Green Space Our Place - Our Volunteers Voice - June 2024

Green Space Our Place

O N T E N T S

FRONT PAGE:

Jabiru volunteer Dave with a huge Ganoderma fungus at Cattana Wetlands.

BACK PAGE:

Zinnia flower at The Green Space education food garden.

In this issue:

• From the Editor....................2

• Weaving workshops...........3

• The Green Space news - Hügelkultur........................4

- Composting.......................5

- Sharing knowledge......6-7

• Friends Making a difference for 35 years......................8-9

• Volunteer Snapshot...10-13

• Shaping the future of North Queensland agriculture...................14-15

• Wetlands: important wildlife support systems .......................................16-17

• Feathered Friends............17

• Mangrove tours in Centenary Lakes.......18-19

• Sugarworld Trees............19

• Small Wonders - nature in miniature..........................20

• Cattana WetlandsSummer of Science 2024 ............................................21

• Nitrogen fertilisers and air pollution...........................22

• ‘Fridgecrab’......................23

Editor - Volunteers Team Leader, Louisa Grandy

Proof readers - volunteers Sandy Long, Jenn Muir

Contributors - Val Schier, Janice

Pichon, Jennifer H Muir, John Peter, Hidetoshi ‘Mikey’ Kudo, Barry Muir and Bridgette Gower, Rob Williams.

From the Editor

Welcome,

In this issue we celebrate The Green Space education food garden gaining popularity with our volunteers, an increase in visitor numbers and Cairns schools and children’s programs (see pages 6-7). Over the winter growing season, the Garden will be open on the last Saturday of the month - please spread the word.

Our volunteers support us in many ways from revegetation, gardening, the native tree nursery, assisting with the kids’ programs, providing tours and writing for this publication. To offer something in return each year we organise monthly information sessions (page 12) and workshops such as the weaving workshops pictured right (page 3). We also promote them at every opportunity (see pages 10-13).

Val Schier, President of the Friends of Botanic Gardens, Cairns, continues the series on the vital role the Friends have at the Cairns Botanic Gardens (pages 8-9).

If you are an enthusiastic gardener and looking to add to your collection, the Friends’ trolley sale is held every Wednesday morning at the Cairns Botanic Gardens. The volunteers are also happy to share their plant knowledge.

Check out the Summer of Science tour program planned for the coming months at Cattana Wetlands (see page 21).

Louisa

The Green Space OPEN DAY last Saturday of each month 8.30am-12.30pm

Weaving workshops

Workshops are arranged each year to provide something in return for all that our volunteers contribute on a weekly basis. Weaving is a popular event and bookings fill quickly. In April we held an afternoon weaving session showing our volunteers how to weave a mini basket using the spent palm inflorence bract and create cord from dried cordyline leaves. We also arranged Rosie Omundsen to teach coconut frond weaving techniques at our first Open Day at The Green Space.

Roberta and Jo

Catherine Sharyn and Chris

Mary and Jeannette

Patrice

Collis

Tanya

Keely

Rosie teaching Bernadette and Gail.

Mary with her coconut frond mat.

Sally

Hügelkultur

Hügelkultur is a process of layering organic garden waste inside a raised garden bed and topping it with a layer of soil. This method saves on the cost of buying soil, in addition to attracting and preserving moisture. The name Hügelkultur is German, translating as ‘mound or hill culture’. It is especially useful in areas where drainage or soil retention are a problem.

Wood debris decomposes slowly which makes it a stable source of organic matter. The best logs to use are those that have already started to rot. The organic matter will decompose over time and the roots will travel down to find the nutrition. It also acts as a sponge to retain water. Above the logs and sticks, grass clippings, coffee grounds, kitchen scraps and leaves are added.

From left: Rosi, Penny, Brett and John.

The Art of Composting

Part 1 - Method

Composting is an easy, cost-effective way to recycle your home and garden waste into a nutrient-rich soil additive.

Essentially decomposed plant material, everything from grass clippings and prunings, to kitchen scraps and chopped up palm fronds, mainly looks after itself.

Do not add meat, fish, cooked food or bread – these not only smell badly when they break down, but can attract vermin such as rats.

You can kickstart your composting with a little manure, then add new layers of greenwaste and dry material, leaves, shredded paper, chopped palm fronds, as your compost breaks down. If adding a large amount of material, mix through a handful of garden lime.

Turning speeds up the composting process, but it isn’t essential.

Dig compost from the bottom of the pile when needed.

THREE METHODS

Heap or pile

This DIY compost heap is a chance to upcycle any building materials you may have lying around.

Use fence palings, pool fencing, chicken mesh, pallets or similar items to create a box or cylindrical container. For best results, aim for an area of one square metre or greater. This will generate sufficient heat to speed up the composting process.

