Why we’re not giving up the search for mainland Australia’s ‘first extinct lizard’



A grassland earless dragon at Jerrabomberra, NSW, November 1991. The search is now on for this species’ Victorian cousin.
CSIRO/Wikimedia Commons, CC BY

Jane Melville, Museums Victoria

You may have seen news in recent days of the suspected demise of the Victorian grassland earless dragon – now thought to be the first lizard species to be driven to extinction by humans in mainland Australia.

That suspicion arose on the basis of a newly published study in Royal Society Open Science by our research team, in which we discovered that the grassland earless dragons of southeastern Australia are not a single species, but four distinct ones: one that lives around Canberra, two in New South Wales, and one restricted to the Melbourne region.

The most recent confident sighting of the Melbourne species was 50 years ago, in 1969 – hence the fears that the Victorian species has already succumbed.

But despite this worrying news, we’re not leaving this lizard for dead just yet. Conservationists are now combing remaining grassland around Melbourne in a search for survivors.




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Although no lizard species have previously been declared extinct on the Australian mainland, the grassland earless dragons (Tympanocryptis) of southeastern Australia have long been the subject of conservation concern. Even before being split into four separate species, they were already officially listed as endangered.

The Victorian grassland earless dragon (Tympanocryptis pinguicolla) is known only to occur in the native grasslands around Melbourne. A review of historical collections at Museums Victoria show that it was found at several locations including Sunbury, Maribyrnong River (then called “Saltwater River”), and as far west as the Geelong area until the late 1960s.

Although there is little information available about the ecology of this species, it was described by Lucas and Frost in 1894 as:

Inhabiting stony plains and retreating into small holes, like those of the ‘Trap-door Spider,’ in the ground when alarmed […] Often met with under loose basalt boulders.

The last confirmed sighting was near Geelong in July 1969.

First mainland extinction?

Globally, 31 reptiles have been listed as extinct or extinct in the wild, according to the IUCN Red List, the global authority on the status of species. Two skinks and one gecko species have been declared extinct in the wild on Christmas Island, a remote Australian territory in the Indian Ocean. But until now there have been no recorded reptile extinctions on the Australian mainland.

Yet it is too early to give up on the Australian grassland earless dragon. Zoos Victoria researchers have completed a mapping analysis of potential grassland habitats. But this doesn’t give us enough information to say whether or not any grassland earless dragons remain.

There are several factors that leave open the possibility that the Victorian grassland earless dragon is still clinging to survival. There are some remaining habitat areas that have not yet been surveyed, and this species is small, secretive and hard to find. We urgently need more surveys to try and find any remaining populations.




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If these lizards are not yet extinct, their protection will clearly become an urgent conservation priority. But it is hard to develop a conservation program without knowing where the target species actually lives, or indeed whether it is still alive at all.

Zoos Victoria is now leading a campaign, alongside expert ecologists and local communities, to try and confirm the presence or absence of the Victorian grassland earless dragon. This involves various methods, including habitat mapping, camera trapping, and active searching. The team is also working to identify unsurveyed areas that might potentially be home to these elusive lizards.

Last year the team deployed a series of small pitfall traps at two locations in Little River. Unfortunately, no earless dragons were detected during the survey and few lizards of any species were caught, despite the fact that these locations seemed to offer appropriate food and habitat.

The team is not giving up yet and is committed to continuing the search, with Zoos Victoria researchers having identified sites with suitable habitat both within and outside of the historical distribution, which they aim to survey intensively over the coming years. Meanwhile, reptile keepers at Zoos Victoria are developing husbandry techniques to help look after the grassland earless dragon species from Canberra and NSW.

The conservation challenge has got harder, because where previously we were tasked with looking after one species, we now have to safeguard at least three – and hopefully four!


This article is based on a blog post that originally appeared here. It was coauthored by Adam Lee and Deon Gilbert of Zoos Victoria.The Conversation

Jane Melville, Senior Curator, Terrestrial Vertebrates, Museums Victoria

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Could Tassie devils help control feral cats on the mainland? Fossils say yes



File 20190222 195876 1pvj44l.jpg?ixlib=rb 1.1
The Tasmanian devil once thrived on mainland Australia.
Shutterstock/mastersky

Michael Westaway, Griffith University and Gilbert Price, The University of Queensland

The Tasmanian devil – despite its name – once roamed the mainland of Australia. Returning the devil to the mainland may not only help its threatened status but could help control invasive predators such as feral cats and foxes.

The idea of returning devils to the mainland has been raised before.




Read more:
Tasmanian devils reared in captivity show they can thrive in the wild


But now we’ve explored the idea from a palaeontological view. We looked at the fossil record of mainland devils, in a paper published online and in print soon in the journal Biological Conservation.

A well preserved devil mandible (lower jaw) recovered from excavations west of Townsville.
Gilbert Price, Author provided

The fossil record helps us better understand how the devils co-existed on mainland Australia with other wildlife. It also helps us see how these iconic animals may possibly interact with small and medium-sized animals if reintroduced to the mainland in the future.

Back in the wild

Ecologists have reintroduced several apex predators to environments where they were once driven to localised extinction. This has helped restore past ecosystems by providing a clearer ecological balance.

One of the best-known examples is the reintroduction of wolves to Yellowstone National Park in the United States, to check the overgrazing and destruction of habitat by elk.

By reintroducing Tasmanian devils into mainland Australia, can we possibly help restore ecological systems that support devils along with small to medium-sized native mammals?

