In less than 250 years, the ravages of colonization have eroded the evolutionary splendor in the relative isolation of this continent. Australia has suffered a horrific demise of perhaps the world’s most remarkable collection of mammals, around of which 87% cannot be found anywhere else.
- Yirratji (northern pork leg bandicoot)
- Parroo (white-footed rabbit rat)
- Kuluwarri (central hare wallaby)
- Yallara (little bilby)
- Tjooyalpi (little stick-nest rat)
- Tjawalpa (sickle-shaped nail-tailed wallaby)
- Yoontoo (short-tailed jumping mouse)
- Walilya (desert bandicoot)
- work pain wallaby
This makes us the world leader in the extinction of mammal species over the past centuries. But this is far from just a historical tragedy.
Another 52 mammal species are classified as either: critically endangered or threatenedlike the southern curved batwho was recently crowned 2022 Australian Mammal of the Year. Fifty-eight mammal species are classified as vulnerable.
Many once abundant species, some scattered over large parts of Australia, have declined sharply and the distribution of their populations has become disjointed. Such mammals include the Mala (red hare wallaby), Yaminon (northern furry-nosed wombat), Woylie (brush-tailed bettong), and the Numbat.
This means that their populations are more susceptible to being wiped out by chance events and changes, such as fires, floods, diseases, invasive predators-and genetic problems. The survival of many species strongly depends on predator free gated sanctuaries and offshore islands.
Without substantial and rapid changes, the Australian list of extinct mammalian species is: almost certain to grow. So what exactly went so terribly wrong? What can and should be done to prevent further casualties and turn things around?
Up to two mammal species disappeared per decade
Australia’s post-colonization the extinction of mammals may have begun as early as the 1840swhen the Noompa and Payi (big-eared and Darling Downs hopping mice, respectively) and the Liverpool Plains striped bandicoot were believed to be extinct.
Many extinct species were ground dwellers, and within the so-called “critical weight rangebetween 35 grams and 5.5 kilograms. This means they are particularly vulnerable to predation by cats and foxes.
Small macropods (such as bettongs, potoros, and hazel wallabies) and rodents have suffered most extinctions—13 species each, nearly 70% of the total mammal extinction in Australia.
Eight bilby and bandicoot species and three bat species have also gone extinct, representing 21% and 8% of the extinctions, respectively.
The most recent fatalities are believed to be the Christmas Island Pipistrelle and Melomys of Bramble Caythe last known record for both species was 2009. The Bramble Cay melomys may be the first mammal species in danger of extinction due to climate change.
In general, research estimates that since 1788 about one to two terrestrial mammal species are in danger of extinction every decade.
When Mammals Reappear
It is difficult to be certain about the timing of extinction events and, in some caseseven though they are actually extinct.
For example, Ngilkat (Gilbert’s potoroo), the mountain pygmy possum, Antina (the central rock rat), and Leadbeater’s possum were once considered extinct, but were eventually rediscovered. Such species are often called Lazarus species.
Our confidence in determining whether a species is extinct depends largely on how extensively and how long we searched for evidence of their survival or absence.
Modern approaches to wildlife exploration, such as camera traps, audio recorders, wildlife dogs, and environmental DNA, make searching much easier than it ever was.
But unfortunately, the ongoing research and analysis of museum specimens also means that we are still discovering species unknown to Western science that have already tragically gone extinct.
What is driving their downfall?
After colonisation, Australian landscapes have suffered extensive, severe, persistent and often inflict blows. Among which:
And most importantly, the continued persecution of Australia’s largest land-based predator: the dingo. In some circumstances, dingoes can help reduce the activity and abundance of large herbivores and invasive predators. But in others, they can threaten native species with small and limited distributions.
Widespread land clearing, urbanization, livestock grazing and fire have obliterated some habitats and drastically altered and reduced others, often resulting in less diverse and more open vegetation. Such simplified habitats can fertile hunting grounds for red foxes and wild cats to find and kill native mammals.
To make matters worse, European rabbits compete with native mammals for food and space. Their grazing reduces vegetation and cover, endangering many native plant species. And they are prey to cats and foxes, maintain their population.
Although cats and foxes, fire and habitat modification and destruction are often cited as the top threats to native mammals, it is important to recognize how these threats and others interact. They should be managed together accordingly.
For example, reducing both overgrazing and the occurrence of frequent, large and intense fires can help maintain vegetation cover and complexity. This in turn will make it harder for invasive predators to hunt native prey.
What needs to change?
Above all, we should really be concerned about what is happening and act quickly and substantially to prevent further damage.
As a mammalian of some 30 years, the ongoing demise of Australia’s mammals is heartbreaking and infuriating. We have the expertise and solutions in house, but the frequent warnings and calls for change are still met with poor response. At other times a seemingly apathetic shrug.
So many species are now gone, probably forever, but so many more are shooting along the extinction highway due to sheer and total neglect.
Improving the prognosis for mammals is eminently feasible, but depends on political will. Broadly speaking, we must:
- minimize or remove their top threats
- policy alignment (such as energy sources, resource use and biodiversity conservation)
- strengthen and enforce environmental laws
- listen to, learn from and work with First Nations peoples as part of Healing Country
- invest what you really need – billions, not breadcrumbs.
The recently announced Endangered Species Action Plan sets an ambitious target to prevent new extinctions. Of the 110 species considered a “priority” to save, 21 are mammals. However, the plan is not fit for purpose and most likely will not succeed.
Political commitments seem flimsy if the same politicians keep making them approve the destruction of the homes on which critically endangered species depend. In addition, the targets for reducing greenhouse gas emissions are far below what climate scientists believe is essential and extremely urgent.
There is simply no time for platitudes and further ravings. Australia’s remaining mammals deserve much better, they deserve a secure future.
Are dingoes the answer to Australia’s feral cat and fox problem?
Quote: ‘Awful and annoying’: why Australia is the world’s leader in mammal extinction, and what to do about it (2022, October 19) retrieved October 19, 2022 from https://phys.org/news/2022-10- heartbreaking -infuriating-australia-world-leader.html
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