Hybrid Inviability and Differential Submergence Tolerance Drive Habitat Segregation Between Two Congeneric Monkeyflowers

Closely related species are often separated at small geographic scales while being broadly sympatric. We studied a pair of species that can co‐occur within local sites but rarely overlap at fine spatial scales. Mimulus guttatus grows in wetter areas and is often submerged for several months, while Mimulus nudatus occupies drier sites. We found that M. nudatus is less tolerant to submergence and herbivory than M. guttatus, and both species produced large proportions of inviable hybrid seed when transplanted into heterospecific populations. Together, these data show that both environmental filtering and biotic interactions shape the fine‐scale distribution of close relatives. These photographs illustrate the article “Hybrid inviability and differential submergence tolerance drive habitat segregation between two congeneric monkeyflowers” by Katherine Toll and John H. Willis published in Ecology. https://doi.org/10.1002/ecy.252