Will Elephants Soon Disappear from West African Savannahs?
Will Elephants Soon Disappear from West African Savannahs?
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DOI：
10.1371/journal.pone.0020619
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发表时间：
2011-06-22
期刊：
影响因子：
3.7
通讯作者：
Vermeulen, Cedric
中科院分区：
文献类型：
--
作者：
Bouche, Philippe;Douglas-Hamilton, Iain;Vermeulen, Cedric
非洲本土的动物群和植物群数量急剧减少，但有关这些变化的全面记录却很少。在这里，我们通过分析过去40年进行的空中和地面调查，评估了西非和中非6，213，000平方公里的苏丹-萨赫勒地区非洲象的种群趋势。这些调查集中在该地区最好的保护区，因此代表了北方稀树草原大象的最佳情况。目前至少有7，745头大象栖息在整个地区，比40年前的估计至少下降了50%。大部分的历史范围现在没有大象，因此，没有调查。在23个被调查的大象种群中，估计有一半的数量不到200只。从历史上看，该地区数量不到200人的大多数种群在几十年内灭绝。下降幅度因地区而异，中非人口的下降幅度（-76%）比西非（-33%）大得多。因此，西非的大象现在占调查总数的86%。两个保护区保留了大象，一个在西非，另一个在中非。这些区域被高密度人类土地使用的大距离（类似于900公里）隔开，这表明区域之间的连通性被永久切断。然而，在每个区内，人口之间的零星接触仍然存在。保持这种联系应该是该地区大象保护的重中之重。提出了旨在减少被调查人口隔离的具体走廊。各国政府的坚定承诺、控制非法象牙贸易的有效执法以及当地社区和私人合作伙伴的参与，对于确保栖息在非洲北方稀树草原的大象的未来至关重要。
Precipitous declines in Africa's native fauna and flora are recognized, but few comprehensive records of these changes have been compiled. Here, we present population trends for African elephants in the 6,213,000 km 2 Sudano-Sahelian range of West and Central Africa assessed through the analysis of aerial and ground surveys conducted over the past 4 decades. These surveys are focused on the best protected areas in the region, and therefore represent the best case scenario for the northern savanna elephants. A minimum of 7,745 elephants currently inhabit the entire region, representing a minimum decline of 50% from estimates four decades ago for these protected areas. Most of the historic range is now devoid of elephants and, therefore, was not surveyed. Of the 23 surveyed elephant populations, half are estimated to number less than 200 individuals. Historically, most populations numbering less than 200 individuals in the region were extirpated within a few decades. Declines differed by region, with Central African populations experiencing much higher declines (-76%) than those in West Africa (-33%). As a result, elephants in West Africa now account for 86% of the total surveyed. Range wide, two refuge zones retain elephants, one in West and the other in Central Africa. These zones are separated by a large distance (similar to 900 km) of high density human land use, suggesting connectivity between the regions is permanently cut. Within each zone, however, sporadic contacts between populations remain. Retaining such connectivity should be a high priority for conservation of elephants in this region. Specific corridors designed to reduce the isolation of the surveyed populations are proposed. The strong commitment of governments, effective law enforcement to control the illegal ivory trade and the involvement of local communities and private partners are all critical to securing the future of elephants inhabiting Africa's northern savannas.