Commercial options

Pre-made composting bins and compost tumblers are sealed, compact and easy to assemble, while keeping your decomposing scraps out of sight (better for kitchen scraps).

Tumblers are more pricey, but are useful if you want to speed up the process. They can be turned every day to aerate and distribute the materials inside, with minimal labour.

Bokashi

Strictly not composting as it relies on fermentation, Bokashi is designed to be used in the kitchen or food preparation area.

Used correctly, the tightly sealed Bokashi container is odour and insect free. This also makes it suitable for meat, fish and dairy.

The end product is not fully composted so needs to be added to a compost bin or pile, or buried in the soil to finish decomposing.

Volunteers Support Officer, Sarah Gosling with the mulch heap at The Green Space education food garden. This nutrient-rich additive is one of the main reasons our food grows so well in this Garden.

Sharing knowledge with the next generation

The Green Space education food garden has become a popular venue for schools. Just Kids visit on a weekly basis and we’ve also engaged Whitfield and Woree State Schools.

Whitfield State School Year 2 students visited The Green Space as a part of their April tour of the Cairns Botanic Gardens. After a tour around the Garden, Sarah shared various techniques and information on how to grow healthy plants - soil, watering and the workings of the composting system. They also had some fun with Mel making nature garlands and decorating the park.

Engage, Empower, Learn program

“As a part of the Engage, Empower, Learn program at Woree State School, Year 8 students embarked on a field trip to Jess Mitchell Park in Edge Hill. This educational garden, known as The Green Space, was established by the Cairns Regional Council to train volunteers in cultivating produce using sustainable methods. Our class had previously worked with volunteers Support Officer Sarah Gosling, on building wicking beds last term. During the excursion, Sarah led an interactive session where students honed practical composting skills, explored seasonal fruits and vegetables, identified various beneficial insects, learned about propagation through cuttings, and participated in the cultivation and harvest of luffas.”

Jodi Shepherd Teacher | Engagement, Humanities and English

Just Kids visit on a weekly basis

The Just Kids program visit The Green Space garden each Tuesday morning to

Damar and a Praying Mantis - a natural garden pest controller.

Exploring the garden for beneficial insects.

Woree State School Year 8 students visited in April.

Making a difference for 35 years

Cairns Botanic Gardens is well known as the best Wet Tropics garden in the nation and the Friends can be satisfied that their efforts have played a major role in enhancing the precinct’s reputation and positioning the Gardens as one of the most-visited and best-loved attractions in Cairns for locals and tourists alike.

Following on from Part 1 featured in Our Volunteers Voice - Issue 42 in March

Raise funds, generate ideas and enable projects

The Friends of the Botanic Gardens, Cairns’ second goal in the Constitution is to raise funds to enable projects in the Gardens. A number of fund raising ideas have been put forward over the years including the events mentioned in the Part 1 article.

There have also been raffles, sausage sizzles, plant cloakrooms and stalls at Carnival on Collins. But the most popular and successful fund raiser is the propagation of plants by the Gardeneers group, sold from the weekly trolley sale or at one of the three larger annual sales at Easter, Carnival on Collins and before Christmas in December.

Gardeneers

This group of Friends contains members who have been propagating plants for decades. Many of them have high-level knowledge of both botany and horticulture and willingly share this with those who purchase plants at the sales. In doing this, they not only raise funds for the Gardens, but also get to know their customers and what they are looking for, creating regular weekly buyers.

Native bees

The idea to develop the interpretive signage on the wall of the Friends House balcony was to draw attention to the very old bee colony within the verandah wall. Many visitors show an interest in this panel and also in the two native bee hives and attractive pedestal and signage that have been purchased by Friends.

Projects

Funds raised have been directed to many projects over the years. The beautiful wrought iron and timber benches and gates have all been funded by the Friends and are frequently admired. The most significant contribution has been the $113,000 for the Conservatory, a structure that Friends lobbied for strenuously.

The Boanic Gardens Curator and Friends members installing the native bee hive at Flecker Gardens.

VAL SCHIER

Gardeneers Wednesday Trolley Sales.

They have bought tens of thousands of dollars of exotic and native plants including rare plants and orchids and also funded and created one of the first vertical gardens in Cairns at the Friends House.

Funds have been used to build the Jade Vine arbour; the creek project that transformed the Aboriginal Plant Food Garden; restoration of the 19th century historic Accessions register; the purchase of library books, camera and audio equipment; plant identification software and hardware and laptops; fogging machines; promotional video and interpretive brochures - the list goes on. All of these initiatives have greatly enhanced the Gardens.

Promoting horticulture and botanical science

Another focus of the Friends is to assist with enhancing the horticultural knowledge of Cairns residents.

Monthly talks

A program of talks is scheduled for 10 months of the year and many enthusiasts and professionals have shared their knowledge with members and visitors. It is rare that attendance is below 40 people and at a recent talk on native orchids, 70 people came along.

