Glider

Fur and Flowers: Melbourne's Mammalian Pollinators

This is a guest post by Mackenzie Kwak.

These days there’s a lot of buzz surrounding pollinators. When most of us think of them, our minds quickly turn to bees and butterflies. However, in Australia we have a diverse range of warm-blooded pollinators working through the night to keep our forests growing strong, and many of them call our city home.

Ancient Australia

Australia is a global hot spot for mammal pollinators. To better understand the close relationships between these warm-blooded creatures and their floral friends, we must turn our minds back millions of years to prehistoric Australia when flowers first appeared on the continent. For a very long time before the present day, Australia sat much farther south and at one point even stood where Antarctica now rests. At that time though, the globe was much warmer and plants could survive on this cool, southern continent known as Gondwana. Although polar forests flourished, temperatures still remained low, especially in winter when the forests often froze over. This provided a real challenge for plants eager to be pollinated.

Brushtail possums are one of the most common mammalian pollinators encountered around Melbourne.  Image: Wikimedia Commons

Brushtail possums are one of the most common mammalian pollinators encountered around Melbourne. Image: Wikimedia Commons

Insect pollinators were not common in Gondwana at this time due to one basic problem with their biology: cold blood. Insects are commonly described as cold-blooded or more accurately poikilothermic, meaning their body temperature fluctuates with the ambient temperature. However, insect body temperature can fluctuate so much that sometimes it rises far above that of mammals and birds,  making the term ‘cold-blooded’ a little erroneous. Fluctuating body temperature creates some major difficulties for insect pollinators - especially when the ambient temperature is close to freezing and pollination activity becomes impossible. It was these cool conditions that gave mammals their first real go at pollination in Australia. Mammals are warm-blooded, or, more technically, homeothermic, and can control their internal temperature even when the ambient temperature majorly fluctuates. This means that they remain active at much lower temperatures than their six-legged competitors and can exploit the rich nectar resources that plants have to offer. Over time, many mammals specialised to feed on this rich food and plants in turn modified their flowers to attract warm-blooded pollinators. 

Possums

Ringtail possums are another extremely common possum species of Melbourne.  Image: Emma Walsh

Ringtail possums are another extremely common possum species of Melbourne. Image: Emma Walsh

Possums are perhaps the most commonly encountered native mammals in the greater Melbourne region. Most folks view them with a strange combination of weak interest and mild irritation because of their all too common habit of taking up residency in our roofs. Possums, though, are important pollinators of many native trees and shrubs throughout Australia. We are most familiar with the common brushtail possum (Trichosurus vulpecula) and common ringtail possum (Pseudocheirus peregrinus) that are regular visitors to the flowers of gum trees. But while these two species supplement their diets of leaves with whole flowers, nectar and pollen, the real heavy lifters among the pollinating possums are the gliders.

In the greater Melbourne region the most common of these is the sugar glider (Petaurus breviceps), which incorporates a huge amount of pollen and nectar into its diet along with insects and tree sap. These little possums live in family groups, reside in tree hollows, and are important pollinators of Eucalyptus trees. Melbourne is also home to the world’s smallest glider, the feathertail glider (Acrobates pygmaeus), which weighs about 14 grams and is small enough to fit in the palm of your hand. While these little possums are far from common, they can still be found in the forests near Frankston and in Melbourne’s north-east. Like the sugar glider, they are also voracious pollen feeders but supplement their diet with insects.  

It's no secret why we call this little possum species the feathertail glider!  Image: Wikimedia Commons

It's no secret why we call this little possum species the feathertail glider! Image: Wikimedia Commons

Bats

Bats are another group of mammal pollinators often viewed with some antipathy by the general public because of their noisiness and propensity towards raiding fruit trees. However, bats are much more important to Australia’s ecosystems than many people realise. It’s important to note that the majority of bats that call Melbourne home do not act as pollinators - these are the microbats and they are in fact carnivores or insectivores. The grey-headed flying fox (Pteropus poliocephalus) is Melbourne’s only bat pollinator and reaches sizes far greater than its small carnivorous relatives, with wingspans up to one metre. Grey-headed flying foxes feed on a range of different flowers throughout the year but particularly favour the Myrtaceae family which includes the eucalypts, honey myrtles and tea trees, as well as the Proteaceae which includes the banksias and grevilleas. Fruit bats are not only important pollinators, but also critical seed dispersers for many native plants as well.

