Word: traille
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...Species Act, habitat-protecting nature reserves and hunting prohibitions are all designed to slow the rate of extinction and preserve dwindling species. But a new paper in the journal Biological Conservation says we may not be trying hard enough. A team of Australian researchers led by environmental scientist Lochran Traill finds that current conservation policy tends to underestimate the number of individuals needed in a population of endangered species to keep it viable. In the face of environmental fluctuation and potential disasters, says Traill, we need animal populations to number in the thousands for survival - not in the hundreds, which...
...hard to understand Traill's logic - the smaller a species population becomes, the more vulnerable it is to extinction. Not only are small, dispersed populations more easily wiped out, but also they are more susceptible to inbreeding, which leads to a decrease in genetic diversity and further pushes the species toward extinction. So the goal is to boost species' numbers, and the long-standing rule for such conservation is 50/500 - meaning that 50 adults in a population are required to avoid the risks of inbreeding, and 500 are needed to avoid extinction due to sudden environmental change...
...Traill and his colleagues, after reviewing the most current data, found that a better rule would be 5,000 - meaning no fewer than 5,000 adult individuals are needed to keep a species safe from the threat of extinction. Dip below that level, and any sudden change - the loss of a valued habitat, a new disease - could wipe out a species before conservationists would have time to act. "Small populations have therefore reached a point of departure: away from the ability to adapt to changing environmental circumstances and toward inflexible vulnerability to those same changes," writes Traill. (Read "Extinction 'Gene...
...protection beyond what is politically possible. That puts conservationists in a bind. Do they push for the tighter levels of protection that might successfully preserve endangered species or do they accept what is politically feasible? "We suggest that most vulnerable species are not really being managed for viability," writes Traill. "Rather, conservation targets in most cases merely aim to maximize short-term [species] persistence and fit with complex political and financial realities...
Indeed, the political realities are sometimes dire. As American environmentalists discovered during former President George W. Bush's Administration, it was difficult enough to preserve existing levels of protection for wildlife, let alone push for tougher standards. Yet if Traill and his colleagues are right, the status quo is not enough to protect endangered species, and it's too weak to stop the sixth great extinction wave...