EFFECTS OF ROADS ON SPATIAL BEHAVIOUR AND ABUNDANCE OF SMALL MAMMALS: GAPS IN KNOWLEDGE

Abstract

The main goal of this study was to update the current understanding of the spatial behaviour and abundance of small mammals in the vicinity of roads through a complete literature review to identify knowledge gaps. We also examined spatial patterns of small mammals taking into account the biological and road-related factors to provide recommendations for future research. We found 38 papers documenting effects of roads on small mammals during 1974-2013, located mainly in North America and Europe. Results were obtained for 56 species in three mammalian orders considered. We found a high diversity of individual behaviours towards roads within the same species in different studies. Nevertheless, we can summarize some general patterns found in the review: 1) roads may not represent a barrier to movements because individuals are able to cross the roads; 2) although road verges with herbaceous cover favour the small mammal's abundance, there is no clear relationship between road verges and their abundance; 3) as expected, home range size and body mass are positively related with road crossing rates; 4) pavement is the road related feature that seems to limit road crossing rates. Based on our review, we found four key knowledge gaps: 1) absence of detailed information related with habitat and climate conditions in the studies; 2) lack of representativeness of small mammals with different ecological traits; 3) missing data on the effects of roads on species dispersal; and 4) scarce data on the role of crossing structures to maintain population connectivity and which features favour their use.