The value of natural tree hollows for Australian fauna

Nothing beats the hollows of old alive or dead trees for offering natural habitat, safety, breeding and roosting space for any number of animals.

What makes a tree hollow?King Parrot Male Guanaba

Ageing, natural fungal decay, insect attack and bushfire create hollows in a handful of Australian tree species that become home to a range of Australian fauna.

Tree hollows take some 100 to 150 years to form in an Australian tree. Long-lived Australian eucalypts are some of the most likely species to form tree hollows.

Example species that form hollows include:
– River red gum (Eucalyptus camaldulensis)
– Manna gum (Eucalyptus viminalis)
– Mountain grey gum (Eucalyptus cypellocarpa)
– Yellow box (Eucalyptus melliodora)
– Brush box (Lophostemon confertus)*
– Antarctic beech (Nothofagus moorei)
– Flooded (or Rose) gum (Eucalyptus grandis)*
– White mahogany (Eucalyptus acmenoides)*
– Grey gum (Eucalyptus biturbinata)*.

National Parks and Wildlife Service NSW: Natural tree hollows: essential for wildlife (PDF)

*Found in the Tamborine Mountain Escarpment Protection Precinct

How do animals use tree hollows?Rosella Crimson Guanaba

In Australia, some 17 per cent of bird species, 42 per cent of mammals and 28 per cent of reptiles use tree hollows.

The significant range of fauna using hollows includes bats, possums, gliders, owls, parrots, antechinus, ducks, rosellas, kingfishers, snakes, frogs and a range of lizards. In South East Queensland, up to 130 species need tree hollows to survive.

Land for Wildlife Queensland: The Value of Habitat Trees (PDF)

Hollows come in various sizes, from 2cm to 30cm. This size difference provides habitat for a range of animal species. The smaller entrances are used by animals, such as bats no larger than 10 grams, while the bigger entrances are used by larger animals, such as the Powerful Owl, the Glossy Black Cockatoo and possums.

Department of Environment and Climate Change: Hollow bearing trees (PDF)

There is a variety of reasons animals use tree hollows, including for shelter, nesting, roosting and foraging. Tree hollows are especially crucial for species that need them for nesting and roosting, including a range of threatened species.

The number of tree hollows required by animalsRainbow Lorikeets Guanaba

As a guide, there needs to be between 3 and 10 hollow-bearing trees producing up to 30 tree hollows per hectare to provide adequate habitat and guarantee the health and genetic diversity of a range of species.

National Parks and Wildlife Service NSW: Natural tree hollows: essential for wildlife (PDF)

The right landscape is vital to producing the necessary number of tree hollows and hollow varieties to house animals from different species as well as animals from the same species.

National Parks and Wildlife Service NSW: Natural tree hollows: essential for wildlife (PDF)

Threats to tree-hollow wildlifeCockatoo White Guanaba

A number of species use dead trees with livable hollows. Dead trees last only for a decade, sometimes a little longer, and provide short-term habitat for animals dependent on them. If human activity reduces forest area, fewer supporting trees are available to create future hollows. Reduction in hollow habitat puts dependent wildlife under stress, which can affect their numbers and lead to local species collapse / extinction.

Eco Magazine: Trees and non-flying mammals: a hollow understanding

Nesting boxes are often used as tree-hollow replacements. But are they adequate compensation for the loss of hollow-bearing trees, where the loss of the tree could be and should be avoided?

“Increasingly, artificial hollows (nest or roost boxes) are being installed to compensate for the loss of hollow-bearing trees. However, there is much debate about how effective nest boxes are as replacements for natural hollows … It is clear that nest boxes should not be used to justify the removal of hollow-bearing trees or unsustainable forestry practices.”

Eco Magazine: Trees and non-flying mammals: a hollow understandingEgernia mcpheii Guanaba

We’ve just scratched the surface of what tree hollows provide and how they’re used by Australian fauna.

We have a good understanding of the effects threats to hollow habitat can have on species numbers. This understanding makes the protection of good, healthy natural hollows vital for the safety and diversity of an amazing range of our native animals.

More information:

Wires Northern Rivers: Tree hollows and nestboxes

Western Australian Museum: Veteran and stag trees

Wet sclerophyll forests of Guanaba Forest – fauna, flora, fire

Magical towering eucalypt giants – symbols of Australia’s amazing wet sclerophyll forests. But they’re not all you’ll find in these beautiful forests, which contain rich understorey, soft-leaved shrubs, ferns and herbs and an incredible collection of fauna.

