Small-scale alterations in carnivore activity patterns close to motorways

Abstract

The effects of roads on the fauna of their surroundings, negative ones for most species, have been widely studied over recent decades. Nevertheless, little is known of changes in the activity patterns of carnivores near roads, which determine what impacts that they may experience. An intensive 2-year study of the carnivore community around a 5-km stretch of Spanish motorway has been carried out in order to clarify this situation. The carnivore activity patterns at three distances from the motorway (0, 500 and 1000 m) were assessed by means of three complementary sampling methods (scat transects, hair traps and camera traps) and by both whole-community analyses (redundancy analysis) and species-specific analyses (generalised linear mixed models, occupancy models). The results show an intense use of the motorway proximities by the carnivore community, with the road possibly acting as an artificial home-range boundary, as well as differential interspecies responses to the presence of the infrastructure. Thus, foxes, stone martens, weasels and genets made more intensive use of the motorway vicinity whereas badgers and cats were indifferent or slightly favoured more distant zones. Knowledge of this alteration in activity patterns near a motorway is important for understanding both the direct effects (e.g. roadkills) and indirect effects (e.g. predation cascades) that roads may trigger in ecosystems, and it may have relevant implications for the design and effectiveness of mitigation measures.