Road verges as habitat for small mammals in Britain

There are 370 000 kilometres of roads in Great Britain, mostly bordered by a verge that is potential habitat for small mammals. The present study asse ssed the importance of road verges as small mammal habitat and investigated the influence of some key features on rodent abundance. Five rodent and th ree shrew species were live-trapped on 14 road verges in late summer 1994 a nd nine verges in autumn 1996 in north Cambridgeshire, UK. On average, betw een three and four species were captured per verge. Bank Voles Clethrionomy s glareolus, Wood Mice Apodemus sylvaticus and Field Voles Microtus agresti s were the most abundant species, with mean densities of 45.5, 40.2 and 29. 5 animals km(-1) in summer and 52.8, 181.9 and 47.2 animals km(-1) in autum n. Numbers varied between verges and this was significantly correlated with particular features on the verge. Bank Vole and Field Vole numbers showed a significant positive correlation with the dimensions of hedges and the wi dth of the tall grass area, respectively. Wood Mice were also more numerous on verges with big hedges but the relationship between mouse abundance and verge structure was complex. The number of mice in 1994 was positively and significantly correlated with hedge features and with the width of the sho rt grass sightline, whereas, in autumn 1996, they were only significantly c orrelated with total verge width (positive association) and ditch width (ne gative association).