 22 500 plants (plus or minus 2 500). The species attained a similar density in the other areas mapped as ‘Heathland on calcarenite’ and also occurred extensively, although not so densely, in areas of ‘Coastal scrub on alkaline sands’. In these two vegetation units this species was found to be very common over much of the Island. Extrapolation from the survey at North Hill suggests that a conservative estimate of 20 hectares


of ‘Heathland on calcarenite’ on the Island could support approximately 100 000 (plus or minus 10 000) plants. The less dense but far more extensive occurrence outside of this vegetation would at least double if not triple this number, producing a conservative estimate of 200 000 (plus or minus 50 000) individuals on Prime Seal Island.

Leucopogon lanceolatus Leucopogon lanceolatus is a tall narrow-elliptical shrub to three metres high (Curtis 1963). Its most noticeable feature is the bright red colouration of the young stems and narrow lanceolate leaves. L. lanceolatus occurs extensively on the eastern side of the Great Dividing Range from Fraser Island in Queensland, through New South Wales and into eastern Victoria. It is further scattered throughout southern Victoria, occurring in the border area with South Australia with an outlying population further north west on Kangaroo Island. It is listed as Rare in Tasmania (TSPA 1995) due to its limited distribution in Tasmania. In the state it occurs on King Island and the Furneaux Islands. On the Furneaux Islands L. lanceolatus occurs on Flinders, Cape Barren, Long, Inner Sister, Badger and Clarke islands (Harris et al. 2001,Tas. Herbarium specimens). It has also been recorded once from Prime Seal Island by Harris et al. (2001), although no herbarium specimen was collected. It was not recorded from the island on the present trip;

however suitable habitat was noted to be present on the hill to the south of Peacock Bay, in herbaceous ‘Allocasuarina verticillata forest’. This site had similarities to Robin Hill and Steep Hill on Clarke where L. lanceolatus occurs commonly (pers obs., Harris & Reimer 1994). It is likely that further surveys in this area would re-locate the species. However the fact that the species was not observed during the six day survey of the island in 2008 suggests that the total population for the species is likely to be low.

Pomaderris paniculosa subsp. paralia Pomaderris paniculosa subsp. paralia is a medium sized shrub in the family RHAMNACEAE. It grows up to two metres tall and can form dense thickets. It is often associated with limestone, coastal dune systems and cliff lines (Walsh & Entwistle 1994). This taxon occurs on the south coast of Western Australia and is not considered threatened in that state. It is common in South Australia and Victoria. It is listed as Rare in Tasmania (TSPA 1995), where it occurs predominantly in the Furneaux Islands and north east Tasmania, with one confirmed outlying population on King Island (NVA July 2009). On Prime Seal Island Pomaderris paniculosa subsp. paralia is widespread and common in a number of heath, scrub and forest communities throughout the areas of native vegetation on the

46

Island. It occurs in ‘Heathlands on calcarenite’ and ‘Coastal scrub on alkaline sands’. This species is a significant component of these heathlands, especially in areas with higher disturbance regimes. Seedlings and individual bushes were also encountered in areas of cleared land. No calculation of the population on the island was made however it is likely to be in the order of tens of thousands.

Par ietaria debilis Parietaria debilis is a small soft light green annual herb in the URTICACEAE family. It is quite widespread but not common, in all temperate areas of Australia, occurring in all states. It also occurs in New Zealand. It favours well drained and often alkaline soils (Harden 1990). In the Furneaux Islands it occurs in shady sites under scrub and heath in slightly damp areas (Harris et al. 2001). Parietaria debilis is listed as Rare in Tasmania (TSPA 1995). It occurs sporadically throughout the coastal areas of the State, with the majority of known populations in the Bass Strait islands. During the 2008 survey of Prime Seal Island Parietaria debilis was occasionally encountered around the southern coast of the island. It was usually under Myoporum insulare in areas of sandy soil around granite tors and on the landward edge of granite coastline. It was also found growing in dense ‘Scrub on alkaline sands’ in the flat plain between Sealers Cove and Peacock Bay. No


population counts were made of this species during the 2008 survey but it is likely that the population is in the order of tens of thousands.

Spyridium vexilliferum var. vexilliferum Spyridium vexilliferum var. vexilliferum is usually a small open shrub (30-90 cm tall) in the family RHAMNACEAE. The taxon is fairly common and widespread in South Australia and Victoria. In Tasmania it occurs in sandy heaths and on rocky outcrops in the east, north and west of Tasmania (Curtis & Morris 1975). On the Bass Strait islands it has been recorded and collected several times from Prime Seal Island. There is one mid 19th century specimen collected by J. Milligan attributed to Flinders Island. Although no specimens have subsequently been collected from Flinders Island (Tas. Herbarium records, AVH July 2009, NVA July 2009) it is reported to still occur there in several localities associated with calcarenite (S. Harris pers com.). Spyridium vexilliferum is listed as rare in Tasmania (TSPA 1995). This species was first collected from Prime Seal Island in the mid 19th century and has been observed there several times since. Observations during the 2008 survey indicated that this species is quite restricted in its distribution on the island. It was observed most often in areas of thin sandy soil over granite and limestone, within SHC and SCA. The majority of populations of Spyridium vexilliferum seen on the island were in areas that

had recent or ongoing disturbance, such as slashed areas and vehicle track edges. Spyridium vexilliferum was observed at three sites in 2008. The largest population was encountered in an area of broken rocky ground in an area of regularly slashed heathland 200 metres to the south east of Wolff Bay. At this site approximately 400 (plus or minus 100) plants were present in an area of about half a hectare. Associated species were Acrotriche cordata, Beyeria lechenaultii and Pimelea serpyllifolia. A handful of plants were also seen on the eastern face of North Hill in ‘Heathland on calcarenite’. A similarly small group of less than ten plants were seen on the western face of the hill to the south of Peacock Bay. All plants seen on the island were characterised by a low dense spreading habit, with most plants being less than 30 cm tall and up to one metre in diameter. This is unusual for the species; but exposure to sea breezes may go some way to explaining this growth form.

Stellaria multiflora is listed as rare in Tasmania (TSPA 1995). On the Bass Strait Islands it is known from Flinders Island, Babel Island, the Kent Group, Curtis Island and Three Hummock Island. The first record of species on Prime Seal island was made during the present survey. Stellaria multiflora was found growing on a granite rock plate approximately 200 m south west of the shearing shed, and was most prevalent in partial shade around the edges of Myoporum insulare shrubs that overhung the rock plates. The vegetation in the surrounding area was ‘Regenerating cleared land’, with the areas around the rock plates retaining some shrubs and native vegetation. Associated species were Cotula australe, Gnaphalium indutum and Galium murale. The population was not fully surveyed but would have been in the range of 70 individuals (plus or minus 30). There were numerous other similar rock plates in the surrounding area that may also have harboured populations of this species.

Stellaria multiflora

Taraxacum c ygnorum

Stellaria multiflora is a tiny annual herb that grows 2-5 cm tall. It has a scattered distribution across the southern half of Australia. It is occasional on the south coast of Western Australia and is listed as rare under the National Parks and Wildlife Act 1972 (NPWA 1972) in South Australia. It also occurs in Victoria and New South Wales. In Tasmania it is widespread but very occasional from sea level to the Central Plateau.

Taraxacum cygnorum is a rosette forming herb in ASTERACEAE. It is very similar in appearance to the introduced dandelion (Taraxacum officinale). It was first described from specimens collected in Western Australia; however it is now listed as extinct in that state. It occurs in four small populations in south western Victoria where there is believed to be significantly less than 1000 plants and it is listed as endangered under

47


the State Act there (Carter 2004). Taraxacum cygnorum is also listed nationally as Vulnerable (EPBCA 1999). It is not listed in Tasmania (TSPA 1995). There are three herbarium specimens of Taraxacum cygnorum collected in Tasmania in the mid 19th century (Harris et al. 2001). They are from King Island, Flinders Island and Prime Seal Island. The taxon has not been collected in Tasmania since this time, despite some efforts to relocate it. In Victoria Taraxacum cygnorum is associated with near coastal grassy woodlands on limestone and limey sands (Carter 2004). A small area of such habitat does still exist on Prime Seal Island which may be worth targeting in future surveys of the island at a different time of year or after a wet spring.

Zygophyllum billardierei Zygophyllum billardierei is a sprawling succulent perennial herb with bright yellow flowers growing up to 40 cm high and one metre wide. It is in the family ZYGOPHYLLACEAE. It occurs along the southern coast of Australia from Western Australia through South Australia and along the Victorian coast. It is listed as rare in Victoria and not threatened in the other states. In Tasmania Zygophyllum billardierei is confined to disturbed area on calcareous sands and limestone’s on the islands of eastern Bass Strait (Underwood 1998, Harris et al. 2001). Zygophyllum billardierei is listed as rare in Tasmania (TSPA 1995). On islands of the Furneaux,

Kent and Hogan groups Zygophyllum billardierei can be locally very common after disturbance (Harris et al. 2001).

Taxa of biogeographic significance

On Prime Seal Island Zygophyllum billardierei was first recorded in the mid 1960s (Whinray 1971), and has been observed there several times since (NVA, May 2009). At the time of the 2008 survey this species was locally dominant over quite extensive areas, predominantly in disturbed areas such as scrub that had been slashed within the last two years and along slashed fence lines. It also occurred commonly within ‘Heathland on calcarenite’. The largest single patch observed was on the north face of the large hill to the south of Peacock Bay. At this site approximately one hectare of regenerating cleared land had been slashed and had been colonised by Zygophyllum billardierei where it provided 70-90% of the vegetation cover. Estimating a density of 0.75 plants per square metre, this population contained about 7 500 individual plants (plus or minus 750). A less dense population occurred along several hundred metres of fence line just inland from Wolff Bay. At this site 1000 mature plants (plus or minus 250) were estimated to occur. Other populations of this species were commonly encountered over most of the island. A estimate of the total population of Zygophyllum billardierei on the island at the time of the visit would be 30 000 (plus or minus 10 000) mature individuals.

Asplenium trichomanes in the family ASPLENIACEAE, is a small fern with a cosmopolitan distribution in temperate areas of the world; occurring in Australia, New Zealand, Africa, Europe, Asia and North America. Within Australia it is listed as rare in Victoria (ALRTPV 2005) and South Australia (NPWA 1972), it also occurs in New South Wales and Western Australia. Within Tasmania the subspecies Asplenium trichomanes subspecies quadrivalens has a localised distribution predominantly on Ordovician limestone (Harris et al. 2001). It has in the past been identified as significant on the Furneaux Islands where it occurs on Tertiary limestone. There is one record from Flinders Island where the population size is unknown. It has been recorded from a limestone outcrop on Badger Island where less than 20 individuals are estimated to occur (S. Harris pers com.). The specimen from Prime Seal Island has not yet been identified to subspecies, however geographically it is likely to be this taxon.

48

Asplenium tr ichomanes

This is the first record of this species from Prime Seal Island. The population is located on a south easterly facing limestone cliff face just north of Mannalargenna Cave. Only a handful of individuals (5-10) were present at this site. Associated


Callitris rhomboidea. Illustration by Brett Littleton

species were Galium australe and Plantago bellidioides.

Callitris rhomboidea Callitris rhomboidea is a medium sized tree up to 10 metres in high with fine dark green foliage (Harris et al. 2001). It is in the family CUPRESSACEAE. It occurs down the eastern seaboard of Australia from Queensland through New South Wales and Victoria and into South Australia. In

Tasmania C. rhomboidea is confined to dry areas on the east and north east coast and it is also widely distributed on the Furneaux islands including a number of the larger outer islands. Callitris rhomboidea was recorded from Prime Seal Island in 1965 (Whinray 1971). It has not been recorded since despite active searching for this species by S. Harris in the late 1980s and early 1990s and during the 2008 survey, see discussion.

Convolvulus angustissimus subsp. angustissimus Convolvulus angustissimus is a small twining pink flowered herb in the family CONVOVULACEAE. It is locally common in all states of Australia except Northern Territory. Within Tasmania it is common in native grasslands and grassy woodlands throughout the midlands and along the east coast. There are no records of this taxon from the Furneaux Islands held at the Tasmanian Herbarium, nor are there any records on the Tasmanian Natural Values Atlas (NVA July 2009). However the National Herbarium of Victoria hold three specimens, two from Flinders Island and one from Prime Seal Island (Royal Botanic Gardens Board, Melbourne, MELISR database, 27th March 2009). The Prime Seal Island specimen was collected by J. Whinray sometime in the 1960s, however it is not included in his species list published in 1971 (Whinray 1971).

49

During the 2008 trip to Prime Seal Island a small population of Convolvulus angustissimus subsp. angustissimus was located at the northern end of the leasehold, on the flats just to the south of North Hill. At this site vegetation was rough pasture with a mix of native and exotic grass as well as emergent saplings of Pomaderris paniculosa subsp. paralia, Myoporum insulare and Ficinia nodosa. This is currently the only population of this taxon that is known from the outer Furneaux Islands.

Eucalyptus ovata Eucalyptus ovata is a medium sized tree in the family MYRTACEAE. It occurs throughout south eastern Australia on damp to wet fertile soils. It is locally common in South Australia, Victoria, New South Wales and Tasmania. Very few of the outer islands have any eucalypts, presumably because those that were present at the time of European settlement were eliminated by a high fire frequency (Harris et al. 2001). Eucalyptus ovata occurs on the larger Islands of Flinders, Cape Barren and Clarke however Prime Seal Island would appear to be the only known site where this species occurs on an outer Island. Eucalyptus ovata has previously been recorded from the Island; however this record from the mid 1980â&#x20AC;&#x2122;s was of a single tree stumbled upon whilst forging through dense Allocasuarina verticillata forest (S. Harris pers com.). The approximate site of this tree on the north face of the large hill


to the south of Peacock Bay was approached from the top of the hill during the 2008 survey. The species was re-located in dense scrubby â&#x20AC;&#x2DC;Allocasuarina verticillata forestâ&#x20AC;&#x2122;. The dense understorey of Myoporum insulare, Bursaria spinosa, Pimelea serpyllifolia and Leucopogon parviflora created difficulties in ascertaining the extent and size of the population. Exploration of the immediate area revealed the population to be made up of three quite distinct size classes. The first of these were large mature trees up to five metres in height with two to three spreading trunks diverging within a metre of the ground with the larger trunks being 20-40 cm in diameter. These trees were large enough to inhibit the growth of other woody plants beneath their canopy and generally were underlain by a herb rich Poa labillardierei grass sward. The second size class was characterised by lignotubers 20-40 cm in diameter supporting 3-7 slightly spreading small mallee trunks 3-10 cm in diameter. These mallee trees were usually around four metres in height

with dead wood present at their extremities and often with one or two dead trunks, the open areas around these individuals was much smaller than for the larger trees. The third size class was comprised of scattered saplings up to one metre in height. The population size was estimated at 20 large trees (plus or minus 3), 45 mallee trees (plus or minus 5) and 25 saplings (plus or minus 5). The surrounding vegetation of large Allocasuarina verticillata and Myoporum insulare were a single cohort that regenerated after a major fire event. The tallest of these trees were seven metres in height, overtopping the E. ovata formed the mid-storey in this vegetation. The majority of trees showed significant signs of stress, with almost all trees having numerous dead branches and had generally sparse foliage. Mature fruit were only found on a handful of the larger trees, with flower buds also present on these and several others. Very few old fruit were seen, indicating seed production in this population has been limited by stress

50

over the last few years. A small seed collection was made and has been lodged with both the Tasmanian Seed Conservation Centre and Millennium Seed Bank.

Orobanche minor sensu lato Orobanche is a genus of holoparasitic herbaceous plants in the family ORABANCHACEAE. Species have no photosynthetic pigments and are only present above ground when they are flowering and fruiting. All records of this genus in Tasmania have been determined as the introduced European species Orobanche minor. Despite its introduced status, the occurrence of the species on Prime Seal Island is of biogeographic interest (see discussion). The site that this taxa was found on Prime Seal Island during the present trip was on an old track on limey sand soils in the northern side of North Hill. Approximately 5 patches of plants were seen, all of which were growing in open


Orobanche in native vegetation. Photo by Micah Visoiu

sandy areas on the track through native vegetation. The only species growing within one metre of these patches were the annual lily Bulbine semibarbata and the native daisy bush Olearia ramulosa. It seems likely that the host for the Orobanche plants was O. ramulosa given that the species has a known preference for ASTERACEAE. ASTERACEAE and FABACEAE are the two most common host families for Orobanche minor sensu lato (Rumsey & Jury 1991).

Threlkeldia diffusa Threlkeldia diffusa is a low growing succulent plant in the CHENOPODIACEAE. It has a mainly coastal distribution from around the 20° line of latitude on the Western Australian coast right around the south west coast, entire coast of South Australia and western coast of Victoria. It reaches its most easterly distribution in Tasmania’s Furneaux Islands. It also occurs sporadically and probably ephemerally on Tasmania’s north coast. Threlkeldia diffusa is not listed as threatened in any of the states in which it occurs. However it has a very restricted distribution in Tasmania. On Prime Seal Island Threlkeldia diffusa was observed occasionally as single plants or small groups of plants in areas that had been exposed to recent disturbance. No population counts were made, however the population on the island would be reasonably small with a high turnover.

GENERAL DISCUSSION The known flora of Prime Seal Island comprises 193 taxa which include 68 introduced species and 130 native taxa of which 2 are endemic to Tasmania. Thirteen threatened species have been recorded from the island. The populations of Acrotriche cordata, Eutaxia microphylla, Lasiopetalum discolor on Prime Seal Island comprise a very significant proportion of the total estimated populations of these taxa in Tasmania. There are no size estimates for the Flinders Island populations of Acrotriche cordata, however anecdotally it would seem that the population on Prime Seal Island which is 3800 mature plants constitute a large percentage of the total Tasmanian population of this species. Anecdotal evidence suggests this taxon has increased in abundance on Prime Seal Island in the last 30 years. Whinray (1971) noted that only three plants were seen on the northwest side of North Hill in the mid 1960s. The low vegetation that this species occurs in and distinct colour it has amongst other vegetation tend to make it quite noticeable where it grows. On the present survey this same site on the northwest side of North Hill was estimated at about 750 mature plants. Aerial photographs taken in 1974 show the native vegetation extent in this area was substantially

51

less at that time. The expansion of native vegetation may account for the apparent population increase in this species. Harris et al. (2001) also gave a considerably lower estimate of the population for this species on the island, suggesting there were only 20 plants in the late 1980s and early1990s. The estimated Prime Seal Island population of Eutaxia microphylla of about 1800 mature plants comprises two to three times more plants than the total estimated population of this species for the rest of Tasmania (Lynch, 1993). This is an increase on the estimates of 600 and 1000 individuals on the island made in the early 1990s (Harris et al. 2001, Lynch 1993). It is unlikely that the increase that was made in the estimated population is a result of population increase; rather it is a factor of increased survey effort. The extensive survey effort on the island during the 2008 trip failed to find new population locations. Lasiopetalum discolor would appear to be confined to Prime Seal Island within Tasmania, although several herbarium specimens have been regarded as coming from other localities historically. There are two early collections made by J. Milligan held in the Australian National Herbarium in Canberra which have been attributed to Three Hummock Island in western Bass Strait (ANHSIR July 2009). This location seems to have been extrapolated from the tag which denotes the locality as “Hummocky


Island”. Prime Seal Island has in the past been known as “Hummock Island’ (Whinray 1971, Harris et al. 2001), so it would seem more probable that it was this locality that Milligan referred to. Indeed, J. Milligan made a number of collections from “Hummock Island” in the 1840s that are held at the Tasmanian Herbarium which have been determined as coming from Prime Seal Island. There is one undated herbarium specimen of L. discolor collected by Leonard Rodway, who collected in Tasmanian from the 1890s until the 1930s , which has been regarded as coming from Sisters Beach (North West Tasmania). The specimen, which is held at the Tasmanian Herbarium has very little original collection information recorded. Other than the collectors name it says ‘the sisters, north _____ coast’, the largely illegible word between ‘north’ and ‘coast’ has been interpreted as ‘west’, although this is by no means explicit. The Sisters Beach and Rocky Cape areas have been surveyed extensively since this time and this species has never been relocated, indeed it is uncertain what locality in this area that is known as ‘the sisters’. No other collections by Rodway have been located that have this same collection locality, which could give further clues to the original locality. It would be reasonable to conclude therefore, that the origin of this particular L. discolor specimen is unknown. This would make the Prime Seal Island population of Lasiopetalum discolor the only known

extant population in Tasmania. The population on the island is large with an estimated 250 000 mature individuals and would seem to be secure. Examination of historical aerial photographs from the 1960s 70s and 80s show that the extent of native vegetation in those areas now dominated by this species has increased significantly since that time. It is therefore reasonable to assume that the population of L. discolor has increased over that period. There were two threatened species that have been recorded from Prime Seal Island in the past, were not recorded during the 2008 trip. Taraxacum cygnorum has not been recorded in Tasmania since the 1840s. Descriptions of the habitat where this species occurs in Victoria (Carter 2004), would suggest that there is still a small amount of suitable habitat for this species present on Prime Seal Island. This area which is located in the area of Eucalyptus ovata on the large hill to the south of Peacock Bay should be surveyed more thoroughly for this species at a time when it is likely to be in flower. This area is also likely to be the habitat for Leucopogon lanceolatus which was also not recorded on the present trip. The serotinus conifer, Callitris rhomboidea, was recorded form Prime Seal Island in the mid 1960s (Whinray 1971), and has not been relocated since, despite active searching by S. Harris in the late 1980s and early 1990s and also on the 2008 expedition. This species is

52

a component of dry vegetation on a number of the Furneaux Islands; however it is killed outright by fire. Fire also triggers the mass dispersal and germination of seed. Therefore the period between fires needs to be greater than eight years to allow maturation of a new cohort of individuals and production of new seed. Any shorter period between fires and the species is lost from the area (Harris 1989). It is possible that this species survived until the mid 1960s and has since become extinct on the island due to several fires in short succession (fires are regular on the island and the extent of them is not mapped). However it is also possible that intensive surveying of those areas that are visible as forest in aerial photographs in the 1950s and 1970s (vegetation cover has expanded significantly since this time) may enable this species to be relocated. The presence of Orobanche minor on Prime Seal Island is a curiosity. Within its native range it is often referred to as Orobanche minor sensu lato and is regarded as presenting significant taxonomic difficulties, with morphologically reduced diagnostic characters combined with unknown host specific effects, and the unrepresentative nature of dried specimens making determining this and a raft of closely related species very difficult (Rumsey & Jury 1991). Orobanche minor sensu lato shows unusually low host specificity for the genus Orobanche, the majority of species of which


show high host specificity. This has led to the idea that Orobanche minor sensu lato is a species aggregate, with morphological characters of lower selective importance than the physiological characteristics that determine host and habitat range (Rumsey & Jury 1991). That is to say that morphologically similar populations that parasitise different species or families in different habitats may in fact be genetically distinct taxa. The fact that species of Orobanche are largely inbreeding lends credence to this theory. Despite the introduced status of Orobanche in Tasmania, the taxon has some curious distributions within the state. The majority of records and specimens are from the fertile vegetable growing and dairy farming areas on the central north coast and in the north west. Specimens have also been collected from Christmas and New Year Islands off the north west coast of King Island, and Prime Seal Island on the opposite side of Bass Strait. These island occurrences are interesting as they all occur in +/- native vegetation and in offshore island habitats. Christmas and New Year islands lie within a couple of hundred metres of each other in western Bass Strait. They are both in a largely natural state (Brothers et al. 2001). New Year Island is reputed to have been the site of a short lived market garden set up in the early 1860s by two Chinese men from Geelong; to where produce was regularly shipped (Hooper 1973). This is the most likely origin

of the other unusual weed on these two islands, Brassica oleracea, which is the wild form, from which kale, Chinese broccoli, cauliflower, cabbage, kohlrabi and broccoli have all been bred. It is one possible origin of an introduced Orobanche species. However, Orobanche minor sensu lato does not seem to have been recorded in Tasmania before the 1960s, or within Australia before the 20th century (AVH July 2009, NVA July 2009). On Prime Seal Island Orobanche was seen in an area of native vegetation along a sandy track edge, and apparently parasitising Olearia ramulosa. Historical aerial photographs show the locality of the population has regenerated from pasture in the last 25 years. Harris et al. (2001) has invoked the lithological and climatic similarities of islands in eastern Bass Strait and the coasts of South Australia and south west Western Australia as an explanation for the high floristic congruity across these areas. They postulated that the very alkaline substrate in conjunction with a Mediterranean climate, explained the distribution of such species as Lasiopetalum discolor, Acrotriche cordata and Threlkeldia diffusa. These species have their strongholds on the limestone coasts of South Australia and Western Australia. This habitat in South Australia also supports populations of the Rare (NPWA 1972) native taxa Orobanche cernua var. australiana (ARBCP July 2009). In this area it is thought to parasitise ASTERACEAE species in coastal

53

dune areas and inland sandy places (ARBCP July 2009, EFSA July 2009). The taxon Orobanche cernua var. australiana is regarded as native in Australia but is poorly defined with no definitive diagnostic characters yet provided (EFSA July 2009). It is however very similar to Orobanche minor sensu lato. The previously described issues with determining Orobanche taxa combined with the habitat of this taxon on Prime Seal Island and presumably also Christmas and New Year Islands would suggest a close look at fresh material from these locations is warranted. Prime Seal Island is a site of very high conservation significance within Tasmania. The expansion of native vegetation in the last 40 years contains important populations of a range of threatened flora species and is the only known site in Tasmania where Lasiopetalum discolor is known to occur. It also harbours a number of species that are biogeographically significant in their occurrence on an outer island of the Furneaux Group. It is probable that other plant species both threatened and non-threatened remain to be found on this unique island.

ACKNOWLEDGEMENTS I would like to thank Jayne Balmer for comments on the drafts, Stephen Harris for general guidance, field data, advice in the field, editing and comments, Oliver Strutt for help in field work, and all others involved in


the Prime Seal Island expedition. I would in particular like to thank the family of Hamish Saunders, who set up the memorial fund that made this expedition possible.