Biology of a wet sclerophyll forest

Wet sclerophyll forest in Guanaba ForestWet sclerophyll forests, often caught between rainforests and more open woodlands, are important habitat for an array of fauna, from marsupials to birds and bats and from insects to snakes, lizards and frogs.

Wet sclerophyll forests, when neighboured by rainforests, will include a mix of rainforest and sclerophyll forest plants where there exists overlap between the two forest types.

Sclerophylls generally occur in places with high rainfall (more than 900mm per year) and with a summer temperature exceeding 30 degrees Celsius and a winter mean temperature of less than 5 degrees Celsius.

Where are wet sclerophyll forests found?Bleeding Heart Tree (Omalanthus populifolius)

In Australia, wet sclerophyll forests are found in all states and territories except South Australian and the Northern Territory.

In Queensland, wet sclerophyll forests are mostly found in the south east part of the State (such as Tamborine Mountain) and, to a much smaller extent, the wet tropics.

What do wet sclerophyll forests look like?

Eucalypts and understorey in wet sclerophyll forests Gunaba ForestWet sclerophyll forests can be distinguished by their mix of very tall eucalypts (such as Flooded Gums) and a rich understorey of soft-leaved plants, many of which are rainforest plants.

The canopy, while open, has leaves that often interlock, leaving little light for the understorey. As well as a reduction in light, the leafy canopy creates a high level of humidity. This blend of low light and humidity provides good growing conditions for a range of mid-story plants that are effective light collectors. This second story of tightly growing plants enables the emergence of the next range of plants prevalent in wet sclerophyll forests, such as tree ferns and vines.

Fires in wet sclerophyll forests

Wet sclerophyll forests can combust easily, with a combustion rate dictated by the wet / dry weather. The peak fire season for sclerophylls in South East Queensland is between late spring and early summer.

Fires in wet sclerophyll forests have a direct and devastating impact on the wildlife, especially if the forest has been fragmented by human encroachment.

(Ref: “Wet sclerophyll forest: Regrowth Benefits – Management Guideline”, Queensland Department of Science, Information Technology, Innovation and the Arts; Department of Sustainability, Environment, Water, Population and Communities 2010; p27.)

Eastern Bristlebirds, in particular, have been the unlucky victims of fires in wet sclerophyll habitat, their populations having dramatically decreased in South East Queensland and north east NSW due to uncontrolled fire.

(Ref: “Wet sclerophyll forest: Regrowth Benefits – Management Guideline”, Queensland Department of Science, Information Technology, Innovation and the Arts; Department of Sustainability, Environment, Water, Population and Communities 2010; p27.)

A fire in Guanaba Forest

While Guanaba Forest comprises rainforest and open grassy forest, most of the property comprises at least two to three different types of fire prone wet sclerophyll forest. This type of forest falls within the highest fire rating of 10 according to the State’s bushfire planning policy, a rating that increases when the property’s geography and aspect are taken into account.

Residents neighbouring Guanaba Forest give an account of a serious fire that occurred in 2003, where fire impacted on a major portion of the property’s 500 acres and threatened nearby properties and homes. After the fire charged out of control, it took urban and rural firefighters 10 days of dedicated effort to bring it under control and guarantee the safety of surrounding properties.

Residents living around Guanaba Forest are deeply concerned about the increased fire risk introduced by the proposed development, where open pit fires are proposed within forest areas.

Animals of wet sclerophyll forests

Red-necked Wallaby in Guanaba ForestWet sclerophyll forests house an amazing variety of flora and fauna. Depending on the time of year, some animal species from both woodland forests and rainforests will move into and take advantage of sclerophyll habitat.

The older trees in sclerophylls develop hollows over time, creating habitat for a range of tree-dwelling animals, such as possums, owls, bats, parrots, kookaburras, pardalotes and more. (Young, regenerating forests cannot offer this type of vital habitat for animals requiring tree hollows to breed.)

