Green Space Our Place - Our Volunteers Voice - Issue 28 - September 2020

Green Space Our Place Our Volunteers Voice

Green Space Our Place

Volunteers enhance local parks

Growing Loridan Dve produce and BMX track connecting revamp community ISSUE 28 SEPTEMBER 2020

Front Page: Volunteer Heather is very happy to be a part of the Clarke & Wallace Pocket Garden.

Back Page: Rufous Owl, photo by Brian Venables.

In this issue: • From the Editor - Page 2 • Volunteer Pictorial - Page 3 • Bringing all ages together Page 4 • Loridan Drive BMX track gets a revamp - Page 5 • Volunteer comments - Page 6 • Revegetation of the Tanks Art Centre surrounds - Pages 6-7 • Enhancing parks - Page 8 • Keith Edwick Park’s four-year transformation - Page 9 • ‘Pocket Gardens’ - growing produce and connecting community - Pages 10-11 • Floating seeds - hydrochory Pages 12-13 • Mystery solved...sort of Page 14 • Did you know...? - Page 14 • Friends’ Moth Night popular despite lack of insects - Page 15 • Australian wetland featheries that are also international Pages 16-17 • Feathered Friends - Page 17 • The world beneath our feet: Part 1 - Soil - Pages 18-19

From the Editor Welcome, The growth of the Green Space Our Place program is pleasing despite this most unusual year. We have continued to offer a range of volunteer opportunities in our parks, gardens and green spaces that are flexible, engaging, community building and, of course, fun for our participants and good for the environment.

To see our vision of bringing Council and community together to enhance our city is rewarding for all of us.

Community spirit is definitely on the rise in our activated areas, especially within the ‘Pocket Gardens’ (see Pages 10-11), the new group Loridan Drive BMX Club (Page 5) and in our local parks (Pages 8-9).

Thank you to Jeff Pretty who spent six years with the program, volunteering with the Down ‘n’ Dirties (Botanic Gardens), Jabirus (Cattana Wetlands) and at the Stratford Nursery. We will miss your positive attitude, huge smile and your willingness to get ‘stuck in’ with any job. See Jeff’s comments about the program on Page 6.

Our contributors have once again submitted some interesting articles for our readers. Thank you to Barry, Jennifer, Tom, David and Janice. Also, a thank you to our proof readers, Jennifer and Sandy. I couldn’t produce this without your support.

Happy reading!

Editor - Volunteers Supervisor, Louisa Grandy Proof readers - Michelle Walkden Volunteers Jennifer H. Muir, Sandy Long; Contributors - volunteers: Janice Pichon, Barry Muir, Jennifer H. Muir, Dr David Rentz AM, Tom Collis 2

Louisa

Volunteer pictorial - happy faces are what we like to see!

Jo gardening.

Catherine planting.

Tony planting at Cattana Wetlands.

Jill watering new plantings.

Brigette ready to prune bamboo.

Lee and Alex shifting rocks in the Botanic Gardens.

Rob blowing at the Pioneer Cemetery.

A well-earned rest at McHugh Crescent.

Social distancing yet still connecting Gary and Lyn.

Elaine pruning at the Pioneer Cemetery.

Jenny and Dit planting at Cattana Wetlands.

Katherine having a break at the ‘Salties’ reveg site.

‘Salties’, from left, Andre, Chris, Omid, Katherine, Joseph and Fran (front).

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Bringing all ages together A combined tree planting effort took place in August at Tiffany Park, involving the Cairns Barrier Reef Lions Club (members now registered with us, Green Space Our Place), Trinity Anglican School (TAS) students and the Banora International Group.

One of the aims of the the Lions Club is to protect the environment. They approached Council with the idea of enhancing the park and invited the TAS students to be involved.

Council’s Gary Warner, Linda Kirchner and Cr Cathy Zeiger supported the tree planting event.

Lions President Brian Little, said the Lions Club will continue to maintain the trees until they can support themselves.

Banora International Group, with 25 years experience as a leading study tourism operator in Far North Queensland, became involved as part of their tree planting program.