REFERENCES ALRTPV: Advisory List of Rare or Threatened Plants in Victoria 2005. Victorian, Department of Sustainability and Environment, East Melbourne, Victoria. ANHSIR: Australian National Herbarium Specimen Information Register, IBIS database, Australian National Herbarium, Australian Government, Canberra, viewed July 2009.<http://www.anbg.gov.au/cgibin/anhsir> ARBCP: Adelaide Region Biodiversity Conservation Program, Threatened species Profile, Orobanche cernua var. australasica, Department for Environment and Heritage, Adelaide, viewed July 2009. < http://www.environment.sa.gov.au/ biodiversity/pdfs/regional_recovery/ flora/orobanche-cernua-varaustraliana.pdf> AVH: Australia’s Virtual Herbarium, via Centre for Plant Biodiversity Research, Council of Heads of Australian Herbaria, viewed July 2009.<http://www.anbg.gov.au/avh/> Buchanan, A.M. (2005) A Census of the Vascular Plants of Tasmania, Fourth Edition. Tasmanian Herbarium Occasional Publication No. 7. Tasmanian Museum and Art Gallery. Hobart

Brothers, N., Pemberton, D., Pryor, H. & Halley, V. (2001) Tasmania’s Offshore Islands: Seabirds and Other Natural Features. Tasmanian Museum and Art Gallery, Hobart. Carter, O. (2004) Draft Flora and Fauna Guarantee Action Statement, Coast Dandelion Taraxacum cygnorum. Department of Sustainability and Environment. Melbourne. Curtis, W.M. (1963) The Student’s Flora of Tasmania, Part 2, Government Printer, Hobart. Curtis, W.M. & Morris, D.I. (1975) The Student’s Flora of Tasmania, Part 1, EFSA: Electronic Flora of South Australia species Fact Sheet: Orobanche cernua Loefl. Department for Environment and Heritage, Adelaide, viewed July 2009. <http://www.flora.sa.gov.au > Harden, G.J. (Ed) (1990) Flora of New South Wales, volume 1, UNSW press. Sydney. Harris, S. (1989) The Ecological Biogeography of Callitris Vent. in Tasmania. M.Sc. thesis. University of Tasmania. Harris, S. & Kitchener, A. (2005) From Forest to Fjaeldmark: Descriptions of Tasmania’s Vegetation. Department of Primary Industries, Water and Environment. Printing Authority of Tasmania. Hobart. Harris, S., Buchanan, A. & Connolly, A. (2001) One Hundred Islands: The Flora of the Outer Furneaux, DPIWE, Hobart. Harris, S. & Reimer, A. (1994) Flora and Fauna of Clarke Island, Furneaux

54

Group, Parks and Wildlife Service report. DELM, Tasmania. Hooper, R.H. (1973) The King Island Story. Peko-Wallsend, Sydney. Jones, D., Wapstra, H., Tonelli, P. & Harris. S. (1999) The Orchids of Tasmania. Melbourne University Press. Victoria. Lynch, A.J.J. (1993) Conservation Biology and Management of 16 Rare or Threatened FABACEAE Species in Tasmania, Australian National Parks &Wildlife Service Endangered Species Program Project No. 4, Parks & Wildlife Service, Hobart. NVA: Natural Values Atlas, Biodiversity Conservation Branch, Department of Primary Industries, Parks, Water and Environment, Tasmanian Government, Hobart, viewed July 2009. < https://www.naturalvaluesatlas. dpiw.tas.gov.au/pls/apex/f?p=200:1:> Royal Botanic Gardens Board, Melbourne, MELISR database, 27th March 2009 Rumsey, F.J. & Jury, S.L. (1991) An account of Orobanche L. in Britain and Ireland. Watsonia 18, 257-295. Underwood, S. (1998) Synecology & Conservation of Vegetation on Aeolian Calcarenite, Flinders Island, Bass Strait, BSc thesis, University of Tasmania. Walsh, N.G. & Entwistle, T.J. (eds) (1994) Flora of Victoria, Volume 2, Inkata Press, Melbourne. Whinray, J.S. (1971) A note on Prime Seal Island, The Tasmanian Naturalist, No. 27, Hobart.


Appendix one Prime Seal Island vascular plant species list The ‘*’ in the right hand columns indicate where the records have come from. There are a number of species that were not seen in the current survey. In most cases this is due to the season in which the survey was undertaken. There are also a number of unverified records, which may have been recorded in error, namely Hibbertia prostrata, Hibbertia riparia and Lasiopetalum macrophyllum. Pomaderris oraria has been recorded in the past, however this taxon has not been included on the list as it is most likely that this refers to Pomaderris paniculosa subsp. paralia which is common on the island. FAMILY

SPECIES NAME

COMMON NAME

Whinray 1971

Harris et al 2001

Other

Current survey

DIOCOTYLEDONS AIZOACEAE

Carpobrotus rossii

native pigface

*

*

*

AIZOACEAE

Disphyma crassifolium

round-leaved pigface

*

*

*

Mesembryanthemum crystallinum

iceplant

*

*

*

*

AIZOACEAE

i

AIZOACEAE

Tetragonia implexicoma

bower spinach

*

AIZOACEAE

Tetragonia tetragonoides

new zealand spinach

*

APIACEAE

Apium insulare

island sea-celery

APIACEAE

Apium prostratum subsp. prostratum var. filiforme

slender sea-celery

APIACEAE

Hydrocotyle hirta

hairy pennywort

APIACEAE

Lilaeopsis polyantha

jointed swampstalks

APOCYNACEAE

Alyxia buxifolia

seabox

ASTERACEAE

Actites megalocarpa

dune thistle

ASTERACEAE

Apalochlamys spectabilis

sticky firebush

ASTERACEAE

i

*

* *

* *

*

*

*

*

*

*

*

*

*

* *

capeweed tall daisy

i

Carduus tenuiflorus

winged thistle

Cassinia aculeata

dollybush

*

i

Centaurea melitensis

malta thistle

*

Cotula australis

southern buttons

ASTERACEAE

* *

Arctotheca calendula

ASTERACEAE ASTERACEAE

*

Brachyscome diversifolia var. maritima

ASTERACEAE ASTERACEAE

*

*

*

ASTERACEAE

Cymbonotus preissianus

southern bears-ears

*

*

ASTERACEAE

Euchiton collinus

cudweed

*

*

ASTERACEAE

i

Gamochaeta calviceps

grey cudweed

ASTERACEAE

i

Gamochaeta purpurea

purple cudweed or spiked cudweed

* *

ASTERACEAE

Gnaphalium indutum

tiny cottonleaf

*

*

*

ASTERACEAE

Helichrysum leucopsideum

satin everlasting

*

*

*

Hypochoeris glabra

smooth catsear

*

*

ASTERACEAE

i

ASTERACEAE

i

Hypochoeris radicata

rough catsear

*

*

ASTERACEAE

i

Leontodon taraxacoides

hairy hawkbit

*

*

Leucophyta brownii

cushionbush

*

*

ASTERACEAE ASTERACEAE ASTERACEAE ASTERACEAE

e

Olearia axillaris

coast daisybush

*

*

*

Olearia phlogopappa var. brevipes

dusty daisybush

*

*

*

Olearia ramulosa

twiggy daisybush

*

*

*

ASTERACEAE

Olearia stellulata

sawleaf daisybush

*

*

ASTERACEAE

Olearia viscosa

viscid daisybush

*

*

55


ASTERACEAE

Ozothamnus turbinatus

coast everlastingbush

*

ASTERACEAE

Pseudognaphalium luteoalbum

jersey cudweed

ASTERACEAE

Senecio biserratus

crosscut fireweed

ASTERACEAE

Senecio glomeratus

purple fireweed

*

ASTERACEAE

Senecio pinnatifolius var. lanceolatus

groundsel

*

Silybum marianum

variegated thistle

*

ASTERACEAE

i

ASTERACEAE ASTERACEAE

Taraxacum cygnorum i

BORAGINACEAE BRASSICACEAE

i

VU

*

* *

Vellereophyton dealbatum

white cudweed

*

*

sweet houndstongue

*

*

Cakile edentula

searocket

i

Cakile maritima

american searocket

i

Hymenolobus procumbens

oval purse

Lobelia anceps

angled lobelia

CAMPANULACEAE

Wahlenbergia gracilenta

annual bluebell

CAPRIFOLIACEAE

Sambucus gaudichaudiana

white elderberry

i Cerastium glomeratum

sticky mouse-ear

CARYOPHYLLACEAE

i Minuartia mediterranea

fineleaf sandwort

CARYOPHYLLACEAE

i Petrorhagia nanteuilii

proliferous pink

CARYOPHYLLACEAE

i Polycarpon tetraphyllum

fourleaf allseed

CARYOPHYLLACEAE

i Sagina apetala

annual pearlwort

CARYOPHYLLACEAE

i Sagina maritima

sea pearlwort

CARYOPHYLLACEAE

i Stellaria media

garden chickweed

CARYOPHYLLACEAE

* *

Cynoglossum suaveolens

BRASSICACEAE

CARYOPHYLLACEAE

*

coast dandelion

BRASSICACEAE CAMPANULACEAE

*

*

Stellaria multiflora

r

* *

*

*

*

*

*

*

*

*

*

*

* *

* * *

*

* *

*

*

*

*

*

rayless starwort

*

CASUARINACEAE

Allocasuarina verticillata

drooping sheoak

*

*

*

CHENOPODIACEAE

Atriplex cinerea

grey saltbush

*

*

*

Chenopodium glaucum

pale goosefoot

*

*

CHENOPODIACEAE

i

CHENOPODIACEAE

i

Chenopodium murale

nettleleaf goosefoot

*

*

CHENOPODIACEAE

Rhagodia candolleana subsp. candolleana

coastal saltbush

*

*

*

CHENOPODIACEAE

Sarcocornia quinqueflora

beaded glasswort

*

*

*

*

*

CHENOPODIACEAE

Threlkeldia diffusa

coast bonefruit

CONVOLVULACEAE

Convolvulus angustissimus var. angustissimus

blushing bindweed

CONVOLVULACEAE

Dichondra repens

kidneyweed

CRASSULACEAE

Crassula decumbens var. decumbens

spreading stonecrop

CRASSULACEAE

Crassula sieberiana subsp. tetramera

wiry stonecrop

DILLENIACEAE

Hibbertia prostrata

prostrate guineaflower

DILLENIACEAE

Hibbertia riparia

erect guineaflower

DILLENIACEAE

Hibbertia sericea var. sericea

silky guineaflower

*

EPACRIDACEAE

Acrotriche cordata

coast groundberry

*

EPACRIDACEAE

Leptecophylla juniperina subsp. oxycedrus r

coastal pinkberry

EPACRIDACEAE

Leucopogon lanceolatus var. lanceolatus

lance beardheath

EPACRIDACEAE

Leucopogon parviflorus

coast beardheath

v

56

* *

*

*

*

*

*

*

*

* *

* * *

* *

* *

*

*


EUPHORBIACEAE

Beyeria lechenaultii var. latifolia

pale turpentine-bush

EUPHORBIACEAE

i

Euphorbia paralias

sea spurge

EUPHORBIACEAE

i

Euphorbia peplus

petty spurge

EUPHORBIACEAE

Phyllanthus gunnii

shrubby spurge

FABACEAE

Eutaxia microphylla var. microphylla

FABACEAE

Pultenaea daphnoides subsp. obcordata

* *

*

*

spiny bushpea

*

*

sweet melilot

*

*

*

heartleaf bushpea

FABACEAE

Pultenaea tenuifolia

slender bushpea

Swainsona lessertiifolia

coast poisonpea

Trifolium campestre

hop clover

i

*

*

FABACEAE FABACEAE

*

r

i Melilotus indicus

FABACEAE

*

* *

*

*

*

* *

FABACEAE

i

Trifolium glomeratum

cluster clover

*

*

FABACEAE

i

Trifolium stellatum

star clover

*

*

GENTIANACEAE

i

Centaurium tenuiflorum

slender centaury

*

*

*

*

*

*

Sebaea ovata

yellow sebaea

GERANIACEAE

GENTIANACEAE i

Erodium cicutarium

common heronsbill

GERANIACEAE

i

Geranium molle

soft cranesbill

* *

GERANIACEAE

Geranium potentilloides

mountain cranesbill

GERANIACEAE

Pelargonium australe

southern storksbill

*

*

LAMIACEAE

Ajuga australis

australian bugle

*

*

i

Marrubium vulgare

white horehound

*

*

Lawrencia spicata

candle saltmallow

MALVACEAE

i

Malva dendromorpha

tree mallow

*

*

MALVACEAE

i

Malva parviflora

smallflower mallow

*

*

LAMIACEAE MALVACEAE

*

*

*

MIMOSACEAE

Acacia longifolia subsp. sophorae

coast wattle

*

MYOPORACEAE

Myoporum insulare

common boobialla

*

MYRTACEAE

Eucalyptus ovata var. ovata

black gum

* *

*

*

*

*

*

MYRTACEAE

Kunzea ambigua

white kunzea

*

MYRTACEAE

Leptospermum laevigatum

coast teatree

*

MYRTACEAE

Melaleuca ericifolia

coast paperbark

*

*

Epilobium billardierianum

willowherb

*

*

Orobanche minor

lesser broomrape

ONAGRACEAE OROBANCHACEAE

i

OXALIDACEAE

i Oxalis corniculata subsp. corniculata

OXALIDACEAE

Oxalis perennans

PAPAVERACEAE

i Glaucium flavum

PITTOSPERACEAE

Bursaria spinosa subsp. spinosa

yellow woodsorrel

*

* *

grassland woodsorrel

* *

yellow poppy prickly box

* *

*

*

*

PLANTAGINACEAE

e Plantago bellidioides

herbfield plantain

*

*

PLANTAGINACEAE

i Plantago coronopus subsp. coronopus

slender buckshorn plantain

*

*

*

*

POLYGALACEAE POLYGONACEAE

Comesperma volubile

*

Accetosella vulgaris

sheep sorrel

*

POLYGONACEAE

Muehlenbeckia adpressa

climbing lignum

*

POLYGONACEAE

Rumex brownii

slender dock

Calandrinia calyptrata

pink purslane

PORTULACACEAE PRIMULACEAE PRIMULACEAE

i

blue lovecreeper

i Anagallis arvensis subsp. arvensis scarlet pimpernel Samolus repens

creeping brookweed

57

* *

*

*

*

*

*

*

*

*

*


RANUNCULACEAE

Clematis microphylla

small-leaf clematis

*

RHAMNACEAE

Pomaderris apetala

dogwood

*

RHAMNACEAE

Pomaderris elliptica

yellow dogwood

RHAMNACEAE

Pomaderris paniculosa subsp. paralia r

shining dogwood

RHAMNACEAE

Spyridium vexilliferum var. vexilliferum

helicopter bush

Acaena novae-zelandiae

common buzzy

ROSACEAE

Acaena pallida

dune buzzy

ROSACEAE

i Aphanes arvensis

RUBIACEAE

Galium australe

tangled bedstraw

Galium murale

small bedstraw

i

RUBIACEAE

i

*

* *

*

*

*

*

*

*

r

ROSACEAE

RUBIACEAE

*

*

*

parsley piert

Sherardia arvensis

field madder

RUTACEAE

Correa alba var. alba

white correa

RUTACEAE

Correa backhouseana var. backhouseana

velvet correa

* *

* * *

*

*

*

*

*

RUTACEAE

Correa reflexa

common correa

*

*

*

SAPINDACEAE

Dodonaea viscosa subsp. spatulata

broadleaf hopbush

*

*

*

SCROPHULARIACEAE

Mimulus repens

creeping monkeyflower

SOLANACEAE

i

SOLANACEAE SOLANACEAE

i

SOLANACEAE

Lycium ferocissimum

african boxthorn

*

*

Solanum laciniatum

kangaroo apple

*

*

Solanum nigrum

blackberry nightshade

*

*

Solanum vescum

gunyang

STERCULIACEAE

Lasiopetalum discolor

STERCULIACEAE

Lasiopetalum macrophyllum

shrubby velvetbush

THYMELAEACEAE

Pimelea serpyllifolia subsp. serpyllifolia

thyme riceflower

URTICACEAE

Parietaria debilis

URTICACEAE

Urtica incisa

URTICACEAE

i Urtica urens

VALERIANACEAE

i Valerianella eriocarpa

ZYGOPHYLLACEAE

*

Zygophyllum billardierei

r

r

coast velvetbush

*

* *

*

*

*

*

shade pellitory

*

*

*

scrub nettle

*

*

*

stinging nettle

*

italian cornsalad r

*

*

coast twinleaf

*

*

*

*

*

PTERIDOPHYTES ADIANTACEAE

Pellaea falcata

sickle fern

*

ASPLENIACEAE

Asplenium flabellifolium

necklace spleenwort

*

ASPLENIACEAE

Asplenium trichomanes subsp. quadrivalens

limestone spleenwort

*

DENNSTAEDTIACEAE

Pteridium esculentum

bracken

*

Callitris rhomboidea

oyster bay pine

*

Zantedeschia aethiopica

arum lily

CENTROLEPIDACEAE

Centrolepis polygyna

wiry bristlewort

CENTROLEPIDACEAE

Centrolepis strigosa subsp. strigosa

hairy bristlewort

CYPERACEAE

Carex breviculmis

shortstem sedge

CYPERACEAE

Ficinia nodosa

knobby clubsedge

*

GYMNOSPERMS CUPRESSACEAE MONOCOTYLEDONS ARACEAE

i

58

*

* *

*

* *

*

*

*


CYPERACEAE

Isolepis cernua

nodding clubsedge

*

CYPERACEAE

Isolepis marginata

little clubsedge

*

CYPERACEAE

Isolepis platycarpa

flatfruit clubsedge

*

CYPERACEAE

Lepidosperma ensiforme

arching swordsedge

* * *

CYPERACEAE

Lepidosperma gladiatum

coast swordsedge

*

*

JUNCACEAE

Juncus bufonius

toad rush

*

*

JUNCACEAE

Juncus kraussii

sea rush

*

*

LILIACEAE

Bulbine semibarbata

smallflower leeklily

*

*

LILIACEAE

Dianella brevicaulis

shortstem flaxlily

*

*

LILIACEAE

Hypoxis glabella var. glabella

tiny yellowstar

ORCHIDACEAE

Caladenia latifolia

ORCHIDACEAE

Cyrtostylis robusta

ORCHIDACEAE

Microtis uniflora

ORCHIDACEAE

Pterostylis sp.

*

pink fairies

*

*

r large gnat orchid

*

onion orchid

*

greenhood

*

POACEAE

i Aira caryophyllea

annual hair grass

*

POACEAE

i Ammophila arenaria

marram grass

*

POACEAE

Austrodanthonia racemosa var. racemosa

stiped wallabygrass

POACEAE

Austrofestuca littoralis

coast fescue

POACEAE

Austrostipa flavescens

yellow spear-grass

POACEAE

Austrostipa stipoides

coast speargrass

* *

*

*

*

*

*

*

*

*

POACEAE

i Briza minor

lesser quaking-grass

*

*

POACEAE

i Bromus diandrus

great brome

*

*

POACEAE

i Bromus hordeaceus

soft brome

*

*

POACEAE

i Bromus sterilis

barren brome

POACEAE

i Catapodium rigidum

ferngrass

POACEAE

Distichlis distichophylla

* *

australian saltgrass

POACEAE

i Holcus lanatus

yorkshire fog

POACEAE

i Hordeum murinum subsp. glaucum

bluish barleygrass

POACEAE

i Lagurus ovatus

harestail grass

*

*

*

*

*

*

*

*

*

*

*

*

POACEAE

i Lolium loliaceum

stiff ryegrass

POACEAE

i Lolium perenne

perennial ryegrass

*

*

POACEAE

i Parapholis incurva

coast barbgrass

*

*

*

*

POACEAE

Poa labillardierei

tussockgrass

POACEAE

Poa poiformis

blue tussock grass

POACEAE

i Polypogon maritimus

*

*

coast beardgrass

*

POACEAE

i Polypogon monspeliensis

annual beardgrass

*

*

POACEAE

i Rostraria cristata

annual catstail

*

*

POACEAE

i Secale cereale

rye

* *

*

POACEAE

POACEAE

i Stenotaphrum secundatum

Spinifex sericeus

spinifex buffalo grass

*

*

POACEAE

i Vulpia myuros

fescue

*

*

59

*


T HE MAMMALS

60


FIGURE 1 Trap sites and recorded locations of cat scats and trapped house mice. Trap references correspond to those in Table 1. Numerous cat scats were also found a few hundred metres north of trap sites E101-125, but their precise location was not recorded.

By C .E. Hawkins , M. Driessen, N. Mooney, D. Van Winkel, B . Moffat and S . Munks Prime Seal Island was surveyed for mammal species from 14th - 18th October 2008. Small mammal traps (Mascots and Elliotts) and a harp trap were deployed, and 26 cat scats analysed for mammal fur. Five wild mammal species were identified. House mice (Mus musculus), feral cats (Felis catus) and the Tasmanian pademelon (Thylogale billardierii) were relatively common. Unidentified species of possum (Trichosurus sp.) and rat (Rattus sp.) were identified as â&#x20AC;&#x2DC;probableâ&#x20AC;&#x2122; through analysis of hair found in cat scats. The swamp antechinus (Antechinus minimus), water rat (Hydromys chrysogaster) and unspecified species of potoroo and rat kangaroo have also been reported in previous surveys. These species may well have died out, but more intensive surveys would be required to confirm this with any confidence.

INTRODUCTION Seventeen native mammal species have been recorded on the Bass Strait islands (Hope 1972), as well as six introduced species having established feral populations. Since 1800, mammal populations on many of the smaller islands have died out. The most recent land bridge between mainland Tasmania and the islands through to Wilsons

Promontory was c. 12 000 years ago, with the link between the islands and Tasmania lost around 9 000 years ago (Jennings 1971). However, Prime Seal Island may have been linked to Flinders on frequent occasions much more recently and at least until c. 6 000 years ago (Jennings 1971). There has been a very limited formal survey effort for mammal species on Prime Seal Island. Earlier surveys reported six species of mammal, including 2-3 feral species (detailed in Table 1). An archaeological investigation in 1988 (Brown 1988) found a large number of mammal bones in a cave on Prime Seal Island from at least four additional species, apparently brought to the cave by humans. Given that these were found among emu shells, these species could have long been extinct from the island at the time of the survey, and could have been alive at a time when Prime Seal Island was connected to Flinders Island and perhaps part of the land bridge between Tasmania and the Australian mainland. The past habitat of Prime Seal Island may additionally have supported Australian sea lions as well as providing rocky foreshores for New Zealand and Australian fur seals to haul-out on. Australian sea lions prefer sandy beaches with scrub and bush adjacent for breeding. Commercial sealing by European settlers commenced in Bass Strait in 1798, with both fur seal species being harvested in the vicinity of Prime Seal Island. Australian sea lions

61

were also harvested from Bass Strait. By 1840, at least 240 000 fur seal skins had come from the Strait (Ling 1999; Ling 2002). Hunting to supply local markets eventually ended in 1923. After the commercial harvest ceased, Australian sea lions, New Zealand fur seals and Elephant seals were extinct in Bass Strait. Australian fur seals remain on the remote offshore islands and New Zealand fur seals are starting to recolonise Bass Strait.

METHODS Two types of terrestrial mammal trap were used: 10 cage traps (30 by 30 by 56 cm, Mascot Wire Works Pty Ltd, Parramatta, Australia) and 100 collapsible aluminium box traps (10 by 10 by 33 cm, Elliott Scientific Equipment, Upway, Victoria). These were set continuously on the nights of the 14th to 17th October 2008, as detailed in the results and on Figure 1, to cover areas of heath and Allocasuarina forest. On the last day of the trapping period, traps were set in a small area of Eucalyptus ovata forest that had subsequently been identified. A harp trap (Faunatech and Austbat, Mount Taylor, Australia) was set along an Allocasuarina forest edge during the nights of 14th to 16th October 2008, and in an open patch of vegetation near the E. ovata forest on the night of 17th October (fig. 1). Cat scats were collected wherever found, so that any mammals preyed


The mammal team. Photo by Dylan van Winkel.

upon could be identified from hair and bone analysis by the expert consultant Barbara Triggs. The island was also traversed each day along a range of different routes from 14th to 18th October 2008, by a minimum of four individuals, searching for vertebrate field signs. This included a thorough search through the E. ovata forest.

RESULTS Small mammal trapping A maximum of six house mice (Mus musculus) were trapped on any one of the four trapping nights (Table 1). The total effort was 321 Elliott trapnights and 35 Mascot trap-nights. No other mammals were trapped.

Harp trap

Other field signs

The harp trap did not catch any species of mammal during the four trap-nights.

Tasmanian pademelons (both living and shot carcasses) were observed, along with grazing sheep and two horse skeletons. Shallow diggings in the Allocasuarina forest were presumed to be signs of Tasmanian pademelons. No seals nor evidence of any other mammal species was found.

Cat scat analyses Twenty-six separate scats were identified, primarily on a track in the south of the island, a few hundred metres north of the most southerly trap site. These were provided to Barbara Triggs for analysis. Each contained house mouse (M. musculus) hair. Seven also contained cat (Felis catus) hair, generally presumed to be from grooming although in one case the cat may have been a source of food. Additionally, one scat contained ‘probable’ possum (Trichosurus sp.) hair, and another contained ‘probable’ rat (Rattus sp.) hair.

GENERAL DISCUSSION AND MANANGEMENT RECOMMENDATIONS Five wild mammal species were identified during the present survey, including at least two native mammals. One of these, the possum, should preferably be confirmed and identified to species level, having only so far been identified as ‘probable’ through analysis of fur in cat scats. The last confirmation of this species on Prime Seal Island was in 1966 and the present manager is not aware of any possum species being

TABLE 1 Details of small mammals trapped on Prime Seal Island Trap type: E = Elliott trap M = Mascot trap No species other than Mus musculus was captured in the traps. Traps

Habitat type

Set

Closed

Total trap nights

No. M. musculus captures/night

E1-49

Heath

14/10/08

18/10/08

196

3,3,6,5

E51-100

Heath

15/10/08

17/10/08

100

1,3

E101-125

E. ovata forest

17/10/08

18/10/08

25

0

M1-5

Scrub

14/10/08

16/10/08

10

0,0

M6-10

Allocasuarina scrub

15/10/08

17/10/08

10

0,0

M11-15

Allocasuarina scrub

16/10/08

18/10/08

10

0,0

M16-20

E. ovata forest

17/10/08

18/10/08

5

0

62


TABLE 2 Observations of mammals on Prime Seal Island during this and previous surveys Species

2008 survey

Other sources

Comments

Scats; hair in scats

Trapped by land manager; Brothers (2001); Whinray (1971)

Present in 1920s & 1930s (Whinray 1971)

Brothers (2001); Whinray (1971)

Present in 1920s & 1930s (Whinray 1971)

Domestic cat Felis catus

House mouse Mus musculus Trapped; fur confirmed in cat scats Rat Rattus sp.

Probable fur in cat scats

No rats observed by land manager

Tasmanian pademelon Thylogale billardierii

Observed

Brothers (2001); John Brothers (2001) noted to Cooper (pers. comm.); Scott be extremely common; (1828); Whinray (1971) land manager shot c.4000 individuals in winter/spring 2008

Possum Trichosurus sp.

