Mention “The Kimberley”, and for most Australians visions of spectacular sunsets, giant boab trees, rocky escarpments and cascading waterfalls spring to mind. But there is a storm on the horizon, and it is about to hit the region hard.
Australia’s Kimberley is roughly the size of Victoria and one of only five great wilderness areas remaining in the world.
Geographically, this region stretches north from a line between Broome in the west to the Northern Territory Border in the east.
A history of great diversity
It is one of the most ecologically intact regions in Australia, containing exceptional biodiversity, high numbers of endemic fauna (more than 50 vertebrate species alone) and many animals listed as threatened or declining elsewhere in Australia.
It also contains a spectacular and fragile coastline, hundreds of offshore islands, numerous undisturbed, unregulated rivers and the world’s most significant aboriginal rock art galleries.
Isolation - combined with little development and few people - has acted to protect the Kimberley and its wildlife since European settlement.
Fire and grazing making their mark
There have been few biological surveys of the Kimberley and all have occurred in the high rainfall areas as opposed to the lower rainfall, rangeland regions. We surveyed a rangeland area in the north Kimberley between the Prince Regent Nature Reserve/Mitchell Plateau in the west and the Drysdale River National Park in the east.
Most sites we visited, no matter how remote from the station homesteads, have had clear evidence of fire. Fire mapping to date indicates that roughly half of this 2 million acre area burns each year.
This results in large tracts of homogenous vegetation - it’s all similar species and of a similar age.
The ground has been pock marked with hoof prints from cattle, donkeys and horses, cattle grazing being the primary pastoral activity in this region.
The number of large grazers is now well above sustainable levels and there is evidence of damage to rainforest patches, rangeland vegetation, mound springs, swamps and river banks were common.
Lots of species but few individuals
Despite all this we found more than 190 different bird species and 80 different reptile species, including several un-described species. It’s a testament to the rich biodiversity of this region.
We also identified more than 26 different frog species, including several unidentified species, and around 50 mammal species.
The variety of different mammals we’ve found has been amazing. But with few exceptions, the density of mammals was low.
For example, northern quolls, which are typically quite trap-happy animals, were only caught four times in 30,000 trap nights. We caught northern brown bandicoots just eight times in the same period.
An urgent need exists to establish good vegetation, fire and geographical maps for the region. These resources will help to make the most of the wildlife data and information being collected.
The extinction wave is on its way
The initial wave of animal extinctions that occurred following European settlement started in the south of this continent. The extinction wave travelled behind clearing, overgrazing, the introduction of a variety of feral pest species, hunting for the fur trade, changed fire regimes and exotic diseases.
Distance, isolation and the inability of foxes and rabbits to take hold in the north protected much of this region of Australia, but many scientists now believe that the tide is turning. We may be on the cusp of the next great wave of extinctions in this country.
So what has changed?
Scientists believe a second period of extinctions in the north is unlikely to be the result of just one single factor. Like the decline of our fauna in the south, it will probably occur as a result of many of the factors mentioned above.
On top of those, we now have cane toads, mining activities, disease and climate change.
Addressing these threatening processes is essential if we are to preserve the unique biodiversity and beauty of the Kimberley.
A move to have the north Kimberley declared a world heritage area has begun. Further information can be obtained by visiting Save the Kimberley. If we don’t act now, the Kimberley as we know and love it, will change forever. Bad things happen when good men fail to act. Don’t say you haven’t been warned!