Mammals found in sclerophylls include:Koala climbing tree in Guanaba Forest

– Koalas
– Fruit Bats
– Possums
– Grey-headed Flying Foxes
– Forest Bats
– Swamp Wallabies
– Red-necked Wallabies
– Antechinuses
– Tiger Quolls (Spotted-tailed Quoll)
– Platypuses (Platypi)

Birds found in sclerophylls include:Barred Cuckoo Shrike in Guanaba Forest

– Albert’s Lyrebirds
– Torresian Crows
– Pied Currawongs
– Pied Butcherbirds
– Black-faced Cuckoo-shrikes
– Barred Cuckoo-shrikes
– Wonga Pigeons
– Eastern Spinebills
– Pheasant Coucals
– Powerful Owls
– Grey-winged Goshawks
– Crimson Rosellas
– Red-backed Fairy-wrens.

Frogs and reptiles found in sclerophylls include:Frog Pearsons Tree Frog in Guanaba Forest

– Pearson’s Treefrogs
– Tusked Frogs
– Peron’s Treefrogs
– Green Treefrogs
– Red-bellied Black Snakes
– Diamond Pythons
– Land Mullets
– Lace Monitors.

Invertebrates found in sclerophylls include:Garden Orb Spider in Guanaba Forest

– Red-triangle Slugs
– Leeches
– Garden Orb Weaving Spiders
– Golden Orb Weaving Spiders
– Christmas Beetles
– Cicadas
– Giant Earthworms (Digaster longmani).

Species list ref: Wet sclerophyll forests: Steve Parish NatureConnect.

Bangalow Palms with eucalypts in Guanaba Forest

Wet sclerophyll forests offer biodiverse ecosytems – places where a variety of plants and animals thrive. There are few of these ecosystems left in Australia, and those remaining are under pressure from increased human activity. It’s time to protect the remaining wet sclerophyll forests to guarantee their legacy for generations to come.

More information:

Queensland Department of Science, Information Technology, Innovation and the Arts: Wet sclerophyll forest: Regrowth Benefits – Management Guideline (PDF)

Wet Tropics: Wet sclerophyll forests

Office of Environment and Heritage NSW: Wet sclerophyll forests (grassy sub-formation

Steve Parish: Nature Connect: Wet sclerophyll forests

Victorian Ecosystems: Wet sclerophyll forests

The Internet IBC Bird Collection: Sounds of the Bristlebird

Queensland’s DSDIP changes agency response after developer requests amendments

After a request from the developer, the Queensland Department of State Development, Infrastructure and PlGuanaba Gorgeanning (DSDIP) has amended its concurrence agency response to the entertainment park development application targeting Guanaba Forest.

Late last year, the developer made representations to DSDIP seeking changes to the Department’s original response to the development application.

The State has amended its response following these representations. Here are the key points to the final response from the DSDIP.

Within the State-regulated vegetation area (the bottom three-quarters of the property and containing wet scleropyll forest and rainforest), the developer can:
1. Set up new infrastructure.Sclerophyll Forest with Cycads
2. Construct vehicle tracks up to 10 metres wide (in accordance with the developer’s amended track plan).
3. Clear immature tree species to establish mountain bike trails and walking tracks.
4. Clear vegetation up to 10 metres wide for zipline towers and bridge structures (supports), and up to 5 metres wide for the actual ziplines and bridges.
5. Install climbing fixtures and fittings necessary for outdoor recreation, BBQ shelters and picnic tables where no clearing of regulated vegetation is required.

In terms of roads, the developer must:
1. Move the steep decent sign from the corner 120 metres further back along Guanaba Road.Water flows in Guanaba Forest Tamborine Mountain
2. Remove vegetation from the corner of Kaiser and Guanaba Roads.
3. Dedicate a 420 square metre strip along Guanaba Road to the Department of Transport and Main Roads.

For detailed information on the response from the DSDIP, go to the development applications section of and search for the DA: MCBd14/053.

The document is titled: “Amended concurrence agency response with conditions Department of State Development Infrastructure & Planning L3 RP181081″.

Note: The State response focuses only on vegetation and Guanaba Road issues. Scenic Rim Regional Council is responsible for the overall assessment of the development application.

Dragonflies in Guanaba Forest in the Tamborine Mountain Escarpment

The Tamborine Mountain Escarpment Protection Precinct is rich with abundant insect life. One of the heroes of the Escarpment is the dragonfly, an amazing flyer, successful hunter and a most intelligent insect.

Blue Skimmer Female

Female Blue Skimmer

Dragonflies are ancient animals, having been around long before the evolution of the dinosaurs. In fact, some 250 million years ago, a species of dragonfly measured a wingspan 70cm across.