Probable fur in cat scats

Trichosurus vulpecula Whinray (1971)

Introduced from Flinders in 1920s and still present in 1966 (Whinray 1971)

Swamp antechinus Antechinus minimus

No evidence

Thomas (1888) (in Whinray, 1971)

Specimen in British Museum (Natural History)

Water rat Hydromys chrysogaster

No evidence

Whinray (1971)

Present in 1920s & 1930s (Whinray 1971)

Forester kangaroo Macropus No evidence giganteus

Brown (1988)

“Wombat”

No evidence

Brown (1988)

“Potoroo, rat kangaroo”

No evidence

Brown (1988)

Bennett’s wallaby Macropus rufogriseus

No evidence

Brown (1988)

“Native rodent”

No evidence

Brown (1988)

63


present on the island. Another species, an unidentified species of rat considered as ‘probable’ on the basis of fur in scat analysis, would merit confirmation and identification to species level to establish whether it is a native or exotic species. House mice and feral cats are clearly fairly common on the island. The water rat and swamp antechinus, previously recorded on the island, were not identified during the present survey. The water rat was last reported on the island in the 1920s and 1930s (Frank Jackson, pers. comm. in Whinray 1971). Our surveys did not specifically target this species, so it is possible it was overlooked as it is not unreasonable for the species to still occur on the island. The only record of a swamp antechinus is a specimen lodged with the British Natural History Museum in 1858 (Thomas 1888). Given our experience surveying for this species elsewhere in Tasmania, it would be surprising if the species were not trapped if it were present. However, the heathland habitat on

the island is very different from the coastal heathland on mainland Tasmania where this species, and other small marsupials and rodents, are found. The heathland on Prime Seal Island is much drier and dominated by shrubs, and lack many of the Restionaceae species found in coastal heathlands of mainland Tasmania. A more intensive, focussed survey would be required to provide confidence in the absence of both the swamp antechinus and the water rat. It is also faintly possible that the diggings observed in the Allocasuarina forest were the same species of potoroo or ‘rat-kangaroo’ identified in bones through Brown’s (1988) archaeological investigation, and again this would require a focussed survey for verification.

64

ACKNOWLEDGEMENTS We are grateful to our fellow expeditioners for their companionship and for lively and enjoyable discussion.


Bridgette and Clare checking a trap.

Nick, Dylan and Sarah setting a bat trap.

Photo by Stephen Harris.

REFERENCES Brothers, N., Pemberton, D., Pryor, H. & Halley, V. (2001) Tasmania’s Offshore Islands: seabirds and other natural features. Tasmanian Museum and Art Gallery, Hobart. Brown, S. (1988) A preliminary report of archaeological investigations on Prime Seal Island, Furneaux Island Group. Report, Department of Lands, Parks & Wildlife, Tasmania. Cumpston, J. S. (1973) First visitors to Bass Strait. Roebuck Society Publications: Canberra.

Photo by Stephen Harris.

Ling J. K. (2002) Impact of colonial sealing on seal stocks around Australia, New Zealand and subantarctic islands between 150 and 170 degrees east. Australian Mammalogy 24 117-126. Scott, T. (1828) Furneaux’s isles. A short geographical memoir thereof. Mitchell Library, A606. Thomas, O. (1888) Catalogue of the Marsupialia and Monotremata in the collection of the British Museum. Taylor and Francis, London.

Hope, J. H. (1972) Mammals of the Bass Strait islands. Proceedings of the Royal Society of Victoria 85 163-95. Kirkwood R., Gales R., Terauds A., Arnould J. P. Y., Pemberton D., Shaughnessy P. D., Mitchell A. T. & Gibbens J. (2005) Pup production and population trends of the Australian fur seal Arctocephalus pusillus doriferus. Marine Mammal Science 21 260-282. Jennings, J.N. (1971) Sea level changes and land links. In Mulvaney D. J. & Golson J. (eds): Aboriginal Man and Environment in Australia ANU Press, Canberra, Australia. Ling J. K. (1999) Exploitation of fur seals and sea lions from Australian, New Zealand and adjacent subantarctic islands during the eighteenth, nineteenth and twentieth centuries. Australian Zoologist 31 323-350.

65

Warneke, R. M. (2002) Seals at Seal Rocks, Western Port, and in Bass Strait, before and after the Baudin expedition’s visit in 1802. In Macwhirter, N., Macwhirter, P., Sagliocco, J. L. and Southwood, J. (eds) ‘Le Naturaliste in Western Port 1802-2002.’ Pp 77-98. Department of Infrastructure, Melbourne. Whinray, J.S. (1971) A note on Prime Seal Island. The Tasmanian Naturalist 27: 1-4.


T HE REPTILES

66


Eastern three-lined skink. Photo by Dylan van Winkel.

By Dylan van Winkel The composition and ecology of the reptile fauna on islands in the Bass Strait, Tasmania, is poorly known. This is especially true for outer lying islands and islands that are privately owned and managed. This paper describes eight species of reptile observed on Prime Seal Island, during an ecological survey in September 2008. Detailed observational accounts of each species, and notes on their habitat use and distribution across the island are provided. The results of the survey indicate that Prime Seal Island supports one of the greatest diversities of reptile species of all the outer Furneaux Islands, and species richness that is comparable to some of the larger Bass Strait Islands. This paper is a contribution to the knowledge of the reptiles found on islands in the Furneaux Group and may aid the understanding of distribution patterns and the origins of the reptile fauna in the Bass Strait region.

(Niveoscincus metallicus; Brothers et al. 2001), eastern three-lined skink (Bassiana duperreyi; Green & Rainbird 1993; Brothers et al. 2001), and the lowland tiger snake (Notechis ater; Brothers et al. 2003). The distribution patterns of reptiles in the Bass Strait area are closely related to climatic and sea level changes during the Late Wisconsin glacial phase (Rawlinson 1974). Many of the reptiles that inhabit the islands in the Furneaux Group area are represented by glacial relicts which displayed widespread distributions across southeastern Australia and Tasmania, and were subsequently isolated c. 12 750 years B.P. by the rising waters of the Bass Strait (Rawlinson 1974). Therefore, identifying which species are present on each island can help provide evidence for the distribution patterns and origins of the reptile fauna in the Furneaux Group and Bass Strait area.

METHODS INTRODUCTION The islandâ&#x20AC;&#x2122;s vegetation has been surveyed extensively by Harris et al. (2001) however, its fauna has received somewhat less attention with Brothers et al. (2001) providing a generalised species list. A systematic inventory of the islandâ&#x20AC;&#x2122;s fauna has never been conducted and only three reptile species have been recorded, including the metallic skink

The survey involved opportunistic observations and hand-searching during daily excursions around the island. Teams of one or more people traversed the island between 0800 and 1800 hours, over 5 days (14 â&#x20AC;&#x201C; 19 September 2008) and recorded any sightings of reptiles. Hand-searching involved actively searching through a variety of habitats including, inter-tidal beach zones, coastal sand dunes, grasslands, heathland, and granite outcrops.

67

Nomenclature for scientific and common names of reptiles follows Hutchinson et al. (2001).

RESULTS Eight species of reptile, comprising three families, were recorded during the survey. Each species is discussed seriatim below, and the appropriate information on observations, ecology, and potential range distributions across Prime Sea Island is presented. References attaining to species previously recorded from Prime Seal Island have been listed for completeness. No amphibians were recorded during the survey, despite listening for calls and searching damp areas.

AGAMIDAE Tympanocr yptis diemensis (Mountain dragon) Observations: A number of specimens were observed sunbasking within openly vegetated areas, by members of the survey team. A higher proportion of males were sighted compared to females and males appeared less threatened by our close approach. Males generally remained still upon our close proximity yet females fled quickly into thick vegetation. This species relies heavily on their cryptic camouflage but will sprint short distances when disturbed (Hutchinson et al. 2001).


Habitat and distribution: T. diemensis occurred extensively throughout the coastal grass and herbfield communities on the western side of the island (Harris & Kitchener 2005). This vegetation is dominated by Austrostipa stipoides, Myoporum insulare, and patches of Leucophyta brownii (S. Harris pers. comm. 2008). T. diemensis appeared to favour openly vegetated areas however, most animals were observed in close proximity to more dense vegetation allowing them to take refuge quickly if disturbed. Restriction to these habitats provides ideal conditions for T. diemensis which are avid thermoregulators who rely heavily on heat from the environment to maintain their high body temperatures (~ 32 °C) and incubate their eggs (Rawlinson 1974; Hutchinson et al. 2001). This species is known to occur on eastern Bass Strait Islands (Rounsevell et al. 1996) however, this survey provides the first records for T. diemensis on Prime Seal Island. Literature records: Nil

SCINCIDAE Bassiana duperreyi (Eastern three-lined skink) Observations: Bassiana duperreyi were commonly observed on the island by lifting debris and searching through low vegetation. Two deceased individuals (male and female) were collected from under a large granite rock near the summit of the island. The male was clearly identifiable by his bright red/ orange throat; a feature associated with the breeding season (Hutchinson et al. 2001). Habitat and distribution: This species was observed in a variety of different habitats on the island, including exotic grassland and improved pasture, coastal heathland, Leptospermum laevigatum scrub (Bursaria spinosa, Leucopogon parviflorus, and Correa alba) (Harris et al. 2001), granite outcrops, and coastal sand dunes. A number of specimens were observed under old farm equipment and debris scattered around the accommodation hut and woolshed situated on the eastern side of the island. Bassiana duperreyi

68

typically occur in habitats which contain low tussocky or heath-like vegetation where tussocks and low herbs are used for basking sites (Rawlinson 1974; Hutchinson et al. 2001). Our observations complement these descriptions and suggest that A. duperreyi occurs widely across Prime Seal Island in openly vegetated and warm areas. Literature records: This species has previously been recorded from Prime Seal Island. Green & Rainbird (1993) list an adult Pseudemoia trilineata collected on Prime Seal Island in 1984 and Brothers et al. (2001) recorded the three-lined skink as one of three reptile species present on the island.

Egernia whitii (Whiteâ&#x20AC;&#x2122;s skink) Observations: Egernia whitii were observed on several occasions while lifting large granite rocks. Specimens were found beneath rocks in Allocasaurina verticillata forest, Juncus krausii rushland, Myoporum insulare closed scrub, and Leptospermum laevigatum scrub (Bursaria spinosa, Leucopogon parviflorus, and Correa


Mountain dragon.

Juvenile Whiteâ&#x20AC;&#x2122;s skink.

Photo by Dylan van Winkel.

alba) (Harris et al. 2001). The lizards were occasionally found in pairs or small groups, often consisting of both large and small-sized animals. A number of large adults were examined, all of which possessed the typical pattern of a reddish brown vertebral stripe bordered by broad blackish stripes, each enclosing a series of pale dots and dashes (ocelli) (Hutchinson 2001; Mackay 1955). A single juvenile was captured and displayed highly speckled markings and a weak vertebral stripe. Habitat and distribution: Egernia whitii were locally abundant across Prime Seal Island in habitats that supported medium to large-sized granite rocks. This species is known to construct tunnels beneath granite rocks where they live in small family groups. These tunnel systems were observed on a number of occasions whereby the resident skink(s) would

Photo by Dylan van Winkel.

use the tunnels as escape routes to evade capture. Although E. whitii has been recorded from Flinders Island (Rawlinson 1967), and several smaller islands in the Bass Strait (MacKay 1955; Rawlinson 1974, Hutchinson et al. 2001), this paper is the first to document them from Prime Seal Island. Literature records: Nil

Niveoscincus metallicus (Metallic skink) Observations: Niveoscincus metallicus was the most frequently observed lizard species and was observed in almost all habitat types on Prime Seal Island. The area surrounding the bunkhouse and woolshed on the eastern side of the island appeared to support a healthy population of N. metallicus. Individuals were found refuging beneath old farm machinery and debris, as well as basking on rocks close to dense vegetation.

69

On several occasions, small brown skinks were seen disappearing into piles of seaweed at the high-tide mark and were assumed to be N. metallicus (based on their size and body shape). One individual was observed during the afternoon on a large exposed boulder, immediately adjacent to the ocean, with a large moth (Lepidoptera) in its mouth. Habitat and distribution: Niveoscincus metallicus was present in a wide variety of vegetation types on Prime Seal Island, including exotic grassland and improved pasture, coastal heathland, Leptospermum laevigatum scrub (Bursaria spinosa, Leucopogon parviflorus, and Correa alba) (Harris et al. 2001), granite outcrops, coastal boulders, and in beach debris at the high-tide mark. They frequently occurred under fallen logs, debris, and under granite rock slabs. This species is the most common and widespread lizard


Metallic skink.

Blotched blue-tongue.

Photo by Dylan van Winkel.

species in Tasmania and is found on all but a few offshore islands (Hutchinson et al. 2001). Literature records: Green & Rainbird (1993) and Brothers et al. (2001) have recorded this species from Prime Seal Island.

Tiliqua nigrolutea (Blotched blue-tongue) Observations: A single individual was captured and examined on the final day of the survey. It was a large, aggressive female that initiated a threat display upon capture. Four large ticks (Acarina) were removed from within the ear cavities and beneath the body scales. The ticks were collected for identification. Habitat and distribution: The individual was found basking on the edge of dense undergrowth (Leptospermum laevigatum scrub Leucopogon parviflorus, Bursaria spinosa and Correa alba) (Harris et al. 2001) and exotic grassland, within 100 m from the hut and during the late afternoon. Tiliqua nigrolutea are most active in clearings bordered

Photo by Dylan van Winkel.

or surrounded by dense heath or arboreal vegetation (Hutchinson et al. 2001). This habitat type is well represented on Prime Seal Island and may provide ideal habitat to harbour a healthy population of T. nigrolutea. Although only one specimen was observed during this survey, the current lease holder of the island has observed T. nigrolutea on several occasions (G. Jennings, pers. comm. 2008). Therefore, it is likely that this species is common and widely distributed across the entire island. This species is known to occur on some of the larger Bass Strait islands (Hutchinson et al. 2001; Rawlinson 1974) however, this survey provides the first records for T. nigrolutea on Prime Seal Island. Literature records: Nil

ELAPIDAE Austrelaps superbus (Lowland copperhead) Observations: No live specimens were observed during this survey. However, a complete sloughed

70

skin, from an adult A. superbus, was found wedged between coastal rocks at the most southern end of Peacock Bay. The species was identified by examining the shape and arrangement of scales on the head region of the skin. The frontal scale of A. superbus being much longer than broad compared with that of Notechis ater (Hutchinson et al. 2001). The current island lease holder has reportedly encountered A. superbus on a number of occasions (G. Jennings, pers. comm. 2008). Habitat and distribution: Austrelaps superbus is usually found in close association with permanent bodies of water, such as marshes, lagoons, and low lying swamps, where prey are abundant (Fearn 1994; Hutchinson et al. 2001). Austrelaps superbus prey largely on diurnal surface active taxa, such as frogs and lizards (e.g. N. metallicus) (Shine 1987). However, on Prime Seal Island areas of free standing water are absent and no frogs have been recorded. The characteristics of this population appear similar


to an â&#x20AC;&#x153;unusualâ&#x20AC;? population of A. superbus that occurs on the plateaulike summit of The Nut at Stanley (north-west Tasmania) (Fearn 1994). The Nut lacks permanent water and frogs, and as a result A. superbus populations have become concentrated around short-tailed shearwater (muttonbird; Puffinus tenuirostris) rookeries. Austrelaps superbus has been recorded using the nesting burrows of P. tenuirostris on other Bass Strait Islands (Green 1969; Fearn 1994). It is likely that A. superbus on Prime Seal Island may restrict their distribution to coastal areas where they have access to small skinks (N. metallicus), and to rookeries where muttonbird chicks and shelter, provided by P. tenuirostris burrows, are available. Austrelaps superbus has been recorded on the larger Bass Strait islands, including Flinders, Great Dog, Little Green, and Preservation islands (Green & Rainbird 1993). However, this survey provides the first records for A. superbus on Prime Seal Island. Literature records: Nil

Dr ysdalia coronoides (White-lipped snake) Observations: A single specimen was observed basking in the afternoon on sand in an open patch of dense scrub at the north-western side of the island. The snake was in close proximity (~ 300 mm) to a male T. diemensis basking in the sun. Once disturbed by our approach, the snake retreated rapidly into the undergrowth. The individual was approximately 250 mm in length, grey in colour, with a prominent white stripe running along the upper lip, from the nostril to the side of the neck (C. Hawkins pers. comm. 2008). Habitat and distribution: The single individual was observed just above the coast, approximately 50 metres from the ocean. The surrounding vegetation included Austrostipa stipoides, shrubbery, and coastal heath. This species is locally abundant in Tasmania and on most Bass Strait islands (Wilson & Swan 2003; Hutchinson et al. 2001); particularly where ground cover is dominated by tussock grasses and heath-like vegetation (Rawlinson

71

1974; Wilson & Swan 2003). Their diet consists almost entirely of small skinks (Wilson & Swan 2003). The vegetation composition, in combination with a high abundance and widespread distribution of prey (i.e. small skinks, including N. metallicus and A. duperreyi) on the island, suggests that D. coronoides may be widely distributed across Prime Seal Island. Drysdalia coronoides is found on many of the Bass Strait islands, including Flinders, Babel, Chalky, and Preservation islands (Green & Rainbird 1993). This survey provides the first record of D. coronoides from Prime Seal Island. Literature records: Nil

Notechis ater (Tiger snake) Observations: Large tiger snakes were sighted on at least five occasions during the survey. Three sightings were reported from the immediate vicinity of the bunkhouse and woolshed. These individuals were all observed in the late afternoon, crossing walking tracks and grazed pasture. Two other


tiger snakes were sighted near the northern and western sides of the island. The western specimen was described as highly coloured, showing intense red colouration under the belly and laterally (M. Visoiu, pers. comm. 2008). This animal was sighted in coastal tussock grassland (Austrostipa stipoides). The northern N. ater sighting was of the side of a large individual which rapidly retreated into low vegetation upon our approach. This specimen appeared superficially black and lacked the bright belly and lateral colouration, as described in the previous observation. Habitat and distribution: On Prime Seal Island, the occurrence of N. ater in areas of human alteration (i.e. surrounding the accommodation hut, wool shed, and open pastures) was particularly apparent. Fearn (1993) noted that N. ater in Tasmania are very common in some semi-rural habitats where there is a mixture of remnant scrub/ re-growth mixed with open pasture or cleared land. It is likely that tiger snakes are attracted to these habitats by the abundance of prey, such as mice and rats, which tend to co-inhabit human occupied areas. Rodents, especially mice, were abundant around the hut and wool shed on the island, which may explain the higher number of N. ater sightings in this area, although may also be a result of greater observer activity in this area. Hutchinson et al. (2001), note that tiger snakes on some Bass Strait islands depend on short-tailed

shearwater (muttonbird; Puffinus tenuirostris) chicks for nourishment. This may be true for some tiger snakes on Prime Seal Island, as the island supports a large colony of short-tailed shearwaters (Brothers et al. 2001). In general, N. ater appeared to be common and widely distributed across Prime Seal Island. This is supported by the island lease holder who regularly encounters tiger snakes in all habitat types on the island (G. Jennings, pers. comm. 2008). On mainland Tasmania, N. ater are known to inhabit a variety of habitat types, from coastal heath at sea level to highland forests above 1000 m (Fearn 1993; Hutchinson et al. 2001). Literature records: Notchis ater have been recorded from Prime Seal Island in the past, by Brothers et al. (2001).

GENERAL DISCUSSION Eight species of reptile were recorded from Prime Seal Island as a result of this survey. We were able to confirm the presence of three previously recorded species (N. metallicus, A. duperreyi, and N. ater) (Green & Rainbird 1993; Brothers et al. 2001) and add a further five previously unrecorded species (T. diemensis, E. whitii, T. nigrolutea, A. superbus, and D. coronoides) to the islandâ&#x20AC;&#x2122;s reptile fauna inventory.

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These results indicate that Prime Seal Island supports a considerable diversity of reptile species, when compared with other surrounding islands. The Furneaux Island Group is made up of three principal islands and a large number of outer islands (Harris et al. 2001). Twelve species of reptiles are known to occur throughout the Furneaux Group (Rawlinson 1974; Hutchinson et al. 2001), and two-thirds of these are shared with Prime Seal Island (8 spp.). The high diversity of reptiles on Prime Seal can be illustrated by comparing the diversity of a similar sized island, Badger Island (1 243 ha) which reportedly supports only five species of reptiles (Green & Rainbird 1993; Hutchinson et al. 2001). In addition, only the largest island in the eastern Bass Strait, Flinders Island (133 300 ha), supports more reptile species (10 â&#x20AC;&#x201C; 12 spp.) than Prime Seal Island (Rawlinson 1967; 1974; Green & Rainbird 1993; Hutchinson et al. 2001). Therefore, Prime Seal Island appears to support the greatest diversity of reptile species of any of the outer Furneaux Group Islands. However, it is possible that the apparent low species diversity on other outer islands may be an artefact of low sampling effort. It is likely that further reptile species, other than those recorded during this survey, may be present on Prime Seal Island. These are listed and briefly discussed below.


Niveoscincus ocellatus (Ocellated skink) Ocellated skinks are moderately sized, beautifully patterned, and are endemic to Tasmania. They are found from sea-level to sub-alpine elevations throughout most of Tasmania and on surrounding islands, including those in the Furneaux Group (Hutchinson et al. 2001). This species exhibits very close associations with rocky habitats, where they use the rocky substrate for sun-basking and shelter sites. On Prime Seal Island, extensive granite outcrops and boulder fields exist across the island and would appear to provide ideal habitat for N. ocellatus. However, no observations of this species were recorded during the current survey. It is possible that this species was simply overlooked due to a lower search effort in rocky habitats.

Lerista bougainvillii (Bougainville’s skink) Bougainville’s skink is a very secretive, burrowing species that is active just below the surface of ground substrates, such as leaf litter, rocks, or granite flakes (Hutchinson et. al. 2001). Lerista bougainvillii is a thigmotherm and is consequently limited to the warm, open habitats of south-eastern Australia, the eastern Bass Strait Islands, and barely colonising the Tasmanian mainland on its two north-eastern most promontories (Cape Portland and Waterhouse Point) (Rounsevell et al. 1996; Hutchinson et al. 2001;

Wilson & Swan 2003). This species is found on several islands in the Furneaux Group, including Babel Island, Mt Chappell Island, Little Anderson Island, and Vansittart Island (Green & Rainbird 1993; Hutchinson et al. 2001). Considering the highly secretive fossorial nature of L. bougainvilii, and the lack of more specialised search techniques (e.g. raking through leaf litter) being employed, it is not surprising that this species was not detected during the survey. Prime Seal Island lies in the centre of L. bougainvillii’s geographic distribution and this species has been found on islands in close proximity to Prime Seal Island (i.e. Mt. Chappell and Big Green Islands). Therefore, it is plausible that L. bougainvillii inhabits the island.

Pseudemoia entrecasteauxii (Southern grass skink) A common but wary species, Pseudemoia entrecasteauxii is found throughout mainland Tasmania and on offshore islands, including Maria Island, King Island, and several islands of the Furneaux Group (Rounsevell et al. 1996; Hutchinson et al. 2001). This species is found in a variety of habitats, but is usually associated with open woody vegetation wherever an understorey of grassy or sedgy plants occurs (Hutchinson & Donnellan 1992). The Bass Strait island populations are usually strongly striped and the midlateral stripe of the male becomes bright red or orange during the breeding season, making them highly

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distinguishable from other species. The wide geographic distribution of P. entrecasteauxii across southeastern Australia, the islands of the Bass Strait, and mainland Tasmania suggest that this species is likely to be present on Prime Seal Island. More intensive, target-specific surveys are required to determine their presence/ absence on the island.

HABITAT FOOD RESOURCES AND PREDATORS A large variety of habitat types exist on Prime Seal Island. This is a direct result of the island’s size, topography, and high alkaline soils, which make it one of the more fertile islands in the Furneaux Group (Harris et al. 2001). Therefore, Prime Seal Island is capable of supporting a variety of vegetation types and consequently, a high faunal diversity in comparison with other outer Furneaux Islands. The high abundance of invertebrates, lizards, and small mammals (pers. obs.) is likely to provide sufficient food resources to support the diversity of reptile species present. For example, the presence of D. coronoides, which feeds exclusively on skinks, suggests that Prime Seal Island probably supports a relatively high abundance of lizard prey. Similarly, the high abundance of house mice (Mus musculus), determined via intensive small mammal trapping during the survey period, appears adequate to support larger species of snakes, such as N.


ater and A. superbus (MacKay 1955). Interestingly, the presence of both N. ater and A. superbus on Prime Seal Island, provides further justification for Prime Seal Island to harbour high reptile diversity, as these two species are not found together except on the largest islands where there is a greater diversity of habitats and abundance of prey (MacKay 1955; Green & Rainbird 1993). The presence of short-tailed shearwater colonies on Prime Seal Island may also provide additional food resources and habitat for N. ater and A. superbus (Hutchinson et al. 2001; Green 1969; Fearn 1994). The presence two feral animal species – cats (Felis catus) and house mice (M. musculus) – could potentially have an effect on the island’s reptile fauna. Feral pests are perhaps the most invasive threatening agent impacting the conservation of native fauna on offshore islands (RPDC 2003; Brothers et al. 2001). Feral cats are known predators of reptiles, especially small skinks (Dickman 1996). Bryant and Shaw (2006) suggested that Cyclodomorphus casaurinae on Tasman Island were being targeted by feral cats as prey, after a number of fresh lizard remains were found. They suggested that cats are the likely cause of decline in the lizard population, since observations had reduced significantly over time (Brothers et al. 2001, Bryant and Shaw 2006). Although both cats and mice exist on Prime Seal Island at relatively high

abundance, no lizard remains were recorded as a result of direct cat or mouse predation. Nor were there any lizard remains found within cat scats, collected and analysed from the island (N. Mooney, pers. comm. 2009). Although only a small number of scats were examined, it is possible that feral cats prey almost entirely on house mice on Prime Seal Island.

ACKNOWLEDGEMENTS I would like to thank the Prime Seal Island survey team, including Stephen Harris, Clare Hawkins, Michael Driessen, Nick Mooney, Micah Visoiu, Emma Betts, Oliver Strutt, Abbey Throssell, Kevin Bonham, Rolan Eberhard, Sarah Munks and Bridgette Moffat for their field assistance and contributions to the reptile inventory. Thanks to the Saunders family and trustees of the Hamish Saunders Memorial Trust for funding this ecological survey, and to Michael Driessen for his comments on the manuscript. Thanks to Phil Bell for assistance in Hobart.

