This item from today's Age is disturbing, and the pattern is also likely
to be replicated in areas thought to be ecologically intact in Qld, NSW,
SA and WA. Note the link between artificial watering points and
ecological impacts ...
____________________________________________________________________________
http://www.theage.com.au/news/20000831/A37709-2000Aug30.html
Many NT species vanishing
By DENNIS SCHULZ DARWIN
Thursday 31 August 2000
Large numbers of birds and mammals have become extinct in grassland
areas of
the Northern Territory previously thought to be ecologically intact,
research
has shown.
The research, which found that in certain areas of the territory a bird
species
has become extinct every five years and a wide range of flora and fauna
species
have severely declined in numbers, was delivered at a rangelands
conference in
Katherine.
In a report delivered by Northern Territory Parks and Wildlife
ecologist John
Woinarski, delegates at a northern grassy landscapes conference heard
that
environmental changes brought about by the introduction of feral
animals, weeds,
grazing, increased fire regimes and land clearing had resulted in marked
declines.
"How you manage the land clearly affects what species will survive on
that
landscape," said Dr Woinarski.
The conference, sponsored by the Tropical Savannas Cooperative Research
Centre,
was given the results of research produced by Dr Woinarski and his
associate,
Carla Catterall, on Coomooboolooaroo station in central Queensland.
In 1873, the property had been managed by amateur naturalist Charles
Barnard,
who meticulously recorded the presence of 183 species of fauna on the
station.
By 1930, Barnard reported the extinction of 12 bird species and the
decline of
42 other species during his lifetime.
Comparing his diaries with their research, Dr Woinarski and Ms
Catterall
discovered a constant and continuing rate of extinction.
Another 13 bird species had disappeared since Mr Barnard's death and
nearly
half the 183 originally recorded had declined.
"That property," said Dr Woinarski, "has been losing one bird species
every
five years."
While most mass extinctions have occurred in central and southern
Australia,
other recent studies showed species declines were also taking place in
the
Kimberley region of Western Australia and the Northern Territory.
Alaric Fisher, another conference speaker and territory ecologist,
showed
results of his work on the Barkly Tableland. He found that 12 vertebrate
species
were significantly more abundant the further they were from artificial
bores
designed to water cattle.
These birds and reptiles showed declines of between 36 per cent and 85
per cent
as the use of bores expanded across the rangelands.
Dr Woinarski also compared the records of other early biologists who
recorded
their findings in northern Australia with recent research.
In 1897, Scandinavian biologist Knut Dahl reported large populations of
brushtailed phascogales on the Mary and Katherine rivers, as well as the
abundant native brush-tailed rabbit-rat in Arnhem Land.
Trappings over the past decade at 3247 sites have not caught one rat
but it has
been identified on offshore islands. The phascogales have been caught in
only
three of the 3000 sites.
"It's unambiguous evidence that there were a whole lot of mammal
species that
were common here a hundred years ago that are nowhere near as common
now, if
they are still present at all," said Dr Woinarski.
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