A direct link between ivory trafficking and elephant decline

Over the last four years, the illegal trade in elephant ivory surged, while tens of thousands of elephants were killed for that ivory each year. Those patterns have coincided with increases in seizures of illegal ivory and with increases in ivory prices on the black market. But quantifying that illegal harvest has always proven incredibly difficult; it is particularly hard to distinguish natural from illegal deaths. But now, Colorado State University researcher George Wittemyer and his team have come up with a new strategy for addressing the problem.

Quantifying the illegal harvest is absolutely critical both for promoting wildlife conservation as well as for linking conservation programs with social and political trends, but since killing it done in secrecy, it’s a tricky prospect. Wittemyer combined field-based carcass monitoring with demographic data, all from a wild African elephant population in Kenya’s Samburu National Reserve. Then, using that as a baseline, they extended the patterns they found to infer trends at both regional and continental scales, using data collected by the Convention on International Trade in Endangered Species (CITES).

At Samburu, the researchers discovered that the local elephant population was particularly hard-hit between 2009 and 2012. Between 1998 and 2008, 0.6 percent of the population was illegally killed each year, on average. In 2011, it was 8 percent of the population. Over the course of those four years, an estimated 1 in 5 elephants was killed illegally in Samburu. That’s more than 33,000 individuals each year. The four-year spike correlated with increases in the price of black market ivory and increases in the seizure of ivory from Kenya. Both of those correlations reflect an increased demand for trafficked ivory in China and Hong Kong, in particular. Extrapolating outwards, the researchers looked to elephant data from 45 additional sites within Africa. From 2010-2012, Wittemyer’s analysis suggested that approximately 7 percent of the total African elephant population was killed illegally each year. Preliminary data for 2013 suggests that it was between 5 and 6 percent that year.

As a result, the current elephant population skews heavily young and female. The smaller forest elephants have suffered more than the larger savannah elephants. There is also significant social disruption and an extraordinarily high number of orphaned elephants. Together, the estimated rates of illegal killing suggest that the illegal ivory trade is unsustainable. More animals are killed each year than can be replaced due to the natural reproductive capacity of the species.

Since it is so hard to ascertain overall elephant population size, the researchers have focused more on determining kill rate rather than the specific number of elephants killed each year. (If estimates for the continental elephant population are inflated, then fewer elephants would be illegally killed each year, though that number would still be in the tens of thousands.)

Practically, Wittemyer writes, “in respect to this study on African elephants, it is obvious that stemming the rate of illegal killing is paramount. Heavy in situ conservation efforts have been shown to stem illegal harvesting and, therefore need to be enhanced in the face of the current offtake rates.” He also argues that the demand for ivory needs to be curbed, particularly in the Far East. Neither of those actions is particularly new or noteworthy. But before conservation measures can be implemented and management actions be instituted, we need accurate estimates of population dynamics. This study, the “first detailed assessment of African elephant illegal killing rates at population, regional, and continental scales,” brings us one step closer to better understanding the true scale of the threat that faces these magnificent creatures. In addition it provides even more evidence that there is a direct link between ivory trafficking and the global decline in African elephants. How long before the ivory well runs dry? – Jason G. Goldman | 20 August 2014

Source: Wittemyer G., et al. (2014). Illegal killing for ivory drives global decline in African elephants, PNAS, DOI: 10.1073/pnas.1403984111

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