REFERENCES Brothers, N, Pemberton, D, Pryor, H, and Halley, V (2001) Tasmania’s Offshore Islands: seabirds and other natural features. Tasmanian Museum and Art Gallery: Hobart. Bryant, S. And Shaw, J. (2006) (Editors): Tasman Island: 2005 flora and fauna survey. Hamish Saunders Memorial Trust, New Zealand and

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Biodiversity Conservation Branch, DPIW, Hobart, Nature Conservation Report Series 06/01. Dickman, C. (ed). (1996) Overview of the Impacts of Feral Cats on Australian Native Fauna. Australian Nature Conservation Agency, Canberra. Fearn, S. (1993) The tiger snake Notechis scutatus (Serpentes: Elapidae) in Tasmania. Herpetofauna, 23, (2), 17-29. Fearn, S. (1994) Some observations on the ecology of the copperhead Austrelaps superbus (Serpentes: Elapidae) in Tasmania. Herpetofauna, 24, (2): 1-10. Green, R. H. (1969) The birds of Flinders Island. Records of the Queen Victoria Museum No. 34. Launceston, Tasmania. Green, R. H. and Rainbird, J. L. (1993) Reptiles from the islands of Tasmania. Technical report 1993/1. Queen Victoria Museum and Art Gallery. Launceston. Harris, S., Buchanan, A., and Connolly, A. (2001) One Hundred Islands: The Flora of the Outer Furneaux. Tasmanian Department of Primary Industries, Water, and Environment: Tasmania. Hutchinson, M. N. and Donnellan, S. C. (1992) Taxonomy and genetic variation in the Australian lizards of the genus Pseudemoia (Scincidae: Lygosominae). Journal of Natural History, 26, 215-264. Hutchinson, M., Swain, R., and


Removing ticks from a blotched blue-tongue. Photo by Dylan van Winkel.

Driessen, M. (2001) Snakes and lizards of Tasmania. Nature Conservation Branch, Department of Primary Industries, Water, and Environment, Hobart, Tasmania. MacKay, R. D. (1955) Notes on the collection of reptiles and amphibians from the Furneaux Islands, Bass Strait. Australian Zoologist, 12: 160-164. Rawlinson, P. A. (1967) The vertebrate fauna of the Bass Strait Islands: 2. The reptilia of Flinders and King Islands. Proceedings of the Royal Society of Victoria, 80: 211-224.

Rawlinson, P. A. (1974) Biogeography and ecology of the reptiles of Tasmania and the Bass Strait area. In Biogeography and Ecology in Tasmania. Monographiae Biologicae No 25. Ed. By W. D. Williams, pp 291-338. Dr W. Junk, The Hague. Resource Planning and Development Commission 2003, State of the Environment Tasmania 2003, last modified <20 April 2009>, http// www.rpdc.tas.gov.au/soer, accessed <20 April 2009> Rounsevell, D., Brereton, R., and Hutchinson (1996) The reptiles of

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northeast Tasmania, with records and a key to species of grass skinks, Genus Pseudemoia. Records of the Queen Victoria Museum and Art Gallery, No. 103. Launceston, Tasmania. Shine, R. (1987) Ecological ramifications of prey size: Food habits and reproductive biology of Australian copperhead snakes (Austrelaps, Elapidae). Journal of Herpetology, 21, (1): 21-28. Wilson, S. and Swan, G. (2003) A complete guide to reptiles of Australia. Reed New Holland, NSW, Australia.


T HE DISTRIBUTION

and MANAGEMENT of ENVIRONMENTAL WEEDS

76


By Oliver Strutt Environmental weeds, as on many islands are a potential threat to the important conservation values of Prime Seal Island. This study is based on the extensive surveillance of the island, mapping the eight most significant weeds. The extent and distribution of infestations were established and populations of new weeds were recorded. Determining the potential impact on natural values, the potential rate of spread and the feasibility of eradication, through the surveillance process, allowed for management actions to be prioritised.

INTRODUCTION Prime Seal Island, located to the west of Flinders Island, is the most significant island of the outer Furneaux for flora conservation as it has eight species listed under the Threatened Species Protection Act 1995 and is the Tasmanian stronghold for several of them (Harris et al. 2001a). Apart from the threatened species, the island also has flora of biogeographic significance, high conservation value vegetation types, sites of geoconservation and heritage significance, and a socially and economically important grazing enterprise. The principal issue for vegetation management on Prime Seal is the control of weeds (Harris et al. 2001a). A weed is a plant that has, or has

the potential to have, a detrimental impact on economic, social or conservation values (WeedPlan 2005). Environmental weeds are plant species that have established self-propagating populations in native vegetation outside of their natural range (Csurhes and Edwards 1998). Impacts of environmental weeds include competition for resources, prevention of recruitment, and alteration of geomorphological processes, hydrological cycles, nutrient content of soil, fire regimes and abundance of indigenous and non-indigenous fauna. Environmental weeds have been implicated in the extinction of indigenous plant species and they can threaten the functional complexity and stability of ecosystems (Williams and West 2001). Weeds are of particular significance on Prime Seal Island due to a number of factors. Some weeds present are capable of invading the habitat of conservation significant flora, potentially outcompeting native species and dominating communities. The productive capacity of the grazing land can be impacted, reducing the resources available to the landholders for managing the island. Beach weeds in particular can cause major impacts, such as the alteration of coastal landforms and the degradation of sea bird habitat and aboriginal heritage. Due to a large percentage of Tasmaniaâ&#x20AC;&#x2122;s beaches having been modified, maintenance of the integrity of the remaining natural coastlines is critical (Rudman 2003). Due to ocean

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currents carrying propagules from the North, the Bass Strait islands are Tasmaniaâ&#x20AC;&#x2122;s early warning frontiers for observing the invasion of exotic plant species dispersed by currents (Harris et al. 2001a; Rudman 2003). Additionally, climate change may allow weed species to move south, with the Bass Strait islands providing an intermediate climate between Tasmania and the Australian mainland. It is widely recognised that detection and intervention at the early stages of infestation maximises chances of eradication, minimises ecological damage and is the most costeffective management of weeds (Csurhes and Edwards 1998; Harris et al. 2001b; Moncrieff 2006; Timmins and Braithwaite 2001; WeedPlan 2005). Surveillance facilitates early detection, and for weed control efforts to be successful, boundaries of the population must be thoroughly assessed to ensure the area is not continually reinfested from adjacent areas. This study aims to provide an example for the thorough weed survey of an island from which management can be informed and control measures prioritised. It also aims to contribute to the objectives of the Prime Seal Island Draft Management Plan, assisting the landholder with vegetation management (Poole et al. 2002), and the Tasmanian Weed Management Strategy (WeedPlan 2005) and the Tasmanian Beach Weed Strategy (Rudman 2003) which call for collaborative monitoring and reporting.


METHODS This study was based on an onground survey of Prime Seal Island from the 14th to the 19th of October 2008. The island was traversed extensively on foot and weed locations were recorded using a hand-held GPS. Approximately 75 kilometres were walked, including the entire coastline and as much of the interior of the island as possible. A map was produced using the MapInfo GIS package, and management recommendations were prioritised by perceived threat to natural values, the rate of spread and the ease or likelihood of control/ eradication. Of the 60 exotic species that have previously been recorded on Prime Seal Island (DPIPWE 2008) only those species that were not highly transient populations and were considered likely to threaten natural values were mapped.

RESULTS The distribution of the nine mapped weeds is shown in the map (Figure 1). African boxthorn was scattered across the island with dense infestations in parts. It was most abundant along the east coast of the island from the house to Spit Point, where it was almost continual along the frontline vegetation and extended upslope scattered amongst the Myoporum insulare scrub. Common iceplant was found in a large infestation of several hectares extending from the granite tor to

the coast at the southern end of the island. The majority of this area consisted solely of iceplant, including a large patch of dead iceplant, but it also extended into the Myoporum insulare scrub and the Austrostipa stipoides tussock grassland. Small individual iceplants were also found scattered along the west coast. Sea spurge was widespread, scattered in patches along the entire coastline, so was not mapped on the coast and is indicated as a broken line around the perimeter of the island on the map. Inland occurrences of Sea spurge were mapped, including a patch growing at the top of a sand blow approximately 120 metres above sea level at the southern end of the island, and another patch near the centre of the island blown inland in a low area between hummocks. Horehound was widespread on the island, but was restricted to disturbed areas such as alongside the tracks, in sand blows and recently cleared areas of pasture. Only one patch of Marram grass was found on the island, covering only approximately two square metres. This was located at an east-facing sandy cove at the southern end of the island. Yellow horned-poppy was also only recorded at one location, on the west coast, just above the high tide line amongst the Austrostipa stipoides tussocks. There were several mature plants with remains of flowering stems and a scattered patch of

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immature plants covering a patch of approximately 50 square metres. Arum lily was restricted to the vicinity of the house and shearing shed. Butterfly bush (also known as swan plant or cotton bush) was found along a 100 metre stretch of track at the northern end of the island. There were approximately 200 mature plants.

GENERAL DISCUSSION The most significant threat to the natural values of Prime Seal Island is the potential invasion of threatened species habitat and high conservation value plant communities by weeds that are capable of dominating those communities or dramatically altering ecosystem, geomorphological or hydrological processes. The comparative potential impact and prioritisation for management actions for the different species is summarised in table 1 and discussed below. African boxthorn was planted on the island as a windbreak by early agriculturalists (Poole et al.2002). It is capable of prodigious expansion, being spread by birds such as ravens and starlings, and it can form dense thickets, shading out other species and can be fatal to cape barren geese (Poole et al. 2002 DPIW 2002a). Since acquiring the lease in 1986, the current landholders have


undertaken extensive control of boxthorn, with evidence of manual removal across much of the island. Although boxthorn has a high potential impact on natural values, the feasibility of total eradication is low due to the extent of the infestation, so unless extensive resources are made available, boxthorn management should focus on eradicating outlying individuals (especially those in the vicinity of high conservation values) and restricting spread. Eradication of all boxthorn apart from the coastal strip from the house to Spit Point should be feasible in the short term. Control methods to be used may be found in the Department of Primary Industries and Water Boxthorn Control Guide (DPIW 2002a). Due to the occurrence of boxthorn on surrounding islands and the likely inter-island dispersal by starlings, continual reinfestation is probable, so continual monitoring will be required.

Common iceplant is a peculiar weed with several characteristics that make it particularly important to control. It is a salt-accumulator and after the plants die salt leaches into the surrounding soil creating an inhospitable environment for many other species. It thus comes to dominate areas, and on Prime Seal Island it occurs as a monoculture in an area of several hectares. Iceplant may also invade pasture and cropping land and can be fatal if eaten by stock (Borger and Stewert 2007). Iceplant is a significant weed of the Wheat Belt in Western Australia, but at present in Tasmania there are only records from Prime Seal and Babel Islands (DPIPWE 2008). Iceplant employs the Crassulacean Acid Metabolism (CAM) photosynthetic pathway, and it has been suggested that such plants will have a competitive advantage following climate change (Watson 2007). On Prime Seal

Island iceplant appears to be spreading, occurring as scattered individuals just above the high tide line in sandy areas along the west coast, and the main population appears to be expanding. The main population appears to be located in an area that was mapped by Harris et al. (2001a) as dense African boxthorn infestation (which was subsequently eradicated), suggesting that iceplant has thrived in the disturbed conditions following boxthorn removal. It also appears to be expanding predominantly into areas with a high cover of bare sand, for example areas of Austrostipa stipoides tussock grassland that have been recently burnt and steep areas below the granite tor where erosion is present. Due to the potential impacts of iceplant, its current restriction to just a two islands in Tasmania and its potential to invade further south following climate change, eradication of iceplant

Table 1: Prioritisation of weed management actions for environmental weeds on Prime Seal Island Common name

Scientific name

Potential impact Potential rate on natural of spread values

Feasibility of eradication

Priority for action

African boxthorn

Lycium ferocissimum

High

Moderate/ High

Moderate/ Low

High

Common iceplant Mesembryanthemum crystalinum

Moderate

High

Moderate

Moderate/ High

Sea spurge

Euphorbia paralias

High

High

Low

Low

Horehound

Marrubium vulgare

Low

Moderate

Moderate

Low

Marram grass

Ammophila arenaria

High

High

High

High

Yellow hornedpoppy

Glaucium flavum

Moderate

Moderate

High

High

Arum lily

Zantedeschia aethiopica

Low

Low

High

Low

Butterfly bush

Gomphocarpus fruticosis

Moderate

Moderate/ High

Moderate/High

High

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should be prioritised. The scattered individuals should be addressed first and may be removed by manual pulling. The West Australian Governmentâ&#x20AC;&#x2122;s Department of Agriculture and Food provides more information for control techniques (Borger and Stewert 2007). Sea spurge is one of the most significant coastal weeds in Tasmania and in only three decades has expanded its range from its first occurrences to cover much of the beaches of the North and West coasts (Rudman 2003). Sea spurge seeds are dispersed by water and it rapidly colonises coastal areas especially bare sand but also invading areas of low vegetation. Dense infestations alter sand movement and it can reduce the available habitat for beach nesting birds (Rudman 2003). Although Harris et al. (2001a) commented that any occurrences of sea spurge should be treated, since then it has become thoroughly established and eradication is very unlikely, especially considering the continual reinfestation from the constant source of seaborne propagules. The Tasmanian Beach Weed Strategy identifies the areas of Tasmania which are priorities for sea spurge control and the Bass Strait Islands lie outside of that zone (Rudman 2003). Sea spurge should be controlled on Prime Seal Island where it particularly threatens significant conservation values and as such the inland occurrences should be eradicated due to their proximity to threatened plant populations.

Horehound is widespread on the island but appears to be restricted to the sides of tracks and other disturbed areas such as recently cleared pasture, so although a potentially significant agricultural weed is not likely to have severe impacts on natural values. Horehound has also been the subject of weed control works on the island with Poole et al. (2002) noting that through aerial spraying it had been reduced to minor localised infestation. Horehound control may be required for the area approximately one kilometre south of the house where it occurs on a slope leading up to the area of native scrub and is adjacent to populations of the threatened plants Zygophyllum billardierii and Lasiopetalum discolour. If monitoring indicates that the horehound is invading this area, control would be a high priority. Control methods are discussed in the DPIW control guide (DPIW 2002b). To minimise the impact of horehound, care should be taken to avoid soil disturbance and the clearance of native vegetation. Marram grass is another of the most devastating coastal weeds in Tasmania and following original deliberate plantings for stabilisation works, it is now widespread around Tasmania (Rudman 2003). Pieces of rhizome can be carried by the sea and establish new populations which spread rapidly by vegetative growth. It traps sands very effectively, dramatically changing beach and dune morphology, degrading the

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habitat of shore-nesting birds and out-competing native sand-binding plants (Rudman 2003). It is present on several of the Furneaux islands, but absent from others (DPIW 2008). Due to the small size of the infestation on Prime Seal Island it is likely to be a recent arrival. Manual removal is the highest priority for weed control due to the potential rate of spread of the weed and the ease of eradication whilst at such an early stage of infestation. Ongoing monitoring of the site to remove any resprouting plants will be necessary. Yellow horned-poppy is also likely to be a recent arrival to the island and its rate of spread and impact on natural values are unknown at this stage. It is an uncommon weed in Tasmania with only four other recorded occurrences, one on Flinders Island, one on Inner Sister Island and two at Freycinet Peninsula (DPIPWE 2008). Early eradication is a priority due to the current restricted size of the population, its limited distribution and its unknown impact and rate of spread. Hand pulling should be an effective control method. Arum lily would have been planted as an ornamental by early agriculturalists on the island. It does not appear to be threatening natural values as its current distribution is restricted to the vicinity of the house and shearing shed, and although it is a self-sustaining population the rate of spread appears to be very low. It does have the potential to invade native vegetation and is


also poisonous to stock (DEWHA 2008), so the population should be monitored and eradication may be considered necessary at some stage. Butterfly bush is another uncommon weed in Tasmania with only two other records on Flinders Island as its only occurrence in the state (DPIW 2008). It is potentially very invasive, although restricted to high light environments (West 1996). At present it only occurs in the cleared strip on either side of a track, however it is a tall growing shrub capable of shading out other vegetation and it appears to be spreading along the track fairly rapidly, so eradication whilst at an early stage of infestation should be prioritised. Hand pulling is effective (West 1996) and other control methods are provided by the West Australian Governmentâ&#x20AC;&#x2122;s Department of Agriculture and Food (DAF 2008). Another potentially significant environmental weed is buckbush, Salsola kalii, and is fortunately rare in Tasmania. It has been previously sighted on Prime Seal Island (Harris et al. 2001a), although it was not found in this survey. When undertaking weed control actions care should be taken to minimise soil disturbance, both to reduce the risk of erosion (which is high due to the sandy soil and strong winds of the island) and to reduce the bare ground available for the re-establishment of weeds. If dense infestations are to be removed soil

stabilisation may be required either through the planting of appropriate native species or the sowing of benign pasture species depending on the situation. If eradication is undertaken for the dense coastal patches of boxthorn, it may also be necessary to assist revegetation with native species that will provide the same habitat and windbreak functions, such as Myoporum insulare, Allocasuarina verticillata and Leptospermum laevigatum. It is also important that control works are not undertaken for the coastal strip of boxthorn approximately one kilometre south of the house during the breeding season of whitebellied sea eagle, as there is a nest in this area that would be disturbed. Control of beach weeds should also not be undertaken during the breeding season of beach-nesting birds. This study has ascertained the extent and distribution of the main environmental weeds of Prime Seal Island, allowing management actions to be planned and prioritised. It has allowed for the impact of the weeds to be assessed and has provided an example of the importance of regular surveillance. Previously unrecorded populations of marram grass, butterfly bush and yellow horned-poppy, were found which provides for allowing for early control options. Regular surveillance is required to monitor the known weed populations and to detect the occurrence of new ones. Mapping the weeds has allowed

81

for the comparison in the future of weed distributions, to determine the spread of populations or the success of control measures. It is hoped that the study has been of some value for informing the land managers with regard to vegetation management.

ACKNOWLEDGEMENTS Many thanks to Stephen Harris for advice in the preparation of this paper and to all the members of the 2008 Hamish Saunders Memorial Prime Seal Island Expedition for making the trip enjoyable and constructive.


Photo by Dylan van Winkel.

REFERENCES Borger, C. and Stewert, V. (2007) ‘Ice plants – clarification and control’ Newsletter of the Department of Agriculture and Food 8(2) 25-27 Csurhes, S. and Edwards, R. (1998) Potential Environmental Weeds in Australia. Environment Australia Biodiversity Group, Canberra Department of Agriculture and Food (DAF) (2008) Declared plant in Western Australia – Cotton bush (Gomphocarpus fruticosus) http:// Date viewed: 1/12/2008

Harris, S., Buchanan, A. and Connolly, A. (2001a) One Hundred Islands: The Flora of the Outer Furneaux. Tasmanian Department of Primary Industries and Water, Hobart Harris, S., Brown, J. and Timmins, S. (2001b) Weed surveillance – how often to search? Science for Conservation 175, Department of Conservation, Wellington, New Zealand

Timmins, S. and Braithwaite, H. (2001) ‘Early detection of environmental weeds on islands’ 311-318 in Veitch, C. and M. Clout (eds) Turning the tide: the eradication of invasive species. IUCN SSC Invasive Species Specialist Group, IUCN, Gland Switzerland Watson, P. (2007) ‘Warming to the iceplants’ The Tasmanian Naturalist 129:8-15.

Harris, S., Department of Primary Industries, Parks, Water and Environment, personal communication, 14/10/2008

WeedPlan (2005) Tasmania’s Weed Management Strategy (2nd Edition). Department of Primary Industries and Water, Tasmania

Department of Environment, Water, Heritage and the Arts (DEWHA) (2008) Weeds in Australia – Zantedeschia aethiopica http:// Date viewed: 1/12/2008

Moncrieff, A. (2006) Invasive Plant Early Detection and Rapid Response in British Columbia (Working Draft) Invasive Plant Council of British Columbia

Department of Primary Industries and Water (DPIW) (2002a) African Boxthorn (Lycium ferrocisimum) Control Guide http:// Date viewed: 1/12/2008

Poole, L., Harris, S., North, J., Stafford, P. and Bayley, S. (2002) Prime Seal Island Management Report. Parks and Wildlife Service, Tasmania

West, C. (1996) Assessment of the weed control program on Raoul Island, Kermandec Group. Science and Research Series 98, Department of Conservation, Invercargill, New Zealand

Department of Primary Industries, Parks, Water and Environment (DPIW) (2002b) Horehound (Marrubium vulgare) Control Guide http:// Date viewed: 1/12/2008 Department of Primary Industries and Water (DPIW) (2008) Natural values atlas http://www. naturalvaluesatlas.dpiw.tas.gov.au, Date viewed: 1/12/2008

Rudman, T. (2003) Tasmanian Beach Weed Strategy for marram grass, sea spurge, sea wheatgrass, pyp grass & beach daisy. Nature Conservation Report 03/2, Nature Conservation Branch, Department of Primary Industries, Water and Environment, Tasmania

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Williams, J. and West, C. (1995) ‘Environmental weeds in Australia and New Zealand: issues and approaches to management’ Austral Ecology 25(5) 425-444


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I NVERTEBRATE SURVEY

84


Map 1 Invertebrate sample sites (Red: pitfall, green: sweep/bash or malaise, blue: light, black: hand collection, purple: carcass. Note that sampling of another kind often occurred at sites designated as being of a particular kind, eg hand collection at pitfall sites.)

By Kevin Bonham

bereft of previous records.

remainder on 18 Oct).

Prime Seal Island, previously apparently unsampled for invertebrates, was sampled for a range of invertebrate groups by methods of pitfall trapping, beating of shrubs, malaise and light trapping, hand collecting, sweeping and carcass sampling. 7168 specimens of at least 32 orders were recorded. Significant finds include a new species of centipede, an undescribed and possibly new species of bristletail, and four known or suspected moth records for the state. Results presented here are preliminary and include identifications for selected groups only (land snails, millipedes, centipedes, crustaceans, collembola, bristletails, spiders, beetles).

The primary aim of invertebrate sampling was to collect as many species of invertebrate from the island as possible.

All traps were retrieved intact with at least some spirits remaining and at least partial lid cover except for traps 6C (lid completely missing and some contents spilled during decanting) and 8D (spirits completely evaporated); results from these traps are therefore likely to be significant undercounts. Sieving in the process of sorting and undercounting during sorting are likely to have led to the loss of most very small mites and some very small collembolans but is unlikely to have caused significant losses among other groups.

INTRODUCTION This report gives interim results for invertebrate surveying conducted on Prime Seal Island, primarily by Abbey Throssell and Kevin Bonham. Detailed results for Orthoptera, Lepidoptera and Aranaea are reported separately by Michael Driessen, Abbey Throssell and Lynne Forster respectively. Prior to this sample, we were unable to find evidence of any previous invertebrate sampling on Prime Seal Island (hereafter PSI). For some groups including land snails, PSI was the largest Tasmanian island (excluding Macquarie for groups absent from that island) that was

METHODS The following methods were employed to survey invertebrates on the island: 1. Pitfall trapping: Ten pitfall trap sites were established. Sites were selected subjectively to cover a substantial range of habitat types and substrates. To limit time taken to retrieve traps, sites were established relatively close to the homestead. At six sites (1, 2, 5, 6, 7, 9) the five traps were arranged in a line, each about 10 metres apart. At the remaining sites (3, 4, 8, 10) the five traps were arranged in a loose cluster with a similar distance of separation. We aimed to place traps in a wide range of microhabitats at each site, in order to increase the number of species likely to be recorded. Pitfall traps were about half-filled with 70% methylated spirits solution and a small amount of ethylene glycol was added to make complete evaporation of contents unlikely. Each trap was covered by a lid held on stakes about 2 cm above the trap (this height was chosen to reduce the risk of vertebrate captures while being unlikely to deter any but the largest ground invertebrates.) Each trap was retrieved after three nights (traps 1-4 on 17 Oct and the

85

2. Beating: Six sites were sampled by beating of shrubs using beating trays. As diverse as possible a range of shrubs or tree foliage at each of these sites was beaten above a tray with litter thus collected from each beat being retained for later sorting where invertebrates were present and discarded where none were visible. Beating was conducted for about twenty minutes at each site. At three sites a single beat sample was taken and at the other three, two beat samples were taken at each. At two of these three (B4, B5), one sampler (KB) focused on habitats along the track or paddock edge of the habitat sampled while one (AT) focused on habitats in the interior. At the third (B3) the habitat sampled was not near a disturbed edge. 3. Malaise Trap: A single malaise trap was erected in a small clearing


within dense Allocasuarina woodland. Contents were retrieved after four nights. 4. Light Trapping: Light traps (contained in a bucket and placed above ground rather than buried) were established near the homestead for a total of six nights. One (LT1) was established at a fixed point for three nights while another (LT2-4) was placed at different sites on each night. 5. Sweeping: Five sites were swept with nets for about half a personhour each. Habitats swept included grasses or other low vegetation in all cases except for one site at which we conducted aerial sweeping of insects swarming around the upper and middle branches of four-metre high vigorously flowering tea-trees. 6. Hand collecting (not including land snails): Opportunistic and unsystematic hand-collecting (including netting of flying specimens) occurred continually. A total of 48 hand-collecting events were recorded (26 by KB and AT and 22 by the remainder of the party). Most of these represented opportunistic collections of a small number of specimens (or several specimens of the same thing) at a given point. Significant hand collecting efforts occurred at the following sites: • HC1 (homestead): primarily moths attracted to homestead lighting over several nights • HC5 (near Mannalargena Cave):

primarily turning of limestone boulders and hand-sampling of leaf litter in and near cave escarpment • HC12 (Bursaria forest on hill south of homestead): under rocks and in leaf litter in Bursaria scrub • HC13 (open area at base of hill): flying insects were frequently seen and netted in this area en route to sites • EF, HB15 (eucalypt remnant): the small Eucalyptus ovata remnant was sampled both by other members of the party in a group, and by AT (combination of hand collecting and bashing from tree branches) and KB (ground litter/ rock hand sampling) Land snails were targeted separately. KB conducted searching for land snails both during the establishment of pitfall trap sites and opportunistically at various points around the island and during other significant hand collection efforts noted above. As land snails were frequently seen lying dead on the ground, and as the species present pose no known identification problems, not all specimens seen were collected; however, numbers of each species seen at each site were recorded or, for more than ten specimens of a species at a site, estimated. The presence of exotic snails at sites was noted, but the exact number of specimens seen was only recorded when that number was very small; otherwise

86

the density of shells of exotic snails seen was recorded as “some” or “many”. Because of the prolonged dry conditions leading up to and during our visit, live snails were rarely observed. Only 8% of native snails observed were alive and for exotic species (both of which have relatively large and durable shells) the percentage was much lower. Specimen tallies therefore included live and dead shells combined. 7. Carcass sampling: Seven pademelon carcasses in varying states of decay were turned and visible invertebrates collected from their undersides. A single pitfall trap was placed immediately adjacent to the remains of an eighth pademelon carcass and retrieved after two nights. Sample locations are shown in Map 1. Specimens were sorted into taxonomic groups, which ranged from family to class depending on ease of rapid sorting. A full list of all sample sites with grid references and habitat types is given in Appendix 1.


