Data from: Ecogeographic isolation and speciation in the genus Mimulus

Despite a long history of examining the geographic context of speciation, differences in geographic range have rarely been considered a legitimate isolating mechanism. This likely results from the complex relationship between historical and ecological processes in determining the spatial distribution of species. Ecogeographic isolation is the proportion of geographic isolation that results from genetically based ecological differences between taxa and should therefore be measured as an isolating mechanism under the biological species concept. In this study, species distribution modeling was used to evaluate the potential ranges of 12 recently diverged pairs of species in the genus Mimulus. Variation in the distribution models showed that these species differ significantly in the niches they occupy. These differences result in substantial ecogeographic isolation, with an average strength of 0.67, revealing that, on average, Mimulus species exhibit only 33% overlap in the extent of suitable habitat with their closest relatives. Because prezygotic barriers act early in the life cycle of organisms, this strong barrier has the potential to contribute greatly to the total isolation experienced between diverging species. Therefore, ecogeographic isolation appears to play an important role in Mimulus, and estimating the strength of this barrier is essential to our general understanding of speciation.

尽管针对物种形成的地理背景已有长期研究，但地理分布范围的差异极少被视作公认的隔离机制。这一现象大概率源于历史过程与生态过程在决定物种空间分布时存在复杂关联。生态地理隔离（Ecogeographic isolation）指由类群间基于遗传的生态差异所导致的地理隔离占比，因此在生物学物种概念（Biological Species Concept）框架下，应将其作为一种隔离机制进行测算。本研究采用物种分布模型（Species Distribution Modeling），评估了沟酸浆属（Mimulus）内12对新近分化的物种类群的潜在分布范围。分布模型的差异显示，这些物种所占据的生态位存在显著差异。此类差异催生了显著的生态地理隔离，平均隔离强度达0.67，这意味着平均而言，沟酸浆属物种与其近缘物种的适宜栖息地范围重叠度仅为33%。由于合子前生殖隔离（Prezygotic barriers）在生物体生命周期中较早发挥作用，这种强隔离机制有望对分化物种间的总隔离程度做出极大贡献。因此，生态地理隔离在沟酸浆属的物种形成过程中似乎扮演着重要角色，而对该隔离强度的估算，对于我们全面理解物种形成机制至关重要。