Page 1

TRANSACTIONS SPIDERS

FROM

FENS I N

THE by

REDGRAVE,

AND

HOPTON

LITTLE

OUSE

VALLEYS

DR. E . A . G . DUFFEY, B.SC.,

PH.D.

WAVENEY

LOPHAM

AND

INTRODUCTION

THE plant ecology of the valley-fens which survive around the head-waters of the Little Ouse and Waveney Rivers has recently been described by Bellamy and Rose (1960). Most of these fen relics are now scattered and relatively small in area but one large section of maior importance remains unspoilt on the Waveney side of the watershed of which three-quarters (Little, Middle and Great Fens) lie in Norfolk, and the remainder (Redgrave Fen) in East Suffolk. The nearest villages are Redgrave on the south side and North Lopham on the north, and all four fens are usually referred to as Redgrave and Lopham Fens. Hopton Fen (approximately 28 acres), which is not described by Bellamy and Rose, lies three and a half miles vvest of the main fen area in the Valley of a small tributary to the Little Ouse in West Suffolk. The few acres of wet fen which may still be found there are largely dominated by the sa- Âťsedge (Cladium mariscus) which grows in and around numerous water-filled pits and depressions which are the remains of old peat cuttings. The Redgrave and Lopham Fens complex covers a little over 300 acres and is the largest and finest example of its type remaining in East Anglia for richness of flora and fauna. Difficulties of drainage and its status as common land are the main factors responsible for its preservation to the present day. Other relic fens in the same general area still exist at Weston, Thelnetham, Hinderclay and Bio Norton. All the surviving Valley fens which have been mentioned have been scheduled by the Nature Conservancy as Sites of Special Scientific Interest under Section 23 of the National Parks and Access to the Countryside Act, 1949. Scheduling requires the Nature Conservancy to notify the scientific interest to the local authority, so that consultation can take place before any proposed development of the area is approved. It does not permit any interference with ownership rights and if these exceptionally interesting areas are to be preserved, some positive action must be taken by a conservation Organisation, to safeguard them in the future and provide protection against the everincreasing threats to uncommitted land of this type.


32

SPIDERS FROM WAVENEY AND LITTLE OUSE VALLEYS

T H E K N O W N BRITISH DISTRIBUTION OF FOUR RARE F E N SPIDERS

A

Lycosa

rubrofasciata

Marpissa

Gongylidiellum

pomatia

O

Hypomma

murcidum

fulvum


SPIDERS FROM WAVENEY AND LITTLE OUSE VALLEYS

THE

SPIDER

33

FAUNA

There are no records of the spider fauna of these fens prior to 1953, when the author first visited Redgrave and Lopham Fens. Further visits were made in 1956 and 1959 (Duffey 1958 ; 1960) and in 1960. In addition, G. P. Lampel (1959) collected spiders in the same area on different occasions in 1955. I am indebted to J. A. L. Cooke, G. H. Locket and D. J. Clark, who have made available unpublished lists of Redgrave and Lopham Fen spiders taken in June and September, 1960. In addition, D. J. Clark has provided records of spiders taken in Hopton Fen in June, 1960. In view of the small number of visits and the absence of records prior to 1953, the spider fauna of these fens must be considered very imperfectly known and the present list of 96 species will be very considerably increased as studies are continued in the future.

COMPARISON

WITH W I C K E N AND W O O D W A L T O N

FENS

Two other fen areas whose spider fauna has been studied in some detail are Wicken Fen, Cambridgeshire (680 acres) and Woodwalton Fen, Huntingdonshire, (514 acres). Both are substantially larger than Redgrave, Lopham and Hopton Fens (approximately 330 acres) and in the case of Wicken araneological studies have been carried out there from time to time since 1896 (Bristowe 1925). As at Redgrave and Lopham Fens, no collections of Woodwalton Fen spiders are known before 1953. The totals for each of the three fen areas are listed below, together with the proportion of Linyphiidae spiders, which in this country is by far the largest family. Linyphiid spiders are particularly numerous in the " litter" and ground Vegetation zones, with far fewer species in the scrub and canopy. The proportion of Linyphiids in the spider fauna of an area increases as one travels north from the tropics and also in relation to the open nature of the habitat, when trees and bushes are absent as on moorlands and mountains. The figures for these fens are probably fairly typical of fens elsewhere in lowland England where the habitat ränge includes open herbaceous communities, scrub and tree growth. Wicken Fen Total species recorded Total linyphiid species

Woodicalton Fen

Redgrave, Lopham and Hopton Fen

181 in 14 families 130 in 13 families 96 in 14 families

79 (43.6%)

