Vegetation structure and ungulate abundance over a period of increasing elephant abundance in Hwange National Park, Zimbabwe
Vegetation structure and ungulate abundance over a period of increasing elephant abundance in Hwange National Park, Zimbabwe
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津巴布韦万基国家公园大象丰度增加期间的植被结构和有蹄类动物丰度
DOI：
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发表时间：
2007
影响因子：
1.4
通讯作者：
S. Saïd
中科院分区：
文献类型：
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作者：
M. Valeix;H. Fritz;S. Dubois;Kwanele Kanengoni;S. Alleaume;S. Saïd
这项研究调查了大象数量的增加是否会影响非洲大草原的结构，从而通过栖息地的变化影响其他食草动物。在津巴布韦万基国家公园，对大象种群密度的两个不同时期进行了比较：20世纪80年代初和90年代末。根据道路计数估计了约400平方公里区域内大象种群密度和其他有蹄类动物种群密度。利用航空照片对同一区域的景观尺度植被结构进行了评价。从20世纪80年代初到90年代末，所有的食草动物都在减少，而大象的数量却增加了16倍。在景观尺度上，植被结构变化不大，没有生境开放的迹象。这些结果不支持大象和其他食草动物之间的任何中期促进。相反，它们表明，当大象密度很高时，大象对其他食草动物产生了负面影响。这项研究排除了一种情况，即不同食草动物种群的减少是由大象活动导致的植被结构的巨大变化引起的。
This study investigates whether increases in elephant populations may influence the structure of African savannas, and consequently may affect other herbivores through changes in habitats. Two contrasting periods in terms of elephant population densities were compared in Hwange National Park, Zimbabwe: the early 1980s and the late 1990s. Elephant population density and other ungulate population densities were estimated for a c. 400-km2 area from road counts. Vegetation structure at the landscape scale was assessed using aerial photographs for the same area. All browsers and grazers declined between the early 1980s and the late 1990s, whereas elephants experienced a 16-fold increase. At the landscape scale, vegetation structure changed little with no evidence of an opening of the habitats. These results do not support any kind of medium-term facilitation between elephants and other herbivores. They rather suggest a negative effect of elephants on other herbivore species when elephants are present at high densities. This study rules out a scenario where the decrease of the different herbivore populations was caused by large changes in vegetation structure due to elephant activity.