Post-Eocene climate change, niche conservatism, and the latitudinal diversity gradient of New World birds
Post-Eocene climate change, niche conservatism, and the latitudinal diversity gradient of New World birds
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DOI：
10.1111/j.1365-2699.2006.01452.x
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发表时间：
2006-05-01
影响因子：
3.9
通讯作者：
Soeller, SA
中科院分区：
文献类型：
--
作者：
Hawkins, BA;Diniz, JAF;Soeller, SA
目的验证鸟类纬度多样性梯度的进化时间假说的一种变体，该假说源于生态位保守性在全球气候变化中的影响。然后，我们使用分解到家族的分子系统发育来量化每个物种的根距离(RD)，作为其进化发展水平的衡量标准。鸟类根据其科的RD被归类为“基生”或“衍生”，并对比了最基本和最衍生30%的物种的丰富度模式。我们还生成了整个西半球古近纪的温度估计，以检验过去和现在气候之间的空间相关性如何使当前丰富度梯度的生态和进化假说难以区分。结果温暖潮湿的热带支持了许多来自基生鸟类支系的物种，而北温带和凉爽或干燥热带则主要是来自较新的进化派生支系的物种。此外，对于评估鸟类之间的生态位保守性如何驱动半球丰富度梯度至关重要，基本类群的丰富度梯度的空间结构与总体梯度在统计上是无法区分的，而衍生类群的丰富度梯度比整体梯度要浅得多。最后，现代温度和始新世以来气候降温的模式并不能作为鸟类物种丰富度的预测因子。主要结论基础分支和派生分支丰富度梯度的差异表明，半球梯度受到了来自世界上变得更冷的更古老、温暖适应的分支中物种差异灭绝的强烈影响。我们认为，生态位保守主义和全球范围的气候变化随进化时间的推移为当代新大陆鸟类的纬度多样性梯度提供了简约的解释，尽管一些高度派生的支系的扩散限制可能起到次要作用。
Aim The aim of this study was to test a variant of the evolutionary time hypothesis for the bird latitudinal diversity gradient derived from the effects of niche conservatism in the face of global climate change over evolutionary time.Location The Western Hemisphere.Methods We used digitized range maps of breeding birds to estimate the species richness at two grain sizes, 756 and 12,100 km(2). We then used molecular phylogenies resolved to family to quantify the root distance (RD) of each species as a measure of its level of evolutionary development. Birds were classified as 'basal' or 'derived' based on the RD of their family, and richness patterns were contrasted for the most basal and most derived 30% of species. We also generated temperature estimates for the Palaeogene across the Western Hemisphere to examine how spatial covariation between past and present climates might make it difficult to distinguish between ecological and evolutionary hypotheses for the current richness gradient.Results The warm, wet tropics support many species from basal bird clades, whereas the northern temperate zone and cool or dry tropics are dominated by species from more recent, evolutionarily derived clades. Furthermore, crucial to evaluating how niche conservatism among birds may drive the hemispherical richness gradient, the spatial structure of the richness gradient for basal groups is statistically indistinguishable from the overall gradient, whereas the richness gradient for derived groups is much shallower than the overall gradient. Finally, modern temperatures and the pattern of climate cooling since the Eocene are indistinguishable as predictors of bird species richness.Main conclusions Differences in the richness gradients of basal vs. derived clades suggest that the hemispherical gradient has been strongly influenced by the differential extirpation of species in older, warm-adapted clades from parts of the world that have become cooler in the present. We propose that niche conservatism and global-scale climate change over evolutionary time provide a parsimonious explanation for the contemporary bird latitudinal diversity gradient in the New World, although dispersal limitation of some highly derived clades probably plays a secondary role.