Research website of Dr Gilbert Price

Archives for January 2018

Saving the Tasmanian Devil

The potential of reintroducing locally extinct species back into their former ranges has garnered increased interest amongst ecologists and conservationists in recent years. The idea is that if you are lucky enough to have a ‘healthy’ population of a given organism, individuals of that species may be reintroduced back into their former home range presuming that it had at some time in the recent past become extirpated from that area.

The hope is that it may be an effective way of staving off species extinctions in the future. There may also be additional benefits such as the restoration of ecological balance to anthropogenically disturbed environments. It’s an idea that is gaining more and more support across the planet.

Tasmanian Devils feeding at the Devil Ark

Tasmanian Devils feeding at the Devil Ark

You may have heard about the reintroductions of wolves to the Yellowstone National Park in the USA and the positive ecological feedback that it had. Even this week, several news outlets have reported plans to reintroduce Spotted Quolls (Dasyurus viverrinus) to the wilds of southeast mainland Australia.

 

Tasmanian Devils

Last week, I was lucky enough to visit the Devil Ark, a Tasmanian Devil (Sarcophilus harrisii) breeding sanctuary nestled in the Barrington Tops of central eastern New South Wales. As the name suggests, Tasmanian Devils are today restricted to the island of Tasmania, but interestingly, they once had a much wider geographic range, having been found across much of mainland Australia in the geologically recent past. The Barrington Tops occurs in highlands and was selected as a breeding site in part because it has a similar climate and vegetation to the modern Tasmania.

The Tasmanian Devil is today a species at risk of extinction. Population numbers have plummeted dramatically over the past 20 years. The main threats include loss of habitat, vehicle strikes, and more than anything, death at the hands of the devastating Devil Facial Tumor Disease (DFTD).

Tasmanian Devil fossil from a cave in Queensland (maxilla)

Tasmanian Devil fossil from a cave in Queensland (maxilla)

This is a non-viral, clonally transmissible cancer that is passed from devil-to-devil via the sharing of bodily fluids, especially saliva. It results in lesions and bumps on the face that eventually develop into tumors. Upon contracting DFTD, death is usually imminent within about six months. The disease has caused devastating impacts on Tasmanian Devils, with overall population estimates thought to have plummeted from several hundred thousand in 1996 (the year that DFTD was first recognised) to just 10,000 today.

One of the primary goals of the Devil Ark is to breed up enough healthy, disease-free individuals as an ‘insurance’ population, with a view that they may be able to be reintroduced back to the Tasmanian wilderness. Healthy, breeding-age individuals were sought from the wilds of Tasmania and various zoos, and are today held in a series of enclosures within the Devil Ark property. To date, the breeding program has proven most successful with several hundred joeys born over the past decade or thereabouts.

 

 

Reintroducing Devils

According to our hosts on the visit, Renae and Mark, there have been some attempts to reintroduce healthy Barrington Tops individuals back to Tasmania, but with varying success (an ongoing local Tasmanian problem being vehicular strikes). A longer-term goal of the Ark is to also introduce Devils, plus a swag of other marsupials such as wallabies, quolls, and bandicoots, into a purpose-built enclosure on the Barrington Tops themselves.

That’s something that I’m particularly interested in – the possibility that Devils could successfully be reintroduced back to the mainland. I was part of a research group a few years ago that even wrote a paper toying with that idea.

Our study was spurred on by previously documented fossil records of Tasmanian Devils on the mainland. In fact, over 100 incidences of mainland Tasmanian Devils have been reported in the scientific literature on the basis of their fossils.

Lower fossil jaw of a Tasmanian Devil from Queensland

Lower fossil jaw of a Tasmanian Devil from Queensland

 

New Tasmanian Devil fossils on the mainland

My research team and I have even been lucky enough to find some Devil bones ourselves in a series of caves just west of Townsville in the tropics of Queensland (we also found Tasmanian Tiger fossils there too!). Remarkably, the specimens were found lying on the surface of the cave and are exactly the same species as the modern Tasmanian Devil. We’re not currently sure how old they are, but we hope to produce new radiometric dates for them in the future.

Cuddling a Tasmanian Devil

Cuddling a Tasmanian Devil (it was a bit shy and didn’t want to show its face!)

Regardless, these fossil records suggest one important thing to us: that the apparent climatic tolerance of the Tasmanian Devil is much greater than what their modern distribution suggests. Devils clearly have the ability to occur in a wide range of climates, from temperate (as per Tasmania today) to tropics.

If we are to seriously explore potential areas for mainland reintroductions in the future, I think that we need to put more emphasis on habitat, rather than climate, in the selection of potential target areas.

Anyway, if you can ever make it up to the Barrington Tops to visit the Devil Ark, I highly recommend it. The tour was great, the knowledge of the guides exceptional, and you might even have the chance to pat a Devil or two!