刚果东部大象数量下降过半

Humans play a far greater role in the fate of African elephants than habitat, and human conflict in particular has a devastating impact on these largest terrestrial（陆地的） animals, according to a new University of British Columbia study published online in PLoS ONE this week. In some of the best-documented cases to date, the study shows the elephant population in the Okapi Faunal Reserve -- one of the last strongholds of forest elephants in the Democratic Republic of Congo (DRC) -- saw a 50 per cent decline in the last decade due to civil war and ivory poaching, from 6,439 to 3,288. In other parks in eastern DRC, the decimation was even greater.

"Having protected areas is not enough to save elephants in times of conflict," says lead author Rene Beyers, a postdoctoral fellow at UBC's Department of Zoology. "The war in the Democratic Republic of Congo had a large impact on elephant populations, including those in parks and reserves."

"We've found that two factors in conservation efforts were particularly effective: a continued presence by a highly committed government field staff and continued support by international organizations -- such as the Widlife Conservation Society, Gilman International Conservation and UNESCO -- made a difference for their survival."

Currently there are an estimated 6,000 elephants left in the wild in eastern Congo, down from approximately 22,000 before the civil war. These remaining animals are the only viable populations left in an otherwise enormous landscape. The war-torn DRC has the largest tract of rainforest in the Congo Basin -- at 1.6 million square-kilometres, it is the second biggest continuous rainforest in the world. Scientists believe most of this forest was probably elephant habitat in the past, but poaching and human encroachment（侵犯） have taken a toll on the animals.

Beyers says that even in times of war, non-governmental organizations (NGOs) with the right funding and staffing can still have a positive impact on elephant conservation. In Rwanda, for example, national parks and reserves that received support from international NGOs were far less affected by the 1994 genocide than sites with no support.

Large-scale hunting of elephants for ivory has occurred in Africa in different periods in the 19th and 20th century. The last big poaching（非法狩猎） event happened in the late 1970s and in the 1980s, when the total population was reduced from 1.3 million to less than 600,000. Since the international ban in ivory trade in 1990, poaching for ivory stopped almost completely, but recent years have seen a resurgence（复活，再现） .

The DRC is particularly hard-hit by poaching due to a combination of increasing demand for ivory and the lawlessness of the civil war. In the savannah（大草原） of West and Central Africa, elephants declined by at least 50 per cent in the last 15 to 30 years. Large shipments of ivory originating from this region and elsewhere in Africa have been seized in Asia. Even in Kenya, which has good elephant conservation programs in place, has also seen a recent surge in poaching.

The research team includes Rene Beyers, Brian Klinkenberg and Tony Sinclair from UBC, John Hart and Simeon Dino from the Tshuapa-Lomami-Lualaba Project in the DRC, and Falk Grossmann from the Wildlife Conservation Society.