Relative importance of habitat use, range expansion, and speciation in local species diversity of Anolis lizards in Cuba

Abstract

Variations in species richness of local assemblages may be explained by local ecological processes or large‐scale evolutionary and biogeographical processes. In Anolis lizards, species with different ecomorphs can coexist by occupying different niches. In addition, several species with the same ecomorph (e.g., trunk‐ground) can coexist, and the number of trunk‐ground anole species varies among local species assemblages. In this study, we assessed the importance of ecological interactions, number of speciation events, and range expansion for local and regional species diversity of these lizards. We examined the species richness and thermal microhabitat partitioning (considered to be a measure of ecological interaction) of 12 trunk‐ground anole species in 11 local assemblages in Cuba. The results indicated that the phylogenetic structure of trunk‐ground anole lizard assemblages was random. However, there was an overdispersion of preferences for thermal microhabitat use, which indicates that differences in microhabitat use are likely to occur within assemblages. We suggest that the number of speciation events within regions and the number of sympatrically coexisting species increases species richness at the local level. Migration appeared to be limited, leading to the range expansion of only three species with different thermal requirements. The thermal niches of species were conserved within Anolis allogus clade, whereas species within the Anolis homolechis and Anolis sagrei clades tended to change their thermal niches. Our results suggest that the species composition and richness in local assemblages could be explained by evolutionary history (the number of speciation events and limits to range expansion) and ecological processes (habitat partitioning). Of the ecological factors, the number of thermal (microhabitat use) and structural niches (e.g., vegetation) could limit the potential number of coexisting species within a local assemblage.