In response to COVID-19 border closures, Banora adapted their programs to offer interactive study experiences on-line under a new entity, Great Barrier Reef Academy.

Their programs often included planting a tree in region so in partnership with Green Space Our Place, they now plant a tree in the name of their virtual students and schools, providing them with the GPS coordinates so students can watch the growth of their tree and hopefully visit their tree when the borders re-open.

Cairns Barrier Reef Lions Club planting trees at Tiffany Park.

Trinity Anglican School with managing director of Banora International Group, Janine Bowmaker (right).

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Janine Bowmaker, Banora Managing Director, said, “We are so proud to be partnering with Cairns Regional Council by educating international youth, helping our local environment and creating a connection to our region so that students might visit in the future.”

Trinity Anglican School students planting.

Loridan Drive BMX track gets a revamp

Neil presenting a reward to Brian, a very keen volunteer.

Loridan Drive BMX track has been upgraded in the past couple of months. This has been a collaboration between Council’s works department Green Space Our Place and the community. There were 11 adults and 32 kids participating in the works with volunteers spending over 10 hours on site to finish stage one.

BMX Club member Neil Muller, who instigated the revamp, said, “We were well supported by the community and were particularly impressed with one young volunteer, Brian Vogel, and how keen he was to be involved with building the track and never nagged if it was done or if he could ride them yet. We are looking forward to what we can create with the users of the area in stage two and beyond.”

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VOLUNTEER COMMENT

1943 site excavation

Jeff Pretty I had the most enjoyable six years working with volunteers at Cattana Wetlands, the Botanic Gardens and the Stratford Nursery. I met some wonderful people; we worked hard but it was fun and we had some great laughs.

Working with a great bunch of people gave me good mental and physical health.

I also felt I was contributing to the Cairns community which has been our home for the last 12 years. Over those past years I’ve learnt so much about gardening in the tropics and the different plants that grow there, and I was able to use this knowledge in my own garden.

Unfortunately as we are aging we need to be closer to family in the Adelaide Hills and with our adorable four grandchildren.

Completed facility alongside Collins Avenue

The disused site in 1992

I intend to seek out and volunteer with gardening groups once we get settled in our new home.

I wish to congratulate all the supervisors of the program as they were so knowledgeable and helpful.

Thanks to all. I will miss you all.

The same vista in 2020 6

The Tanks Arts Centre today with the realigned Collins Ave.

Revegetation of the Tanks Arts Centre surrounds JANICE PICHON

A popular misconception among visitors to the Tanks is that the lush vegetation cloaking the complex predates the Arts Centre. The tallness of the trees and the absence of formal garden features contribute to this illusion.

Installation of the Australian Navy oil storage facility in Edge Hill during WWII transformed a once verdant corridor along Collins Avenue into an industrial landscape. Construction of the three massive concrete tanks and their associated infrastructure destroyed the natural vegetation and scarred the hillslope backdrop.

Even after the war, the tanks continued to store oil until 1987. During those 40-odd years as a fuel installation, the tanks’ surrounds were dominated by lawn, from the bund wall on Collins Avenue extending to at least 10 metres up the hillslope. This lawn was diligently maintained to serve as an early warning sign – any oil leakage from a tank would kill the nearby grass resulting in tell-tale brown patches.

Conversion of the tanks into an arts centre began in 1993. An integral feature of this repurposing was the desire to create a tropical rainforest garden in the surrounds. Embryonic gardens were planted using

native species, with the Tanks site initially planned to double as a native plant collection for the adjacent Botanic Gardens. Over time, the gardens have been expanded with further plantings and nature has also done its part through the natural recruitment of some common plants like ferns and vines.

Fast forward almost three decades and this early vision for the centre has come to fruition.

The industrial landscape has changed beyond recognition; the austerity of the oil tanks has been transformed through the re-greening of the site.

Today, a large fig tree stands sentinel at the front entrance, a newcomer since the repurposing of the tanks in the mid-1990s.

