2010) and population viability (Newman et al. 2018), population growth (Bascompte et al. 2012) and movement patterns (Poessel et al. Habitat fragmentation, through habitat loss and habitat patch isolation, changes animal behaviour including dispersal (Janin et al. Habitat degradation and fragmentation are key drivers of the current global biodiversity crisis (Sala et al.
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. 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. 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. There was clear spatial structuring with genetic distances increasing with geographic distance. 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. Spatial genetic structure was determined using both Bayesian and non-Bayesian clustering analysis of 13 polymorphic microsatellite loci genotyping 247 individuals. 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. Functional connectivity is key for species persistence in human-modified landscapes. Habitat fragmentation and loss reduce population size and connectivity, which imperils populations.
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