RESULTS Not counting exotic snails, 7168 specimens were either collected or, in the case of uncollected native snails, recorded. Summary totals by sorted group are shown in Table 1. The figure for native snails is greatly inflated by deliberate collecting focus on snails, by the inclusion of sighted specimens and by the inclusion of dead shells. A total of 31 different orders were recorded, not counting mite orders (mites have not yet been sorted to order). It is difficult to derive exact numbers of orders from the previous expeditions to Tasman Island and Three Hummock Island because of incomplete information about collembola and centipedes collected, but it is estimated that 24 different orders excluding mite orders were collected on each of those expeditions. The following are excluded from the map: HC21,23,29 (no grid reference but very near P4 and HC1), WC2 and 5 (same as 1 and 4 respectively), HC41 (within metres of HC38), HC22, 32 and 34 (no grid reference).

Results by collecting method: 1. Pitfall trapping Pitfall trapping specimen totals by group are given in Appendix 2. 4 444 specimens representing at least 24 orders (order count excluding Acari) were collected

from the fifty pitfall traps. Acari were present in all 50 traps. The most frequently present orders excluding Acari were Aranaea (50 traps), Hymenoptera (49), Diptera (48), Entomobryomorpha (48), Coleoptera (44), Hemiptera (40), Poduromorpha (20), Gastropoda (16 â&#x20AC;&#x201C; but mostly dead shells) and Isopoda (15). Excluding the 1165 Acari specimens the most numerous orders collected were Hymenoptera (1342 specimens), Diptera (666), Entomobryomorpha (329), Hemiptera (229), Aranaea (216), Coleoptera (192), Isopoda (71) and Poduromorpha (48). Two orders (the millipede order Polyxenida and the collembolan order Poduromorpha) were captured only by pitfall trapping and not by any other method. The 10% of traps with the most Hymenoptera included 44% of specimens for that order, and a similar result (43%) was obtained for Diptera. With the exceptions of 87 of 229 Hemiptera occurring in a single trap and 33 of 71 Isopoda likewise, the other relatively common orders were generally less concentrated in a small number of traps. Specimen totals varied considerably by site. The lowest total (169) was at the recently burnt site 7, and the highest occurred in Myoporum scrub at site 4 (665) and grassland on dunes at site 5 (658). Site 4 had unusually high numbers of Acari, Diptera and Collembola while Site 5 had very high numbers of ants in two traps.

87

Total numbers of orders varied relatively little by site; 12-15 orders were collected from each site except for sites 9 (pasture) and 10 (low tea tree scrub near pasture), which had only ten orders each. The mean number of orders per trap varied relatively from 6.8 orders at site 9 to 10 orders at site 4. The two traps that were not retrieved intact each had the lowest specimen runs for their site, and shared the lowest order total by trap (5) for the entire survey. Four sites (2, 3, 4 and 5) generally had high than average total specimen numbers, total order numbers and mean order numbers per trap. The other sites generally ranked below average on all these figures, although site 10 had a high specimen total because of very high numbers of Diptera (36% of pitfall survey total). 2. Bashings 947 specimens representing just twelve orders plus Acari were captured in the relatively limited bashing tray sampling conducted. Acari (275 specimens) were common in most bashing samples, and Hemiptera (195), Thysanoptera (131), Aranaea (71), Entomobryomorpha (70), Lepidoptera (59 â&#x20AC;&#x201C; mostly larvae), Hymenoptera (52) Coleoptera (42) and Psocoptera (30) were the commonest discrete orders. A large collection of scale insects at site SB1 contributed 81 of the 195 Hemiptera. No order absent from the pitfall samples was collected in


Table 1 Specimen totals by group and sampling method for all invertebrate groups. Five of 33 gastropods pitfall-trapped were exotic. Breakdowns of Collembola, Diplopoda and Chilopoda by order can be found in â&#x20AC;&#x153;Results by groupâ&#x20AC;?. Group

Level

Pitfalls

Bash

Malaise

Light

Sweep

Formicidae

Family

1189

23

Hymenoptera ex Form.

Order (part)

153

29

7

1

11

14

Diptera

Order

665

14

61

21

85

50

Diptera Larvae

(juv)

1

3

1

9

9

1231 215

72

968

96

100 3 6

6

26

96

6

2

5

275

3

8

4

118

4

4

Order

5

2

Heteroptera

Suborder

20

39

2

Sternorrhyncha

Suborder

125

137

Auchenorrhyncha

Suborder

84

19

Blattodea

Order

Coleoptera

Order

Coleoptera Larvae

(juv)

6

3

Lepidoptera

Order

17

3

Lepidoptera Larvae

(juv)

24

56

Neuroptera

Order

Neuroptera Larvae

(juv)

1

Thysanoptera

Order

7

Archaeognatha

Order

Psocoptera

Order

29

30

Orthoptera

Order

2

1

Odonata

Order

1

Total

1

Order

Dermaptera

39

Carc

1

Mecoptera

186

Hand

3

593

2

10

6

38

312

6

12

27

30

55

27

52

5

189

4

5

1

89

1

1

4

3

4 138

131

3

3

60

1 2

8

3 1

1 1

477

1

28

14

1491

13

17

3

323

Collembola

Subclass

404

72

Acari

Subclass

1165

275

8

Aranaeae

Order

216

71

2

Opiliones

Order

8

1

9

Scorpiones

Order

2

1

3

Pseudoscorpionida

Order

3

2

5

Diplura

Order

1

1

Isopoda

Order

16

87

Amphipoda

Order

4

4

Diplopoda

Class

12

36

48

Chilopoda

Class

12

7

19

Gastropoda

Class

33

531

564

Unknown Total

1

71

4

1

4444

947

5 123

88

92

167

867

528

7168


Table 2 Bashing specimen numbers by specimen group. Small letters in code denote collector (a=Abbey Throssell, k=Kevin Bonham) At sites 4 and 5 Abbey sampled the interior of the habitat type while Kevin sampled the edge. SB1 Formicidae

2

Hymenoptera

8

Diptera

2

SB2

SB3Ak

SB3Ba

10

6

1

4

2

SB4Ak

SB4Ba

SB5Aa

SB5Bk

1 1

4

2

Diptera Larvae

1

2

7

1

4

SB7

TOTAL

4

23 29 14

5

3

2

Heteroptera

3

1

1

2

10

6

3

4

9

39

Sternorrhyncha

82

2

12

7

11

7

4

7

5

137

Auchenorrhyncha

11

4

1

1

1

19

6

10

2

3

39

1

1

1

3

1

1

1

23

2

Coleoptera

1 10

6

2

Coleoptera Larvae Lepidoptera Lepidoptera Larvae

4

1

3

6

5

1

56

1

1

20

3

131

2

14

30

1

1

11

Neuroptera Thysanoptera

14

Psocoptera

3

19

11

48

4

1

9

1

6

6

3

Orthoptera Collembola

2

1

5

12

3

31

10

7

1

72

Acari

76

13

36

82

3

22

10

28

5

275

Aranaeae

9

4

8

2

12

19

6

8

3

71

Unknown

1

Total

1

217

54

99

194

55

109

59

103

57

947

Table 3 Specimen totals by sorted group for malaise and light traps.

Nights deployed

Malaise

LT1

LT2

LT3

LT4

TOTAL

4

3

1

1

1

10

1

1

Formicidae Hymenoptera

7

1

Diptera

61

9

Heteroptera

2

2

Sternorrhyncha

6

6

Auchenorrhyncha

3

3

Coleoptera

2

6

Lepidoptera

30

15

Neuroptera

1

1

Psocoptera

1

1

Acari

8

Aranaeae

2

Total

123

8 3

4

3

6

82

1

5

3

1

12

11

25

85

8 33

7

89

17

1

3

35

215


the bashings although there were significant differences in fauna at lower taxonomic levels (eg see Coleoptera, Aranaea and Collembola sections in Results by Group).

orders plus Acari. These results included six orders (Blattodea, Archaeognatha, Odonata, Diplura, Amphipoda and the centipede order Scolopendromorpha) that were not captured by any other collection method.

3. Sweep samples

The single malaise trap, deployed for four nights, collected 123 specimens of eight orders plus Acari â&#x20AC;&#x201C; predominantly Diptera (61) and Lepidoptera (30).

167 specimens representing eight orders plus Acari were collected in five sweep samples. Diptera (85) were by far the most numerous order captured. At site HC5 sweep sampling was specifically directed at Lepidoptera seen flying in large numbers over Acaena patches so it is not surprising that Lepidoptera were the commonest order in that sample. One order not captured by any of the above methods, Mecoptera, was captured by sweep sampling.

2. Light Traps

4. Hand collection

5. Carcass sampling

A total of six trap-nights of light trapping produced 91 specimens of six orders, predominantly Lepidoptera (55) and Diptera (21). One light trap location (LT4) produced more specimens in one night than another (LT1) had done in three.

Hand collection results by sorted group are given in Appendix 3.

Carcass sampling results by sorted group are given in Table 5. 528 specimens of seven orders were collected but these results were numerically dominated by the single pitfall trap (WC3), which trapped 464 specimens in two nights. This is higher than the total invertebrate

Bashing specimen totals are given in Table 2. 1. Malaise Trap

Specimen frequencies for the groups collected are essentially meaningless since hand collection was deliberately biased towards groups of interest, and some groups were much easier to capture when seen than others.

Excluding gastropods, for which hand collection results are treated separately (see Gastropoda under Results by Group), hand collections produced 336 specimens of 25

Table 4 Specimen totals for sweep samples HC5

SB6

Hymenoptera Diptera

10

14

SB7

HC12

P2

TOTAL

1

3

7

11

13

41

7

85

Mecoptera Heteroptera

2

Sternorrhyncha Auchenorrhyncha

6

2

2 1

2 25

1

3 2 1

Aranaeae

4 37

8 6 27

Orthoptera Acari

4

1

Lepidoptera Larvae

Total

2

7

Coleoptera Lepidoptera

2

2 2

1

4 2 1

27

15

90

6

3

13

61

27

167


arrangements for transfer of specimens to an expert for further sorting have been made.

count for any of the fifty pitfall traps left out for three nights elsewhere.

Results by group: In this section, groups are ordered alphabetically by class or subclass, then by order, then by lower classifications as necessary. At the end of the section are some comments on groups that were conspicuously absent.

Arachnida: Acar i Mites were very common in pitfall and bashing samples and a minor component of the malaise trap, carcass, sweep and handcollection samples. Additionally, 26 Acari were removed from a single blue-tongue lizard. No attempt at morphospecies assessment has been made although preliminary

there are some minor unresolved discrepancies between datasets.

In pitfalls, Acari were commonest at sites 4 (Myoporum scrub near house), 2 (dense tea tree woodland) and 3 (dune scrub). They were least common at sites 8 (low shrubby heathland), 7 (recently burnt heathland) and 9 (pasture).

There was very little relationship between abundance and diversity of spiders at specific pitfall sites. Spiders were most diverse at sites 3 (dune scrub) and 6 (low rocky scrub) and least diverse at sites 9 (sheep pasture) and 7 (recently burnt heath).

Arachnida: Aranaea

Arachnida: Opiliones

Spiders occurred in relatively low numbers in pitfalls, but with remarkable consistency: every pitfall contained at least one spider. Spiders were also fairly common in bashing samples and were collected by all remaining collection methods. A separate report on the spider fauna has been provided by Lynne Forster. Spider identifications by site are given in Appendix 5 â&#x20AC;&#x201C;

Eight harvestmen were pitfalltrapped. Six came from site 4 (Myoporum scrub near house) with one each from sites 1 (Allocasuarinadominated diverse scrub) and 8 (low shrubby heathland). One harvestman was hand-collected in dense Bursaria woodland (HC12). At least two species are present as the two specimens from sites P1 and HC12 are clearly distinct from the

Table 5 Specimen totals by sorted group for pademelon carcasses WC1

WC2

WC3pit

WC4

WC5

Formicidae

WC6

WC7

WC8

9

9

Diptera

1

70

Diptera Larvae

6

2

88

Coleoptera

5

6

279

Coleoptera Larvae

TOTAL 72

1

96 10

4

4 4

1

3

4

312 12

4

1

5

Neuroptera

1

1

Neuroptera Larvae

3

3

Collembola

1

1

Acari

14

14

Aranaeae

3

3

Lepidoptera

Total

3

14

1

10

464

11

91

8

14

3

4

528


Scorpion (Cercophonius squama). Photo by Dylan van Winkel.

Arachnida: Scorpionida The scorpion Cercophonius squama (Gervais, 1844), a ubiquitous Tasmanian species that also occurs widely in south-eastern Australia, occurred twice in pitfalls and was also hand-collected once and seen sporadically. The species is the only scorpion recorded in Tasmania and although the PSI specimens are very colourful, no external morphological difference between them and specimens collected near West Ridgley on the Tasmanian mainland is apparent.

Chilopoda

remainder.

Arac hnida: Pseudoscorpionida A single species of pseudoscorpion was collected from three pitfall traps (two in low rocky tea tree scrub and one in low shrubby heathland)

and twice by hand collection from eucalypt woodland (EF and HB15). The species has not been identified but was also collected at Whitemark on Flinders Island immediately before the survey.

Nineteen centipedes representing five species from three orders were collected. Twelve specimens were collected in pitfalls and the remainder by hand collection. Results are shown in Table 6

Table 6 Species results for Chilopoda. Pitfall site numbers without a pit number (A-E) indicate hand-collection at that pitfall site. Specimen from HB15 was hand-collected. Species Lamyctes emarginatus (Newport, 1844)

P1A

P1B

P1D

P2D

P2E

P4A

2

1

1

1

3

1

P5E

P2

HC5

HC10

Cryptops sp. A Tuoba laticeps (Pocock, 1891)

HC12

HB15

1

10

1

1 3

3

Tuoba n. sp.

1

Unidentified geophilomorph - not Tuoba

1

1 1

92

TOTAL

1

4 1


Diplopoda

more specimens. Two specimens of “Orchestia” australis FearnWannan 1968 were collected in such a habitat at site HC4. The only truly non-marginal terrestrial sites where amphipods were even seen were sites HC5 (especially around the cave mouth) and HC12. A single specimen of an undescribed Keratroides sp. (“kershawi” group) was captured at each of these sites.

Lamyctes emarginatus (Lithobiomorpha: Henicopidae) is dubiously native to Tasmania (Mesibov, 2007) as it prefers Europeanised habitats. However, in these samples it was found almost exclusively at forested sites with relatively little disturbance. Cryptops sp A (Scolopendromorpha: Cryptopidae) is widespread in northern and eastern Tasmania.

48 millipedes representing four species from three orders were collected. Twelve were pitfall-trapped and the remainder hand-collected. Results are given in Table 8. The record of Propolyxenus forsteri from PSI is the first record of the Order Polyxenida from any Bass Strait island. All four specimens were pitfall-trapped.

Crustacea: Isopoda

Tuoba laticeps (Geophilomorpha: Geophilidae) is strictly coastal and apparently widespread in Tasmania. A completely new species of Tuoba having 73 leg pairs compared to 59 for T. laticeps (R. Mesibov pers comm.) was hand-collected four times during this survey, in a range of forested environments, none of them strictly coastal.

Entognatha: Collembola

87 slaters representing at least six species were collected. All species collected were native. Slaters were common at site P3 (coastal scrub on sand) and were present in low numbers at five of the remaining pitfall sites. Results are given in table 7.

Collembola were common in pitfalls and bashing trays but were not collected by any other methods. Collembola were identified to morpho-genera, 16 of which were recorded.

The sole specimen of Styloniscidae? sp was collected by hand under a large calcarenite slab despite the pitfalls at that site collecting no slaters. This was the same rock under which the first specimen of the centipede Tuoba sp. nov was collected.

Crustacea: Amphipoda Amphipods were remarkably scarce in the collections, although more targeted sampling above high-tide lines would have produced many

Collembola were most common and diverse at pitfall sites 2 (Allocasuarina woodland), 4 (Myoporum scrub near house) and 10 (low tea tree scrub near pasture), and to a lesser extent site 5 (grassland on dunes). They were less common and less diverse at all other pitfall sites, and

Table 7 Species by site results for Isopoda. Pitfall site numbers without a pit number (A-E) indicate hand-collection at that pitfall site. Site

Ctam

P3A

P3B

1

3

P3C P3D

9

2

P3E

P4C

6

P5C P5D

2

1

P5E

P7A

1

1

P7B

P7C

P7E

P9D

P2

1

Ctas

HC4 HC5 HC6

8

2

HC24

sum

1

38 1

1

Pulv

1

2

1

S?

1

1

Lig P?

P8A

2

2 4

3

24

1

1

3

1

1

1

3

42

Species codes: Ctam = Cubaris tamarensis Green 1961, Ctas = C. tasmaniensis Green 1961 (?), Pulv = Plymophiloscia ulverstonensis Green 1961, S? = Styloniscidae? sp (tiny but mature), Lig = Ligia australiensis Dana 1853, P? = Porcellionidae? unidentified.

93


Gastropoda

were scarcest at site 8 (low shrubby heath). A bashing sample at the same location as site 8 (SB7) also contained only a single collembolan. The commonest collembolan by far in pitfalls, Acanthocyrtus, was not collected in bashing samples at all. The only two remotely common collembola in bashing samples, Drepanura and Lepidobyra, were both present in pitfalls, but in relatively low numbers. Drepanura was common at one pitfall site (P5) and one bashing site (SB4) but the habitats at these two sites – grassland on dunes and dense Allocasuarina woodland respectively – were very dissimilar. Results are given in table 9.

Entognatha: Diplura A single immature dipluran was collected in eucalypt litter at site HB15. It has not been identified.

from large areas of suitable habitat, and it is possible that the species is an Aboriginal introduction to some or all of its Tasmanian range. In this survey, the species was collected abundantly by hand at site P1, and single damaged shells were collected from sites P3 and P4.

Six native and two introduced land snails were collected. Land snail shells both native and introduced were very common on the island, but because of the dry conditions, live land snails were very seldom seen. Thus the totals given in Table 10 are primarily for dead specimens.

The remaining four native species commonly occur together in coastal areas around the Tasmanian coastline. However, many specimens assigned to Paralaoma caputspinulae are unusually small and may turn out not to be that species when Tasmanian specimens attributed to it are revised. These specimens are very similar to unusual Kent Group specimens, and Paralaoma are very much commoner on PSI than on Flinders Island.

Tasmaphena sp. “Whinray” is a wellknown undescribed rhytidid that is apparently endemic to the Furneaux and Kent Groups. It was collected sporadically during this survey, most commonly in wooded habitats with some development of litter. As a result of these collections, the species was photographed alive for the first time. Pupilla australis is widespread on the Australian mainland, but known Tasmanian records are confined to the eastern Bass Strait islands and the east coast south to Triabunna. Tasmanian populations tend to occur in dense colonies while being absent

The native snail fauna of Prime Seal Island appears to be depauperate compared to that of Flinders Island (even taking into account habitat differences) and far more similar to that of the Kent Group (on which all

Table 8 Species by site results for Diplopoda. Pitfall site numbers without a pit number (A-E) indicate hand-collection at that pitfall site. Specimens from HB15 were hand-collected. P2B

Po

P2C

P2D

P3A

1

1

1

P3B

P4E

pi sp

P7E

P8E

P7

SB4

HC1

HC5

HC12

HB15

HC24

EF

1

1

TOTAL

4 1

1

P8B

1

No Di

P7A

1

1

1

4

1

1

2

2

1

3

1

15

2

1 1

28

2

5

2

10

Species codes: Po= Propolyxenus forsteri Conde, 1951 (Polyxenida), No= Notodesmus scotius Chamberlin, 1920 (Polydesmida: Paradoxosomatidae), Di = Dicranogonus sp (Polydesmida: Paradoxosomatidae), pi = unidentifiably immature polydesmidan, probably one of the previous two, sp = unidentified native spirostreptidan (Spirostreptida, Iulomorphidae)

94


Table 9 Species by site results for Collembola. Pitfall records are given by site with pits merged for space reasons. “Others” are specimens collected by other collectors without grid references. No

Ac

Xe

En

Si

Dr

Ra

Br

Ka

P1T

32

26

P2T

60

39

1

P3T

32

29

1

P4T

72

42

13

7

P5T

50

11

2

2

P6T

27

18

P7T

20

13

P8T

9

5

P9T

23

2

11

1

P10T

79

51

4

3

WC1 Pit

1

1

SB1

2

SB2

1

SB3Ak

5

2

3

SB3Ba

12

3

7

SB4Ak

3

2

1

2

SB4Ba

31

29

2

2

SB5Aa

10

10

SB5Bk

7

3

SB7

1

1 7

3

5 1 24

Di

Cr

Co

Pa

Ls

Po

1

2

?

D

Spp

2

1

3

1

8

1

4

1

1

1

3

1

1

Lp

2

3 1

2

Lb

2

1

1 3

1

3

8

1

6

6 4

3

4

3

1

1 5 1

3

2 3

4

6

1

2

2

4

3

3

8 1

1

2

1

1

1

2 1

3

1

1 2

3

2

1

1

Pitfall

236

35

24

5

28

6

13

1

14

6

2

1

2

1

14

16

Sites

10

7

8

3

3

4

5

1

5

1

2

1

1

1

7

6

49

1

1

16

2

2

1

6

1

1

6

2

1

1

77

7

2

30

2

2

15

Bashing

Total

237

35

24

5

13

6

2

1

2

1

72

16

Key to top row: No – total collembola as sorted. Ac – Acanthocyrtus, Xe – Xenylla, En – Entomobrya, Si – Sinella, Dr – Drepanura, Ra – Rastriopes, Br- Brachystomella, Ka – Katianna, Lb – Lepidobrya, Di – Dicyrtomidae, Cr- Cryptopygus, Co – Corynephoria, Pa – Paronellides (?), Ls – Lepidosira, Po – Polykatianna, ? – unidentified, D – discrepancy (created through sorting and preservation loss of specimens).

95

404

477


six PSI species plus two others have thus far been recorded). However, the amount of searching devoted to snails was not enough to rule out the possibility of other species. In particular, Succinea australis Ferussac 1821 was not recorded but may well occur. It was surprising to find only two exotic snail species, although it is possible that exotic slugs were present on the island but not found because of the dry conditions. The common garden snail Helix aspersa was found relatively scarcely on the island, mainly in dune habitat near the homestead and around Sealersâ&#x20AC;&#x2122; Cove. Although destructive in gardens, this species is not very invasive. Another introduction, Prietocella barbara, was almost ubiquitous on the island, and in some places very common.

Insecta: Archaeognatha Bristletails are a poorly known group in Tasmania with only two named species and some known undescribed species (Peter McQuillan pers comm.) Three specimens were collected during this survey. A single specimen of the very widespread southern Australian species Allomachilis froggatti Silvestri 1906 was collected from under boulders at the high tide mark at site HC4. Two specimens of an undescribed species of Machiloides Silvestri 1905 were collected under rock sheets at the southern end of the limestone scarp at site HC5. Only one species of Machiloides is described from

Tasmania (M. hickmani Womersley 1939) and while these specimens are not that species, it is unknown whether they represent a previously collected undescribed species or not.

Insecta: Blattodea Cockroaches were scarcely observed on PSI. Four specimens of two species were hand-collected.

Insecta: Coleoptera Beetles were collected fairly commonly by most collection methods, and abundantly in the sole pitfall trap placed next to a wallaby carcass. 82 beetle species were collected (a similar diversity to that recorded in the preceding Three Hummock Island survey). True weevils (Curculionidae) were very diverse (17 species) and staphylinids and tenebrionids were also fairly diverse, however carabids (only two species collected in small numbers) and leiodids (only one species in small numbers) were exceptionally scarce. Chrysomelids were also scarce but the large black species Paropsisterna morio was present on the few eucalypts examined â&#x20AC;&#x201C; the other two species collected were tiny. The pitfall beetle collections (186 specimens of 40 species) and the bashing collections (39 specimens of 14 species) had only a single species of Rhyzobius in common. The single most numerous beetle species in the collections by far was Saprinus cyaneus, however this

96

species was only collected from carcass samples, together with several other well-known carrion feeders. In pitfalls, the commonest species were the staphylinid Anotylus sp, the latridiid Aridius minor, the weevil Mandalotus? sp 2 and an as yet unidentified scydmaenid. Of these Anotylus was the most numerous, but it occurred in only five out of 50 pitfall traps. Beetles were relatively numerous and diverse at pitfall sites 2 (sheoak woodland), 3 (low scrub on dunes), 4 (Myoporum scrub near house) and 5 (grassland on dunes). They were numerous but not diverse at site 9 (sheep pasture), where Anotylus was commonest, and neither numerous nor diverse at the remaining five pitfall sites. Totals for all beetle species and names of species collected (in some cases identifications remain incomplete) are given in Appendix 4, with individual pitfall traps merged for space reasons. Many of the beetles collected are difficult to identify to known species and it is likely that full study of all available collections will result in some being identified as new at least for Tasmania.

Insecta: Dermaptera A single species of earwig was trapped in pitfalls at sites 3 (1 specimen) and 4 (4 specimens) and hand-collected on a tied island at the far north of PSI at site 10 (1 specimen).


