Division of Biology and Natural Environment Research Council Centre for Population Biology, Imperial College London, Silwood Park Campus, Ascot, Berkshire, UK.
Am Nat. 2010 Mar;175(3):316-34. doi: 10.1086/650369.
Area is generally assumed to affect speciation rates, but work on the spatial context of speciation has focused mostly on patterns of range overlap between emerging species rather than on questions of geographical scale. A variety of geographical theories of speciation predict that the probability of speciation occurring within a given region should (1) increase with the size of the region and (2) increase as the spatial extent of intraspecific gene flow becomes smaller. Using a survey of speciation events on isolated oceanic islands for a broad range of taxa, we find evidence for both predictions. The probability of in situ speciation scales with island area in bats, carnivorous mammals, birds, flowering plants, lizards, butterflies and moths, and snails. Ferns are an exception to these findings, but they exhibit high frequencies of polyploid and hybrid speciation, which are expected to be scale independent. Furthermore, the minimum island size for speciation correlates across groups with the strength of intraspecific gene flow, as is estimated from a meta-analysis of published population genetic studies. These results indicate a general geographical model of speciation rates that are dependent on both area and gene flow. The spatial scale of population divergence is an important but neglected determinant of broad-scale diversity patterns.
区域通常被认为会影响物种形成的速度，但关于物种形成的空间背景的研究主要集中在新兴物种的分布范围重叠模式上，而不是在地理尺度上的问题。各种地理物种形成理论预测，在给定区域内发生物种形成的概率应该（1）随着区域的大小而增加，并且（2）随着种内基因流动的空间范围变小而增加。我们利用对广泛分类群的孤立海洋岛屿上的物种形成事件的调查，发现这两个预测都有证据支持。蝙蝠、食肉哺乳动物、鸟类、开花植物、蜥蜴、蝴蝶和飞蛾、蜗牛等物种的原地物种形成的概率与岛屿面积成正比。蕨类植物是这些发现的例外，但它们表现出较高的多倍体和杂交物种形成的频率，这预计是与规模无关的。此外，物种形成的最小岛屿大小与从已发表的种群遗传研究的荟萃分析中估计的种内基因流动强度相关。这些结果表明，物种形成率的一般地理模型取决于面积和基因流。种群分歧的空间尺度是广泛多样性模式的一个重要但被忽视的决定因素。