The presentations provide information on a wide range of topics, and are also an opportunity for the public of all ages to learn about the environment generally. Topics have varied over the years and have included night tours through the Gardens and Cattana Wetlands; the Northern Betong; Seagrass Meadows of Queensland; Evolution of Australia’s orchid diversity; Fungal Friends & Foes; Evolution of the Wet Tropics wildlife; The Australian Tropical Herbarium to name a few.

Friends House - shop and information centre

Friendly volunteers are rostered in the Flecker Gardens Friends House during the week to answer questions from visitors to the Gardens. Many visitors arrive at the Flecker Gardens before proceeding to other areas within the Cairns Botanic Gardens. This Friends ‘information centre’ has provided much needed additional support to the Botanic Gardens Visitors

Centre over the years. If specialist advice is sought then the volunteers seek out Council staff or more knowledgeable Friends to provide information.

Gardeneers

As well as raising significant funds as detailed above, Gardeneers members perform the role of assisting in the beautification of the whole region. The engagement with buyers, the questions answered, the advice given, the problems solved all ensure that residents have greater success with their gardening and make Cairns a more attractive place to live and visit.

Supporting Gardens staff

Over the years the Friends have supported the Gardens staff to increase their knowledge and skillset by providing funding for training and attending interstate and international conferences.

Peter and Lee planting out the veritcal garden.

VOLUNTEER SNAPSHOT

The Sugarworld group monthly working bee is increasing in popularity and as a result we are achieving more in the Garden.

The Friends put on a great morning tea too!

Sugarworld Friends & volunteers pruning the sugarcane collection.

Emma and Kardi installing new plant label posts at Sugarworld Gardens.

Sugarworld Friends president Fran Lindsay (right) invited Division 2 Cr Matthew Tickner to the group’s morning tea.

The Egrets have been busy this wet season, planting 60 natives in the Russell St revegetation site.

Brigette preparing the Russell St reveg site for planting.

On Mondays you can find the Egrets working in the Russell St revegetation site, the wetland behind the Edge Hill Primary School. Here they are planting a new section.

VOLUNTEER SNAPSHOT

The sign installed along the Smithfield Bypass has had a huge impact with putting Cattana Wetlands on the map! This was the result of a collaboration between the GSOP’s Jabiru volunteers, Council and Cr Rhonda Coghlan (second from left) who used her discretional funds to support the project.

Gary with a large group of Down

‘n’ Dirty volunteers thinning Heliconias.

Down ‘n’ Dirty’s Corben, Helen and Jann weeding at the Botanic Gardens Visitor Centre.

Down ‘n’ Dirty volunteers moving 30m3 mulch at Freshwater Lake Gardens.

Down ‘n’ Dirty volunteers from left: Jenny, Jim, Corben, Marian, Chris, Brigette and Graeme.

VOLUNTEER SNAPSHOT

The Forest Gardens’ volunteer group (right) spent four mornings weeding and pruning. They finished the ‘Duck Pond’ garden beds at their June working bee, carting and spreading 4m3 of mulch.

Volunteer Di Mason said, “I feel very proud that I had the opportunity of initiating the Forest Gardens volunteer group as a part of the Green Space Our Place program. The outcome has been a bigger success than I ever imagined. It has been only a few months and already we have an amazing team of like-minded residents who have joined as volunteers. I feel it gives me a strong community connection, with the bonus of forming great friendships. The work to maintain this beautiful space is creating benefits for families and the local community to enjoy.”

VOLUNTEER INFORMATION SESSIONS

The Forest Gardens group feeling accomplished after spreading 4m3 mulch - from left, front row: Trevor, Jeff, Di, Cathy; back row: Naoko and Janice.

Kawana St Krew volunteers, from left, Roxanne, Jeannette and Sue. Sue inspired her neighbours (who meet socially) to hold a monthly working bee to beautify their area. This year they have added over 100 plants to the streetscape.

Helen supporting the Little Sprouts kindy kids with their creations.

Friends of the Gardens tour guide, Zac leading a group of Green Space Our Place volunteers through Flecker Gardens in June.

In March, Friends of the Gardens bird tour guides shared their knowledge with our volunteers on a tour through the Centenary Lakes.

Mikey led a Mangrove Tour at the Centenary Lakes for the May Information Session.

VOLUNTEER SNAPSHOT

The Tracks ‘n’ Trails team have been busy as usual on Mt Whitfield’s Arrow Tracks. They are pictured here after installing new direcitonal signage.

Mike volunteers his time each month to cook the sausage sizzle for the Friends of the

Wednesday night event.

Stratford Nursery volunteers installing Ant Plants, from left: Keely, Rosi, Mary, Horticulturalist Ryan Zihrul, Gabrielle, Robbie and Elaine.

