Species richness and evenness in Australian birds
Species richness and evenness in Australian birds
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DOI：
10.1086/528960
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发表时间：
2008-04-01
影响因子：
2.9
通讯作者：
Johnson, Christopher N.
中科院分区：
文献类型：
--
作者：
Symonds, Matthew R. E.;Johnson, Christopher N.
物种丰富度和均匀度是生物多样性的两个主要组成部分，但它们相互关联的方式是一个有争议的主题。我们发现，在澳大利亚92个林地地点的鸟类群落中，这两个变量之间存在负相关关系，并寻求解释。实际蒸散发（AET）是迄今为止物种丰富度的最佳预测因子。当AET被控制后，丰富度与均匀度之间的关系变得不显著。丰富度在AET高的地点更大，因为这些地点支持更多的个体。然而，这些地点有更多的稀有物种，导致较低的均匀度。一个复杂的因素是，均匀度最好通过植被覆盖程度来预测，植被稀疏的地点均匀度明显较低。我们得出的结论是，有两个相互竞争的生态过程，与能源和水的可用性有关，决定了丰富度和均匀度。前者驱动总丰度（导致高丰富度，低均匀度），而后者驱动生产力和生态位可用性（导致高丰富度，高均匀度）。这两个过程的相对强度以及观察到的丰富度和均匀度之间的关系可能取决于分析的规模以及所研究的物种和生境范围。
Species richness and evenness are the two major components of biodiversity, but the way in which they are interrelated is a subject of contention. We found a negative relationship between the two variables for bird communities at 92 woodland sites across Australia and sought an explanation. Actual evapotranspiration (AET) was by far the best predictor of species richness. When AET was controlled for, the relationship between richness and evenness became nonsignificant. Richness is greater at sites with higher AET because such sites support a greater number of individuals. However, such sites have a greater number of rare species, resulting in lower evenness. A complicating factor is that evenness is best predicted by degree of vegetation cover, with sparsely vegetated sites having significantly lower evenness. We conclude that there are two competing ecological processes, related to energy and water availability, that determine richness and evenness. The first drives total abundance ( leading to high richness, low evenness), while the second drives productivity and niche availability ( leading to high richness, high evenness). The relative strength of these two processes and the observed relationship between richness and evenness are likely to depend on the scale of the analysis and the species and range of habitats studied.