Effects of roads on European badger occurrence in intensively used Mediterranean farmland

Abstract

Understanding how transportation infrastructure affects wildlife is a key goal in conservation biology. This goal is particularly relevant in intensively used landscapes, where species are potentially impacted both by roads and the scarcity of suitable natural habitats. We investigated how road density and landscape composition and configuration affect the occurrence of the European badger (Meles meles) in intensively used Mediterranean farmland. Although most studies documenting road impacts on carnivores species in Mediterranean areas have been largely focused on the factors driving mortality at roads or habitat use near and far from roads, few have explicitly assessed how road density impacts species occurrence, particularly in intensively used farmland, where their preferred native woodland habitats are relatively scarce. Based on badgers’ presence signs surveys conducted in three occasions (spring, summer and autumn) across 60 landscape units (3.14-km2 circles) scattered through SW Portugal, we used occupancy-detection modelling to quantify the effect of paved road density on the occurrence of the species in intensively used Mediterranean farmland. In addition, we tested the prediction that forestry plantations and hedgerows embedded in the agricultural matrix should in turn result in increased probabilities of badger occupancy, as these habitats should provide substitute refuge areas for the species. According to our predictions, badger occupancy significantly decreased with increasing paved road density, and increased with increasing amount of forestry plantations and arboreal hedgerows. These results suggest that badger conservation in intensively used Mediterranean farmland requires the protection of areas with low road density, and the retention of wood cover, even where these are mostly forestry plantations and arboreal hedgerows.