Kardi, Emma and Gabrielle washing pots at Stratford Nursery.

Botanic Gardens, Cairns

The Stratford Nursery volunteers potting up seedlings, from left, Rosi, Gabrielle, Keely, Emma, Kardi, Mary and Rowan.

Rob, Rosi and Bob lifting plants at Stratford Nursery.

Shaping the future of North Queensland agriculture

Early years at the Kamerunga State Nursery

“There’s a place in Cairns history that should be made known For people now living in this tropical zone.

‘Twas a garden of beauty, not far from town, Idyllic surroundings, with scrub all around.” *

Following European settlement in Far North Queensland from the 1870s, it became vital to establish local industries to sustain permanent populations. In particular, the Queensland Government was keen to develop tropical agriculture in the region and set up an experimental farm in the North to conduct plant trials. Thus, the Kamerunga State Nursery (KSN) came into being in 1889.

The KSN was tasked with trialling food plants that had the potential to be useful and profitable to Northern landowners. The most promising plants were then to be propagated to supply seeds or cuttings to prospective farmers and nurseries. The scope for the research extended beyond food crops to fodder grasses, as well as commodities such as timber, rubber, oil, and fibre; and even silkworm plants and ornamentals.

Nursery setup

The KSN was established on an 8-hectare scrubby reserve close to the township of Kamerunga. A nearby railway siding allowed easy delivery of plant material from the Cairns port. As more of the reserve was cultivated, increasing water needs were supplied by a pipeline from the Barron River. By the mid-1890s, 105 hectares were under cultivation.

Ebenezer Cowley, a British horticulturalist with tropical experience, was appointed as the Overseer. After clearing and fencing the land, specimens were sourced and planted in neat rows, sections or as border trees. Tidy pathways were formed with gravel from the Barron River. As the inventory expanded and the plants grew, the KSN gained popularity as a public garden admired by locals and visitors.

Will it grow?

With a free hand to experiment widely, Cowley gathered plant material from near and far like Torres Strait sweet potatoes, Mangosteen from Java, Palestine Orange, and Sierra Leone oil palms. One of the more exotic introductions was the Double Coconut, the largest seed in the world, solicited from the Seychelles for its decorative interest.

Commercialisation of the economically promising plants from the KSN was the domain of the farmers who were provided with stock. By the early 1890s, scores of species and varieties had been trialled and the list of propagated plants for distribution was growing. The annual report of 1895 contained horticultural notes on around 25 “economic” species including fruit, vegetables, spices, beverages, grasses, and ornamentals.

Will it pay?

Early experimentation with coffee demonstrated that the region would be a natural home. It became widely grown in the district and provided 40% of Queensland’s needs. However, stiff competition from imports grown in countries with lower labour costs reduced the economic viability and the local industry declined. Further, the 60 coffee farms around Kuranda were decimated by severe frost in 1901.

The Nursery’s cacao plot was planted on the banks of the Barron River. The results looked promising until the trees were washed away by severe flooding in 1911, when some two metres of rain fell in three days. An experimental plantation of rubber was also decimated.

Of all the plants tested at the KSN, sugarcane was the only crop which had enduring success. Numerous varieties were collected in 1892-95 from New Guinea, and species No. 15 proved of commercial interest. Later named Badila, it became the dominant sugarcane planted throughout North Queensland for the next fifty years. Today, the Sugarworld Botanic Gardens has a display of Badila and other superseded experimental lines.

Ten years later

After a decade on the job, Cowley died in 1899. By that time, he had enriched the local gene pool for commercial tropical crops and established which varieties were most suited to the North Queensland environment. Even rice and bananas which were originally introduced to the region by Chinese immigrants were targeted for varietal trials.

Over the following years, the KSN continued its research but without the momentum of the first decade. The early optimism about the establishment of new crops for the benefit of the North was dampened by regular farm failures, as well as the lack of forthcoming government financial support. The KSN closed in 1916 but was reopened in 1940 as the Kamerunga Horticultural Research Station.

Legacy

Most of the crops now grown successfully in the Far North were initially trialled at the KSN. Sugarcane selected by the Nursery helped the sugar industry become the dominant agricultural pursuit in the North. From the early “try anything” approach with new plants selected by the KSN, farmers increasingly converted to sugarcane when their ventures were cruelled by climate and economic forces.

JANICE PICHON

Some of the introduced plants have changed the local landscape. The coconut palms on Green Island are not native but brought in from the KSN in 1889 to provide sustenance for stranded sailors and fishers. The shady Beach Almond trees growing in coastal areas of North Queensland were originally introduced from the Nursery and have become naturalised.

Not all plant introductions through the KSN have proven to be beneficial. Algaroba, a South American native, was brought in as a potential fodder in 1895. This thorny legume is now naturalised in many parts of Australia and considered a noxious weed. A handful of other species have subsequently become unwelcome intruders, such as the Turbine Vine in the Wet Tropics.

