Energetic constraints on species coexistence in birds

The association between species richness and ecosystem energy availability is one of the major geographic trends in biodiversity. It is often explained in terms of energetic constraints, such that coexistence among competing species is limited in low productivity environments. However, it has proven challenging to reject alternative views, including the null hypothesis that species richness has simply had more time to accumulate in productive regions, and thus the role of energetic constraints in limiting coexistence remains largely unknown. We use the phylogenetic relationships and geographic ranges of sister species (pairs of lineages who are each other’s closest extant relatives) to examine the association between energy availability and coexistence across an entire vertebrate class (Aves). We show that the incidence of coexistence among sister species increases with overall species richness and is elevated in more productive ecosystems, even when accounting for differences in the ev...物种丰富度（species richness）与生态系统能量可获得性之间的关联，是生物多样性领域的核心地理趋势之一。该关联通常以能量限制（energetic constraints）假说进行阐释：低生产力生境中，相互竞争的物种共存会受到约束。然而，要驳斥其他替代假说——包括认为物种丰富度仅在高生产力区域拥有更长积累时长的零假设（null hypothesis）——却颇具挑战，因此能量限制在限制物种共存过程中所发挥的作用，目前仍未得到充分阐明。我们利用互为现存最近亲缘类群的姊妹物种（sister species）对的系统发育关系（phylogenetic relationships）与地理分布范围（geographic ranges），针对覆盖整个脊椎动物纲的鸟纲（Aves），探究能量可获得性与物种共存之间的关联。研究显示，即便在控制物种整体丰富度差异以及演化相关差异的情况下，姊妹物种间的共存发生率仍随整体物种丰富度升高而增加，且在生产力更高的生态系统中更为普遍。