51 (39.2%)

39 (40.6%)


34

SPIDERS FROM WAVENEY AND LITTLE OUSE VALLEYS

A detailed comparison of the spiders recorded for each area is probably of little value until more is known about the fauna at Woodwalton Fen and Redgrave and Lopham Fens, but certain points can be established by inspection of the species-lists. The Little Ouse river flows from the Redgrave /Lopham Valley fens into the Fenland basin, becoming a tributary to the Great Ouse which reaches the sea at King's Lynn. The River Cam which passes close to Wicken Fen is also a tributary to the Great Ouse as is the River Lark. The spider fauna of the fen relics in the Lark Valley have already been shown to have similarities with Wicken Fen (Duffey, Locket and Millidge, 1957) and the sarae can be established for Redgrave and Lopham Fens. Woodwalton Fen is situated in the north-west corner of the Fenland Basin and has no connection with the river Valleys east of the Great Ouse. Seven rare or local spiders confined to fen and marsh areas are found both at Wicken Fen and in the Redgrave and Lopham Fen complex, but not so far at Woodwalton Fen : Marpissa pomatia (Fig. 1), Sitticus caricis, Pirata piscatorius, Entelecara omissa, Hypomma fulvum (Fig. 1), Gongylidiellum murcidum (Fig. 1), and Lycosa rubrofasciata (Fig. 1). Although the species list for Redgrave, Lopham and Hopton Fens totals only 96 compared with Wicken Fen's 181, four rare or local spiders are known there but are not recorded for the other two fens : Dolomedes plantarius (only British locality), Theridiosoma gemmosum (tall herbage and bushes in damp places), Notioscopus sarcinatus (wet swampy areas) and Hillhousia misera (wet, swampy areas, widespread in the north but less so in the south).

SPECIES OF SPECIAL

INTEREST

Dolomedes plantarius Clerck. The discovery of this large raft spider in 1956 in the Suffolk section of Redgrave and Lopham Fens and subsequently on the north side of the Waveney in Norfolk has been described in earlier papers (Duffey 1958, 1960). In 1960 it was looked for in the nearby Hopton Fen but not found and at present Redgrave and Lopham Fens remain the sole British locality. The pattern of past peat excavation makes an important contribution to the habitat requirements of this species. This fen peat lies within the common land of three adjacent parishes and the traditional method of exploitation by local people appears to have been rather indiscriminate, merely by digging a circular depression of shallow depth. Each digging was presumably made by one or two individuals or a family who did not want to carry the fuel further than was necessary, so the depressions never became very large. A firm ridge or " bench " some two feet in width separates each peat cutting from its neighbours and was probably used to Stack the peat to dry and was the route followed when carrying or wheelbarrowing the fuel away. These


SPIDERS FROM WAVENEY AND I.ITTLE OUSE VALLEYS

35

narrow ridges linked up with several broad causeways which led straight to the upland. These features can be clearly seen on the aerial photographs (plate 1) which was taken obliquely looking south. Redgrave Fen, on the far side of the river, is identifiable by the mosaic of small depressions, while on Middle Fen (nearer the camera) a series of dark lines, looking like a system of drainage Channels, are the firm causeways Standing above the general level of the fen. They stand out clearly on the photograph because the Vegetation on them is predominantly Meadowsweet (Filipendula ulmarid) in contrast to the reed, grasses and sedges in the wetter fen. The circular peat cuttings at Redgrave and Lopham Fens effectively retain seepage water from the upland and a very large number of pools of varying depths have been formed. These undisturbed water bodies provide an ideal habitat for Dolomedes plantarius, which is able to hunt and shelter around the marginal aquatic Vegetation. It is therefore most important that the present water regime is preserved so that the pools are not polluted or dried out. Gongylidiellum murcidum Simon. A small erigonid spider of about 1.5 mm. length ; it is rare in this countrv and only found in fen habitats. Apart from Redgrave and Lopham Fens, it has been taken in Wicken Fen, Cambridgeshire, where it is well established ; in the New Forest bogs, Hampshire, and as an aeronaut in a very wet fen at Cranberry Rough in West Norfolk. In Scotland it has been taken at Nethy Bridge, Inverness in November, 1952, by Millidge and Locket (1955). Marpissa pomatia (Walckenaera). This large, handsome jumping spider is closely associated with fen reedswamp but has a curiously restricted distribution in this country. Until recently it was known from only four localities : Wicken and Chippenham Fens (where it is common), Dorset and Lancashire. In 1953 and 1954 it was found to be widespread in the Norfolk Broads area excepting (to date) the Yare Valley. Later it was found commonly in Redgrave and Lopham Fens and in 1961 recorded from the Breckland Meres at East Wretham, Norfolk. It is also common in the relic fens of the Lark Valley at Icklingham, and Tuddenham, Suffolk (Duffey, Locket and Millidge, 1957). It is unknown, however, in the large fen and reedswamp areas of East Suffolk at Walberswick ; Buss Creek Marshes ; Covehithe, Benacre and Easton Broads, and Butley Mill, although these habitats appear quite suitable. Lycosa rubrojfasciata (Ohlert). A fen wolf-spider with a verv restricted distribution. Apart from old records in Lincolnshire, Nottinghamshire and near Thetford, this spider was only known until recently to be well established at Wicken and Chippenham