Since the 1994 opening of the Tanks Arts Centre, this natural looking rainforest garden has developed alongside the thriving arts programs. Undeniably, it contributes to the centre’s popular appeal. Visitors are greeted by a flourish of greenery, which tempers the drabness of the concrete walls and creates an ambience of discovery. Moreover, when seen from the air, the tanks today are more embedded in a leafy landscape than they ever were during their career as a secret wartime fuel depot.

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McHugh Crescent

Enhancing parks builds community spirit and pride Cairns residents are coming together each month across the region to take part in working bees to enhance their local parks.

These working bees involve weeding, planting and also getting to know your neighbour - a great way to create pride in the community.

McHugh Crescent volunteers have turned a grassy slope into a beautiful landscaped garden and have created connections throughout the neighbourhood.

Parks involving Green Space Our Place volunteers on weekends include McHugh Crescent, Whitfield; Jalarra Park, Stratford; Strooper’s Park, Freshwater; Keith Edwick Park, Machans Beach; Burrawungal Park, Barron Waters; Rainy Mountain Park, Smithfield; Leonard Park, Kewarra Beach; Esplanade, Kewarra Beach; Upolu Espalande, Clifton Beach; Melaleuca Creek, Bramston Beach.

Strooper’s Park

Jalarra Park

Jalarra Park volunteers have spent three dedicated years removing Singapore Daisy weed from the creek and replanting with natives with wonderful results.

Gerald Strooper’s passion has encouraged locals to replant and enhance their park.

Ryan weeding at Jalarra Park.

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Keith Edwick Park’s four-year transformation Keith Edwick Park in Machans Beach has been transformed over the past four years.

Machans Beach Community Association members joined the Green Space Our Place volunteer program to create a native garden to enhance their local park. Deb, pictured planting at the ďŹ rst working bee, designed the native garden.

Before the project begins.

First planting working bee.

Another planting session in 2019.

Construction begins and soil delivered.

Growth one year on -2017.

Growth of the trees four years on - 2020.

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‘Pocket Gardens’ - growing prod

The Clarke & Wallace Pocket Garden installed in April has proved to be very popular with the locals. Meade Oswald, pictured, was the founder of this project.

Heather planting strawberries.

The Green Space Our Place ‘Pocket Garden’ model is a wonderful way to grow produce and at the same time build community spirit in your neighbourhood.

This model differs from the Community Garden model by mainly targeting residents in close proximity to the garden and are generally created at a smaller scale. They are also unfenced and entirely communal.

If the Pocket Garden is permitted by Council, residents register as volunteers with our volunteer program and are then supported to create the garden to specified standards.

We now have five Pocket Gardens in Cairns: Draper Place, Crathern Close, Trundle Terrace, Torrence Avenue and this year’s addition, Clarke & Wallace. This type of community gardening suits varying ages and abilities, with the maintenance work being divided up to suit each participant’s capability and time, with enough produce grown for all involved.

Pocket Garden application process: • Discuss ideas with neighbours and form an interested group of at least eight people.

• Contact GSOP to register your interest.

• GSOP will discuss possible sites with you.

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• GSOP will then organise a community meeting on site to discuss ideas.

• Following the discussion residents send GSOP an e-mail with their proposal.

• Council considers proposal.

• If approved, an agreement is drawn up between Council and volunteers, outlining expectations and visual standards required by Council.

• GSOP inspects regularly to ensure the garden is compliant.

duce and connecting community

Celebrating in style after a successful ďŹ rst working bee for the Clarke & Wallace Pocket Garden.

Rob, Heather and Annette preparing a wicking bed.

Rob and his dog, Ace picking a few greens.

Annette inspecting the tomatoes.

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Seed pod of the Black Bean Castanospermum australe.

Globular fruit of Leichhardt Tree Nauclea orientalis.

Swamp Pandan Pandanus solms-laubachii

Tiny fruits of Bleeding Heart Homalanthus populifolius.

Looking-Glass Mangrove Heritiera littoralis.

Floating seeds of the Cannonball Mangrove Xylocarpus granatum.

