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 twelve 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 only exhibit 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.尽管学界对物种形成的地理背景开展研究已有悠久历史，但地理分布范围的差异却极少被视作一种合理的隔离机制。这一现象或源于历史过程与生态过程在调控物种空间分布时存在复杂关联。生态地理隔离（ecogeographic isolation）指的是由分类群（taxa）间基于遗传的生态差异所导致的地理隔离占比，因此在生物物种概念（biological species concept）框架下，应将其作为一种隔离机制进行量化评估。本研究借助物种分布模型（species distribution modeling），评估了沟酸浆属（Mimulus）中12对新近分化物种的潜在分布范围。物种分布模型的结果差异显示，这些物种所占据的生态位存在显著分化。这些差异催生了显著的生态地理隔离，平均隔离强度达0.67，这意味着沟酸浆属物种与其近缘物种的适宜栖息地重叠度仅为33%。由于合子前生殖隔离（prezygotic barriers）在生物生命周期中较早发挥作用，这种强隔离机制可极大地提升分化物种间的总生殖隔离程度。因此，生态地理隔离在沟酸浆属的物种形成过程中发挥着关键作用，对该隔离机制强度的量化评估，是我们全面理解物种形成机制的必要前提。