Effects of natural and anthropogenic features on functional connectivity of anurans: a review of landscape genetics studies in temperate, subtropical and tropical species

Abstract

Habitat loss, overexploitation, the presence of invasive species, climate change and the proliferation of diseases continue to put at risk anuran species that represent 90% of all amphibians. Biphasic life cycle, habitat specialization to oviposit and forage, low dispersal abilities, and permeable skin make anurans particularly susceptible to the effect of landscape composition and configuration on their capacity to move through the landscape (connectivity). Limited connectivity can result in reduced gene flow, low genetic variation and high genetic structuring. Therefore, identifying landscape elements that promote or limit the dispersal of anurans is fundamental to propose conservation plans that allow maintaining areas that enhance connectivity to assure the evolutionary potential of the species by preserving genetic diversity. Here, we reviewed studies evaluating the effect of natural and anthropogenic elements of the landscape on gene flow across temperate, tropical and subtropical landscapes. Our results suggest that roads have the strongest negative effect on connectivity resistance in anurans from temperate regions. Urbanization, fragmentation, and land cover change into agriculture and grasslands are other anthropogenic landscape elements that provide resistance to connectivity in anurans worldwide. In temperate and tropical regions, rivers are the most important natural element negatively affecting connectivity, having a stronger effect in the tropics. Contrary, streams and forests cover promote connectivity in all regions. We provide a review of the growing progress of landscape genetics in this group of vulnerable organisms and highlight the importance of considering this research field for the conservation of the threatened ecosystems that anurans inhabit.