There are 6,000 species of dragonflies and damselflies in the world, with Australia housing some 320 known species.

Dragonflies – very agile flyers
Dragonflies are agile flyers, with some flying across oceans to get to their destination. They can fly up, down, forwards, backwards, left and right. They have four different flying styles; counter-stroking, phased-stroking, synchronised-stroking and gliding, and use these different styles for different reasons, such as needing to change direction very quickly (for this, they use synchronised-stroking).

Female Fiery Skimmer

Female Fiery Skimmer

Where do they live?
They start their lives as nymphs, which is the larval stage of the insect. They may spend several years as a nymph; while the adult may live for a few days or weeks only.

Dragonflies are most often seen around water, but not always, and are found on every continent except Antarctica.

Some dragonflies live in and near running water and some in still water. But, if partial to still water, they don’t cross over into running water and visa versa.

Threats to dragonfly species
Because many species of dragonfly rely on precise water temperatures, good oxygen levels and unpolluted water to survive, they can act as good bio-indicators to water quality. Some dragonflies in NSW are endangered, because their habitats have been negatively impacted on by human activity.

Australian Emerald

Australian Emerald

Loss of habitat – chiefly wetlands – threatens dragonfly populations worldwide.

For example, in Japan, the loss of 60 per cent of the country’s wetlands has forced dragonflies out of their natural habitat and into domestic ponds and local creeks.

In Africa, their numbers have dropped dramatically, making them a focus of conservation attempts on the continent.

A beneficial predator against disease

A study reported by United Press International argues small insects, such as the dragonfly, are “essential for a healthy ecosystem”. And they can contribute to protecting humans from infectious diseases, such as lime disease and malaria.

Female Blue Skimmer

Female Blue Skimmer

The report suggests that the 20th Century reduction in biodiversity might be linked to a global increase in infectious diseases in humans.

The study undertook a range of research methods, such as field surveys, lab experiments and mathematical modelling to find out if the presence of dragonflies (and other predator insects) reduces infections in frogs caused by trematodes (parasitic flatworms).

It found that where more flatworm predators existed, fewer frog infections caused by the flatworm were found.

United Press International: Small predator diversity key to a healthy ecosystem

To be identified dragonfly

To be identified

Amazing sight

According to a report cited in the New Scientist, dragonflies have between 11 and 30 different visual opsins (light-sensitive proteins in the eyes of animals).

This means dragonflies can see beyond our red, blue, green colour combination and may have vision that sets a precedent for the entire animal kingdom.

Add this to other studies, which have found dragonflies see ultraviolet as well as red, blue, green and they can recognise polarised light reflections off water and you have yourself an insect with amazing visual capacity.

New Scientist article: Dragonfly eyes see the world in ultra-multicolor

The celebrated dragonfly

Many cultures revere the dragonfly. Native American tribe, the Navajos, use them as a symbol for water purity. And in Japan they’re seen as symbols of courage, strength and happiness.

While not celebrated in Europe, they play a big part in folklore, where the dragonfly is seen as sinister. UK-ites have referred to them as the “Devil’s darning needle” and in Portugal they’ve been referred to as the “eye-snatcher”.

Dragonflies in poetry

Male Fiery Skimmer

Male Fiery Skimmer

Dragonflies have found themselves in poetry.

One of Alfred Lord Tennyson’s earlier poems celebrated the dragonfly …

Today I saw the dragon-fly
Come from the wells where he did lie.
An inner impulse rent the veil
Of his old husk: from head to tail
Came out clear plates of sapphire mail.
He dried his wings: like gauze they grew;
Thro’ crofts and pastures wet with dew
A living flash of light he flew.

There are many great online and print resources on dragonflies. Find out more about the dragonfly, an amazing animal.

They rely heavily on the protection of their habitat, chiefly, water quality for their survival. Any change to their environment can impact on the very water they need to survive.

More information:

Buglife: Saving the small things that run the planet

PNAS article on dragonfly sight: Extraordinary diversity of visual opsin genes in dragonflies

PNAS article on predator diversity: Predator diversity, intraguild predation, and indirect effects drive parasite transmission

Find a dragonfly: Australian Dragonfly Identification Key

Brisbane Dragonflies Field Guide

Australian Museum: Dragonflies and damselflies: Order Odonata