Friday, December 23, 2011

Elephant contraception possible to save from culling

Contraception May Save Future Elephants from Culling

In South Africa they have a problem, a big one: too many elephants.
For most of the 1900s extensive poaching threatened to wipe out the country’s elephants. In response, conservationists established reserves throughout the region and relocated as many herds as they could. Now those herds are doing quite well. So well, in fact, that they’re causing problems. Wildlife managers are currently facing a dilemma: how to deal with too many elephants. While some advocate for culling the giants, a group of scientists has outlined a different plan to control their populations: contraception.

Rather than simply setting a quota and culling the extras, immunocontraception could be a tool to allow land managers to control elephant populations in response to conditions on the ground such as food availability. "The approach now has to be much more dynamic and look at the influence the animals are having on the land," says Robert Slotow, a biologist at the Amarula Elephant Research Program in Durban, South Africa. His team recently published a paper in PLoS ONE describing how scientists might be able to use immunocontraception—a vaccine that gets the body to make antibodies that target sperm receptors on the surface of the egg cell. Slotow and his team outlined an immunocontraception schedule that would halt the growth of herds in a South African park and even out their population structure.

The problem
In the wild, two things control elephant populations: natural mortality and environmental conditions. Calves and full-grown animals get sick and die from all kinds of things, from predation to viruses. And when the environment is unfavorable–during years of drought or food shortages, for instance–females will put off having babies. In closed systems like conservation parks, however, neither of those controls is in place. The fences around the park keep out new animals and pathogens, and controlled park conditions make sure that there is ample food. Mothers keep having babies, and the death rate seems to slow to a crawl

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