Native and exotic predators

Tasmanian devils and thylacines (Tasmanian tigers) were displaced across the mainland of Australia sometime after the dingo was introduced from southeast Asia at least 3,500 years ago.

But these iconic Australian predators were still able to survive in Tasmania. The island was created 10,000 years ago by rising sea levels, well before the arrival of dingoes on mainland Australia.

Dingoes have now been eradicated across much of mainland Australia, particularly within the seclusion zone of the dingo fence in the southeast of the continent. The 5,400km fence stretches eastwards across South Australia into New South Wales and to southeast Queensland.

Exotic predators such as foxes and cats now thrive across many parts of Australia, and have devastating impacts on small to medium-sized Australian mammals.

But until recently they have not been able to gain a foothold in Tasmania. Many ecologists believe the presence of the devil has prevented these other animals making their destructive mark on the ecology of Tasmania.

Sadly the situation is changing as a result of the deadly devil facial tumour disease, an infectious cancer that has destroyed many populations of Tasmanian devils. Estimates range up to 90% of some population groups now wiped out.

As a result, feral cats are now moving into former devil habitats and hunting native species on Tasmania.

A fossil window to the past

So what does the fossil record tell us about the past life of the Tasmanian devil in mainland Australia?

The Willandra Lakes World Heritage Area, in southeast Australia, provides an extraordinary archaeological and palaeoecological record of Ice Age Australia.

Recovery of fossils and devil coprolites from eroding bettong burrows at the Willandra Lakes World Heritage Area.
Michael Westaway, Author provided

In the past, skeletal remains buried within the landscape were commonly fossilised. Evidence of small animals that dug burrows (such as burrowing bettongs) and the predators that pursued them in their burrows, are exceptionally well preserved.

Our excavations reveal how devils and other small-to-medium sized mammals and reptiles interacted over more than 20,000 years in this area. Even during the peak arid phase, known as the Last Glacial Maximum, it seems that devils and their prey successfully co-existed.

The fossil record (10,000 to 4,000 years ago): This shows the fauna reference condition prior to the arrival of the dingo. (1 Western Quoll, 2 Tasmanian Devil, 3 Thylacine, 4 Bilby, 5 Western Barred Bandicoot, 6 Southern Brown Bandicoot, 7 Burrowing Bettong, 8 Brush Tailed Bettong, 9 Wombat, 10 Nail-Tailed Wallaby, 11 Hare Wallaby, 12 Western and Eastern Grey Kangaroo, 13 Red Kangaroo, 14 Crest Tailed Mulgara, 15 Greater Stick Nest Rat, 16 Hopping Mouse, 17 Fox, 18 Cat, 19 Rabbit)
Toot Toot Design, Author provided
The contemporary record: This shows today’s situation in the Willandra Lakes World Heritage Area. Light grey animals represent those animals that are now locally extinct.
Toot Toot Design, Author provided

The fossil record shows that the range of habitats occupied by devils in the past was far more diverse than today, with populations being found across environments from the central arid core to the northern tropics.

This suggests that devils today should, theoretically, be able to reoccupy a similarly extensive range of habitats.

Former devil range across Australia as revealed by the known fossil record.
Toot Toot Design, Author provided

Better the devil you know

Some ecologists suggest dingoes should be reintroduced into Australian habitats in order to reduce the impact of cats and foxes on native mammals.

One problem is that dingoes also prey on livestock. This is the reason the dingo fence was constructed during the 1880s.

But devils are not active predators of cattle and sheep. So reintroducing a predator that has a much longer evolutionary history with other native mammals in this country would likely receive far less opposition from pastoralists.




Read more:
Deadly disease can ‘hide’ from a Tasmanian devil’s immune system


A reintroduction of devils back to the mainland may be a new approach to consider for controlling the relentless, destructive march of exotic predators and restore crucial elements of Australia’s biodiversity.

It still needs to be demonstrated that devils can suppress the activities of cats and foxes on the mainland, as they seem to have done in Tasmania. Experiments with devils in a range of different settings would help to establish this.

A new research approach involving palaeontologists, conservation biologists and policy makers may help us understand how we can restore biodiversity function in Australia.The Conversation

Michael Westaway, Senior Research Fellow, Australian Research Centre for Human Evolution, Griffith University and Gilbert Price, Lecturer in Palaeontology, The University of Queensland

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Australia: The Eastern Quoll


The link below is to an article that reports on the extinction of the Eastern Quoll on mainland Australia, however there are plans to reintroduce the species near Sydney.

For more visit:
http://www.australiangeographic.com.au/journal/resurrecting-locally-extinct-eastern-quolls.htm

Article: War on Rats – Lord Howe Island


The link below is to an article reporting on the battle against rats on Lord Howe Island, to the east of the Australian mainland. 

For more visit:
http://www.news.com.au/news/bombs-to-fight-the-killer-rats/story-fnejlrpu-1226426452786

Introduced Species: Macquarie Island


The link below is to an article on Macquarie Island, which is located to the south of the Australian mainland (Macquarie Island – not the article). The article provides a good case study of problems associated with introduced species.

For more visit:
http://www.mentalfloss.com/blogs/archives/121598

News Report on Aboriginal Population Growth Prior to European Occupation of Australia


I have come across an interesting news article on the Aboriginal population prior to European occupation of Australia. Though not exactly wilderness or environmental news, the article does shed some light (or at least sparks interest) on the Australian situation prior to European colonisation of our country. Of particular interest is the suggested impact on the Tasmanian Tiger on mainland Australia.

For more visit:
http://www.abc.net.au/news/stories/2011/05/11/3214132.htm