Today, most of the Nursery’s remnant trees onsite have died. However, descendants of the original plantings may be found in farms and gardens around North Queensland, a fitting reminder of the golden days of the Kamerunga State Nursery as a birthplace of much tropical horticulture.

* Extract from the poem “An Echo of the Past” by J C Robinson, granddaughter of Ebenezer Cowley

Nursery 1899. © Centre for the Government of Queensland

Ebenezer Cowley, his wife and friend sitting beside Nursery homestead. Cairns Historical Society

Nursery layout Cairns Historical Society

Breadfruit trials 1898 Cairns Historical Society

Wetlands: important wildlife support systems

Wetlands are defined as coastal or inland areas seasonally (sometimes dry/muddy) or permanently saturated with water, which may be static, flowing, or tidal; fresh, brackish, or saline. They may be natural, eg rivers, swamps, lakes/ponds, floodplains, estuaries, mudflats, or salt marshes; or artificial, eg dams, or man-made lakes such as the Cattana Wetlands at Smithfield, Cairns.

Planet Earth needs wetlands. They are a crucial part of the environment: rich in nature and vital for life. They vary widely in their salinity and surrounding geography, playing a crucial role in maintaining biodiversity and healthy ecosystems. They are also important in supporting human communities: around half the world’s humans get their basic water needs from inland freshwater wetlands.

However, many wetlands have been lost to the environment due to infill for human development resulting in habitat loss, pollution, and invasive species. Remaining wetlands cover around five to six per cent of the Earth. They’ve become a focus for conservation because of the various benefits that humans derive from the healthy ecosystems that wetlands provide. They help recharge the groundwater; and are important natural carbon stores. They provide essential habitats for wildlife, and play a vital role in purifying polluted waters and mitigating damaging effects of floods and storms. And they offer a diverse range of recreational activities including fishing, photography, and wildlife observation.

Wetlands such as tidal mangroves and salt marshes are important shelters and nurseries for dozens of species of fish, including recreational and commercial species such as Barramundi, Yellowfin, Bream, Sand Whiting, Mullet, Garfish and eels. They also provide feeding and breeding habitat for crustaceans such as crabs and shrimps. Thus they provide food sources and shelter for many wildlife species including birds, and support commercial and recreational fishing.

Throughout the world, fish and prawn farms, housing and recreational development are putting these habitats at risk. Significant loss of salt marsh, and the sudden widespread death of mangroves in 2015 in northern Australia, has increased concern about these important habitats.

Photo: Barry Muir

Jennifer H. Muir

Cattana Wetlands’ Jabiru Lake, a quarry that filled with water to become a man-made lake popular with birds and birders.

Rhizophora mangrove wetland at low tide in a North Qld estuary. The aerial roots provide shelter and a nursery for numerous fish and crustacean species.

A pioneering Mangrove salt marsh in Cattana Wetlands.

Photo: Barry Muir

A salt marsh in the early tropical Dry Season, with seasonal, muddy pool surrounded by mudflats and Avicennia mangroves on the margin - Cattana Wetlands.

Photo: Barry Muir

Birds and Wetlands

Many bird species depend on wetlands. And as birds are such a crucial part of, and indicator of health of the world’s environments, numerous Australian Government Laws and International Agreements have been established over the years to protect birds.

These Laws include the Australian Environmental Protection and Biodiversity Conservation (EPBC) Act 1999; and in Qld, the Qld Government Environmental Protection Agency (EPA) Nature Conservation Act 1992 (NCA).

Further protection is provided by Australia’s Commonwealth Wildlife Conservation Plan for Migratory Shorebirds (2015), and international Agreements (eg with China, Japan and Korea) for the many migratory shorebird species that rest and feed on our shores and wetlands during our Southern Hemisphere summer, avoiding the severe Northern Hemisphere winters during which food is extremely limited.

Much of Planet Earth is now so disturbed by human activity, that long-term viability of bird populations is also more affected by the lifespans of some species. For example, a species that lives only three or four years, and doesn’t breed until its second year, may only have the opportunity to breed two or three times in its entire life. If habitat loss or disturbance prevents breeding in just one year, it could result in the loss of at least 25 per cent of breeding opportunities for such species, resulting in population decline.

Before humanity had such an impact on the environment, Mother Nature’s ‘boom and bust’ cycle was a natural population control, helping to keep nature in balance. In today’s world however, wetland destruction and flora and fauna loss, along with length of species’ breeding restrictions, make birds much more vulnerable to further change.

It is essential that wetlands are protected, as well as the plants and animals that occupy them. Globally, too many wetlands have been drained or filled for human purposes. Without wetlands, many birds, other animals and plants wouldn’t exist. In particular, wetlands are important habitats for waterbirds. It’s interesting that the body, leg and bill shapes of waterbirds have evolved to enable many species to occupy and thrive in this specialised habitat.

