Ecological and evolutionary drivers of the elevational gradient of diversity

Ecological, evolutionary, spatial and neutral theories make distinct predictions and provide distinct explanations for the mechanisms that control the relationship between diversity and the environment. Here, we test predictions of the elevational diversity gradient focusing on Iberian bumblebees, grasshoppers and birds. Processes mediated by local abundance and regional diversity concur in explaining local diversity patterns along elevation. Effects expressed through variation in abundance were similar among taxa and point to the overriding role of a physical factor, temperature. This determines how energy is distributed among individuals and ultimately how the resulting pattern of abundance affects species incidence. Effects expressed through variation in regional species pools depended instead on taxon-specific evolutionary history, and lead to diverging responses under similar environmental pressures. Local filters and regional variation also explain functional diversity gradients, ...

生态学、进化、空间及中性理论（neutral theories）对调控多样性与环境间关系的机制均提出了迥异的预测，并给出了差异化的解释。本研究聚焦伊比利亚熊蜂（Iberian bumblebees）、蝗虫与鸟类，对海拔多样性梯度（elevational diversity gradient）的相关预测展开检验。由局域丰度（local abundance）与区域多样性（regional diversity）介导的生态过程，共同解释了沿海拔梯度分布的局域多样性格局。通过丰度变异体现的效应在各分类类群间表现相似，揭示出物理因子温度的主导作用：温度决定了能量在个体间的分配模式，并最终决定了由此形成的丰度格局如何影响物种的出现率。而通过区域物种库（regional species pools）变异体现的效应，则依赖于类群特异性的进化历史，并在相似的环境压力下引发了分化的响应。局域过滤作用与区域变异同样可解释功能多样性梯度（functional diversity gradients），……