Data from: Extinction as a driver of avian latitudinal diversity gradients

The role of historical factors in driving latitudinal diversity gradients is poorly understood. Here we used an updated global phylogeny of terrestrial birds to test the role of three key historical factors – speciation, extinction and dispersal rates – in generating latitudinal diversity gradients for eight major clades. We fit a model that allows speciation, extinction and dispersal rates to differ, both with latitude and between the New and Old World. Our results consistently support extinction (all clades had lowest extinction where species richness was highest) as a key driver of species richness gradients across each of eight major clades. In contrast, speciation and dispersal rates showed no consistent latitudinal patterns across replicate bird clades, and thus are unlikely to represent general underlying drivers of latitudinal diversity gradients.

历史因素在驱动纬度多样性格局（latitudinal diversity gradient）形成中的作用迄今尚未得到充分阐释。本研究利用更新后的全球陆生鸟类系统发育树（phylogeny），针对8个主要演化支（clade），检验了成种速率（speciation）、灭绝速率（extinction）与扩散速率（dispersal）这三大关键历史因素在纬度多样性格局形成中的作用。我们构建了一个允许成种、灭绝与扩散速率随纬度以及新大陆与旧大陆之间存在差异的模型。研究结果一致表明，灭绝速率是8个主要演化支物种丰富度梯度形成的核心驱动因素：所有演化支均在物种丰富度最高的区域呈现最低的灭绝速率。与之相反，成种速率与扩散速率在各鸟类演化支中均未表现出一致的纬度分布规律，因此难以成为纬度多样性格局形成的普适性内在驱动因素。