Feathered Friends

JOHN PETER BirdLife Australia

Welcome Swallow

Three species of swallows breed around Cairns, and by far the most abundant of them is the Welcome Swallow. They were dubbed Welcome Swallows by early sailors, as they were a welcome sight — their appearance usually meant that land was nearby.

Large numbers are readily seen perched in long, twittering rows on powerlines in the evening, as they assemble before heading off to roost in the branches of nearby trees. They are also often seen foraging in flocks at other times of the day, though occasionally singly or in twos.

Present around Cairns throughout the year, there’s a noticeable influx of Welcome Swallows during the Dry Season, as flocks of ‘winter refugees’ migrate northwards from the southern states to escape the colder months (when there’s little food on offer).

They often forage in the company of Fairy Martins — another swallow which heads north for the winter. Their food comprises tiny, flying insects, snatched mid-air, either sweeping at speed just above the ground, mudflats or water, or higher in the air, above the trees, where their aerobatic twists, turns and swoops come to the fore.

Welcome Swallows build nests which are half-cups made of mud, with overhead cover usually provided by sheltering eaves or verandahs of buildings, as well as in sheds and under bridges. They lay up to five eggs, which, like most laid in ‘closed’ nests (with a roof), are white. Only the females incubate, but both sexes feed the young birds, sometimes with the assistance of helpers.

Comb-crested Jacana - photo: Jennifer H. Muir

Mangrove tours in Centenary Lakes

HIDETOSHI ‘MIKEY’ KUDO

One of the unique features of Cairns Botanic Gardens Centenary Lakes area, is having both freshwater and saltwater lakes. This is gives diversity to the plant community and also wildlife, parti cularly bird species.

Mangrove Tours were provided by MangroveWatch volunteers to the Friends of Botanic Gardens and the community in November 2023 and also to our Green Space Our Place volunteers in May this year.

On November 11, 2023, some of the botanic garden guides and mangrove enthusiasts were led by MangroveWatch volunteers, Mandy Soymonoff and Mikey Kudo, who shared their knowledge of the local mangroves.

One of the impressive figures is that 18 varieties of mangroves (including subspecies and hybrids) naturally occur in Centenary Lakes. This is half of all mangrove varieties found in the Cairns region (including Daintree). The most common ones are Grey Mangroves, Avicennia marina; Black Mangroves, Lumnitzera racemosa; and Red Mangroves, Rhizophora stylosa. The flowering season of Grey Mangroves is in October to November and the tour was fortunate to find some early flowers at the bridge over Saltwater Lake.

In contrast, Black Mangroves flower almost throughout the year. However, you see more flowers in the wet season. Mandy spotted some flowers while we were walking.

We also visited mangrove planting sites where we could have a closer look at the rarest mangroves in the world: Haines's Orange Mangrove, Bruguiera hainesii; and a newly discovered mangrove: Dungarra Orange Mangrove, Bruguiera dungarra (discovered by Mikey Kudo).

One of Haines's Orange Mangroves flowered in April - May last year (2023) and we are expecting more this year. There is a temporary sign for these trees so that anyone can visit and find them easily (50 meters north of the bridge over Saltwater Lake). These trees are now nearly seven years old and about 2mtrs in height.

Another interesting fact is that mangroves belong to a plant community that occurs in the intertidal zone of the seawater. In fact, just walking over 10mtrs, we can find five or more different mangrove species along the narrow water edge! This plant community also includes ferns and palms.

Mangrove ferns (Acrostichum speciosum) have been purposefully maintained at the mangrove planting site at the bridge over Saltwater Lake.

It was a great Sunday morning and mosquitoes seemed to have taken the day off due to the dry conditions. At the end of this walk, we stopped at the bridge over Saltwater Creek and checked the nest of Brown-backed Honeyeaters. The nest was already empty. So, here is a picture of the parent feeding a chick taken the previous week.

Sugarworld Trees

FRAN LINDSAY

President Friends of Sugarworld Botanic Gardens

Pouteria caimito (Abiu) - from the Sapote family.

A delicious fruit with smooth white juicy flesh that can be spooned from the thick bright yellow skin. The latex in the skin, when cut, should be avoided. An old recipe I found from Australian Tropical Foods advises to cut the Abiu in half and remove the seeds. Scoop out the flesh into a glass bowl and sprinkle with a little lime juice to bring out the flavour. Chill and serve.

Abiu is a good source of calcium, phosphorus, Vitamins A and C.

Originating in the Amazonian region of South America, Abiu requires a warm moist tropical climate and will grow to an average of 10 mtr high.

The specimen is in Sugarworld Gardens Tropical Fruit Tree Orchard, behind the Lions Club bench seat.

