Kaspari M, O'Donnell S, Kercher JR
Am Nat. 2000 Feb;155(2):280-293. doi: 10.1086/303313.
Species richness describes the number of species of a given taxon in a given time and space. The energy limitation hypothesis links the species richness of consumer taxa to net primary productivity (NPP) through two relationships: NPP limits a taxon's density, and taxon density limits species richness. We study both relationships with a survey of 15 ground ant assemblages, along a productivity gradient from deserts to rain forests. Ant density (colonies m-2) was a positive, decelerating function of net aboveground productivity (NAP). A stepwise regression suggests that the efficiency with which NAP is converted to ant colonies increases with maximum summer temperature and decreases with precipitation. Ant species richness was a positive decelerating function of density at three spatial scales. This supports the energy limitation hypothesis' assumption that average population densities are higher in environments that are more productive. These two nonlinear functions (NAP-density and density-species richness) combine to create, at a variety of scales, positive, decelerating, productivity-diversity curves for a common, ecologically dominant taxon across the terrestrial productivity gradient. However, variance in the density and diversity explained by NAP decreases with scale, suggesting that energy limitation of diversity predominates at small spatial scales (<1 ha).
物种丰富度描述了在给定的时间和空间内特定分类单元的物种数量。能量限制假说通过两种关系将消费者分类单元的物种丰富度与净初级生产力（NPP）联系起来：NPP限制了一个分类单元的密度，而分类单元密度限制了物种丰富度。我们通过对15个地面蚂蚁群落进行调查，研究了这两种关系，调查范围涵盖了从沙漠到雨林的生产力梯度。蚂蚁密度（巢数/平方米）是地上净生产力（NAP）的一个正的、递减的函数。逐步回归分析表明，NAP转化为蚁巢的效率随着夏季最高温度的升高而增加，随着降水量的增加而降低。在三个空间尺度上，蚂蚁物种丰富度是密度的一个正的、递减的函数。这支持了能量限制假说的假设，即在生产力更高的环境中平均种群密度更高。这两个非线性函数（NAP-密度和密度-物种丰富度）相结合，在各种尺度上为跨越陆地生产力梯度的一个常见的、生态上占主导地位的分类单元创建了正的、递减的生产力-多样性曲线。然而，由NAP解释的密度和多样性的方差随着尺度的增加而减小，这表明在小空间尺度（<1公顷）上，多样性的能量限制占主导地位。
