Data from: Wolves at the crossroad: fission-fusion range biogeography in the Western Carpathians and Central Europe

Aim: Population fragmentation represents a leitmotif of conservation biology, but the impact of population reconnection is less well studied. The recent recolonization of large carnivores in Europe is a good model for studying this phenomenon. We aim to show novel data regarding distribution and population genetic structure of the grey wolf in Central Europe, a region considered a frequent crossroad and contact zone of different phylogeographic lineages, in a biogeographic context. Location: Western Carpathians, Central Europe. Methods: In concordance with the presumption of a highly mobile mammal, individual-based Bayesian clustering and a posteriori definition of populations were used. Integrating the frameworks of landscape genetics and biogeography enabled the identification of transitions in population architecture. These patterns could be ascribed to isolating factors based on historical knowledge about species demography. Results: Genetic differentiation mirrors population isolation and recognized environmental clusters, suggesting ecotypic variation. The east–west split in the Western Carpathians likely represents the signature of range fragmentation during bottlenecks in the 20th century. Mitochondrial variability is more depleted than nuclear variability, indicating founder-flush demography. Microsatellites show finer-scale differentiation in the Carpathians compared to the European plain, corresponding to topographic heterogeneity. Long-range dispersal of a Carpathian wolf (ca. 300 km), the establishment of enclaves originated from the lowland population and admixture with mountain wolves were ascertained, indicating a population fraction producing large-scale gene flow. Main conclusion: Carpathian wolves are characterized by periods of population and range decline due to eradication, facilitating refugial role of alpine habitats and peripatric effects, followed by expansions and fusions probably caused by forest transition, population adaptation and efforts in conservation management. New occurrence and hybridization events predict further contacts between formerly isolated populations, with potential opposing effects of heterosis and outbreeding depression. Population recovery might be hindered due to isolation by environment and anthropogenic impacts.