Photographs by: Forest and Kim Starr

Abiu

Small Wonders nature in miniature

Bridgette Gower

Nearly everyone around Cairns has at least one of the six species of Cordyline growing in their garden.

Most species have plain green leaves but careful selection by horticulturalists has produced spectacular purple and red varieties. Flowers are inconspicuous; but take a closer look! They are delicate mauves or pinks, tubular at first then burst open into threepetalled flowers with large yellow anthers. They produce abundant nectar and pollen and are very popular with native bees.

This beautiful animal is a male Disrupted Beautiful-Masked Bee (Palaeorhiza disrupta). They probably evolved in New Guinea and migrated to Australia during the Last Glacial period 20-30,000 years ago when Australia and New Guinea were joined by a land bridge. It is found in high rainfall areas in the Northern Territory and Queensland, but it is not known when or where they breed, but probably in burrows in the soil. The brilliant iridescence is not caused by pigment – it is light diffracted by thousands of microstructures in the animal’s integument.

These are one of several species of Bird Nest Fungi appearing on mulch in the Botanic Gardens under very wet conditions. They start as little balls with a brown furry covering, but as they mature the covering tears away exposing a ‘bird-nest’ about 5mm in diameter. The nest contains tiny ‘eggs’ which are capsules containing the spores. Raindrops hit the edge of the cup and flick the spore capsules out. The skin of the capsules later breaks down, releasing the spores.

Barry Muir

CATTANA WETLANDS SUMMER OF SCIENCE 2024

FREE FAMILY TOUR PROGRAM

All tours start in the car park.

MICROBAT NIGHT

Saturday 6 July at 6pm

Assist the Bats and Trees Society of Cairns conduct a survey of insect-eating bats with ultrasonic detectors. Includes a nocturnal tour.

THE IMPORTANCE OF CATTANA WETLANDS

Saturday 3 August at 8am

An information smorgasbord including history, management and threats to the Wetlands; inspecting the Feather Palm Forest and 'possum boxes' with a pole camera; and bird watching with a telescope. All with specialist guides.

MOTH NIGHT

Saturday 28 September at 6.30pm

Dr David Rentz AM installs light sheets to survey critters of the night. Includes free nocturnal tours. Sponsored by Friends of Botanic Gardens, Cairns.

AUSSIE BACKYARD BIRD COUNT

24 & 25 October

School excursions with specialist guides, by booking only. Enquiries by email: crocconsult@gmail.com

MICROBAT NIGHT

Saturday 23 November

By popular demand – assist the Bat and Tree Society of Cairns conduct a survey of insect-eating bats with ultrasonic detectors. Includes a nocturnal tour.

Nitrogen fertilisers and air pollution

Under the forest floor, and even beneath the vegetable patch or flower bed in our garden, lies the complex, hidden world of fungi. These tiny organisms form intimate connections with plant roots - the fungi and plant roots sharing resources with each other and influencing the soil around them.

Some of these are called endomycorrhizal fungi: they penetrate the roots to form fungal networks within and between the cells. The other kinds of fungi are ectomycorrhizal, which grow outside the root filaments and produce many of the mushrooms that we see on the forest floor, and occasionally in our gardens. All the trees and shrubs are interconnected and supported by fungi.

Most trees and other plants form partnerships with either endomycorrhizal or ectomycorrhizal fungi, but only occasionally associate with both. Plants support both endo- and ectomycorrhizal fungi with sugars they make with sunlight and carbon dioxide, through the process known as photosynthesis. In return these fungi give plants access to lots of soil resources such as nitrogen, carbon, phosphorous, trace elements and water. Plants grow poorly when their associated fungi are damaged.

As well as helping our plants to grow, ectomycorrhizal fungi, in particular, also act as ‘carbon guardians’: they help slow down decomposition and increase the amount of carbon dioxide locked away out of the atmosphere into plants and soil. However, excess nitrogen, produced by the burning of fossil fuels, and the over-use of nitrogen-based fertilisers on farms, parks and gardens are making these carbon-protecting fungi less abundant.

When we fertilise with nitrogen, plants have less need to use the fungi to provide them with nitrogen, and thus invest less sugar in their fungi. The fungi then become less abundant.

Losing these fungi could tip the balance towards

forests that do not store as much carbon in the soil, and cause stored carbon dioxide to re-enter the atmosphere, accelerating climate change. To find out if forests are indeed sensitive to nitrogen pollution, and if this pollution affects carbon sequestration, scientists in the United States have overlaid maps of nitrogen pollution onto those of temperate forest distribution, and studied the forest soils.

The researchers found that forests exposed to high levels of nitrogen pollution had far fewer trees associated with ectomycorrhizal fungi. Instead, in these forests, trees that harbour endomycorrhizal fungi grew faster and more frequently than trees with ectomycorrhizal fungi. As mentioned above, most trees and other plants form partnerships with either endomycorrhizal or ectomycorrhizal fungi, but are rarely associated with both.

