The relationships between species age and range size

Abstract

AbstractSpecies range size is a central topic in macroecology, biogeography and conservation biology. Species age has been frequently regarded as a contributor to range size in previous studies on range size, but this has rarely been specifically examined. Using global data from four living terrestrial vertebrate classes (birds, mammals, reptiles and amphibians) as a case study, we examine how species range size might be related to species age at a global scale. We found statistically significant positive, albeit weak, species age–range size relationships for all four species groups. However, although the age–range relationships were positive, species with young ages had very different range sizes (both large and small), and those with very old ages always had small ranges. The observed age–range relationships were more complex than expected. The weak, rather than strong, species age–range relationships could be because our data set included all living species with different stages of their life spans (durations) that are either expanding or fluctuating or contracting, which would necessarily have minimized or cancelled species age–range relationship when all species in a group are considered collectively. Our findings shed new light on temporal dimension and macroecological correlates of species ranges.