Seeds of the Nypa fruticans, Nypa Palm or Mangrove Palm.

Nypa Palm seedling.

SEED DISPERSAL MECHANISMS TOM COLLIS

Floating seeds - hydrochory

Propagules of a Rhizophora mangrove.

Are floating seeds really dead? A test used by gardeners to check seed viability is to put seeds in water and if they float they probably won’t germinate. However, while this may be true for some plants, it is definitely not the case for plants that live near or in water. Many plants that live near rivers, wetlands or the sea have seeds that float as a means of dispersal.

On the coast the most well-known example is the Coconut, Cocos nucifera, a palm that can spread its floating seed far and wide across the ocean.

The process of dispersing seed by water is called hydrochory and seeds of this type must be able to float. Flotation is achieved by surrounding the seed or seeds with light materials that resist sinking such as a fibrous, woody or corky tissue.

Water-dispersed seeds also have adaptations to protect the seed from water damage, such as a hard seed coat.

Plants with water-dispersed seeds put little effort into producing fruits that are attractive to animal dispersers. Very little, if any food reward is on offer except possibly the seed inside the fruit and it can be difficult to extract. The fruits have no odour and rarely have bright colours, being more likely to be green or brown.

In the rainforest, there are numerous plants near watercourses that use water to spread their seed. The large seed of the Black Bean, Castanospermum australe, float and remain viable for some time. The globular-shaped fruit of the Leichhardt Tree, Nauclea orientalis, can float and carry numerous small seeds to sites further downstream.

In wetlands, water lilies produce seeds that float for a few days and then sink to the bottom where they germinate. The Swamp Pandan, Pandanus solms-laubachii, lives in frequently inundated areas. The large pineapple-like fruits break up into segments that float and contain just a single seed.

Some plants that produce fruit aimed primarily at dispersal

by animals also use water to disperse seeds. For example, many Syzygium fruits float, and this additional method of seed dispersal ensures recruitment of the next generation of trees.

Another example is the Bleeding Heart, Homalanthus populifolius, a rainforest species with tiny purple fruits. Birds usually disperse the seeds but they also float, spreading this pioneer species far and wide.

All of the fruits and seeds in the mangroves can float; a necessary feature for plants in the intertidal zone.

The Looking-Glass Mangrove, Heritiera littoralis, produces large, woody fruits that have a ridge that may act as a sail when the seed is in the water. The Cannonball Mangrove, Xylocarpus granatum, produces a large round fruit that splits open when ripe, spreading the large seed segments into the water below. Each segment consists mostly of light, woody material that allows the seed to float and drift away in the tide. The Mangrove Palm, Nypa fruticans, has a huge, woody fruit loaded with segments of floating seeds.

Some mangrove trees have highly specialised ways of dispersing seed. The seeds of Rhizophora, Bruguiera and Ceriops mangroves germinate on the parent plant (a process called vivapary) producing long seedlings called propagules.

Eventually the propagules drop into the sea and drift off with the tide. And this is where magic happens – the seedlings have evolved to travel in ways that vary with water salinity. In salt water they float horizontally and move quickly, but in brackish water they turn and float vertically. This slows down the movement and allows the roots to lodge in mud at a suitable site.

There are many other examples of plants in the Wet Tropics that use water to disperse seed, so the popular test for seed viability is not a valid test for our local plant species.

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Mystery solved...sort of

DR DAVID RENTZ AM In the last issue of the ‘Volunteer’s Voice’, I noted a caterpillar that seemed to be devastating our Mangosteen tree. It was especially fond of the new growth. A couple of caterpillars were collected but they soon succumbed.

Eventually another caterpillar was found and it successfully formed a cocoon, and an adult moth emerged.

The moth has been identified by Ted Edwards, retired from CSIRO National Insect Collection, as Stictoptera aequisecta and is a member of the family Euteliidae (formerly placed as a subfamily of the Noctuidae) https://en.wikipedia. org/wiki/Stictoptera.

