Poachers Killed 8 Percent of All African Elephants in 2011

It's obvious that rampant poaching is not good for elephant populations. But a new paper has determined just how much of an effect the illegal ivory industry is having on Africa's elephant population, and the results aren't pretty.

Between 2010 and 2012, poaching could be directly attributed to a 3 percent decline in the elephant population, with as many as 8 percent of all elephants being killed illegally in 2011, a number that the US government researchers call "unsustainable."

"As a result of this illegal killing, the population currently suffers from few prime-aged males, strongly skewed sex ratios, and social disruption in the form of some collapsed families and increased numbers of orphans," George Wittemyer of Colorado State's Department of Fish, Wildlife, and Conservation Biology wrote in a paper published today in Proceedings of the National Academy of Sciences.

The result is hardly surprising—poaching rates have soared to record levels throughout much of Africa and ivory prices and seizures are through the roof. But until now, it's been difficult to pin specific numbers on just how damaging poaching is to the elephant population.

Using elephant carcass surveys in 19 different sites throughout Africa combined with overall population and demographic data at those sites,  Wittemyer was able to "disentangle drivers of population trends," such as habitat destruction and other things that are potentially causing the elephant population to decline.

In other words, Wittemyer was able to determine the cause of death for thousands of elephants, then extrapolate that out to get a good idea of what's really going on with the population. In general, elephants that die of natural causes don't spontaneously have their tusks cut off, making it pretty easy to determine if one was illegally killed.

Using that data, he estimates that roughly 40,000 elephants were killed in 2011, a record number. That's roughly 8 percent of all African elephants, which is particularly shocking: Between 1998 and 2008, just .6 percent of elephants were poached annually.

After 2011, the population decline attributed to poaching declined slightly, but Wittemyer says that the rate is still unsustainable, and that the elephant population is still in extreme danger. In fact, poaching isn't believed to have made a real dent in the population until 2010, at which point, his results "demonstrated an overharvest-driven decline in African elephants."

Of course, all of this builds on itself. If the demand for ivory remains as high as it is and if poachers are determined to continue killing elephants in record numbers, that two or three percent decline is going to go up in a hurry. At which point, an "unsustainable" population decrease becomes a disastrous one.