Table 10 Species by site results for Gastropoda. Pitfall records are given by site with pits merged for space reasons. “Others” are specimens collected by other collectors without grid references. Tw

Pa

Pc

1

8

P1

Pitfalls

P2

Pitfalls

P3

Pitfalls

P4

Pitfalls

2

P5

Pitfalls

3

P6

Pitfalls

2

P7

Pitfalls

P9

Pitfalls

P1

hand

P2

hand

P3

hand

P4

hand

P5

hand

P6

hand

P7

hand

P9

hand

P10

hand

HC5

hand

HC8

hand

HC9

hand

HC18

hand

HC12

hand

HB15

hand

HC16

hand

SB1

hand

SB2

hand

SB3

hand

SB4

hand

SB6

hand

EF

hand (o)

7

others

hand (o)

2

TOTAL

Lc

Mt

Po

Ha*

Pb*

3

1 1 2 1 1

3 2 3

35 1

7

12

20

1

50

some

20 some

3

1

5

8

1 3

2

many

many

5

some

50

some

5

some

many some

3

5

7

2

1

some

50

many many

2 1

1

many

5

some

12

many

56

some

1

some

4

some

2

25

many

3

15

some

2 5

17

13

20

2

1 1 4 1

many 1

36

5

14

13 4

38

59

64

many

35

many 2

3

3

332

Key to species: Tw Tasmaphena sp. “Whinray”, Pa Pupilla australis (Angas, 1863), Pc Paralaoma caputspinulae (Reeve, 1851) (?), Lc Laomavix collisi (Brazier, 1877) , Mt Magilaoma sp. “tasmanica”, Po Pernagera officeri (Legrand, 1870), Ha* Helix aspersa Muller, 1774 (exotic), Pb* Prietocella barbara (Linneaus, 1758) (exotic)

97


Insecta: Diptera Flies were the second most numerous insect order collected and were collected in numbers by most collection methods. They were by far the commonest order in the malaise trap and in sweep samples. Relatively few flies were collected in bashing samples but this is probably because they tended to escape.

catch for most collecting methods but less than 0.5% for pitfalls. Diversity has not yet been assessed but is unlikely to be high.

Insecta: Hemiptera: Sternorrhyncha

Although flies were present in nearly every pitfall trap, there was great variation in fly numbers between pitfall sites. 241 flies (36%) were collected at site P10 (low tea tree scrub near pasture) and 152 flies (23%) at site P4 (Myoporum scrub near house). Less than three flies per trap were collected from the two Allocasuarina scrub and woodland sites P1 and P2, from the open pasture site P9 and from recently burnt heath at site P7.

This suborder including aphids and scale insects was more numerous than the other hemipteran suborders but two events contributed to this. In one pasture pitfall (site 9B) 87 specimens of an aphid believed to be introduced were trapped, and in one bashing sample 82 scale insects, apparently all of the same species, were captured. Aside from this the suborder occurred patchily in pitfalls (most commonly in sand dune grassland at site 5), fairly commonly in the remaining bashing samples, and rarely by other collecting methods. Diversity has not yet been assessed.

Insecta: Hemiptera: Auc henorrhyncha

Insecta: Hymenoptera: Formicidae

Hoppers were collected sporadically by several collection methods. In pitfalls, they were commonest at sites 4 (Myoporum scrub near house) and 8 (low shrubby heath). They were absent from site 9 (sheep pasture) and very scarce at sites 7 (recently burnt heath) and 10 (tea tree scrub near pasture). Diversity has not yet been assessed.

Ants were abundant in pitfall traps but very few were collected by other methods. The collection will be referred to a specialist for identification.

Insecta: Hemiptera: Heteroptera True bugs were relatively scarce, and contributed a few percent of the

Insecta: Hymenoptera: Other Hymenoptera Wasps were collected in moderate numbers by most collecting methods. In pitfalls they were most numerous at site 3 (scrub on dunes) but scarce at sites 7 (recently burnt heath), 8 (low shrubby heath) and 9 (pasture). Wasps will be sorted

98

to morphospecies and identified to family by Abbey Throssell.

Insecta: Lepidoptera 189 adult moths and butterflies (including two butterflies) and 89 caterpillars were collected. Adult Lepidoptera were captured by a wide range of methods while caterpillars were captured mainly in bashings and pitfall traps. Results are being reported separately by Abbey Throssell (see Throssell ,this volume).

Insecta: Mecoptera Scorpionflies were seen fairly frequently on Target Hill and the track leading to that hill from the house. Three were captured, all the same species (as yet unidentified).

Insecta: Neuroptera Four adult and three juvenile lacewings were collected by a range of methods. The adults include at least two species.

Insecta: Odonata A single dragonfly, a female Adversaeschna brevistyla (Rambur, 1842), was netted at site HC17. This species is widespread in Australia, New Zealand, New Caledonia and Vanuatu (Theischinger and Hawking 2006). Dragonflies were seen sporadically on the island, but typically at great distance.

Insecta: Or thoptera A total of eight juvenile grasshoppers were collected in pitfalls, bashing samples, sweeps and hand


Cave cricket. Photo by Dylan van Winkel.

collections. All were too small to be identified. Remaining Orthoptera results are reported separately by Michael Driessen (see Driessen, this volume).

Insecta: Thysanoptera

Insecta: Psocoptera

Groups conspicuously absent

Psocopterans (barklice or booklice) were mainly captured in pitfalls and bashing samples. Most pitfall specimens were of a single species collected at site P5 (grass on sand dunes). Specimens collected by bashing are likely to be more diverse. Psocoptera were especially numerous in bashings at SB7, in which they were the most common order collected.

Some groups of terrestrial invertebrates that might have been expected on PSI were not recorded at all. The absences of flatworms, earthworms, leeches and slugs in the samples may have been a result of the very dry conditions at the time of our visit. Both flatworms and introduced slugs were seen abundantly on Flinders Island during

Thrips were rare in pitfall traps but very common in bashing samples. Diversity has not yet been assessed.

99

the same trip, but Flinders Island clearly experienced more rain than PSI during the time of our stay. Other groups not recorded included silverfish, symphylans, onychophorans (habitat probably unsuitable), and most insect groups dependent on fresh water for some stage of their life cycle. Possibly some of the groups not found in this survey would be found with more targeted searching on the island, perhaps during wetter conditions.


Photo by Nick Mooney.

GENERAL DISCUSSION & MANANGEMENT RECOMMENDATIONS These interim results show that the invertebrate fauna of Prime Seal Island is quite diverse both at ordinal and lower levels, and likely to be relatively intact, with fewer obviously exotic species than expected. Much more work will need to be done on the samples to obtain meaningful biogeographic results for most groups, and to determine how many species previously unrecorded from Tasmania have been collected. The results thus far suggest there will be many. Sampling was conducted with the primary aim of collecting as many species of invertebrate as possible from the island, and the samples are not suitable for testing any particular hypothesis about environmental impacts on the island, because of: • the relatively small number of pitfall traps deployed • the concentration of pitfall traps in one localised site per habitat type • deliberate bias in favour of diverse microhabitats when placing pitfalls

The results indicate the benefits of hand collection by workers familiar with invertebrates as well as more systematic methods such as pitfall trapping. Many species and higher groups collected would have been missed had surveying been largely confined to methodical sampling. The invertebrate fauna of the island is likely to be best conserved by maintaining the island generally in a condition similar to its present condition. No specific management recommendations are made on the basis of these results, although some may follow when more material has been identified.

ACKNOWLEDGEMENTS Thanks to Lynne Forster (spider identifications and assistance with beetle identifications), Bob Mesibov (millipede and centipede identifications), Alastair Richardson (crustacean identifications), Penny Greenslade (identifications of most collembolan vouchers), Peter McQuillan (comments on beetles) and all on the PSI expedition team for their assistance with collection and documentation of invertebrates.

Nonetheless, the sheep pasture and recently burnt heathland sites, while far from bereft of native invertebrate fauna, appeared depauperate compared to the other sites sampled.

100

REFERENCES Mesibov, R. (2007) Tasmanian Multipedes http://www.qvmag.tas. gov.au/zoology/multipedes/mulintro. html Theischinger, G. and Hawking, J. (2006) The Complete Field Guide to Dragonflies of Australia. CSIRO Publishing, 366 pp.


101


P RELIMINARY

OBSERVATIONS of the SPIDERS

102


Huntsman. Photo by Bridgette Moffat.

By Lynne For ster A total of 317 spiders representing 75 species from 15 families was collected by a variety of methods on Prime Seal Island. Generally, the spider fauna assemblage reflected the dry habitat conditions, low numbers of litter-decomposing prey and the abundance of ants. Vagrant ground hunting spiders were dominated by the Lycosidae, Gnaphosidae, Salticidae and some species of tiny, introduced Theridiidae which prey on ants. Foliage species included a diversity of Aranaeidae, Theridiidae and Thomisidae. The largest spiders sampled were two burrowing spiders: the tube trapdoor, Stanwellia pexa (Nemesiidae) at 23 mm and Tasmania’s largest wolf spider, Tasmanicosa godeffroyi (Lycosidae), with a body length of 26 mm. A number of spider species on the island were ground hunters that have an association with ants.

INTRODUCTION Tasmania has approximately 1,800 species of spider, of which only 300 have been described, and 50 of approximately 66 spider families found across Australia. The number of described species represents little more than 15% of Tasmanian species and it is not uncommon for ecological studies of Tasmanian spiders to be unable to name over 90 percent of morphospecies (e.g. Churchill 1993, Coy et al. 1993). No previous account of the spider

fauna on Prime Seal Island is known. Spiders were collected as part of a general invertebrate survey by Kevin Bonham and Abbey Throssell in October 2008 and passed on to the author for examination.

METHODS Details of collection methods and sites are provided by Bonham (2009) in this volume. The specimens will be lodged with Tasmanian Museum and Art Gallery. Specimens were identified to species level where possible and those that could not be identified with certainty were allocated a morphospecies code at family level.

RESULTS AND DISCUSSION Altogether, 317 spiders representing 75 species from 15 families were collected by a variety of methods on Prime Seal Island (Table 1; images of several species are shown in Fig. 1). Fifteen percent were identified to species level and a further nine percent were identified to genus level. The families with highest numbers of species were Araneidae (orb weavers), Salticidae (ambushers) and Lycosidae (vagrant hunters) with 15, 14, and 12 species respectively (Fig. 2). In terms of abundance, however, the three dominant families were Lycosidae, Theridiidae and Gnaphosidae (Fig. 3).

103

Collecting methods provided distinct differences in spider families sampled (Table 1). Not surprisingly, no orb weaving Araneidae or Thomisidae ambushers were caught in pitfall traps - they were all collected by hand, sweep netting or beating vegetation. Ground hunting Gnaphosidae, Oonipdae, Prodidomidae, Lycosidae, Zodariidae and Zoridae were caught only in pitfall traps or by hand. Some Salticidae and Theridiidae species were caught only in pitfall traps while others were collected from vegetation — a reflection of different habitat adaptations in this family. Five species caught in pitfall traps were also collected by hand. It must be noted that collecting intensity differed between collection methods and that all habitats were not surveyed by all methods. Hence, the absence of many ground hunters from, for example, ‘Bursaria forest with grassy understory’ is a result of no pitfall trapping in that habitat. For these reasons it is unwise to use this data to associate spider species with particular vegetation types. Nevertheless, it was possible to make a few comparisons amongst the 226 spiders caught in pitfall traps and amongst the 91 spiders caught by other methods. The greatest numbers of ground hunting spiders were caught in low tea tree shrub with grasses and in mature shrubby heath (50 spiders, Fig. 4). Sand dunes contained the next highest number of ground hunting spiders, both in the grassland on the dunes and at


the edge of boobyalla dune scrub. Fewest ground hunting spiders were found in flowering tea tree habitat beside track, eucalypt remnant amid Allocasuarina forest and in very dry boobyalla scrub. The largest number of web builders and ambushers on vegetation caught by methods other than pitfall trapping were in the interior of dense Allocasuarina forest (19 spiders, Fig. 5). This spider abundance decreased at the edge of the Allocasuarina forest and was lowest in heathland, very dry boobyalla scrub and tea tree/Bursaria scrub around the cave. The largest spiders in the sampled Prime Seal Island fauna were two burrowing spiders: the tube trapdoor, Stanwellia pexa (Nemesiidae) at 23 mm and Tasmaniaâ&#x20AC;&#x2122;s largest wolf spider, Tasmanicosa godeffroyi (Lycosidae), with a body length of 26 mm. Both were found where ground cover was grassy (native and pasture), a terrain for which T. godeffroyi is well adapted with long legs for running after prey such as butterflies. It was not possible to distinguish any particular species of Prime Seal Island spiders which showed an affinity with Tasmanian or with mainland species. For example, Myandra bicincta (Prodidomidae), Ambicodamus sororius (Nicodamidae), Tasmanicosa godeffroyi, Venatrix pseudospeciosa (Lycosidae), Cymbacha ocellata (Thomisidae) Stanwellia pexa (Nemesiidae) and Carelpaxis poweri (Araneidae) are widely distributed across Tasmania

and the southern mainland, while the latter genus includes a Gondwanan distribution. The disturbance history of the island is reflected by the presence of several small, introduced species: Oonops pulcher, Gmogala scarabaeus and Steatoda grossa. A number of spider species on the island were ground hunters that are thought to predate on antsâ&#x20AC;&#x201D;from which they are protected by their sclerotised bodies. They include Oonops pulcher, (Oonopidae), the colourful Dipoena setosa and Gmogala scarabaeus (Fig. 1) (Theridiidae). The latter was the most abundant adult species collected (21 individuals, Fig. 6), present in 13 samples out of 75 in a variety of habitats from Allocasuarina forest to heathland and dune grasses. Another myrmecophile, Myandra bicincta (Prodidomidae), has a pair of exceptionally long spinnerets on the middle of its ventral abdomen to rapidly spin silk to bind ants. Habronestes sp 1 (Zodariidae) is a member of a genus of spiders which contain species that emit an ant alarm pheromone to attract meat ants upon which it preys e.g. Habronestes bradleyi (Allen et al. 1996). Also present were Gnaphosidae which are larger predators known to mimic ants. An introduced spider, Dysdera crocata (Dysderidae) known to have an aversion to ants was absent from the collected spiders, further suggesting that ant-spider interactions may have shaped the spider fauna of the island. It would be interesting to compare the spider and ant data at some stage.

104

Generally the spider fauna reflected an assemblage adapted to dry habitat conditions, low numbers of litter-decomposing prey and an abundance of ants. Vagrant ground hunting spiders were dominated by Lycosidae, Gnaphosidae, Salticidae and some species of tiny, introduced Theridiidae. Foliage species included a diversity of Aranaeidae, Theridiidae and Thomisidae.

REFERENCES Churchill, T. (1993) Effects of sampling method on composition of a Tasmanian coastal heathland spider assemblage. Memoirs of the Queensland Museum 33,475-81. Coy, R., Greenslade, P., and Rounsevell, D. (1993) A survey of invertebrates in Tasmanian rainforest. Tasmanian NRCP Report No. 9. Parks and Wildlife Service, Tasmania, and Department of Arts, Sport, the Environment and Territories, Canberra. Main, B. (1999) Notes on the biogeography and natural history of the orbweaving spider Carelpaxis (Ananea, Araneidae), including a gumnut mimic from Southwestern Australia. The Journal of Arachnology 27,183-8. Allen, R., Elgar, M., and Capon, R. (1996) Exploitation of an Ant Chemical Alarm Signal by the Zodariid Spider Habronestes bradleyi Walckenaer, Proceedings Royal Society London 263, 69-73.


Figure 1. Photographs of some spiders from Prime Seal Island.

Neostorena sp1 (Zodariidae) 5.3mm

Habronestes sp 1 (Zodariidae) 5mm

Amaurobioidea sp 2 6.8mm

Dipoena setosus* (Theridiidae) 2mm

Gmogala scarabaeus* (Theridiidae) 1.8mm

Oonops pulcher* (Oonopidae) 3.8mm

Myandra bicincta* (Prodidomidae) 2mm

Argyrodes sp 1 (Theridiidae) 5.3mm

Thomisidae sp 2 4mm

Salticidae sp 2 4.2mm

Hedana sp1 (Thomisidae) 6mm

Dolophones maximus (Araneidae) 7.5mm

*=known to be associated with ants.

105


15

10

5

0 2

10 10

0

0 0

10 50

60

60

50

50

Species name Family

20

10

0

Species name Species name Family

25

Fig. 4 – Abundance and species richness of ground hunting spiders in pitfall traps in different habitats. 25

20

Families represented: Gnaphosidae, Linyphiidae, Lycosidae, Nemesiidae, Oonopidae, Prodidomidae, Salticidae, Theridiidae, 20 Zoridae. 20 Zodariidae, 15

60

Number of individual spiders

Number of spider species

405

30 0

Habitat type

106

Number of individual Number spiders of individual spiders

Number of spiderNumber species of spider species

20

20

18

18

16

16

14

14

12

10

12

8

10

8

Bursaria forest with grass understorey

Family Number of spiders

20

Boobyalla around pigface dominated clearing

4

30

Allocasuarina and teatree, grassy understorey

60

Allocasuarina forest with shrubby understorey - interior (B)

60

Prodidomidae Theridiosoma Nicodamidae Oonopidae Zoridae

60

40

Lycosidae Theridiidae Gnaphosidae Salticidae Araneidae Linyphiidae Lycosidae Zodariidae Theridiidae Amaurobioid Gnaphosidae Thomisidae Salticidae Nemesiidae Araneidae Prodidomidae Linyphiidae Theridiosoma Zodariidae Nicodamidae Amaurobioid Oonopidae Thomisidae Zoridae Nemesiidae

70

Number of spiders

70

Diverse mixed shrubby heath

0 14 10 12

Allocasuarina forest with shrubby understorey - track edge

2 80

Coastal grasses, Ozothamnus and pigface

4 80

Edge of dense Allocasuarina thicket

6 8

50

Interior of dense Allocasuarina thicket

8 105

Number

10 15 16

umber

12

Flowering tea tree beside track Linyphiidae sp 3 Salticidae sp 4 Eucalypt remnant amid Allocasuarina forestGnaphosidae sp 4 Very dry boobyalla scrub Linyphiidae sp 4

14

Araneidae Salticidae Lycosidae Number of species Number of individuals Theridiidae Gnaphosidae Linyphiidae Araneidae Gmogala scarabaeus Thomisidae SalticidaeTheridiidae sp 1 Amaurobioid Lycosidae Gnaphosidae sp 2 Zodariidae Theridiidae Neostorena sp 1 Nemesiidae Gnaphosidae Gnaphosidae sp 3 Nicodamidae Linyphiidae Salticidae sp 2 Oonopidae Thomisidae Linyphiidae sp 2 Prodidomidae Amaurobioid Lycosidae sp 9 Theridiosoma Zodariidae Theriidae sp 3 Zoridae Nemesiidae Amaurobioidea sp 2 Nicodamidae Araneus sp 1 Oonopidae Gnaphosidae sp1 Prodidomidae Gnaphosidae sp 6 Theridiosoma Salticidae sp 9 Zoridae Araneidae sp 3 Dipoena setosa Linyphiidae sp 3 Salticidae sp 4 Gnaphosidae sp 4 Linyphiidae sp 4

16

Gmogala scarabaeus Theridiidae sp 1 Gnaphosidae sp 2Number Number of individuals Neostorena sp 1 Gnaphosidae sp 3 Salticidae sp 2 Low tea tree scrub with grasses Gmogala scarabaeus Linyphiidae sp Theridiidae sp 21 Mature shrubby heath Lycosidae sp Gnaphosidae sp 92 Theriidae sp Grassland on dunes Neostorena sp 31 Amaurobioidea sp Gnaphosidae sp 23 Edge of low boobyalla dune scrub Araneus sp Salticidae sp 12 sp12 Myoporum scrub near house Gnaphosidae Linyphiidae sp Gnaphosidae sp 69 Lycosidae sp Allocasuarina forest with shrubby understorey Salticidae sp Theriidae sp 93 Araneidae sp Allocasuarina and tea tree, grassy understorey Amaurobioidea sp 32 Dipoena setosa Araneus sp 1 Sheep pasture Linyphiidae sp 3 Gnaphosidae sp1 Recently burnt low grassland with shrubsGnaphosidae Salticidae sp sp 46 Gnaphosidae sp 94 Salticidae sp Diverse mixed shrubby heath Linyphiidae sp 34 Araneidae sp Bursaria forest with grass understorey Dipoena setosa

Number of species

Fig. 2 – Numbers of species in each family. 20

umber

Number of individuals

25

Fig. 3 – Numbers of individual spiders in each

50

40

30

20

Family

18

16

14

12

10

8

6

4

2

0

Habitat ty

Numbe

Numbe


Number of species 12

10

8

6

4

2

0

Family

Habitat type

25

20

15

10

5

0

Species name

107

Fig. 6 â&#x20AC;&#x201C; The top 20 most abundant spider species sorted in decreasing order of abundance Lycosidae Theridiidae Gnaphosidae Salticidae Araneidae Linyphiidae Zodariidae Amaurobioid Thomisidae Nemesiidae Prodidomidae Theridiosoma Nicodamidae Oonopidae Zoridae

Teatree/Bursaria scrub around cave

Number of spiders

Very dry Boobyalla scrub

Heath

Allocasuarina forest with shrubby understorey

14

Grassland on dunes

16

Low teatree scrub with grasses

Number 18

Edge of low Boobyalla dune scrub

Mature shrubby heath

Araneidae Interior of dense Allocasuarina thicket Salticidae Lycosidae Edge of dense Allocasuarina thicket Theridiidae Coastal grasses, Ozothamnus and pigface Gnaphosidae Allocasuarina forest with shrubby understorey - track edge Linyphiidae Thomisidae Diverse mixed shrubby heath Amaurobioid AllocasuarinaZodariidae forest with shrubby understorey - interior (B) Nemesiidae Allocasuarina and teatree, grassy understorey Nicodamidae Boobyalla around pigface dominated clearing Oonopidae Prodidomidae Bursaria forest with grass understorey Theridiosoma Eucalypt remnant amid Allocasuarina forest Zoridae

2 16 0 14

Gmogala scarabaeus Theridiidae sp 1 Gnaphosidae sp 2 Neostorena sp 1 Gnaphosidae sp 3 Salticidae sp 2 Linyphiidae sp 2 Lycosidae sp 9 Theriidae sp 3 Amaurobioidea sp 2 Araneus sp 1 Gnaphosidae sp1 Gnaphosidae sp 6 Salticidae sp 9 Araneidae sp 3 Dipoena setosa Linyphiidae sp 3 Salticidae sp 4 Gnaphosidae sp 4 Linyphiidae sp 4

Number of individuals

Fig. 5 â&#x20AC;&#x201C; Abundance and species richness of web builders and ambushers on vegetation caught by methods other than pitfall trapping in different habitats.

Families represented: Amaurobiidae, Araneidae, Linyphiidae, Nicodamidae, Salticidae, Theridiidae and Thomisidae.

20

Number of individual spiders

Number of spider species

12

10

8

6

4

80

70

60

50

40

30

20

10 0

Family


TABLE 1 List of Araneae species collected from different habitat types on Prime Seal Island

Amaurobioidea Amaurobioidea sp. 1 Amaurobioidea sp. 2 Araneidae Araneidae sp. 1 Araneidae sp. 2 Araneidae sp. 3 Araneidae sp. 4 Araneidae sp. 6 Araneidae sp. 8 Araneidae sp. 9 Araneidae sp. 11 Araneidae sp. 13 Araneus sp. 1 Araneus sp. 2 Araneus sp. 3 Carelpaxis poweri Dolophones maxima Gnaphosidae Gnaphosidae juvenile Gnaphosidae sp. 1 Gnaphosidae sp. 2 Gnaphosidae sp. 3 Gnaphosidae sp. 4 Gnaphosidae sp. 5 Gnaphosidae sp. 6 Linyphyiidae Linyphyiidae sp. 1 Linyphyiidae sp. 2 Linyphyiidae sp. 3 Linyphyiidae sp. 4 Linyphyiidae sp. 5 Linyphyiidae sp. 7 Lycosidae Lycosidae juvenile Lycosidae sp. 1

H1 B1

B4

1 7

B2 H1

1 2 5 1 2 2 1 1 1 7 1 1 1 2

H1 B1 B2

S2

H1 S1 S2

B2 B1 B1 B1 B2

S3

S2

S1 B1 H1 B1

B1 P1 P1 P9 P1 P1

P1 P1

P2 P2 P4 P2 P1

P4 P1 P1

P1

P2 B1

P2 P5 P2 P3 P3 P1

P1

C1 C1 P1 P1

P1 P2 P1

P5 P1 P3 P1

B4 B1 P3

P1 P3 P1

P5 P1

108

Total

Sheep pasture

Coastal grasses, Ozothamnus and pigface

Boobyalla around pigface dominated clearing

Very dry Boobyalla scrub

Edge of low Boobyalla dune scrub

Grassland on dunes

Heath

Diverse mixed shrubby heath

Mature shrubby heath

Recently burnt low grassland with shrubs

Myoporum scrub near house

Bursaria forest with grass understorey

Teatree/Bursaria scrub around cave

Flowering teatree beside track

Low teatree scrub with grasses

Allocasuarina and teatree, grassy understorey

Allocasuarina forest with shrubby understorey –track edge

Allocasuarina forest with shrubby understorey –interior (B)

Interior of dense Allocasuarina thicket

Edge of dense Allocasuarina thicket

Allocasuarina forest with shrubby understorey

Eucalypt remnant amid Allocasuarina forest

Method of collection: B = beating, C = pitfall next to wallaby carcass, H = hand, P = pitfall, S = sweep Numbers refer to the number of specimens of a species collected in different habitats.

3 7 17 15 4 1 6 3 9 5 4 2 3 9 2


Lycosidae sp. 2 Lycosidae sp. 3 Lycosidae sp. 4 Lycosidae sp. 5 Lycosidae sp. 6 Lycosidae sp. 7 Lycosidae sp. 8 Lycosidae sp. 9 Tasmanicosa godeffroyi Venatrix pseudospeciosa Nemesiidae Stanwellia pexa Nicodamidae Ambicodamus sororius Oonopidae Oonops pulcher Prodidomidae Myandra bicinta Salticidae Salticidae juvenile Salticidae sp. 1 Salticidae sp. 2 Salticidae sp. 3 Salticidae sp. 4 Salticidae sp. 5 Salticidae sp. 6 Salticidae sp. 7 Salticidae sp. 8 Salticidae sp. 9 Salticidae sp. 10 Salticidae sp. 11 Salticidae sp. 12 Salticidae sp. 13 Theridiidae Argyrodes sp 1 Achaeranea sp. 1 Achaeranea sp. 2 Gmogala scarabaeus Dipoena setosa Steatoda grossa Theridiidae sp. 1 Theridiidae sp. 2 Theridiidae sp. 3 Theridiosommatidae

39 2 1 1 P1 1 P1 1 1 8 H1 1

P2 P1 P1

P1 P8

P1 H1

H2 P1

1

P1

1

P1

P1 P1

P1

B1 P1

4 B1

2 1 P3 P1 P1 C1 11 P1 1 P4 5 1 4 1 1 B1 B3 6 1 1 1 1

P1 P4 P1 P1 P1

H1

H1

P1

S1 S1 B1 B1 B1 B1 B1 P1 H1

1 1 1 24 5 1 18 1 8

P1 B1 P2

P1 P6 P1

P6 P1

P4 P5 P3

P1 B1 P1

B14

S1 L1

B1 B3

B3

B2 B1

1 1

B1 H1

1 1 2 2 2

B1 B1

B1 B2 B1

B1 P1 P1 P10

P1

4

1 4

B1

Theridiosommatidae sp. 1 Theridiosommatidae sp. 2

Thomisidae Cymbacha ocellata Diaea sp. 1 Hedana sp. 1 Thomisidae sp. 1 Thomisidae sp. 2 Zodariidae Habronestes sp. 1 Neostorena sp. 1 Zoridae Zoridae sp. 1 Total

P2

P37

13 12 19

4

8

16 52

1 16

P1 P3

1

109

1

8

P1 15 10 53 10

1 1

35 31

2

4

9

9

317


T HE MOTHS

110


Aeolochroma sp. Illustration by Georgina Davis.

