Author:

Keywords:

Science & Technology, Life Sciences & Biomedicine, Biodiversity Conservation, Genetics & Heredity, Biodiversity & Conservation, Epidalea calamita, Natterjack toad, Metapopulation, Dispersal, Gene flow, Landscape genetics, TOAD BUFO-CALAMITA, EFFECTIVE POPULATION-SIZE, QUANTIFYING FUNCTIONAL CONNECTIVITY, POLYMORPHIC MICROSATELLITE LOCI, NATTERJACK TOAD, MAXIMUM-LIKELIHOOD, COMPUTER-PROGRAM, RANA-TEMPORARIA, BAYESIAN METHOD, CIRCUIT-THEORY, SITE FIDELITY, 05 Environmental Sciences, 06 Biological Sciences, Evolutionary Biology, 31 Biological sciences, 41 Environmental sciences

Abstract:

Functional connectivity is crucial for the persistence of a metapopulation, because migration among subpopulations enables recolonization and counteracts genetic drift, which is especially important in small subpopulations. We studied the degree and drivers of connectivity among occupied patches of a coastal dune metapopulation of the Natterjack Toad (Epidalea calamita Laurenti), on the basis of microsatellite variation. As spatial landscape heterogeneity is expected to influence dispersal and genetic structure, we analyzed which landscape features affect functional connectivity and to what extent. Sixty different landscape resistance scenarios as well as the isolation-by-distance model were compared using two landscape genetics approaches. We identified three subpopulations with unidirectional levels of gene flow among the two most geographically separated subpopulations, while inferred gene flow into the geographically intermediate subpopulation was limited. Urbanization and vegetation height negatively affected connectivity. Low estimates of genetic diversity and effective population size indicate that conservation measures in the smallest and most isolated subpopulation are required.