July 30, 2010 | 3
The common wombat (Vombatus ursinus) is, as its name suggests, fairly common in Australia. In fact, the indigenous badgerlike mammal is often considered to be a pest. But widespread species are usually ignored because they are pervasive, and in the case of V. ursinus new research warns that the meter-long marsupials could soon be in trouble if Australians don’t start paying attention.
Biologist Erin Roger of the Australian Wetlands and Rivers Center at the University of New South Wales has been studying how many wombats are killed by cars and trucks in New South Wales (NSW). According to her research, at least 3,000 common wombats die annually on NSW highways. This represents a shocking 13.6 percent of the total common wombat population.
“There is certainly the potential for that sort of death rate (especially in combination with other threats) to not be sustainable,” says Roger, whose research on the common wombat is pending publication.
Roger conducted five years of field research along a 23-kilometer stretch of highway in Kosciuszko National Park. She counted the number of dead wombats she encountered during the 560 times she traversed the highway, then extrapolated the data to 8,000 kilometers of the NWS highway system within prime wombat habitat, taking into account such factors as road traffic and data on other wildlife collisions.
Now we come to the real question: What is the impact on the ecosystem of this large number of wombat deaths? Right now, no one knows the answer nor is anyone looking for the answer because, for now, common wombats remain true to their name.
“Management agencies have such a relaxed attitude towards ‘common species’ and no one quite seemed to think that wombat deaths were of concern,” Roger says. “There is all this money invested in threatened species, but there is a real problem with this approach, as it doesn’t preserve ecosystems. We are ignoring other species and the overall functioning of ecosystems.”
Roger points to previous research (such as this paper from Trends in Ecology & Evolution) that says common species are vital to healthy ecosystems.
As for the wombat’s role in its own ecosystem, amazingly, no one really knows the details for sure. “We simply don’t know because there is no funding for monitoring or research,” Roger says. But in her paper Roger presents a possibility: “As burrow-dwelling animals that turn over large quantities of soil, common wombats likely play an important role in maintaining ecosystem functioning, particularly by impacting soil nutrition. Evidence of their role as ecosystem engineers would help place common wombats firmly within the conservation agenda.”
Roger is now calling for a quantitative evaluation of wombats’ roles in their ecosystems. Hopefully that will happen before the common wombat becomes rare, like its critically endangered cousin the northern hairy-nosed wombat (Lasiorhinus krefftii), which now number fewer than 120 individual animals.
Photo via Wikipedia