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bioRxiv2026

Wolf microevolution in the melting pot: range expansion, population sympatry, dynamic mosaic admixture zone and asymmetric gene flow

Here we describe substantial range shifts of historically differentiated wolf populations and formation of novel sympatric zones during the recent decade in Central Europe. This region provides a natural laboratory for testing alternative scenarios of population interactions from continued isolation or restricted gene flow to progressive population fusion, while prompting a reassessment of their geographic ranges. Based on sampling across the Czech Republic and Slovakia obtained from large-scale monitoring programmes over five wolf years (2020/21_2024/25), complemented by comparative material from neighbouring regions, we analysed mitochondrial haplotypes, autosomal microsatellite genotypes and sex-linked loci. The Central European population with Baltic ancestry predominated across large parts of Central Europe including the Bohemian Massif with enclaves in the Western Carpathians. The Carpathian population was predominant in Slovakia, with a smaller satellite occurrence in the northern part of the Bohemian Massif. Alpine population was centred in the Alps but extended into southern parts of Bohemian Massif and Central German Uplands. Following the sporadic occurrence of admixed individuals, broad mosaic and dynamic sympatric zones have formed in the Czech Republic and Slovakia in the last decade. These scenarios could be facilitated by the presence of intermediate habitats and isolation of the Bohemian Massif structural basin, framed by a massive ring fault system. Recent-immigration estimates are asymmetric, with the largest mean contributions from the Alpine to the Central European population and from the Central European to the Carpathian population, with the second case potentially linked to source-sink dynamics driven by the hunting pressure within the Carpathian population (whereas the others are protected year-round). Whether increasing admixture will enhance viability of populations (that currently have small effective sizes) through genetic rescue or carry risks of outbreeding depression remains uncertain, highlighting the need for continued transboundary monitoring within conservation biology framework.

genetics↗

bioRxiv2024

Human footprint and forest disturbance reduce space use of brown bears across Europe.

Three-quarters of the planets land surface has been altered by humans, with consequences for animal ecology, movements and related ecosystem functioning. Species often occupy wide geographical ranges with contrasting human disturbance and environmental conditions, yet, limited data availability across species ranges has constrained our understanding of how human impact and resource availability jointly shape intraspecific variation of animal space use. Leveraging a unique dataset of 752 annual GPS movement trajectories from 370 brown bears (Ursus arctos) across the species range in Europe, we investigated the effects of human impact (i.e., human footprint index), resource availability, forest cover and disturbance, and area-based conservation measures on brown bear space use. We quantified space use at different spatio-temporal scales during the growing season (May - September): home range size; representing general space requirements, 10-day long-distance displacement distances, and routine 1-day displacement distances. We found large intraspecific variation in brown bear space use across all scales, which was profoundly affected by human footprint index, vegetation productivity, and recent forest disturbances creating opportunity for resource pulses. Bears occupied smaller home ranges and moved less in more anthropized landscapes and in areas of higher resource availability. Forest disturbances reduced space use while contiguous forest cover promoted longer daily movements. The amount of strictly protected and roadless areas within bear home ranges were too small to affect space use. Anthropized landscapes may hinder the expansion of small and isolated populations, such as the Apennine and Pyrenean, and obstruct population connectivity, for example between the Alpine or Carpathian with the Dinaric Pindos populations. Our findings call for actions to maintain bear movements across landscapes with high human footprint, for example by maintaining forest integrity, to support viable bear populations and their ecosystem functions.

ecology↗