Ted notes that the caterpillars of this species have been

implicated in feeding on Garcinia sp (Mangosteen) in southeast Asia and on other plants as well.

To date no further caterpillars have been found in my garden but the new Mangosteen leaves are ravaged by something: more later, perhaps.

DID YOU KNOW...?

Of approximately 17 orders of living terrestrial mammals, Australia has native species from only four: monotremes, marsupials, rodents and bats. Monotremes, i.e. egg-laying mammals such as the Echidna (pictured), occur only in Australia and New Guinea; about two-thirds of the world’s living marsupials are in Australia and New Guinea; Australian rodents comprise about 4% of the world total; and we have about 7% of the world’s bat species, many of which also occur outside Australia.

This is partly explained by Australia’s origins.

Millions of years ago, Australia was part of the southern super-continent, Gondwana, which 14

Jennifer H. Muir

also included the land masses we know today as South America, Africa, Madagascar, India and New Zealand. First Africa, then India, separated and, over a very long time, drifted northwards.

Later New Zealand moved eastwards, and later again, Australia (including New Guinea) moved towards Asia ‘bumping into’ the Indonesian Archipelago.

Australia’s oldest native mammals are descended from monotremes and marsupials that were on board and so remained when Australia subsequently separated from Antarctica. Rodents probably came on board via New Guinea from Indonesia, and some bats probably flew here.

Australia is still moving (north-east) at about 6cm a year.

Friends’ Moth Night popular despite lack of insects

Guest speaker and patron of the Friends, David Rentz advising a young participant.

DAVID RENTZ AM

The Friends’ Moth Night, the first for the year, was a success to some extent! Approximately 35 folks attended, practising some social distancing, and the weather was perfect: no moon, warm and not windy. The only problem was that we were unaware that the Cairns Regional Council had sprayed the area for mosquitoes about a month prior to our Moth Night. As a result, there were very few insects to be seen either at the lights or on the vegetation along the walks.

The highlight of the night was the appearance of nocturnal bees, Reepenia bituberculata, a species that James Dorey, a graduate student at Flinders University, tells me is associated with palms.

We were amongst a number of palm species, some flowering but the flowers were well off the ground. Perhaps the bees were high in the palms and had escaped the depredation of the spray.

We will have to return and see if we can find them foraging on some more accessible palms. Nothing is known of the nesting habits of these bees, according to James.

A few moths did come to the lights but nothing really spectacular.

If we do this again, we will work with the Gardens’ staff so it is not affected by the spraying regime.

Light sheets were erected in Fitzalan Gardens for this year’s Moth Night.

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Australian wetland featheries

Eastern Great Egret

breeding grounds in the Northern Hemisphere during our winter, are good examples.

They undertake these incredible journeys because food in the Northern Hemisphere summer (our winter) is abundant, enabling excellent conditions for raising their young. Many of these waders are in non-breeding plumage while they’re here, except for some still in their breeding plumage when they first arrive. For the return trip, some start dressing up in their breeding plumage before they leave Australia to return to the Northern Hemisphere to breed and feast.

In this article we look at some of our wetland birds that also live in other countries. Let’s start by defining the term ‘wetland’. A wetland is a permanent or temporary, natural or artificial, area of still or moving fresh, brackish or saline water.

Australian Pelican (Pelecanus conspicillatus)

As Australian birders, we might think our ‘resident’ (nonmigratory) birds are only Australian. But some of our ‘resident’ birds are also ‘international’ birds i.e. the same species also reside in other countries besides Australia. Sometimes it’s the same full species, or a race or sub-species, depending on how long they’ve been geographically separated. I’ll just deal with species level here.

Widespread throughout Australia, the Australian Pelican is also present in the Torres Strait (between Australia’s Cape York Peninsula and Papua New Guinea). It’s also recorded as resident in Indonesia, and as an occasional visitor to New Guinea; Bismarck Archipelago; Solomon Islands; Vanuatu; and Fiji, especially during Australian drought.

