Friday, 23 March 2012

Brisbane's Koala controversy

Since my previous post on our local koalas I have now found Mount Gravatt is on the edge of a significant area of koala habitat, the 'Koala Coast': "the area South of Brisbane: Redland City, the eastern portion of Logan City and the south-eastern portion of Brisbane City... is regarded nationally as one of the most significant koala populations because of its size and genetic structure" (DERM 2010).

So, how many Koalas live in Brisbane?  Are numbers still declining, or stable?  These questions are at the heart of continuing controversy over the status of koala populations around Brisbane. Due to its iconic status in Australia, koala population declines get more airtime in the press than most of the other species facing serious population declines as Australia rapidly urbanises.  Such airtime inevitably increases close to the forthcoming state election!  However, without independent, up-to-date, scientifically collected data, the article states that conservationists claim they are fighting a loosing battle against figures that are 'fudged'.  The most recent state government report (2010) with a survey of the population in this regions was compiled by DERM (Department of Environment and Resource Management). As Koala numbers are now reported to be low but the margin of error in the government survey remains high, it is increasingly difficult to statistically prove a decline without better survey methods that reduce the uncertainty.  With such uncertainty in the 2010 report it is simply inconclusive about whether the decline continues or not and open to interpretation by politicians, such as state Environment Minister Vicki Darling, claiming that this means they have stabilised without any proof.  Better census methods seem to be urgently required.

Populations on the Koala Coast are now somewhere around 1/3 of the population of 20 years ago - but the sustainability of the population is not mentioned in the DERM report.  The 'Australian Koala Foundation' (AKF) and Australian Research Council are funding scientists at the University of Queensland and DERM to work on this question, and they have been examining the impacts of multiple threats (dog attacks, vehicle collisions and disease) on the koalas in this region and the impact this is likely to be having on the sustainability of the population.  Their conclusion is that the population will continue to decline unless there is intervention that can drastically reduce more than one of these threats.  With such rapid urbanization in Brisbane the threats look set to increase, not decline, a chilling thought.

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