Dingoes Threaten Extinction of Hairy-Nosed Wombats
Copyright 2001
Independent on Sunday (London)
July 1, 2001
By Kathy Marks In Sydney
The northern hairy-nosed wombat is on the brink of extinction as dingoes threaten a species already ravaged by overgrazing and drought.
The reclusive marsupials once ranged across the whole of eastern Australia, but recently the population has dwindled to just 112, confined to a pocket of a tropical forest in northern Queensland.
Conservationists have long feared that the single colony could be wiped out by disease, bushfires or floods. Now it faces a new menace in the shape of dingoes - native wild dogs.
Dingoes have killed eight wombats in the past nine months, dealing a devastating blow to the species. Wildlife officers say unless pounds 100,000 is found to build an anti-dingo fence around their habitat in Epping Forest National Park, the remaining animals have a precarious future.
The northern hairy-nosed wombat is among the world's half dozen rarest mammals, its numbers comparable to those of the Javan rhino. But in contrast to other endangered species, such as the giant panda, of which there are still 1,000 in the wild, few people - even in Australia - know or care about this shy, nocturnal creature.
One of three species of wombat, the northern hairy-nosed is extraordinarily difficult to conserve. The animals' reproductive patterns are a mystery and they ignore food and water left out for them in times of drought. They are hard to trap, as they are not lured by baits and they quickly become stressed in cages. Efforts to set up a captive breeding programme have failed; in captivity, they do not breed and refuse to eat.
"It's almost as if they don't want our help," said Alan Horsup, a Queensland Parks and Wildlife Service biologist who co-ordinates conservation. "They're frustrating to work with."
Dr Horsup has spent the past decade painstakingly monitoring the wombats in their habitat, a network of burrows in a 1.2 sq mile thickly wooded patch of the remote park. He was dismayed to find the carcasses of wombats savaged by dingoes. Five died in one week alone.
"It got to the point where I didn't want to walk around the burrows any more," he said. "I would go to a burrow where there had been activity the previous day and find it silent, like a graveyard. I knew what that meant: another dead wombat."
Another major threat confronting the wombats, which are heavily built with hairy muzzles, weighing up to 88lbs, is buffel grass. The introduced African variety is taking over the park and smothering native grasses on which the wombats feed.
While their numbers have risen from a low of 65 in the early 1990s, only 30 per cent of the current population are believed to be female. "It's of great concern," said Andrea Taylor, a geneticist at Monash University in Melbourne. "It makes every female absolutely vital." The paucity of breeding females means that in-breeding and lack of genetic variety are inevitable. It also makes wildlife officers reluctant to risk moving some of them to start a second population at another site.
Dr Taylor oversaw a project last year in which the animals were counted by stringing up sticky tape at wombat height outside their burrows and extracting DNA from hairs caught on the tape.
Attempts to start a captive breeding programme proved disastrous. In 1996 a young male was trapped and sent to Western Plains Zoo in New South Wales, where he refused all food for six weeks and had to be force-fed. The animal lost one -third of his body weight and died suddenly from a twisted bowel.
A veterinary surgeon at the zoo, David Blyde, recalled: "He used to just stand there. It was like he was just absolutely bewildered by the whole thing." The breeding programme was halted by the Queensland government when a second wombat died of heat exhaustion later that year after being trapped.
It is nearly 70 years since the last extinction of an Australian mammal. The Tasmanian tiger was hunted to oblivion by European settlers.