The study also found that the loss of ectomycorrhizal fungi was associated with loss of carbon dioxide from the forest soil, and that the effect of nitrogen pollution was greater than they had expected. This is scary because it implies that by overuse of nitrogen fertilisers, or by polluting the atmosphere with nitrogen compounds, we have accidentally put a lot of carbon normally held in soil back into the atmosphere as carbon dioxide without realising it.

Quite apart from accelerating climate change, the loss of ectomycorrhizal and endomycorrhizal fungi could also mean the loss of potential antibiotics, and other biologically important compounds derived from fungi. Soil fungi are the predominant source of antibiotics that humans use because soil fungi spend their lives fighting with bacteria. We now know nitrogen pollution affects the diversity of fungi and, as we lose fungal species, we may also be losing all sorts of biological compounds that could have huge industrial or medical applications.

Reference: Averill C, Dietze MC & Bhatnagar JM. (2018). Continental-scale nitrogen pollution is shifting forest mycorrhizal associations and soil carbon stock.

These trees and shrubs are interconnected and supported by fungi.

BARRY MUIR

Many people were dealt with the unexpected from the ‘Jasper Flood’. I gained a flat mate; a White-clawed Mangrove Crab (Tiomanium indicum) that lives under my fridge.

I foraged in the mangroves for classic crab food and also threw it some lettuce.

‘Fridgecrab’ pushed the mangrove stuff away, but ate the lettuce. I decided it might need protein, so dropped it some pine nuts and carob buttons - now both at the top of my shopping list.

I also built ‘Fridgecrab’ a mangrove mud pond, a freshwater pond and a sand dune system beside the fridge. I top up the ponds on a daily basis and ‘Fridgecrab’ has adapted to an instantaneous 12 hour tide that deposits delicious postJasper food items. I am ‘CrabSlave’. I have an extra friend and ‘Fridgecrab’ has a new lifestyle. When it is friendly, we can do a fingers to claw shake. Sometimes it only lets me shake one of its skinny sticklike legs. Maybe it’s not so concerned about losing a leg. I collected a pile of seeds and sticks for it to shuffle around and everyday it does a new flotsam and jetsam installation, usually not too far from its safe spot under the fridge, and sometimes in one of its ponds.

White-clawed Mangrove Crabs are a burrowing type and at the top of the tidal limit. Their thumb size tunnels are surrounded by excavation mud and can be seen in most healthy mangroves. Due to rising sea levels, they have moved their burrows to higher ground. In some parts of the world this has caused serious erosion problems as the ground is less stable due to the crab tunnels.

My flat mate can’t burrow into the concrete floor, so I decided to look upon it as the first non-burrower of the species. When released back into the wild it could run workshops on how to live sustainably in the mangroves. When that time comes I will have to call upon all the Mangrovewatch volunteers to help with the food parcels of lettuce, pine nuts and carob that will have to be delivered to the fridge-free habitat.

My new flat mate gets on OK with the locals. My three green tree frogs enjoy the new freshwater pond but if they flop in the mangrove mud pond and then climb the wall I’ve got some cleaning to do. The geckos stay above floor level and the night-time skink seems to get past the crab with no major drama so far. The remnant cockroaches that the frogs haven’t eaten might be a protein hit for ‘Fridgecrab’, I don’t know. What have I learnt (so far) from this experience? ‘Fridgecrab’ gets a good deal. Glad it can’t do Facebook. I’d wake up one morning with 2,000 crabs hanging round my fridge waiting for the tide to refresh the ponds and drop carob, pine nuts and lettuce. Maybe that could be the venue for the “Non Burrowing Crab Workshop”. You don’t need a permit to keep crustaceans, but my landlord might be concerned about 2,000 crabs. Go Go Fridgecrab!

Join the Friends

Friends of the Botanic Gardens, Cairns

Membership details email - 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

Magazine Contributions:

Please submit articles (must be volunteer or nature based) by first week of August for the next quarterly publication in September.

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, Cairns

Green Space Our Place

• Mondays - Russell St Environmental Park Egrets 9am-noon

• Tuesdays - Cattana Wetlands Jabirus 9am-noon

• Wednesdays - Botanic Gardens Down ’n’ Dirty volunteers 9am-noon

• Wednesdays - Tracks ‘n’ Trails 9am-noon

• Thursdays - Stratford Nursery 9am-noon

• Thursday (once a month) - Sugarworld Friends & Gardeners

• Fortnightly Thursdays - Children’s Nature Activities Program - Little Taccas / Little Sprouts

• Heritage Tour Guides - Thursday 10am from the Botanic Gardens Visitor Centre

• The Green Space education food garden - Wednesdsays / Fridays

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