Australian Pelicans are nomadic (see definition above), often arriving in immense numbers to feast on fish in large seasonally inundated, otherwise dry, wetlands such as Lake Eyre. Pelicans’ large wings enable them to glide just above the water surface, and soar on air thermals, conserving energy and enabling them to travel long distances. Thus for them a trip to Lake Eyre from north Queensland is ‘chicken (pelican) feed’. Thus it’s most likely Australia’s Pelican population stays in Australia during good or adequate rainfall years.

Australian Pelicans are just as happy on permanent, fresh water Lake Barrine as they are in Cairns foreshore salt water where the photo below was taken. Such adaptability is a big advantage for the success of a species.

Many of our ‘resident’ birds are also nomadic in their food requirements. For example, some follow fruiting or flowering after rains, others fly to seasonally inundated (otherwise dry) wetlands, such as Lake Eyre in South Australia, after good rains or flooding from rains further north, to feed on fish, crustaceans (e.g. Australian Pelican, see below), and aquatic vegetation (e.g. some ducks). Nomadic movements are Great Cormorant (Phalacrocorax carbo) variable and erratic.

The Great Cormorant is widespread in Australia and resident from On the other hand, a migratory species does regular, usually East to South Asia, Indonesia, New Guinea and New Zealand. In seasonal, geographical movements to another location, later New Guinea its known as the Black Cormorant. This species is also returning to the place from which it left. Migratory waders recorded in Iceland, Europe, Africa, north-eastern North America, that arrive in Australia in our summer, and return to their and Greenland.

Australian Pelican 16

Great Cormorant

that are also international

Jennifer H Muir

Feathered Friends

The Great Cormorant is nomadic over much of Australia, feasting on fish in seasonally inundated wetlands like Lake Eyre, as well as in permanent wetlands such as the Locks on the Murray River where this ‘Great Cormorant’ photo was taken. Australian Pelicans were also feeding there at the time, as were Hardhead (White-eyed Duck) and Maned Duck at left in this photo.

Great Cormorants are generally black with white or grey throat feathers. With yellow, bare skin on its face and throat, and green eye, the cormorant pictured is in breeding plumage.

Australasian Grebe (Tachybaptus novaehollandiae) Widespread and nomadic in Australia, this species is known as the Australian Little Grebe in New Zealand and the Australian Dabchick in Asia. It breeds in Australia; as well as Indonesia including Java, Sulawesi, Timor, and the north Moluccas; the Solomon Islands; Vanuatu; New Hebrides; New Caledonia; New Guinea; and New Zealand. In Indonesia it’s known as the Black-throated Grebe.

Australasian Grebes prefer open fresh water near tall aquatic vegetation, and are rarely seen on brackish or saline water. They can undertake long flights at night sometimes arriving at small, isolated wetlands.

An Australasian Grebe, pictured below, in breeding plumage, with its distinctive chestnut mark from behind the eye down the side of its neck, and the oval patch of bare, pale yellow skin between eye and bill.

Eastern Great Egret (Ardea modesta (alba)) The elegant, beautiful Eastern Great Egret is common and nomadic in Australia. It is recorded from India to Australia, and known to breed in Central, South, East and South-east Asia, including parts of Indonesia.

In New Zealand, its English common name is White Heron. The Maori name is Kotuku. To Maori people this bird symbolises everything rare and beautiful, and to liken someone to the Kotuku is an exquisite compliment.

In New Zealand’s past, the nuptial (courtship, breeding) plumes were used from captive caged birds to adorn the heads of Maori chieftans. Later, in the 1870s, the species was almost exterminated in New Zealand when European women wanted the feathers for their hats during a ‘feather fad’. Since then conservation measures have enabled a recovery and the Kotuku became the New Zealand Wildlife Service’s official symbol.

Australasian Grebe

Jennifer H. Muir

Radjah Shelduck The Radjah Shelduck is familiar to many Far North Queenslanders, though most know it as the Burdekin Duck, a name bestowed by the pioneers.

