Olff Han, Ritchie Mark E, Prins Herbert H T
Tropical Nature Conservation and Vertebrate Ecology Group, Wageningen University, Bornsesteeg 69, 6708 PD Wageningen, The Netherlands.
Nature. 2002 Feb 21;415(6874):901-4. doi: 10.1038/415901a.
Large mammalian herbivores occupy half of the earth's land surface and are important both ecologically and economically, but their diversity is threatened by human activities. We investigated how the diversity of large herbivores changes across gradients of global precipitation and soil fertility. Here we show that more plant-available moisture reduces the nutrient content of plants but increases productivity, whereas more plant-available nutrients increase both of these factors. Because larger herbivore species tolerate lower plant nutrient content but require greater plant abundance, the highest potential herbivore diversity should occur in locations with intermediate moisture and high nutrients. These areas are dry enough to yield high quality plants and support smaller herbivores, but productive enough to support larger herbivores. These predictions fit with observed patterns of body size and diversity for large mammalian herbivores in North America, Africa and Australia, and yield a global map of regions with potentially high herbivore diversity. Thus, gradients of precipitation, temperature and soil fertility might explain the global distribution of large herbivore diversity and help to identify crucial areas for conservation and restoration.
大型哺乳动物食草动物占据了地球陆地表面的一半，在生态和经济方面都很重要，但其多样性正受到人类活动的威胁。我们研究了大型食草动物的多样性如何随全球降水量和土壤肥力梯度而变化。我们在此表明，更多的植物可利用水分会降低植物的养分含量，但会提高生产力，而更多的植物可利用养分则会增加这两个因素。由于较大的食草动物物种能够耐受较低的植物养分含量，但需要更高的植物丰度，因此最高的潜在食草动物多样性应该出现在水分适中且养分充足的地区。这些地区足够干燥，能够产出高质量的植物并支持小型食草动物，但又足够肥沃，能够支持大型食草动物。这些预测与北美、非洲和澳大利亚大型哺乳动物食草动物的体型和多样性的观测模式相符，并生成了一幅潜在食草动物多样性高的地区的全球地图。因此，降水量、温度和土壤肥力梯度可能解释了大型食草动物多样性的全球分布，并有助于确定保护和恢复的关键区域。
