Abstract
We know little about the general links between broad-scale biodiversity patterns at the nuclear genetic and species levels. Recent work in mammals suggests environmental carrying capacity and ecological opportunity link these two base levels of biodiversity. Energy- and resource-rich environments are thought to support larger populations with higher genetic diversity and species richness. Niche availability is expected to limit population size causing drift while increasing genetic differentiation due to environmental specialization. Several of the processes underlying these links are temperature-dependent, so we might expect different patterns for endotherms and ectotherms. We use a database comprised of raw microsatellite genotypes for 13616 individuals of 18 species sampled at 548 locations in the United States and Canada. We analyzed salamander and frog species separately and simultaneously fit our hypotheses with structural equation models. Similar to mammals, niche availability was the primary contributor to diversity at both the genetic and species levels in frogs, and energy availability was an important predictor of species richness for both taxa. Different than mammals, environmental energy availability was not linked to genetic diversity. There are shared underlying mechanisms linking genetic and species-level diversity but the processes are not entirely general across these species groups.
Competing Interest Statement
The authors have declared no competing interest.
