Roads disrupt landscape connectivity for many species. These infrastructures can be barriers to movement and, in the long-term, threaten the persistence of several mammal populations living on roadsides. It is widely recognized that small mammals use road verges as habitat and corridor when roads cross intensively managed landscapes. Nevertheless, the role of road verges is still unknown within well preserved habitats. On those areas, defining habitat corridors is controversial due to similar vegetation composition and structure on road verges and surrounding landscape. Low intensity land management on road surroundings may have an impact on the role of road verges as fine-scale connectivity providers for small mammals on a well-preserved habitat. Our goal was to quantify how road verges and paved lanes affect fine-scale landscape connectivity for the wood mouse (Apodemus sylvaticus) in a well-preserved Mediterranean woodland. We also evaluated the effects of management practices related to the road (verge vegetation cutting and firebreak opening) and to a traditional agro-silvo pastoral system (i.e. grazing, ploughing and cork stripping) on fine-scale landscape connectivity. We quantified fine-scale landscape connectivity using graph theory based on two years of capture-recapture data. We used the probability of connectivity as an index to obtain a set of connectivity metrics that were compared in a road and in a virtual roadless scenario. Our results showed that the presence of the road reduced overall fine-scale landscape connectivity. Moreover, although the road was a partial barrier for movement, road verges were strong promoters of connectivity along road surroundings. Vegetation cutting on verges, and land ploughing in the surrounding landscape were the only management practices hampering fine-scale connectivity. Our findings support the key role of road verges as corridors for small mammals. Additionally, our study quantifies the increase on fine-scale connectivity provided by road verges and shows that this role is extremely important even in well-preserved landscapes. Based on our results, we suggest guidelines for vegetation management on road surroundings to enhance the role of road verges as connectivity providers for small mammals.
Wildlife movement: connectivity, safety, across eco-tones
Fine-scale landscape functional connectivity
Probability of connectivity index