Climatic niche breadth and species richness in temperate treefrogs

Aim Patterns of species richness are often closely linked with climate, but the specific mechanisms by which species’ climatic niches underlie large-scale richness patterns remain poorly understood. It has been hypothesized that reduced temperature seasonality in the tropics promotes the evolution of species with narrow temperature niche breadths, and that this hypothesis helps explain high tropical richness. However, the relationship between species’ climatic niche breadths and species richness has yet to be tested. We have addressed this issue using treefrogs (Hylidae) in eastern North America.