Environmental heterogeneity, species diversity and co‐existence at different spatial scales
Environmental heterogeneity, species diversity and co‐existence at different spatial scales
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DOI：
10.1111/j.1654-1103.2010.01185.x
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发表时间：
2010-08
影响因子：
2.8
通讯作者：
Riin Tamme;Inga Hiiesalu;L. Laanisto;R. Szava-Kovats;M. Pärtel
中科院分区：
文献类型：
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作者：
Riin Tamme;Inga Hiiesalu;L. Laanisto;R. Szava-Kovats;M. Pärtel
空间环境异质性与物种多样性之间的正相关关系是一个被广泛接受的概念，通常与生态位限制有关。然而，生态位限制不能解释负异质性多样性关系（HDR）在几个案例研究中发现。在这里，我们探讨了HDR如何在不同的空间尺度上变化，并为小规模物种共存提供了新的理论，解释了积极和消极的HDR。在异质性的大空间尺度（如景观水平），不同的社区共存，促进大的区域物种库的大小，并导致积极的人类发展报告。在较小的尺度上，物种共存可以通过增加不同斑块的数量来增强，正如生态位限制理论所预测的那样，或者受到异质性的限制。我们对实验性和观察性HDR研究进行了元回归，发现负HDR在较小的空间尺度上显着更常见。我们提出了三种理论来解释小空间尺度上的生态位限制。(1)微碎片理论：随着空间异质性的增加，大的同质斑块失去面积并变得孤立，这反过来又抑制了新植物个体和种群的建立，从而降低了物种丰富度。(2)异质性混淆的平均值：当异质性发生在空间尺度小于个体植物的大小，通过补丁饲料，物种多样性可以是积极的或消极的影响，平均环境因素的变化。(3)异质性作为一个单独的生态位轴：物种在小于植物大小的空间尺度上容忍异质性的能力各不相同，影响HDR。我们的结论是生态位限制以外的过程可以影响异质性和多样性之间的关系。
The positive relationship between spatial environmental heterogeneity and species diversity is a widely accepted concept, generally associated with niche limitation. However, niche limitation cannot account for negative heterogeneity–diversity relationships (HDR) revealed in several case studies. Here we explore how HDR varies at different spatial scales and provide novel theories for small-scale species co-existence that explain both positive and negative HDR. At large spatial scales of heterogeneity (e.g. landscape level), different communities co-exist, promoting large regional species pool size and resulting in positive HDR. At smaller scales within communities, species co-existence can be enhanced by increasing the number of different patches, as predicted by the niche limitation theory, or alternatively, restrained by heterogeneity. We conducted meta-regressions for experimental and observational HDR studies, and found that negative HDRs are significantly more common at smaller spatial scales. We propose three theories to account for niche limitation at small spatial scales. (1) Microfragmentation theory: with increasing spatial heterogeneity, large homogeneous patches lose area and become isolated, which in turn restrains the establishment of new plant individuals and populations, thus reducing species richness. (2) Heterogeneity confounded by mean: when heterogeneity occurs at spatial scales smaller than the size of individual plants, which forage through the patches, species diversity can be either positively or negatively affected by a change in the mean of an environmental factor. (3) Heterogeneity as a separate niche axis: the ability of species to tolerate heterogeneity at spatial scales smaller than plant size varies, affecting HDR. We conclude that processes other than niche limitation can affect the relationship between heterogeneity and diversity.