Past deforestation of Mediterranean Europe explains the present distribution of the strict forest dweller Myotis bechsteinii

Abstract

Habitat loss and degradation are perceived as main factors threatening biodiversity. Historical rather than contemporary processes are often responsible for present patterns of species’ distribution, but their respective contributions are not always easy to disentangle. The strict forest specialist, sedentary, highly phylopatric Bechstein’s bat (Myotis bechsteinii) is an ideal model species to assess the effect of historical landscape transformations in the current distribution patterns of forest species. Although to date the species has been considered almost absent from the Mediterranean range (Southern Europe), recently it has been shown to be common in certain spots there. We test whether the present distribution and ecological preferences of the species in this area are related to biogeographical constraints or to clearance of forests from preferred areas. We assessed roost selection, spatial ecology, foraging habitat selection, and prey selection in Atlantic and Mediterranean domains of the Iberian Peninsula. Ecological requirements appeared conserved throughout, but roost selection appeared less constrained in the Mediterranean localities. Hunting occurred preferentially inside closed deciduous oak forest in both regions, but commuting distances and foraging areas were larger in the Atlantic, together with higher habitat fragmentation and lower prey availability. The same prey taxa were eaten in both regions, although their frequency in the diet varied, matching differences in availability. Consequently, scarcity of these bats in Mediterranean Iberia seems to be better explained by the retreat or loss of deciduous forests due to human impacts, coupled with climate change.