Maintenance of biodiversity on islands
Maintenance of biodiversity on islands
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DOI：
10.1098/rspb.2016.0102
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发表时间：
2016-04-27
影响因子：
4.7
通讯作者：
O'Dwyer, James P.
中科院分区：
文献类型：
--
作者：
Chisholm, Ryan A.;Fung, Tak;O'Dwyer, James P.
麦克阿瑟和威尔逊的岛屿生物地理学理论预测，岛屿物种丰富度应该随着岛屿面积的增加而增加。这一预测一般适用于大岛屿，但在小岛屿之间，物种丰富度往往独立于岛屿面积而变化，产生所谓的“小岛效应”和总体双相物种-面积关系（SAR）。在这里，我们开发了一个统一的理论，解释双相岛SAR。我们的理论的关键假设是，随着岛屿面积的增加，移民总数的增长速度快于生态位多样性。一个简约的机械模型近似这些过程再现了双相SAR，并提供了很好的适合100个群岛数据集。根据我们的理论，双相岛SAR可以被解释为从小岛屿上的生态位结构制度的过渡到大岛屿上的殖民灭绝平衡制度。第一个区域是典型的确定性生态位理论的特征，第二个区域是随机性理论的特征，包括岛屿地理学理论和中性理论。数据进一步证实了我们的理论的关键预测，两个SAR制度之间的过渡应该发生在较小的地区，移民是强（即分类群，更好的分散和群岛，是不那么孤立）。
MacArthur and Wilson's theory of island biogeography predicts that island species richness should increase with island area. This prediction generally holds among large islands, but among small islands species richness often varies independently of island area, producing the so-called 'small-island effect' and an overall biphasic species-area relationship (SAR). Here, we develop a unified theory that explains the biphasic island SAR. Our theory's key postulate is that as island area increases, the total number of immigrants increases faster than niche diversity. A parsimonious mechanistic model approximating these processes reproduces a biphasic SAR and provides excellent fits to 100 archipelago datasets. In the light of our theory, the biphasic island SAR can be interpreted as arising from a transition from a niche-structured regime on small islands to a colonization-extinction balance regime on large islands. The first regime is characteristic of classic deterministic niche theories; the second regime is characteristic of stochastic theories including the theory of island biogeography and neutral theory. The data furthermore confirm our theory's key prediction that the transition between the two SAR regimes should occur at smaller areas, where immigration is stronger (i.e. for taxa that are better dispersers and for archipelagos that are less isolated).