A conspicuous waterfowl, from a distance these ducks look black and white, but on closer inspection, their upperparts are actually rich chestnut, which also extends in a band across the breast. Yet, despite its conspicuousness, sometimes the first you know that a Burdekin Duck is in a wetland is when you hear its hoarse, whistling call.

Burdekin Ducks usually feed in the shallows, scything their pink bills from side to side, or dabbling in shallow water or muddy banks, filtering out aquatic invertebrates and seeds.

They also upend when swimming, reaching down into the mud at the bottom.

When not foraging, they usually rest in pairs or small groups on the banks of swamps, lakes, pools and rivers, on tidal mudflats, or perched among the branches of riverside trees.

During the Dry Season, they may congregate in larger flocks, some numbering hundreds of birds, when they can be rather pugnacious: they become increasingly feisty during breeding season.

Cranky Burdekin Ducks aren’t the only hazard in tropical wetlands: there’s a record of a brood of Burdekin ducklings being picked off by a crocodile — one by one — as they paddled across a wetland. To escape danger, adults often simply fly away, and that’s when they reveal an apparently magic quality: in flight, they expose a dark wing bar, which creates the illusion that the bird is flapping two pairs of wings!

JOHN PETER BirdLife Australia 17

Rainforest

Carbon-rich layer Weathered pale clay layer

Deep layer where clays and iron have collected Bedrock

THE WORLD BENEATH OUR FEET: Part 1 - Soil This is the first in a series of articles on the world beneath our feet – that usually ignored and often much-maligned world on which all life on Earth depends. How many times have you heard this living system being referred to as ‘dirt’, ‘full of bugs and things’ and something to be removed rapidly from the feet, hands and face (or even mouth) of small children who have not yet learned adult prejudices.

Gardeners and farmers know differently: they recognise that their pleasures or livelihood depend on soil. But what, in a nutshell (or flowerpot), is soil?

BARRY MUIR

such as lime. Organic carbon is eventually returned to the atmosphere (mostly as carbon dioxide) through the process of respiration carried out by organisms that live in the soil, but a substantial part is retained in the soil in the form of soil organic matter (humus). Because ‘turning the soil over’ (tillage) increases the rate of soil respiration, it leads to the depletion of soil organic matter.

Since plant roots need oxygen, ventilation is also an important characteristic of soil. This ventilation is achieved by networks of interconnected soil pores, and, Soil is an ecosystem resulting from the interaction of time, if earthworms are present, they even act like little pistons, geology, climate, and living organisms. This interaction pulling or pushing air in or out of the soil as they move creates a material in which billions of organisms can live about.

– some tiny like bacteria and fungi and some huge such The pores also absorb and hold rainwater, making it readily as rainforest trees. The soil contains most of the Earth’s available for plants. Since plants require a nearly continuous genetic diversity, with one gram of soil containing billions supply of water, but most regions receive sporadic rainfall, of organisms belonging to thousands of species, mostly the water-holding capacity of soils is vital for plant survival. still unexplored and unstudied.

Soils also supply plants with nutrients, most of which A typical healthy soil is about 50% solids (45% mineral and are held in place by particles of clay, organic matter and 5% organic matter), and 50% voids (or pores) of which glomalin. The nutrients may be adsorbed directly onto clay half are occupied by water and half by gas. The soil forms mineral surfaces, bound within the clay minerals or bound clods (technically called ‘peds’) because it is held together within carbon-based compounds as part of the living mainly by glomalin – a “super glue” manufactured by fungi. organisms or dead soil organic matter.

Organic carbon is one of the most important components of soil, binding nutrients and providing an energy source for Except for nitrogen, most nutrients originate from the organisms. Organic carbon in the soil can be in many forms: minerals that make up the soil parent material, being released as pure carbon; as organic carbon such as sugars, starches, from the minerals by the activities of bacteria and fungi. fats and proteins; or as inorganic carbon in carbonates This process is closely tied to soil acidity. Some nitrogen

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falls to the ground in rain as extremely dilute nitric acid and ammonia (some resulting from lightning activity which causes all sorts of chemical reactions in the atmosphere), but most of the nitrogen in soils is a result of nitrogen fixation by bacteria, and, in some places, by specialised algae.

