Department of Zoology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, 69978, Israel.
Department of Ecology and Evolutionary Biology, Yale University, New Haven, CT, 06520, USA.
Ecol Lett. 2015 Jun;18(6):563-71. doi: 10.1111/ele.12438. Epub 2015 Apr 27.
Regions worldwide differ markedly in species richness. Here, for birds and mammals worldwide, we directly compare four sets of hypotheses regarding geographical richness gradients: (1) evolutionary, emphasising heterogeneity in diversification rates, (2) historical, related to differences in region ages and sizes, (3) energetic, associated with variation in productive or ambient energy and (4) ecological, reflecting differences in ecological niche diversity. Among highly independent regions, or 'evolutionary arenas', we find that richness is weakly influenced by richness-standardised ecological niche diversity, questioning the significance of ecological constraints for producing large-scale diversity gradients. In contrast, we find strong evidence for the importance of region area and its changes over time, together with a role for temperature. These predictors affect richness predominately directly without concomitant positive effects on diversification rates. This suggests that regional richness is governed by historical and evolutionary processes, which promote region-specific accumulation of diversity through time or following asymmetrical dispersal.
全球各地区的物种丰富度差异显著。在这里，我们直接比较了关于全球鸟类和哺乳动物地理丰富度梯度的四个假设：（1）进化，强调多样化率的异质性，（2）历史，与地区年龄和大小的差异有关，（3）能量，与生产力或环境能量的变化有关，（4）生态，反映生态位多样性的差异。在高度独立的地区或“进化舞台”中，我们发现丰富度受丰富度标准化生态位多样性的影响较弱，质疑生态限制对产生大规模多样性梯度的重要性。相比之下，我们发现区域面积及其随时间变化的重要证据，以及温度的作用。这些预测因子主要通过直接作用影响丰富度，而没有对多样化率产生积极影响。这表明区域丰富度受历史和进化过程的控制，这些过程通过时间或通过不对称扩散促进了特定区域多样性的积累。
