Biome and migratory behaviour significantly influence vertebrate genetic diversity

Abstract

Genetic diversity (GD) is largely determined by effective population size, which may vary dramatically for species that differ in key aspects of their biology such as vagility. To identify evolutionary patterns associated with animal distributions and movements, we examined relationships among GD (i.e. microsatellite heterozygosity and allelic richness), taxonomic class, biome and migratory behaviour. Linear regression revealed that migratory mammals, reptiles, amphibians and fishes had less GD compared to nonmigratory species, whereas migratory birds had more GD than their nonmigratory counterparts. We also found that the biome a species inhabits influences the GD of migratory and nonmigratory species differently. For example, migratory amphibians at low latitudes are more genetically diverse than migratory amphibians at higher latitudes. However, we found the reverse relationship (i.e. decreased GD in low-latitude migratory species compared to higher latitude migratory species) in mammals and fishes and no influence of biome on reptile GD. We suggest that these differences are a result of differences in vagility, the extent of philopatry among the classes and perhaps differential selection between terrestrial and aquatic species. We argue that these categorical disparities in GD reflect changes in effective population size driven at least partly by differences in habitat.