Dasyurids

Perhaps the strangest mammal pollinators to call the Melbourne region home are the Dasyurids, a group which few people have even heard of let alone considered as pollinators. For those unfamiliar with the often complex world of mammal taxonomy, the Dasyuridae is a family of mammals that includes quolls, Tasmanian devils, the now extinct Tasmanian tiger, and a range of other small, carnivorous marsupials. Many small Dasyurids resemble rodents superficially, but all possess a pouch which sets them apart. The genus Antechinus is one of these rodent-like groups of marsupials and Melbourne is home to three species: the swamp antechinus (Antechinus minimus), dusky antechinus (Antechinus swainsonii) and agile antechinus (Antechinus agilis). In other parts of Australia, Antechinus species are known as excellent pollinators of Banksia sp. but it remains unclear what role our Melburnian species may play in the pollination of local flora.

The agile antechinus is one of three  Antechinus  species to call Melbourne home.  Image: Wikimedia Commons

The agile antechinus is one of three Antechinus species to call Melbourne home. Image: Wikimedia Commons

It is not yet clear what role Melbourne's  Antechinus  species play in pollination.  Image: Wikimedia Commons

It is not yet clear what role Melbourne's Antechinus species play in pollination. Image: Wikimedia Commons

One Melbourne resident known to be a good pollinator is the brush-tailed phascogale, which resembles a squirrel but is actually a nocturnal, carnivorous marsupial. These secretive little mammals have been recorded gorging themselves on nectar and pollinating flowers with masses of pollen adhering to their furry muzzles. However, like many of our shy native marsupials, it is believed that the brush-tailed phascogale is sadly declining around the Melbourne region due to habitat loss.

So next time you see fruit bats glide overhead or hear a possum scurry across your roof, just remember the surprising task that these pollinators undertake. Although they may not be as glamorous or well-liked as native bees or butterflies, mammals are key pollinators of many of our native plants. It's now our responsibility to halt their decline, as losing them could be catastrophic. 


Mackenzie Kwak is a zoologist with a broad interest in Australia's diverse flora and fauna. His research focuses on the biogeography, systematics and ecology of Australasian ectoparasites, particularly ticks, fleas and lice. 

Banner image of a grey-headed flying fox courtesy of Wikimedia Commons.

Review: Mountain Ash

THE BOOK: Mountain Ash: Fire, Logging and the Future of Victoria’s Giant Forests
EDITED BY: David Lindenmayer, David Blair, Lachlan McBurney and Sam Banks

Less than two hours’ drive from the centre of Melbourne, the towering skyscrapers of the city are replaced by giants of a different kind: the Mountain Ash. These remarkable trees are the tallest flowering plants in the world and the forests they populate are home to Victoria’s only endemic mammal, the critically endangered Leadbeater’s Possum. Despite making up some of the most spectacular landscapes Victoria has to offer, montane ash forests are currently facing threats on two fronts: fire and logging.

The authors of Mountain Ash, professors and researchers at the Australian National University, know the montane ash forests of the Central Highlands of Victoria intimately. ANU research has been conducted in the region for more than 30 years; it is the longest-running environmental study in the world. The authors’ aim to distil decades of research within a 150-page book could have resulted in a dense account of their findings, but this is not the case. Instead, the authors have created a vivid and accessible narrative describing the challenges facing Victoria’s giant forests.

This publication utilises images in abundance to create a visual reference for the reader; the accompanying captions provide just as much insight as the body of the text. These images allow the reader to see for themselves the patterns of fire across the forest, the differences between old growth and post-logging regrowth, and between areas of forest burned at varying severity. These images are an invaluable tool to understanding the text, but at all times the authors communicate their subject clearly and with enthusiasm.

Beginning with an overview of the Black Saturday fires and the flora of the forest, the book goes on to examine the responses to fire of possums, gliders, birds, invertebrates and small terrestrial mammals, as well as the impacts upon large old trees and carbon stocks. Finally, recommendations are made for the forest’s future management. In succinct descriptions broken up by ‘myth-busting boxes’, diagrams and many photos, the book spells out clearly the extent of the destruction that has already occurred in our forests and how further damage can be avoided.

Uniquely placed by their ongoing research to examine the same areas of forest in detail both before and after the Black Saturday fires, the authors are able to offer a comprehensive view of the destruction caused by fire. Intriguingly, they have discovered that the cycle of logging in montane ash forests actually enables further damage by fire, in turn degrading the habitat of the Leadbeater’s Possum, for which large old hollow-bearing trees are vital habitat.

Mountain Ash is essential reading for all Victorians. It alerts the reader to the degradation of the crucial habitat of our faunal emblem, the Leadbeater’s Possum, and an iconic tree species, the Mountain Ash. The closing chapters indicate that change is possible as well as necessary to ensure that our forests are protected; reading this book is only the first step towards joining the cause.

This book belongs on your bookshelf if… you’ve ever felt enchanted by the forest. 

All photos taken by Alex Mullarky


Alex Mullarky

Alex Mullarky is a freelance journalist and works part-time in threatened species conservation. Her other passion is ex-racehorse rehabilitation and she is currently completing her Masters.

You can find her on Twitter at @ajmullarky