By Abbey Throssell This is the first account of moths on this large Furneaux Island. Forty-nine Lepidoptera species in 16 different families were identified, from 132 specimens. Nearly half of these were from three families: Geometridae, Noctuidae and Tortricidae. An undescribed geometrid moth, Aeolochroma sp., is a new record for Tasmania. A species of Stathmopoda (Oecophoridae), was also identified as a new record for Tasmania. There were several other possible new records and/or undescribed species collected. The most abundant moth found on the island was the geometrid Chrysolarentia insulsata, which occurs in New South Wales, Victoria and Tasmania.

INTRODUCTION There are no known previous records of Lepidoptera (or any other invertebrates) from Prime Seal Island. Therefore, collection methods were primarily aimed at collecting as many species as possible. Sweeping and hand collecting especially were largely opportunistic rather than systematic, and more time was spent in areas where more invertebrates seemed to be present.

METHODS Detailed description of collection methods and sites is given in a separate report by Kevin Bonham. Specimens were sorted into

morphospecies, and identified at least to family and to species level where possible. This report deals only with Lepidoptera from sweeping, beating and hand collections; specimens collected in pitfall traps, and a small number of others that were stored in alcohol, have not been identified and are not included here. Specimens have been lodged with the Tasmanian Museum and Art Gallery.

RESULTS AND DISCUSSION A total of 49 Lepidoptera species in 16 different families were identified, from 132 specimens collected by hand, sweep netting and in light traps. Nearly half of these species were from three families: Geometridae, Noctuidae and Tortricidae. More than half of the species collected were represented by only a single specimen, which suggests that further sampling, especially at different times of the year, would likely lead to many other species being found. Names, totals, collection methods and sites for all species are given in Appendix 1. An undescribed geometrid moth, Aeolochroma sp., is a new record for Tasmania. This is a coastal species, usually found on the south coast of Victoria and southern Australia. The larvae feed on low Beyeria or Melaleuca scrub (P. McQuillan, University of Tasmania, pers. comm.), both of which are present on the island. The single specimen was hand

111

collected in the evening, near a light outside the homestead. There were several other possible new records and/or undescribed species collected. A species of Stathmopoda (Oecophoridae), also collected at the homestead light, was identified as a new record for Tasmania. One species of tortricid, known to feed on Beyeria, is undescribed. Two other tortricid species (subfamility Olethreutinae) and one species of Lepidoscia may also be undescribed (P. McQuillan, University of Tasmania, pers. comm.). A member of the species group Microdes villosata (Geometridae) was collected at the homestead light and in UV bucket traps. The species usually referred to by this name is known to feed on Acacia; however, Acacia plants are rare on the island, the species found may be an undescribed member of the M. villosata species group (P. McQuillan, University of Tasmania, pers. comm.). One specimen of Microdes diplodonta was also collected from the homestead light. The most abundant moth found on the island was the geometrid Chrysolarentia insulsata, which occurs in New South Wales, Victoria, Tasmania and South Australia (Zborowski and Edwards 2007). It was seen during the day in large numbers, especially in pasture and grassland, and collected by both daytime sweep netting and light traps at night. Another very common moth was the undescribed


noctuid known as Ectopatria “DPILMbrownshortpecten”, of which many were seen at night and caught in light traps. Ten species of noctuid moths were collected, although one of these, Dasypodia selenophora, was identified only from its distinctivelypatterned wings lying inside the small cave on the island. The others were all collected in UV bucket traps and/or at the house light, with only one specimen of Agrotis infusa, the bogong moth, caught in daylight. A. infusa is well known for its mass migrations south and east in spring, to escape the summer heat of mainland breeding grounds, before returning to those breeding grounds for the winter. Two of the other noctuids, Agrotis munda and Persectania ewingii, are also known to migrate south in large numbers. All three species, along with Agrotis porphyricollis and Diarsia intermixta, are pests of various crops.

The vast majority of Lepidoptera species were collected at night, either in light traps or at the homestead light, though a number of these were also collected during the day. A number of species were found only in UV light traps, and conversely, some were hand collected at the homestead light and seen nowhere else, including the single specimen of Aeolochroma sp. A few species were collected solely during the day, by sweep netting, beating and/ or hand collecting. These included the butterflies Vanessa kershawi and V. itea, the magpie moth Nyctemera amica, the tortricid “Tortrix” standishana, and the arctiid Halone sejuncta. It was therefore valuable to use a range of different collecting methods, so as to cover a wide range of habitats and activity periods of different species.

112

ACKNOWLEDGEMENTS Many thanks to Cathy Young, Peter McQuillan and Lionel Hill for identification of, and comments on, many specimens, and to all on the PSI expedition team for their assistance with collection and documentation of invertebrates.

REFERENCES Zborowski, P. and Edwards, T. (2007) A Guide to Australian Moths. CSIRO Publishing.


Hand (at light)

Sweep/hand

Hand

Hand

Hand

Hand

Hand

Hand

Hand

Hand

Hand

Hand

Hand

Hand

Hand

Hand

Hand

Beat

Beat

Sweep

Light trap

Light trap

Light trap

Light trap

Species/site

HC5

HC11

HC12

HC13

HB15

HC16

HC32

HC35

HC36

HC37

HC38

HC40

HC42

EF

WC1

P2

SB3

SB5

SB6

LT1

LT2

LT3

LT4

Geometridae

Chrysolarentia insulsata

3

21

Geometridae

Epyaxa hypogramma

2

1

Geometridae

Microdes villosata (grp.)

3

Geometridae

Microdes diplodonta

1

Geometridae

Aeolochroma sp.

1

Geometridae

Neritodes verrucata

Geometridae

Scopula perlata

1

Noctuidae

Agrotis infusa

1

Noctuidae

Agrotis munda

1

Noctuidae

Agrotis porphyricollis

1

Noctuidae

Diarsia intermixta

Noctuidae

Ectopatria “DPILMbrownshortpecten”

4

Noctuidae

“Leucania” exarans

1

Noctuidae

Persectania ewingii

1

Noctuidae

Proteuxoa nr. melanographa 1

1

Noctuidae

Proteuxoa nr. melanographa 2

Collection method Family

HC1

APPENDIX 1

Nyctemera amica Damias procrena

Arctiidae

Halone sejuncta (?)

Arctiidae

Thallarcha jocularis

Arctiidae

Thallarcha pellax

1

Tortricidae

Capua sp. (Tortricinae)

1

Tortricidae

Epiphyas nr. posvittana

1

Tortricidae

Ericodesma liquidana

1

Merophyas divulsana

1

1 1

1

1

2

1 1

2

1

1

1 1

2

2

2

1

1 1 1 1 1 1 1

1 1 2

2

Tortricidae

“Tortrix” standishana

Tortricidae

Crocidocema plebejana

1

Tortricidae

Olethreutinae sp. 1

1

Tortricidae

Olethreutinae sp. 2

Tortricidae

undescribed Tortricidae

Oecophoridae

Stathmopoda sp.

Oecophoridae

Oxythecta sp. 1

Oecophoridae

Oxythecta sp. 2

Oecophoridae

Zacorus carus

Depressariidae

Eutorna sp.

Gelechiidae

Unidentified Gelechiidae

Psychidae

Lepidoscia sp. Unidentified Phycitinae

1

4

Arctiidae

Faveria tritalis

3

1

Dasypodia selenophora

Pyralidae

1

1

Arctiidae

Pyralidae

1

1

Noctuidae

Tortricidae

1

1

1

1 1 1 2 1

3 1

1 1 1 1

2 1 1

Crambidae

Eudonia sp.

Anthelidae

Anthela nicothoe

3

Anthelidae

Anthela ocellata

1

Nymphalidae

Vanessa itea

Nymphalidae

Vanessa kershawi

Pterophoridae

Wheeleria sp.

Lymantriidae

Acyphas semiochrea

Tineidae

Monopis ethelella

Plutellidae

Plutella xylostella

1

Specimens

37 27 1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

10 4

11 25

Species

27 6

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

6

9

1 1 1 1

1

1 1 1

1

113

1

4

16


O BSERVATIONS on ORTHOPTERA

114


Austracris guttulosa. Photo by Michael Driessen.

By Michael Dr iessen Three species of Orthoptera and several unidentified immature Acrididae were recorded on Prime Seal Island. A survey conducted during summer or autumn would substantially increase this species list for the island. A notable discovery was the Flinders Cave Cricket Carvernotettix flindersensis in Manalargenna Cave; a species previously known only from Flinders, Babel and Little Dog Island. The spurthroated locust Austracris guttulosa, a vagrant from the Australian mainland, is believed to be the first record of this species for eastern Tasmania with all previous records occurring in north west Tasmania.

INTRODUCTION Sixty three described species of Orthoptera in 10 families have been recorded in Tasmania (Semmens et al. 1992) which represents about 4% of Australian species and 50% of Australian families. Twenty three species (37% of Tasmanian total) are endemic to Tasmania and most of these (14 species) are crickets in the family Rhaphidophoridae (cave/camel crickets). Prime Seal Island has not previously been surveyed for Orthoptera and it appears that no systematic surveys of the Furneaux islands have been undertaken. However, a number of taxonomic papers contain records of ten species in four families for the eastern Bass Strait islands (Table

1). Notable among these records are four species in two genera (Parvotettix and Cavernotettix) of Rhaphidophoridae that are restricted to the Furneaux and Kent islands. The Rhaphidophoridae of the Bass Strait islands are of significant interest because they have potential to provide insights into speciation and land connections between the islands, and between mainland Australia and Tasmania, during the Pleistocene. Rhaphidophoridae are wingless insects, extremely sensitive to temperature changes and requiring very high relative humidity which severely limits their ability for dispersal across water. Current distribution evidence supports a Tasmanian origin for Parvotettix and an Australian mainland origin for Cavernotettix (Richards 1974). Prime Seal Island has the potential to support Rhaphidophoridae given the presence of caves and seabird rookeries and, should they occur there, it is of interest to determine whether it supports its own species or a previously described one. The aim of this report is to document observations made on Orthoptera during a short survey in October 2008 on Prime Seal Island.

METHODS Observations of Orthoptera were made by the author during four day visit to the island in October 2008. Additional Orthoptera were collected by Kevin Bonham and Abbey Throssell as part of their

115

invertebrate surveys and their sampling methods are detailed elsewhere in this report (Bonham this volume).

RESULTS AND DISCUSSION Acrididae (locusts and grasshoppers) Austracris guttulosa Spur-throated Locust Two adult females were collected and several other adults were observed in the coastal grass and herbfield vegetation on the western side of the island. This species breeds in northern parts of mainland Australia but ventures south into localities where they do not successfully breed (Rentz et al. 2003). No juveniles were observed which is consistent with this species being a vagrant. The species has occasionally been recorded on parts of north west Tasmania including King Island (Table 2). This is believed to be the first record of this species from eastern Tasmania and the Furneaux Islands Juvenile Acrididae Eight immature grasshoppers were collected by hand, pitfall trapping, sweeping and beating by Kevin Bonham and Abbey Throssell as part of their invertebrate surveys. These specimens were early instars and were difficult to assign to a species or genus with confidence. They all appeared to be one species and


their features were most consistent with that of the Southeastern Austroicetes Austroicetes vulgaris (Rentz et al. 2003).

Rhaphidophoridae (cave cr ic kets/camel cr ic kets) Cavernotettix flindersensis Flinders Cave Cricket A search of the rear chamber in Manalargenna Cave during daylight hours on two separate days revealed a small population of cave crickets. A total of 34 crickets were observed comprising 26 adult males, 4 adult females and 4 juveniles. Apart from two juveniles occurring on the wall near the cave floor, all crickets occurred on the domed ceiling. All adult females were in one small rounded crevice in the ceiling with an adult male. Other adult males were scattered around the ceiling or in other crevices.

Two adults of each sex were collected from the cave for the purposes of identificationâ&#x20AC;&#x201C;which could only be done with the aid of a microscope. The characteristics of the suranal and subgenital plates were consistent with those described for Cavernotettix flinderensis (Richards 1967). The presence of this species on Prime Seal Island, as opposed to a new and endemic species, makes sense given the proximity of the Prime Seal Island to known populations of C. flindersensis and the history of land connection between Prime Seal Island and Flinders Island. C. flindersensis is known from Flinders Island, Babel Island and Big Dog Island (Richards 1967, 1974). Notably the species has been recorded from North Pats River on Flinders Island which is immediately east of Prime Seal Island. Since the last interglacial about 120 000 years ago, a land connection existed between

116

Prime Seal Island and Flinders Island more often than not and the last connection was approximately 8 000 years ago (Eberhard this volume).

Gr yllacrididae (raspy crickets) Kinemania sp.2 A single juvenile female raspy cricket was found on a track adjacent to the Allocasuarina verticillata forest while spotlighting. In Tasmania there is one described species of raspy cricket (K. ambulans) and two undescribed species (Rentz and John 1990). This individual is consistent with the features provided by Rentz and John (1990) for one of the two undescribed species, Kinemania sp. 2. It had 3 spines on the middle tibia and the hind tibia was distinctly quadrate with a flat dorsal surface bearing distinct spines.


Cavernotetrix flindersensis (captive specimen from PSI photographed in Hobart). Photo by Michael Driessen.

TABLE 1 Known records of Orthoptera for the eastern Bass Strait Islands Taxa

Location

Source

Minyacris nana

Cape Barren Island Fisher Island Flinders Island

(Key 1992)

Phaulacridium vittatum

Cape Barren Island Flinders Island

(Key 1992)

Tasmaniacris tasmaniensis

Cape Barren Island Flinders Island

(Key 1991)

Austroicetes vulgaris

Babel Island Flinders Island Great Dog Island

(Key 1954)

Flinders Island

(Key 1972)

Cape Barren Island

(Otte and Alexander 1983)

Cavernotettix flindersensis

Babel Island Flinders Island Little Dog Island

(Richards 1974)

Cavernotettix craggiensis

Craggy Island

(Richards 1974)

Parvotettix whinrayi

Kent Group islands (Erith, Dover, North East Island, Deal Island)

(Richards 1974)

Parvotettix rangaensis

Cape Barren Island Flinders Island

(Richards 1971)

Acrididae

Pyrgomorphidae Psednura pedestris Gryllidae Bobilla tasmani Rhaphidophoridae

TABLE 2 Previous records of Austracris guttulosa for Tasmania. Location

Observer

Date

Accession No.

Devonport, K-Mart carpark

L. Hill

2 Sep1992

33038

Devonport, Stony Rise

L. Hill

1 Apr 1996

51268

King Island

A.B Wherrett

Aug 1943

51269

Smithton

L. Hill

17 Apr 1992

33037

Devonport, Stony Rise

P. Gardam

4 Apr 2008

103896

East Devonport, TT Line wharf

F. Viney

17 Apr 2008

103897

Source: DPIPWE Invertebrate Collection, New Town

117


Photo by Nick Mooney.

CONCLUSION

REFERENCES

Only a small number of Orthoptera species were recorded on Prime Seal Island, largely reflecting the time spent searching and the time of year the survey was undertaken. A survey undertaken in summer or autumn would substantially increase the species list for the island and would include several of the species already known from other islands in the Furneaux group. The survey has resulted in the first record of the spur-throated locust from eastern Tasmania, the first record of a raspy cricket from the eastern Bass Strait Islands and a range extension for an endemic Furneaux island cave cricket.

Bonham, K. (2009) Invertebrate Survey of Prime Seal Island. This volume. Eberhard, R. (2009) Geodiversity of Prime Seal Island. This volume. Key K. H. L. (1954) The taxonomy, phases, and distribution of the genera Chortoicetes Brunn. and Austroicetes Uv. (Orthoptera: Acrididae). CSIRO, Canberra. Key K. H. L. (1972) A revision of the Psednurini (Orthoptera: Pyrgomorhpidae) Australian Journal of Zoology Supplementary Series 14, 1–72.

ACKNOWLEDGEMENTS

Key K. H. L. (1991) On four endemic genera of Tasmanian Acrididae (Orthoptera). Invertebrate Taxonomy 5, 241–88.

Thanks to Craig Read, Liz Turner and Cathy Young for searching their museum records for records of Austracris guttulosa.

Key K. H. L. (1992) Taxonomy of the genus Phaulacridium and a related new genus (Orthoptera: Acrididae). Invertebrate Taxonomy 6, 197–243. Otte D. & Alexander R. D. (1983) The Australian Crickets (Orthoptera: Gryllidae). The Academy of Natural Sciences Philadelphia. Monagraph 22, Philadelphia.

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Rentz D. C. F. & John B. (1990) Studies in Australian Gryllacrididae: Taxonomy, Biology, Ecology and Cytology. Invertebrate Taxonomy 3, 1053–210. Richards A. M. (1967) The Rhaphidophoridae (Orthoptera) of Australia. Part 5. The Rhaphidophoridae of Flinders Island. Proceedings of the Linnean Society of New South Wales 92, 151–6. Richards A. M. (1971) The Rhaphidophoridae (Orthoptera) of Australia. Part 9. The distribution and possible origins of Tasmanian Rhaphiophoridae, with descriptions of two new species. Pacific Insects 13, 575–87. Richards A. M. (1974) The Rhaphidophoridae (Orthoptera) of Australia. Part II. Pacific Insects 16, 245–60. Semmens T. D., McQuillan P. B. & Hayhurst G. (1992) Catalogue of the Insects of Tasmania. Department of Primary Industry Tasmania, Hobart.


119


B IRDS

120


White-bellied Sea-eagle. Photo by Dylan van Winkel.

By Nick Mooney

RESULTS

This survey is arguably the most comprehensive for avifauna in the locality yielding 47 bird species observed. A surprising record was a pair of wedge-tail eagles. No presently used nest of this species was found on the island although a disused nest was observed from a low aerial inspection.

RECORDS

INTRODUCTION There is no exhaustive list of birds published from Prime Seal island, the only useful list coming from Brothers et al. (2001). The opportunity of having several experienced observers on an island in Bass Strait for 5 days was an invaluable opportunity to contribute to our knowledge of the biogeography of avifauna in eastern Bass Strait.

METHODS Birds were recorded from 14 to 19 October 2008 using binoculars and telescope by three experienced observers in the course of other surveys, each covering about 80km and occasional specific survey as several excursions looking for eagle nests and searching beaches. Habitat coverage was therefore not systematic and bias undoubtedly exists toward those areas frequented (near the farmhouse at Peacock Bay, North Hill and open pasture, low scrub, and coast in between).

and immature offshore.

1. Brown Quail Coturnix ypsilophora Irregularly flushed in small covies of 3-5 individuals. 2. Cape Barren Goose Cereopsis novaehollandiae At least 10 broods seen varying in age from 1 week old to fledging and in number from 1 to 4 goslings. Estimated that about 50 goslings were produced, mainly on the south but also scattered along the east and centre. Seven recent nests found, mainly under boobyalla. 3. Grey Teal Anus gracilis A flock of 5 regularly seen in east coast rocky bays. 4. Little Penguin Eudyptula minor Commonly seen pursuing fish close in shore on the east in less than 1m of water at all tides 5. Common Diving-petrel Pelecanoides urinatrix Several seen within 2 km of the island while travelling to the island by boat. 6. Short-tailed Shearwater Puffinus tenuirostris Several old, beachwashed carcasses along the tide-line. 7. Black-browed Albatross Diomedea melanophris Reasonably common as adults

121

8. Australasian Gannet Morus serrator Commonly patrolling along all coastlines and at times 50+ diving close inshore in late afternoon along the seagrass/ sand interface in 2-4m of water. Snorkelling survey showed their prey appeared to be Pilchards Sardinops neopilchardus, apparently common in that area. 9. Black-faced Cormorant Phalacrocorax fuscescens Common offshore in particular in areas of strong current on the north of the island. A daytime roost of 20+ on a large boulder on the northeast tip. 10. Australian Pelican Pelecanus conspicillatus Several adults seen irregularly in sheltered waters on east and west coast, flying over the island and on the north east beaches. 11. White-faced Heron Egretta novaehollandiae Reasonably common around all rocky shoreline. One seen catching crabs on east coast rock shelving at low tide. 12. White-bellied Sea-eagle Haliaeetus leucogaster A nest was previously known from just inshore of Koh-i-Noor Rocks on the southern east coast. The nest was in a broken Allocasurina about 1/5 up the hill. The nest is visible by telescope from the farm house and at


Hooded Plovers. Photo by Dylan van Winkel.

almost all times an adult was sitting on the nest suggesting either eggs or very young chicks. From below with telescope, remains of little penguin were seen on the nest edge. An adult was seen to leave the nest to catch and eat what appeared to be small fish on the sand flats inside the above rocks on an ebb tide. One adult seen flying in from several km out to the south east. Estimated only 1 pair. 13. Wedge-tailed Eagle Aquila audax fleayii A surprise record. A pair, mostly seen laminar soaring over North Hill. At times they were airborne for over 4 hrs and on one occasion appeared to be completely stationary for 40 minutes while under telescope observation. One individual (the larger, assumedly the female) was unusually vocal and made a low pass over NJM whilst on top of North Hill. The male was

seen by NJM gliding north from the area of Wolff Bay with a mature Cape Barren Goose in its talons at 0620 one morning. Telescope surveillance and a ground-based nest search was ineffective because of dense scrub. An empty nest in an Allocasuarina (the first such record in Tasmania) was located up in a depression on the north east face of North Hill during a private survey using John Duiganâ&#x20AC;&#x2122;s ultralight aircraft (JD the pilot, NJM the observer). 14. Brown Falcon Falco berigora Adult pairs very active with territorial displays and low quartering hunting. Estimated 6 pairs (NJM). Only adults were seen. One pair was seen (NJM) flying directly east toward Flinders Island until out of sight. One was seen eating a European Goldfinch and another briefly (unsuccessfully) pursuing a

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Hooded Plover and another a Richardâ&#x20AC;&#x2122;s Pipit (result unknown) (NJM). 15. Ruddy Turnstone Arenaria interpres A flock of 4 regularly seen on the north east corner. 16. Pied Oystercatcher Haematopus longirostris Common along all beaches. Three nests seen all with eggs. No chicks seen. Estimate 20+ pairs. 17. Sooty Oystercatcher Haematopus fuligonosus Less common. No nests seen. Estimate 10 pairs. 18. Hooded Plover Thinornis rubricollis Pairs seen at Peacock Bay and Spit Point but incomplete survey. 19. Banded Lapwing Vanelles tricolor One pair seen and again heard inland from Peacock Bay.


Blue-winged Parrot. Photo by Dylan van Winkel.

20. Masked Lapwing Vanelles miles Two pairs with one young usually inland from Peacock Bay, another with one young inland from Split Point and possibly the same birds along the eastern slopes of Target Hill. Very nervous. Breeding appeared finished. Incomplete survey. Estimate 5 pairs. 21. Pacific Gull Larus pacificus Common around the coast and regularly crossing the island. Seen mobbing both (flying) White-bellied Sea-eagles and Wedge-tailed Eagles. No breeding survey. 22. Silver Gull Larus novaehollandiae Common around the coast. Not overly inclined to fish offal. Seen mobbing White-bellied Seaeagles, Brown Falcons and Forest Ravens. 23. Caspian Tern Sterna caspia Uncommon, occasionally seen along north east coast. Only 1 pair confirmed. 24. Crested Tern Sterna bergii Commonly seen along the east coast. Day roost for 25+ on large rocks north west of Split Point. 25. Brush Bronzewing Phaps elegans Individuals were seen both in

open paddocks, on tracks and in tea tree, typically exiting the latter at the last minute with explosive vertical flight (even more typically causing near-heart stoppage of passing people). 26. Green Rosella Platycercus caledonicus A pair was seen just inland from Peacock Bay early in the survey. There were no more records. 27. Blue-winged Parrot Neophema chrysostorna A pair were seen in dense scrub on Target Hill a day after a strong north-westerly change on 17th October. There were no more records. 28. Fan-tailed Cuckoo Cacomantis flabelliformis There were uncommon sightings until a day after a strong northwesterly change on 17th

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October when they appeared to be much more common. One was being scolded by Tasmanian Scrubwrens and White-fronted Chats. 29. Horsfieldâ&#x20AC;&#x2122;s Bronze-cuckoo Chrysococcyx basalis One record until a day after a strong north-westerly change on 17th October when they appeared to be much more common and often seen typically calling from the tops of trees. 30. Tasmanian Scrubwren Sericornis humilis This species was relatively common in all scrubby habitats at times including bushes and small trees isolated in paddocks, habitually roosting in African Boxthorn adjacent to the farmhouse behind the Peacock Bay beach.


31. New Holland Honeyeater Phylidonyris novaehollandiae This species was uncommon, usually being recorded amongst tall tea-tree between Target and North Hill. A dead one was found at the mouth of Mannalargenna Cave on Target Hill. 32. Tawny-crowned Honeyeater Phylidonyris melanops A pair were twice seen (and heard) in scrub above Sealers Cove. 33. White-fronted Chat Epthianura albinfrons This was one of the more abundant small birds and occurred in all grassy habitats around the island, even Poa above beach tide-lines. Several nests with 3 eggs were found (usually by back-tracking from adult distractive displays). 34. Grey Fantail Rhipidura fuliginosa This was one of the more abundant (and obvious) small birds and occurred in all tall scrubby habitats around the island at times including bushes and small trees isolated in paddocks.