Once in the soil/plant system, most nutrients are recycled through living organisms, plant and microbial residues (humus), mineral-bound forms, and the soil water with its minerals in solution.

Both living organisms and soil organic matter are of critical importance to this recycling, and therefore to soil formation and soil fertility. Bacterial and fungal activity in soils may release nutrients from minerals or organic matter for use by plants and other organisms, incorporate them into living cells, or cause their loss to the atmosphere as gases or be dissolved out by leaching.

Here in Tropical North Queensland around Cairns, where we get about 2000mm per year of rainfall, soil leaching is significant. The soils can only support the massive trees and other plants by depending on mycorrhizal fungi to extract hard-to-get nutrients, by having nitrogen-fixing bacteria in their roots, and by being specially adapted to low-nutrient soils. The illustration on the left (from Central Borneo) shows a typical high-rainfall soil profile similar to those near Cairns.

In Flecker Garden much of the soil has been highly modified and enriched with fertilisers, mulch and soil brought in from elsewhere. In other parts of the Botanic

JOIN THE FRIENDS

Friends of the Botanic Gardens, Cairns Membership details - phone 4032 3900 or email info@botanicfriendscairns.org.au After joining you can support the Friends in many ways; as a committee member, in the Friends Shop, as a tour guide or assisting with events.

Friends of Sugarworld Botanic Gardens Contact Fran Lindsay frantastic10@bigpond.com

Newsletter Contributions: Please submit articles (must be volunteer or nature based) by first week of November for the next quarterly publication in December.

Email: l.grandy@cairns.qld.gov.au Please note articles are subject to editing.

Like us on Facebook to keep up to date with all events or visit our websites: - Green Space Our Place - Cairns Botanic Gardens - Friends of the Botanic Gardens

• • • • • • • • • • • •

Gardens Precinct, most of the soils are naturally occurring, although some have been fertilised and mulched. There are seven habitats within the precinct: Lowland Paperbark Forest; Remnant Monsoon Rainforest; Coastal Sand Ridge; Mangroves; rank grassland; Freshwater Lake and adjacent swamp; and Saltwater Creek and Lake.

Each of these habitats has soils of differing age and composition and has unique characteristics which favour the plants that grow on them. For example, around Saltwater Lake, the heavy clay soils are saline and waterlogged and toxic to most plants except mangroves. Mangroves tap the uppermost soil layer that has more oxygen and where the salt is diluted by rain and surface runoff.

A single sand grain eaten into by fungal threads, thereby releasing the minerals. There are a couple of fungal threads shown. The scale bar at the bottom is in 10 micron intervals (a micron = 1/1000th of a millimetre). Internet image.

Green Space Our Place

Tuesdays - Cattana Wetlands Jabirus 9am-noon First Tuesday of the month - Friends of McLeod St Pioneer Cemetery Wednesdays - Botanic Gardens Down ’n’ Dirty volunteers 9am-noon Thursdays - Stratford Nursery 9am-noon Thursdays - South Side Mountain Bike Club 9am-noon Thursday (once a month) - Sugarworld Gardeners & Friends Fridays - Saltwater Creek ‘Salties’ 9am-noon Wednesdays and Fridays - Tracks ‘n’ Trails 9am-noon Children’s Nature Activities Program - Little Taccas Visitor Enhancement Volunteers - rostered hours to suit Historcal Tour Guides - Tuesday and Thursday 10am Plant Collection Database volunteers - hours to suit individual

Interested in becoming involved with your local park, reserve or tracks in your community? Contact us to register as a Council volunteer and be involved in beautifying your park (enhance planting, weed management, litter clean-up), reporting on issues (graffiti and vandalism, anti-social behaviour, maintenance issues) and building community participation (networking activities) with Council support.

If you are interested in supporting any of our weekly groups or volunteering in your local area contact Volunteers Supervisor Louisa Grandy 4032 6648 or email greenspaceourplace@cairns.qld.gov.au

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Green Space Our Place