Anderson Sean A S, Matute Daniel R
School of Biological Sciences, Georgia Institute of Technology, Atlanta, Georgia, USA.
Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina, USA.
Ecol Lett. 2025 Apr;28(4):e70108. doi: 10.1111/ele.70108.
A much remarked-upon pattern in nature is elevated trait disparity in sympatric relative to allopatric populations or species. Early explanations focused on secondary contact between allopatrically speciating taxa and emphasised adaptive divergence driven by costly interactions in sympatry (i.e., 'character displacement'). Here we consider a related hypothesis, 'species sorting', which describes a bias in the outcome of secondary contact wherein lineages are unlikely to establish sympatry unless and until they evolve sufficient trait differences in allopatry. Sorting-like processes are prevalent in community assembly theory but are more seldom discussed in the context of speciation and secondary sympatry. We first define ecological and reproductive species sorting as analogous to ecological and reproductive character displacement, and we synthesise 'differential fusion' and the 'Templeton effect' within this framework. Through the logic of coexistence and assembly theories, we distinguish the types of allopatry-derived trait differences that will likely promote sympatry from those that likely will not, and we discuss biogeographic consequences of the latter. We then highlight new empirical approaches to distinguish sorting from displacement and survey the mixed evidence to-date. We finally suggest key priorities for future research into the hypothesized role of species sorting as a generator of major biodiversity patterns.
自然界中一个备受关注的模式是，同域分布的种群或物种相对于异域分布的种群或物种而言，其性状差异更大。早期的解释集中在异域物种形成的分类单元之间的二次接触，并强调同域中由代价高昂的相互作用驱动的适应性分化（即“性状替换”）。在这里，我们考虑一个相关的假说——“物种分选”，它描述了二次接触结果中的一种偏向，即除非谱系在异域中进化出足够的性状差异，否则它们不太可能建立同域分布。类似分选的过程在群落组装理论中很普遍，但在物种形成和二次同域分布的背景下很少被讨论。我们首先将生态物种分选和生殖物种分选定义为类似于生态性状替换和生殖性状替换，并在这个框架内综合“差异融合”和“坦普尔顿效应”。通过共存和组装理论的逻辑，我们区分了可能促进同域分布的异域衍生性状差异类型与可能不会促进同域分布的类型，并讨论了后者的生物地理后果。然后，我们强调了区分分选和性状替换的新实证方法，并审视了迄今为止的混合证据。我们最后提出了未来研究的关键优先事项，以探讨物种分选作为主要生物多样性模式产生者的假设作用。
