Phylogeography of European Hedgehogs Revisited: Pleistocene Northern Refugia and Ecological Differentiation

This study re-evaluates the Pleistocene history of the European hedgehog (Erinaceus europaeus) and the Northern white-breasted hedgehog (E. roumanicus), by integrating genetically verified occurrence records, complementary allopatric GBIF records and ecological niche modelling (ENM). We assessed differences in broad-scale environmental associations, identified climatic predictors associated with their distributions, and reconstructed potential past climatic suitability during the Last Glacial Maximum. Niche overlap, equivalency and similarity analyses were applied across allopatric regions and areas of sympatry. Human Footprint showed a strong signal in exploratory models for both species, with a stronger effect in the Northern white-breasted hedgehog. Climatic predictors differed between the species: predicted suitability for the Northern white-breasted hedgehog was more strongly associated with temperature-related variables, whereas the European hedgehog models were mainly influenced by annual temperature range and precipitation-related variables. Niche comparisons across the Central European (CE) and Russian–Baltic (RB) contact zones revealed contrasting patterns, with stronger realized climatic niche differentiation in the CE zone and apparently greater, but less clearly resolved, niche overlap in the RB zone. The location of the CE contact zone may partly coincide with the transition between oceanic and continental climates, consistent with the trapping hypothesis of hybrid zones. Palaeoclimatic projections indicated suitable areas beyond the classical Mediterranean peninsulas, supporting the possibility of northern or extra-Mediterranean refugial areas. Our results suggest that broad-scale environmental gradients may contribute to the spatial structuring of contact zones and may interact with species-boundary dynamics despite ongoing hybridization, while palaeoclimatic reconstructions support a more complex Pleistocene history than implied by the classical southern-refugia paradigm. These findings highlight the importance of considering both ecological and historical processes when interpreting the evolutionary history of European temperate taxa.