American Society of Naturalists

A membership society whose goal is to advance and to diffuse knowledge of organic evolution and other broad biological principles so as to enhance the conceptual unification of the biological sciences.

“Genetic diversity-area relationships across bird species”

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Haiying Fan (樊海英), Qingchen Zhang (张清臣), Juanjuan Rao (饶娟娟), Jingwen Cao (曹静文), and Xin Lu (卢欣) (Nov 2019)

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The first step towards quantifying the effect of habitat loss on genetic diversity

Tibetan eared pheasants (<i>Crossoptilon harmani</i>) are a high-altitude bird endemic to the Tibetan plateau.<br />(Credit: Xin Lu)
Tibetan eared pheasants (Crossoptilon harmani) are a high-altitude bird endemic to the Tibetan plateau.
(Credit: Xin Lu)


The genetic diversity-area relationship (GAR), compared to the extensively explored species-area relationship (SAR), remains poorly recognized despite the importance of understanding it for the development and application of biodiversity theory. It has been hypothesized that maintaining genetic diversity within a population is mechanistically similar to maintaining species diversity within a community, implying that GAR trajectories should mathematically behave as SAR ones. Here we test this prediction by fitting microsatellite heterozygosity and allelic richness in relation to distribution range size across bird species against eight well-known SAR models. The Monod model best described the data of resident and migratory species combined, and especially the data of resident species only, showing that with increasing range size, genetic diversity across species rapidly increased up to a certain level and then tended towards an asymptote. None of the candidate models provided an adequate fit for the data of migratory species, likely because their breeding range size mostly is large in that a GAR curve has become flat. Our work takes the first step towards formulating GARs and applying them to predicting the effect of habitat fragmentation on genetic diversity.


理解遗传多样性-面积关系(Genetic diversity-area relationship, GAR)对于生物多样性理论的发展和应用具有重要意义。但与已被广泛探索的种-面积关系(Species-area relationship, SAR)相比,我们对GAR的认识仍然不足。根据现有假说,种群内遗传多样性的维持机制平行于群落内物种多样性的维持机制,这意味着GAR与SAR的轨迹在数学上应该相似。本文使用8个著名的SAR模型来检验这一预测,分别对不同鸟类物种的微卫星杂合度和等位基因丰富度与其繁殖分布范围的大小进行拟合。Monod模型最好地描述了居留和迁徙物种合并的数据,尤其是居留物种的数据拟合度最高。这表明,随着分布范围的增大,物种的遗传多样性迅速增加至一定水平,然后增速变缓并趋近于一条渐近线。没有一个候选模型能够充分拟合迁徙物种的数据,原因可能是它们中大多数的繁殖分布范围很大,使其GAR曲线变得平坦。我们的工作迈出了模型化GARs,并将其应用于预测栖息地片段化对遗传多样性影响的第一步。