36

SPIDERS FROM WAVENEY AND L I T T L E OUSE VALLEYS

Fens, Cambridgeshire. In the Lark Valley, Suffolk, it is now known from Icklingham, Tuddenham and Lakenheath Poor's Fens. In Redgrave and Lopham Fens it appears to be rare, only one speeimen having been taken by J. A. L. Cooke in 1960. In Norfolk it was taken at Foulden Common by the author in April, 1959, but there are no records for the extensive fens of the Broads area in East Norfolk. Neither has it been recorded in the East Suffolk Fens and Broads. In June, 1960, P. Merrett took a female in the New Forest, Hants. Pirata piscatorius (Clerck). The largest and most striking of the British Pirata species found commonly at Redgrave and Lopham Fens in the same habitat as Dolomedes plantarius. A rather rare spider in Great Britain, although widespread and found only in very wet fens with Standing water. In East Anglia it has been recorded from the Lark Valley Fens, Redgrave and Lopham Fens, and the Norfolk Broads. Bristowe (1940) does not record if for Suffolk. Hypomma fulvum Bösenberg. A small dark-bodied erigonid spider with a reddish cephalothorax and orange legs, confined to fen areas in this country. Until recently only three females had been taken in Britain, from Norfolk and Wicken Fen. In June, 1954, several more females were taken by the author from the flowering heads of reed at Crome's Broad, Ludham, Norfolk, where they had constructed a silk retreat for the egg cocoon. Düring the last three years it has been recorded from Hopton Fen, West Suffolk (June, 1960), by D. J. Clark ; Wicken Fen, Cambridgeshire (both sexes in June, 1960) by A. M. Wild, and from reed beds in a creek by Fiatford Mill Field Centre, Suffolk, 1961, by A. M. Wild and J. A. L. Cooke.

SYSTEMATIC LIST OF SPIDERS FROM REDGRAVE, LOPHAM AND HOPTON FENS Nomenclature as in Locket and Millidge (1951-53) Dictynidae Dictyna arundinacea (L.) J D . (latens) Dysderidae Harpactea hombergi (Scop.) Gnaphosidae JZelotes latreillei (Simon)

Clubionidae Clubiona stagnatilis (Külz.) C. phragmitis (C. L. Koch) C. terrestris (Westr ) C. subtilis (L. Koch.) Cheiracanthium erraticum (Walck) *Agroeca proxima (O. P.-Cambridge) Zora spinimana (Sundevall)


SPIDERS F R O M W A V E N E Y

Thomisidae

Misumena vatia (Clerck) Xysticus cristatus (Clerck) X . u l m i (Hahn) Oxyptila t r u x (Blackwell) 0 . brevipes (Hahn) Philodromus aureolus (Clerck) Thanatus stiiatus (C. L . K o c h ) Salticidae

{Heliophanus flavipe3 (C. L . Koch) JMarpissa pomatia (Walck.) JNeon reticulatus (Blackwall) Euophrvs sp. Sitticus caricis (Westr.) i * M y r m a r a c h n e formicaria (Degeer) Lycosidae

Lycosa pullata (Clerck) L . prativaga ( L . Koch) L . amentata (Clerck) L . nigriceps (Thorell) L . lugubris (Walck.) L . rubrofasciata (Ohlert) Trochosa terricola (Thorell) * T . spinipalpis (O. P.-Cambridge) Pirata piraticus (Clerck) P. hygrophilus (Thorell) P. piscatorious (Clerck) Pisauridae

Pisaura mirabilis (Clerck) *Dolomedes plantarius (Clerck.) Agelenidae

Argyroneta aquatica (Clerck) *Antistea elegans (Blackwall) Mimetidae

Ero sp.

