Reyne, Marina I.Dicks, KaraFlanagan, JasonNolan, PaulTwining, Joshua P.Aubry, AurélieEmmerson, MarkMarnell, FerdiaHelyar, SarahReid, Neil2024-03-252024-03-252023-02-21Reyne, M.I., Dicks, K., Flanagan, J., Nolan, P., Twining, J.P., Aubry, A., Emmerson, M., Marnell, F., Helyar, S. and Reid, N. (2023) ‘Landscape genetics identifies barriers to Natterjack toad metapopulation dispersal’, Conservation Genetics. Springer Science and Business Media LLC. Available at: https://doi.org/10.1007/s10592-023-01507-4.1572-9737https://doi.org/10.1007/s10592-023-01507-4Publication history: Accepted - 1 February 2023; Published online - 21 February 2023Habitat fragmentation and loss reduce population size and connectivity, which imperils populations. Functional connectivity is key for species persistence in human-modified landscapes. To inform species conservation management, we investigated spatial genetic structure, gene flow and inferred dispersal between twelve breeding sites of the Natterjack toad (Bufo calamita); regionally Red-Listed as Endangered in Ireland. Spatial genetic structure was determined using both Bayesian and non-Bayesian clustering analysis of 13 polymorphic microsatellite loci genotyping 247 individuals. We tested the influence of geographic distance, climate, habitat, geographical features, and anthropogenic pressure on pairwise genetic distances between breeding sites using Isolation-by-distance and Isolation-by-resistance based on least-cost path and circuit theory models of functional connectivity. There was clear spatial structuring with genetic distances increasing with geographic distance. Gene flow was best explained by Isolation-by-resistance models with coniferous forestry plantations, bog, marsh, moor and heath, scrub, anthropogenic presence (Human Influence Index) and rivers (riparian density) identified as habitats with high resistance to gene flow while metapopulation connectivity was enhanced by coastal habitats (beaches, sand dunes and salt marshes) and coastal grassland. Despite substantial declines in census numbers over the past 15 years and its regional status as Endangered, the Natterjack toad population in Ireland retains high genetic diversity. If declines continue, maintaining habitat connectivity to prevent genetic erosion by management of coastal grasslands, pond construction and assisted migration through translocation will be increasingly important.enOpen Access. This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/.Genetic connectivityFragmentationGene fowEpidalea calamitaLandscape resistance modellingPopulation structureArticle