35. Black-faced Cuckoo-shrike Coracina novaehollandiae This species was not recorded until a day after a strong northwesterly change on 17th October when it was then locally abundant. One was seen to catch a small skink (NJM). 36. Dusky Woodswallow Artamus cuanopterus This species was not recorded until a day after a strong northwesterly change on 17th October when a small flock of 9 individuals was seen coming in from the north to the top of North Hill (NJM). What were probably these birds were later seen in a loose flock hawking from high perches on the eastern slope of Target Hill. 37. Black Currawong Strepera fulinosa This was an obvious, relatively abundant species seen in most habitats including foraging under seaweed along tide-lines. One was seen being mobbed by Silver Gulls and another by a grey Fantail (NJM). Often seen mobbing Brown Falcons. Pellets that likely came from Black Currawongs contained at least Christmas beetle wing covers

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(genus unknown) and seeds from Pimelea serpyllifolia and they were seen feeding on the latter (NJM) 38. Forest Raven Corvus tasmanicus This was an obvious, relatively abundant species seen in most habitats including foraging under seaweed along tide-lines. It regularly mobbed raptors and was in turn occasionally mobbed by Silver Gulls and Crested terns, Masked Lapwing, Black Currawong and Black-faced Cuckoo-shrikes. There were occasional vigorous disputes with Brown Falcons inland from peacock bay, probably over nests in Allocasurina there. 39. Skylark Alauda arvensis This was an obvious, relatively abundant species seen over most pastures, typically hovering and calling then diving to ground. Several nests with eggs (2, 3 and 4) in exposed pasture were seen along the eastern slopes of Target Hill (NJM). 40. Richardâ&#x20AC;&#x2122;s Pipit Anthus novaehollandiae This was an obvious, relatively abundant species seen over most pastures and venturing into


Black Currawong. Photo by Dylan van Winkel.

low scrub. Several individuals were unusually confiding inland from Peacock bay and displayed breeding behaviour although no nests were seen. 41. Beautiful Firetail Stagonopleura bella Uncommon generally although commonly heard in dense tea tree thickets south of Peacock Bay and between Target Hill and North Hill. One occasionally seen in African Boxthorn adjacent to the farmhouse behind the beach at Peacock Bay. Several old nests found in tea-tree. 42. European Goldfinch Carduelis carduelis An uncommon species recorded in most pastures and weedy areas, occasionally (and unusually) individuals being seen and heard crossing exposed habitats at height. One (not surprisingly) was seen being eaten by a Brown Falcon (NJM). One was seen collecting nesting material (NJM). 43. Welcome Swallow Hirundo neoxena Pairs frequented the areas of Mannalargenna Cave (several old nests, one with chicks within) the top of North Hill and the area of the farmhouse behind the beach of Peacock Bay. Several were hunting Marsh Flies themselves hunting people along Peacock Bay beach.

44. Silvereye Zosterops lateralis This species was common in most scrubby habitat. Individuals were seen feeding on berries on African Boxthorn (NJM). 45. Common Starling Sternus vulgaris This invasive species was surprisingly uncommon and a small flock of 7 was regularly seen foraging in open pasture and along the shore-line. 46. Ring-necked (Common or Mongolian) Pheasant Phasianus colchichus A few pairs of this invasive species were seen around the island and one old nest was found behind Peacock Bay. 47. Indian Peafowl (peafowl, Peacock or Peahen) Pavo cristarus A few individuals including at least one male with full display tail were seen Peacock Bay. They were often heard and evidence of their foraging often seen in this area.

was clear on several occasions that mobile species (eg brown falcon) freely travel between the island and Flinders Island. Several species listed by Brothers et al. (2001) were not recorded and vice versa but with such low numbers of individuals such differences can occur by chance. Arrivals of migratory species (eg dusky wood-swallows) seemed to be closely associated with north westerly fronts. Despite continued control by trapping and shooting, numbers of feral cats remain on the island. Although analysis of cat scats suggest house mice are a main dietary item, pressure is probably maintained on bird populations by cats. It is possible that house mice themselves exert a pressure on species such as whitefronted chats and brown quail. 1. Eradication of cats would be possible and seems an obvious step in reconstituting such islands. It might be especially useful since Prime Seal Island, with its large population of wallabies, would seem a possible translocation site for Tasmanian devils in managing Devil Facial Tumour Disease.

GENERAL DISCUSSION & MANANGEMENT RECOMMENDATIONS

2. Better fencing to keep sheep from some prime areas of original habitat may benefit birds on Prime Seal Island.

The bird list is typical of what might be found in similar habitat on Flinders Island (Green 1969), except for nesting Cape Barren geese. None of these species would likely be restricted to the island and it

3. Fire should be carefully managed on the island

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4. The eagle nests should be avoided during early springsummer.


Table 1 List of birds observed on Prime Seal Island and the vegetation habitats in which they were observed NAV

NAV

SCA

SHC

GHC

SRC

GLC

OSM

PEP

FAG

Brown Quail

X

X

X

Cape Barren Goose

X

X

X

FWU

FRG

ARS

TPR

SEA

X

Grey Teal

X

X

Little Penguin

X

Common Divingpetrel

X

Short-tailed Shearwater

X

Black-faced Cormorant

X

Australasian Gannet

X

Black-browed Albatross

X

Australian Pelican

X

White-faced Heron

X

White-bellied Seaeagle

X

X X

Wedge-tailed Eagle

X

X

X

Brown Falcon

X

X

X

Ruddy Turnstone

X

Pied Oystercatcher

X

Sooty Oystercatcher

X

Hooded Plover

X

Banded Lapwing

X

Masked Lapwing

X

X

Pacific Gull

X

X

X

Silver Gull

X

X

X

Caspian Tern

X

X

Crested Tern

X

X

X X

Horsfieldâ&#x20AC;&#x2122;s Bronze-cuckoo

Striated Fieldwren

X X

Blue-winged Parrot

Tasmanian Scrubwren

X

X

Green Rosella Fan-tailed Cuckoo

X

X X

Brush Bronzewing

X

X

X

X X

X

X X

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New Holland Honeyeater

X

Tawny-crowned Honeyeater White-fronted Chat Grey Fantail

X

Black-faced Cuckoo-shrike

X

X

Dusky Woodswallow

X

X

X

X

X

X X X

Black Currawong

X

X

X

X

X

Forest Raven

X

X

X

X

X

Skylark

X

X

Australian (Richard’s) Pipit

X

X

Beautiful Firetail

X

X

European Goldfinch Silvereye

X

X

X

Welcome Swallow

X

Common Starling

X

Ring-necked Pheasant

X

Peacock

X

X X

X

(NAV= Allocasuarina verticillata forest; DOW= Eucalyptus ovata forest and woodland; SCA= Coastal scrub on alkaline sands; SHC=Heathland on calcarenite; GHC=Coastal grass on herbfield; SRC=Seabird rookery complex; ARS= Saline sedgeland/ rushland; GLC= lowland grassland complex; OSM= SandMud; FPF= Pteridium esculentum fernland; FAG= agricultural land; FWU= Weed infestation; FRG= Regenerating cleared land. (nomenclature follows Harris and Kitchener 2005)

ACKNOWLEDGEMENTS

REFERENCES

John Duigan for the voluntary use of his ultra-light in checking and searching for eagle nests.

Brothers, N., Pemberton, D., Pryor, H. & Halley, V. (2001) Tasmania’s Offshore Islands: Seabirds and Other Natural Features. Tasmanian Museum and Art Gallery: Hobart. Green. R. H. (1969) The Birds of Flinders Island. Records of the Queen Victoria Museum No. 34.

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Harris, S. & Kitchener, A. (2005) From Forest to Fjaeldmark: Descriptions of Tasmania’s Vegetation. Department of Primary Industries, Water and Environment. Printing Authority of Tasmania. Hobart. Whinray, J.S. (1971) A note on Prime Seal Island. The Tasmanian Naturalist 27: 1-4.


N OTES on

NEARSHORE FISHES

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Shawâ&#x20AC;&#x2122;s Cowfish. Etching by Brett Littleton.

By Nick Mooney Fifty-one fish species were recorded inshore on a small portion of the east coast of Prime Seal Island in eastern Bass Strait. The species are typical of what could be expected to be observed in this locality.

To give a measure of abundance, each species seen alive was scored using a Log3 scale as 1 = 1-2 individuals 2 = 3-9 individuals 3 = 10-25 individuals 4 = 26-80 individuals

INTRODUCTION The inshore fish fauna of Tasmania is generally well known although detailed site surveys at remote locations such as Prime Seal Island contribute to the confidence we can develop in predicting the fish fauna around the coast.

METHODS Survey was by snorkelling for approximately 200 m south of the farmhouse just inland from the beach on Peacock Bay. Survey was from the high tide mark to 4m depth and encompassed sandy bottom, rocky headlands and seagrass beds. Three swims each of 1 hour were carried out over the same ground at different stages of tide. A small underwater torch was used to aid survey in crevices. Rocks were not overturned. Fish names follow Last et al (1983).

5 = 81-250 individuals 6 = 251-750 individuals 7 = 751=2000 individuals 8 = 2001-7000 individuals 9 = >7000 individuals An average estimate over the three dives was used with 1 being the minimum for species recorded. Water temperature varied closely around 14 degrees Celsius.

3. Pilchard Sardinops neopilchardus Small scattered schools seen in 3m over seagrass (4). 4. Bearded Rock Cod Peudophycis barbata One seen under a ledge in 2-3m (1). 5. South Australian Garfish Hyporhamphus melanochir Several small specimens (estimated 20cm) seen in 1-2m over sand (2). 6. Hardyhead Atherinason sp. Several small schools seen in 1m over sand (3). 7. Deep-bodied Pipefish Kaupus costatus Several seen in seagrass (2 but probably more abundant) 8. Common Red Rock Cod Scorpaena ergastulorum Several seen deep in crevices in 2-3m (2).

RESULTS Comments on species are presented under species accounts and include an abundance score. 1. Draughtboard Shark Cephaloscyllium laticeps Three 1-1.2m specimens dead on the Peacock Bay beach as bycatch of local gill-netting for feral cat bait. 2. Spotted Stingaree Urolophagus gigas One seen in 0.5m deep water (1).

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9. Rock Flathead Platycephalus laevitagus One large (2kg) specimen collected on seagrass in 3m (1). 10. Castelnauâ&#x20AC;&#x2122;s Flathead Platycephalus speculator Several 1-2 kg specimens collected along sand/seagrass edges in 2-3m (2). 11. Sea Moth Acanthopegasus lancifer One partial specimen dried out as beachwash.


12. Blotch-tailed Trachinops Trachinops caudimaculatus Occasional small schools under ledges in 2-3m (3). 13. Southen Cardinalfish Vincentia conspersa Occasional under ledges in 2-3m (2) 14. Long-finned Pike Dinolestes lewini A small, dispersed school in 3-4m (2). 15. Eastern Australian Salmon Arripis trutta Several moderate sized specimens (estimated 1kg) seen in 4m; one seen used as cat bait (2). 16. Silverbelly Parequula melbournensis Occasional individuals and pairs over sand in 2-4m (2). 17. Western Red Mullet Upeneichthys sp. Occasional individuals and pairs on sand patches in seagrass in 3-4m (2). 18. Common Bullseye Pempheris multiradiatus Occasional under ledges in 2m (2) 19. Black Drummer Girella elevata Several seen over reef in 2m (1).

20. Zebrafish Melambaphes zebra Large and small specimens common along rocky shoreline in 1-3m (4). 21. Mado Sweep Atypichthys strigatus Occasional specimens over reef in 1-3m (2) 22. Sea Sweep Scorpis aequipinnis Occasional juveniles at more wave-active sites in 2-3m (2) 23. Sweep Scorpis lineolatus Occasional juveniles at more wave-active sites in 2-3m (2) 24. Old Wife Enoplosus armatus Unusually common in along rocky foreshore in 0.5-2m; one seen used as cat bait (2). 25. Long-snouted Boarfish Pentaceropsis recurvirostris A pair under a ledge in 4m (1). 26. Scalyfin Parma victoriae Regularly seen on reef (3). 27. Marblefish Dactylosargus arctidens Several large specimens on reef in 2-3m (2). 28. Magpie Perch Cheilodactylus nigripes Several specimens over reef in 2-3m (2).

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29. Dusky Morwong Dactylophora nigricans One juvenile seen on seagrass in 4m (1). 30. Yellow-eyed Mullet Aldrichetta forsteri A school regularly seen in 1m (3). 31. Short-finned Pike Sphyraena novaehollandiae One large specimen seen in 4m (1). 32. Castlenauâ&#x20AC;&#x2122;s Wrasse Dotalabrus aurantiacus Common in reef of 1-3m (3 but could be more abundant). 33. Senator Wrasse Pictilabrus laticlavius Common on reef/seagrass edge in 1-4m (3). 34. Purple Wrasse Pseudolabrus fucicola Small specimens locally common around reef in 0.5-4m (4). 35. Blue-throated Wrasse Pseuodlabrus tetricus All sizes regularly seen in 2-4m (3). 36. Blue Rock Whiting Haletta semifasciata Common in seagrass at 2-4m (3 but could be more abundant) 37. Little rock Whiting Neoodax balteatus Common in seagrass at 2-4m (3 but could be more abundant)


DISCUSSION

38. Long-rayed Rock Whiting Common in seagrass at 2-4m (3 but could be more abundant)

46. Six-spined Leatherjacket seuschenia freycineti One seen in seagrass in 4m (1).

39. Rainbowfish Odax acroptilus One specimen seen in 3m in seagrass (1).

47. Horse-Shoe Leatherjacket Meuschenia hippocrepsis A small school seen over reef in 3m (2).

Fishes recorded seemed typical for shallow water Bass Strait with a mixture of seagrass, sand and foreshore reef in a semi-exposed, highly tidal area (Last et al. 1983, Edgar et al. 1982).

41. Pygmy Rock Whiting Siphonognathus beddomei Common in seagrass at 2-4m (3 but could be more abundant)

48. Toothbrush Leatherjacket Penicipelta vittiger Occasional on reef in 2-3m (2).

REFERENCES

49. Shawâ&#x20AC;&#x2122;s Cowfish Aracana aurita One female seen over seagrass in 2m (1).

Edgar, G., Last, P.R. and M. Wells (1982) Coastal Fishes of Tasmania and Bass Strait. Cat & Fiddle Press, Hobart

50. Barred Toadfish Contusus richei One seen dead on beach.

Last, P.R., Scott, E.O.G. and F.H. Scott (1983) Fishes of Tasmania. Tasmanian Fisheries Development Authority.

40. Herring Cale Odax cyanomelas Occasional over reef (2). 42. Dragonet Bovichthys variegatus Common in crevices from 0.5-4m (3) 43. Common Weedfish Heteroclinus perspicillatus Several specimens seen in 2m (2 but could be more abundant).

51. Globefish Diodon nicthemerus One seen in seagrass in 3m and several beach-washed around island (1).

44. Blenny Pictiblennius tasmanianus Common in crevices from 0.5-4m (3) 43. Goby Nesogobius sp. Occasional over sand in <0.5m (3). 44. Brown-striped Leatherjacket Meuschenia australis One seen on reef in 3m (1). 45. Yellow-tailed Leatherjacket Meuschenia flavolineata A pair seen over reef in 3m (1).

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B RIDGETTE MOFFAT

132


Bridgette Moffat traversing Poa tussock grassland habitat. Photo by Dylan van Winkel.

By Bridgette Moffat Hamish Saunders Memorial Trust Travel Award Recipient 2008

As an undergraduate student, with no qualifications, relatively little field experience and next to no contacts in the world of science, it is an extremely rare occasion when someone is willing to offer you an opportunity to work with skilled people and undertake significant research as a part of their team. Rarer still, is the chance to do this in another country, with the full support of funding from home. Hamish Saunders Memorial Trust goes out of its way to work alongside the Tasmanian Government to be able to provide opportunities such as this and for undergraduate students; it is an absolute eye opener to the potential which science has to offer.

My personal encounter with the Hamish Saunders Memorial Trust, led me to an uninhabited island in the Bass Strait, with a team of scientists who I had known for less than two days. As the youngest member of the team undertaking the biological survey and geological diversity assessment, I had a lot to learn. Throughout the survey, I had exposure to many new situations which presented me with occasions for discussion and observation. It was great to be able to ask questions and get really in depth answers from a variety of people. Consequently, this gave me new knowledge and a perspective on many things which studying at University cannot always provide. My own achievements were acquiring new skills in animal handling and management, as well as the ability to set live traps. Discovering the characteristic features of animals such as scats, tracks and behaviours was an aspect of the trip that I really enjoyed. I also gained a lot from identifying

133

organisms because it highlighted how important physiology is to taxonomy, which was something I had previously overlooked. The experience in working with various forms of animals and their habitats has given me better insight into conservation management. It was especially exciting to be working in an overseas environment, where the plants and wildlife differ so greatly from home. Finally, I would like to thank the Trust for their offer and for giving me a really valuable learning experience. It has taught me more about wildlife and conservation, but also about myself and what Iâ&#x20AC;&#x2122;m capable of. Thanks to the Tasmanian research team, for their hospitality and support. Thank you for accepting me â&#x20AC;&#x201C;even as that 19 yr old undergraduate student, with no qualifications and little field experience. It was really encouraging to have such a great team to be a part of and I wish you the very best for future surveys.


D YLAN VAN WINKEL

134


Dylan van Winkel with a blotched blue-tongue lizard. Photo by Dylan van Winkel.

By Dylan van Winkel Hamish Saunders Memorial Trust Travel Award Recipient

Experiences Like any like ecological minded person, the opportunity to travel to a remote destination and document plants and animals, was quickly snapped up. I often dream about travelling to far away lands and learning about new and exciting plants and animals. I was fortunate enough to be selected to travel to an island off the coast of Tasmania and work with a team of ecologists to conduct the first ecological survey of Prime Seal Island. Information on the island’s flora was documented some time ago (by Stephen Harris) however; there is a very limited knowledge of the wildlife present there. After a three hour flight to Melbourne, followed by a one hour flight to Hobart, I was greeted at the airport by Louise Jerrim. At this point I was aware that Bridgette would be travelling on the same flight but, I had not met her yet. After a light chat with Louise, Bridgette arrived, introduced herself, and we left for town. In downtown Hobart we were introduced and shown around by Phil Bell of the Department of Primary Industries and Water (DPIW). That night we settled into a hotel for some much needed shuteye. The next few days were spent

familiarising ourselves with Hobart and getting ourselves organised for the island excursion. On the 13th we drove up to Launceston and boarded a light plane to Flinders Island. Here we spent the day playing with baby orphaned wombats and purchasing groceries from the island’s only local supermarket. Our team managed to purchase the island’s entire stock of fresh fruit and vegetables and left most of their shelves bare! We also spent time at the local bakery filling up on wallaby pies and coffee. The next morning we set off in a charter boat to Prime Seal Island, while watching huge soaring albatross as we motored across the ocean. The island falls within a group of islands in the eastern Bass Strait, known as the Furneaux group. Prime Seal Island is Crown owned but is leased for private farming practices. With only two members of the team having spent time on the island, we were all excited to get going and explore. Both Bridgette and I were assigned to the mammal team and over the following 5 days we trekked across much of the island setting up and checking small mammal traps. All we ever seemed to catch were introduced house mice! The particular mammal we were targeting on the island was the New Holland mouse; endemic to Tasmania and highly threatened; and apparently it looks identical to a common house mouse… except much cuter! (we were told). Apparently, the only way to tell them

135

apart is to perform a dental check to find a tiny notch in the back of their front incisors. This is not the easiest task to perform on tiny 3 gram animals, which are very inclined to bite! However, the job soon became routine and unfortunately we did not detect any New Holland mice on the island. Every day was filled with adventure and if we weren’t scrounging around in pitch black caves for cave crickets, or tracking wedge-tailed eagles to their nest sites, we were hiking vast distances and bashing through thick bush in order to set up bat traps. No stone went unturned (or any object on the ground for that matter) when we were around, and under every one a new and exciting critter. We caught beetles, crickets, lizards, scorpions and huge spiders! Everything recorded and labelled in our trusty notebooks. Every night around the dinner table, the team discussed their discoveries and swapped funny stories from the day. Our species lists for the island kept growing and growing! Even up until the last day when I stumbled upon, pursued into a thorn bush, and captured a huge blotched bluetongue lizard! But unfortunately, our time in paradise had to end. Our final evening on the island was filled with a huge feast of freshly caught abalone (Tassie delicacy), fish (hilariously filleted on an open laptop computer which was brought along for just such an occasion!), followed by an enormous barbeque


of steak, burgers, chops, wallaby sausage, and a heap of salads. The next morning we departed back to the mainland via Flinders Island.

Success of the expedition The expedition was a huge success as noted by all those involved. Almost every part of the island was visited at least once and extensive flora and fauna surveys were conducted in all habitats. The expedition teams were divided into sections depending on the specialties of the members. Bridgette and I formed part of the four man mammal team, while the other teams comprised three botanists including a weed specialist, two entomologists, two geologists, and a raptor (bird of prey) expert. I was nominated as the expedition’s herpetologist (reptile expert) due to my knowledge, lizard catching skills, and enthusiasm for stalking tiger snakes. Hundreds of invertebrate specimens were collected from all habitats across the island. All the specimens collected were previously unrecorded from the island since no previous invertebrate surveys have been conducted there. It is very possible that many of these specimens represent new species. Prime Seal Island supports a huge diversity of vegetation types, including several rare and threatened species. The vegetation on the island was first recorded and mapped by Stephen Harris (current team leader) in 1986 and was documented in his book titled ‘One Hundred Islands: The Flora of

the Outer Furneaux’ (2001). During our expedition, many more species were recorded and the distribution of several plants extended. The island shares many species commonly found on mainland Australia but some of which are absent in Tasmania. This is of interest as it provides evidence for the biogeographic history of the Bass Strait Islands and the separation of Tasmania from mainland Australia. Prime Seal Island was found to support large patches of plants that are rare in Tasmania and the island also supports several plant species of biogeographic importance, including Apalochlamys spectabilis and Threlkeldia diffusa. Large extended areas of the island are covered in pasture for grazing. Apart from pademelons (small wallabies), house mice, and large brown, woolly animals that roamed the island (which actually turned out to be sheep covered in dry dust), we found no confirmed evidence of other native mammals or marsupials during our expedition. The mammal team focused on detecting New Holland mice (a small, highly endangered Tasmanian mouse). However, after a week of intensive trapping efforts only introduced house mice were captured much to our dismay. We did manage to find some animal sign, in the form of ‘nosings’ in the dirt, which provided some hope for the presence of bandicoots on the island although no confirmed sightings eventuated.

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No frogs were found or heard on the island, probably due to the lack of free-standing water and the absence of high altitude cloud forest. Eight species of reptile (three snake and five lizard species) were confirmed inhabiting the island. The results from our expedition added six unrecorded species to the list of reptiles previously recorded from the island. Upon returning to Hobart, a press release was launched immediately and the success of our expedition was voiced to the Australian public, via a radio broadcast on the ABC network. Stephen Harris, Bridgette Moffat, and I were interviewed in front of TV cameras and asked to speak about the Hamish Saunders trust, describe our experiences on the island, and talk about what we gained from participating in the expedition. What an experience this was!!! The official results of the survey are to be written up as individual papers that will be compiled into a single report. This compilation will describe and document our trip to Prime Seal Island.

Personal gains from participation Pages upon pages could be written on my experiences from the trip to Prime Seal Island however, I will keep it short by describing some key experiences that I will carry with me into my future career and for the rest of my life. A key ingredient to any successful expedition is the ability of the team members to work together. This can be especially


daunting if all the members are unfamiliar to you. However, our team was fantastic and I got along with everyone really well. I tried to learn and work with all the different parties and this meant that I broadened my knowledge extremely about the flora and fauna of Tasmania, both theoretically and practically through application of field techniques for surveying Tasmanian species. Prior to the expedition, I was familiar with several of the survey techniques but I had no experience actually applying them in the field. Getting the chance to learn and apply these was extremely important to me and I will use what I have leant in my future career. Since many of the techniques differed from those used in New Zealand, I feel I have gained some understanding of international approaches to conservation. This is very important and has allowed me to convey new perspectives to the conservation of New Zealandâ&#x20AC;&#x2122;s wildlife. Being surrounded by such a knowledgeable group of people was great! I really enjoyed discussing, listening, and absorbing their experiences and advice about Tasmanian wildlife around the dinner table. Ninety percent of the time my obscure questions regarding the formation, cultural history, and wildlife of the island were answered. Everything is new and exciting when you travel to a place you have never been before!!! But, the most important and meaningful (possibly life-changing) element I gained from this

experience is that it ignited my drive for exploration and travel. I regularly dream about travelling, exploring, and documenting remote parts of the world but I thought that watching adventurers on the discovery channel is as close as I would get. The Prime Seal expedition was a dream come true and has taught me that there are still many places worth exploring. The importance of conveying experiences such as these to others and promoting further conservation perspectives should not be underestimated. Passing on personal experiences to others may inspire them to become involved in similar programmes and think about the environment that surrounds and supports us. Like Hamish, this is a legacy I would like to become a part of. Exploration must be one of the most gratifying and exhilarating experiences in life and I am eternally grateful to the Hamish Saunders memorial trust for providing this opportunity and allowing me to experience what Hamish loved doing best.

Recommendations I have thought long and hard about how I could offer advice and/ or recommendations about future Hamish Saunders trust surveys, but I cannot think of a single one. From the point of filling in the application forms to flying back to New Zealand everything was perfectly organised and went unbelievably smoothly. The DPIW team was amazing and offered their hospitality and

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services throughout the entire trip. I am sure Bridgette will agree that both of us were looked after extremely well. I think the structure of the project works really well (i.e. survey, follow-up report to the trust, and the survey results published). A photograph collection was completed for the Trust. There is only one element that I would like to recommend for future volunteers. This would be to personally meet members of the Saunders family and trustees of Hamish Saunders trust. As a representative for the trust it seems only natural to speak directly to those who were close to Hamish, and share experiences about adventure and conservation. In saying this, I really hope I will get the opportunity to meet the family and trustees of the HSMT.

Thanks and acknowledgements I would like to extend my many thanks to the Saunders family and trustees of the Hamish Saunders Memorial trust for the opportunity to travel to Prime Seal Island and partake in the ecological survey. I would also like to thank the team members from Tasmania including, Phil Bell, Stephen Harris, Clare Hawkins, Michael Driessen, Nick Mooney, Micah Visoiu, Emma Betts, Oliver Strutt, Abbey Throssell, Kevin Bonham, Rolan Eberhard, Sarah Munks, and Bridgette Moffat. Special thanks to Bridgette for her companionship, friendship, and laughs during our trip.


NOTES

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Cover and inside cover photos by Rolan Eberhard. Moth illustration by Georgina Davis. This report is printed on Monza Satin recycled paper, derived from sustainable forests, elemental chlorine free pulp and certified environmental systems.


The Hamish Saunders Memorial Island Survey Program Hamish Saunders Memorial Trust, NZ Biodiversity Conservation Branch Department of Primary Industries. Parks, Water and Environment GPO Box 44 Hobart, Tasmania 7001

10363BL

Prime Seal Island Report  

A Survey report on the flora and fauna found to be present on Prime Seal Island during the 2008 Hamish Saunders Memorial Trust expedition.

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