Theridiidae

F.pisinus angulatus (Blackwall) t * T h e r i d i o n saxatile (C. L . K o c h ) J T . impressum ( L . K o c h ) T . bimaculatum (I..) JEnoplognatha thoracica ( H a h n ) Robertus lividus (Blackwall)

AND

L I T T L E OUSE

VALLEYS

37

Tetragnathidae

JTetragnatha nigrita ( L e n d l ) Pachygnatha clercki (Sundevall) Argiopidae

Meta segmentata (Clerck) Araneus diadematus (Clerck) A . quadratus (Clerck) A . marmoreus pyramidatus (Clerck) A . cornutus (Clerck) A . redii (Scop.) Zygiella atrica (C. L . K o c h ) i T h e r i d i o s o m a gemmosum (L. Koch) Linyphiidae

Walckenaera acuminata (Blackwall) t * W i d e r i a melanocephala (O. P.-Cambridge) Cornicularia unicornis (O. P.-Cambridge) JEntelecara omissa (O. P.-Cambridge) G o n g y l i d i u m rufipes (Sundevall) JDismodicus bifrons (Blackwall) H y p o m m a bituberculatum (Wider) t t * H . f u l v u m Bosenberg G o n a t i u m rubens (Blackwall) JPocadicnemis pumila (Blackwall) *Oedothorax gibbosus (Blackwall) Oe. tuberosus (Blackwall) Cnephalocotes obscurus (Blackwall) Lophomma punctatum (Blackwall) t*Gongylidiellum murcidum (Simon) t*Notioscopus sarcinatus (O. P.-Cambridge) Araeoncus humilis (Blackwall) Erigone dentipalpis ( W i d e r ) E. atra (Blackwall) J:*Hillhousia misera (O. P.-Cambridge) Meioneta rurestris (C. L . K o c h ) M . saxatilis (Blackwall) *Centromerus expertus (O. P.-Cambridge) Macrargus rufus ( W i d e r )


38

SPIDERS FROM WAVENEY AND LITTLE OUSE VALLEYS

Lepthyphantes tenuis *Bathyphantes pullatus (Blackwall) P.-Cambri B. gracilis (O. (Blackwal l) dge) JL. mengei (Külz.) *B. parvulus (Westring) L.flavipes(Blackwall) *Tapinopa longidens (Wider) *L. tenebricola (Wider) Floronia bucculenta (Clerck) JL. ericaeus (Blackwall) Taranucnus setosus Linyphia triangularis (Clerck) L. clathrata (Sundevall) (O. P.-Cambridge) L. pusila (Sundevall) Stemonyphantes lineatus (L.) N.B. * new county record for Suffolk (Bristowe 1940 ; Duffey 1958 ; Duffey, Locket and Millidge 1957 ; Locket and Millidge 1957). f recorded only from Hopton Fen, West Suffolk. t new county record for Norfolk (Bristowe 1939). REFERENCES

Bellamy, J. and Rose, F. 1960. The Waveney-Ouse Valley Fens of the Suffölk-Norfolk Border. Trans. Suff. Nat. Soc., Vol. XI, Pt. Bristowe, W. S. 1925. The Spiders and Harvestmen (in The Natural History of Wicken Fen), pt. II. Cambridge. Bristowe, W. S. 1939. The Comity of Spiders, Vol. I. Ray Society, London. Bristowe, W. S. 1940. The Arachnida of Suffolk. Trans. Suff. Nat. Soc., Vol. IV, Pt. III.

Duffey, E. 1958. Dolomedes plantarius Clerck. A spider new to B found in the Upper Waveney Valley. Trans. Norfolk Norw. Nat. Vol. 18, Pt. 7.

Duffey, E. 1960. A further note on Dolomedes plantarius Clerck in Waveney Valley. Trans. Norfolk Norw. Nat. Soc., Vol. 19,

Duffey, E., Locket, G. H. and Millidge, A. F. 1957. The Spider Fauna of the Heaths and Fens in West Suffolk. Trans. Suff. Nat. Soc., V Pt. III.

Lampel, G. P. 1959. Additions to the County Records of Spiders with notes on two species of interest. Jour. Soc. Brit. Ent., Vol. 6, P Locket, G. H. and Millidge, A. F. 1951, 1953. British Spiders, 2 Vols., Ray Society, London.

Locket, G. H. and Millidge, A. F. 1957. On new and rare British Spiders. Ann. and Mag. Nat. Hist. (12) 10 481-492. Millidge, A. F. and Locket, G. H. 1955. New and Rare British Spiders. Ann. and Mag. Nat. Hist. (12) 8 161-173.

Spiders from Redgrave, Lopham and Hopton Fens in the Waveney and Little Ouse Valleys  
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