Environmental niche factor analysis (ENFA) relates environmental parameters to abundance and genetic diversity in an endangered amphibian, the fire-bellied-toad (Bombina bombina)

Increasing attempts are made to understand the factors responsible for both the demographic and genetic depletion in amphibian populations. Landscape genetics aims at a spatially explicit correlation of genetic population parameters to landscape features. Using data from the endangered fire-bellied toad Bombina bombina in Brandenburg (Northeastern Germany), we performed an environmental niche factor analysis (ENFA), relating demographic (abundance) and genetic (diversity at 17 microsatellite loci and partial sequences of the mitochondrial control region in 434 individuals from 16 populations) parameters to ecological and anthropogenic variables such as temperature, precipitation, soil wetness, water runoff, vegetation density, and road/traffic impact. We found significant correlations between road disturbance and observed heterozygosity and between soil wetness and mitochondrial diversity. As the influences of the environmental variables can differ between different indicators for genetic diversity, population size and abundance data, our ENFA-based landscape genetics approach allows us to put various aspects of long- versus short term effective population size and genetic connectivity into an ecological and spatially explicit context, enabling potentially even forecast assessment under future environmental scenarios.