Monday, April 27, 2009

"Creatures' rush to extinction..." (Australia)

From The Australian:

ONE hot, dark night midway through March, John Woinarski, principal scientist at the Northern Territory's Department of Natural Resources, Environment, the Arts and Sport, was out doing what he most loves: surveying the wild landscape of the Top End bush. But this task, in recent years, has become a burden. Woinarski, dropped by helicopter on to the high stone-country plateau of West Arnhem Land, already half-knew what he would find at one of his remotest monitoring sites, a stretch of 50sqm - rainforested, lush - beside a waterhole: nothing. Not one native mammal.

During recent decades, scientists have been recording a vast decline in the original mammal fauna of north Australia. In the past five years, for most species, that decline has become a death spiral. The picture is consistent across the north: in parks and in Aboriginal reserves, in pastoral country, in pristine rangelands, in coastal swamps. The pattern has been too plain to miss and many of the likelier causes have been identified, but the dizzying disappearance of animals from the landscape seems like something new. It is Australia's most profound ecological crisis; it is little known in the nation at large and still quite imperfectly understood.

Woinarski, a man of precise words and restrained manner who has spent much of his life studying northern landscapes and received the 2001 Eureka Prize for his work, describes the evidence.

His group's 220 long-term monitoring sites cover the Top End's most untouched regions, places where one would expect the native wildlife to be surviving fairly well. Between 1996 and 2001, he and his colleagues observed the falling away and traced the ongoing pattern, but in the following five years it was as though the native fauna population had plunged from a cliff's edge. The newest findings were "the game-stopper". They recorded an average 70 per cent drop in species numbers and an 82 per cent drop in the total of animals seen at each site. These declines were in all environment types and all family groups. Even in national parks, where protection regimes are in place, the figures were devastating. "The most recent results are extremely alarming; indeed, catastrophic," Woinarski says...

Just more than a year earlier, Woinarski and his core team had published a preliminary report card on the vanishing. Lost From Our Landscape, their 250-page overview, constitutes an unusual field guide, a book of what's not out in the environment any more. It is filled with the details of the NT's most threatened species, including 40-odd small mammals: bilbies, mice, wallabies, quolls, bettongs, rat-kangaroos in obscure and appealing variations. It weaves a familiar narrative.

The last great wave of Australian extinctions was experienced in the Centre, between the 1930s and '60s, when most of the 20 mammal species known to have been lost from this continent disappeared. That pattern is now repeating further north: animals that were once common are critically endangered...

Scientists know very well, from fossil evidence, that animals have been dying out in Australia for the past 60,000 years as a result of large-scale climate shifts, and also as a consequence of man's arrival, and the use of fire to control the landscape. But today's looming round of extinctions is a strong clue to the strain placed on the tropical and sub-tropical region in recent decades by modern development pressures and by the abandonment of traditional land use techniques.

Mines, ports, dams, cattle stations, all these have changed the workings of the landscape. But the remote bush is also being transformed. More subtle, pervasive, insidious long-term shifts are under way. Hence a paradox: it is in the untouched far country that the most startling declines in animal populations are being recorded. As Woinarski observes, central and north Australian mammals are susceptible precisely because they had evolved through millennia to fit the scarcities and slow pace of the continent. They tend not to reproduce fast or in great numbers. When there are changes in an ecosphere, as in the north in the past century, sharp consequences ripple through the natural kingdom...

1 comment:

Blogger said...

If you're searching for the best bitcoin exchanger, then you should choose YoBit.