Individual study: Under road tunnels were used by amphibians, reptiles and mammals in Catalonia, Spain
Rosell C., Parpal J., Campeny R., Jove S., Pasquina A. & Velasco J.M. (1997) Mitigation of barrier effect on linear infrastructures on wildlife. Pages 367-372 in: Habitat Fragmentation & Infrastructure. Ministry of Transport, Public Works and Water Management, Delft, Netherlands.
This study is summarised as evidence for the intervention(s) shown on the right. The icon shows which synopsis it is relevant to.
Install tunnels/culverts/underpass under roads
A replicated study in 1993–1994 along four roads in Catalonia, Spain (Rosell et al. 1997) found that underpasses were used by several mammal species. Small mammals used all rectangular culverts and 94% of circular culverts. Hares Lepus spp. and rabbits Oryctolagos cuniculus used 83% and 23% of rectangular and circular culverts respectively whilst carnivores used 88% and 75% respectively. Carnivores recorded were weasel Mustela nivalis, beech marten Martes foina, badger Meles meles, genet Genetta genetta and fox Vulpes vulpes. Wild boar Sus scrofa and roe deer Capreolus capreolus also used underpasses. Use was greater by small mammals for underpasses at the same level as the surroundings and those with natural substrate on the floor. Those with water were used less frequently. Rabbits did not use narrow structures (<1.5 m), whereas wild boar used underpasses >7 m wide. A total of 39 circular (1–3 m diameter) and 17 rectangular drains (4–12 m wide) and other underpasses were surveyed along four 10-km sections of road. Underpasses were monitored for four days/season over a year, in 1993–1994. Animal tracks were monitored using marble power (50 cm wide) across the centre of each structure. Infra-red and photographic cameras were used at entrances.
(Summarised by Rebecca K. Smith)
Install culverts or tunnels as road crossings
A replicated, site comparison study in 1993–1994 of 56 tunnels under roads in Catalonia, Spain (Rosell et al. 1997) found that amphibians used 23% of circular and 59% of rectangular tunnels. Use was greater for wider tunnels with water within or at entrances. Tunnels with steps or wells at the entrances or within large embankments were used less frequently. A total of 39 circular (1–3 m diameter) and 17 rectangular cross-section (4–12 m diameter) drains/underpasses were surveyed along four 10 km stretches of roads. Tunnels were monitored for four days each season over a year in 1993–1994. Tracks were obtained using marble power across the centre of each structure. Infra-red and photographic cameras were used at entrances.