Conservation Evidence strives to be as useful to conservationists as possible. Please take our survey to help the team improve our resource.

Providing evidence to improve practice

Individual study: The permeability of highway in Gorski Kotar (Croatia) for large mammals

Published source details

Kusak J., Huber D., Gomerčić T., Schwaderer G. & Gužvica G. (2009) The permeability of highway in Gorski Kotar (Croatia) for large mammals. European Journal of Wildlife Research, 55, 7-21


This study is summarised as evidence for the intervention(s) shown on the right. The icon shows which synopsis it is relevant to.

Install overpasses over roads/railways Terrestrial Mammal Conservation

A study in 1999–2003 along a road through beech and fir forest in Gorski kotar, Croatia (Kusak et al. 2009) found that medium-large mammals used a wildlife overpass (a green bridge) and two other overpasses not specifically designed for wildlife. Monitoring of the green bridge revealed tracks of hare Lepus europaeus (49 tracks), wild boar Sus scrofa (66), roe deer Capreolus capreolus (166), red deer Cervus elaphus (103), fox Vulpes vulpes (83), badger Meles meles (2), brown bear Ursus arctos (39), grey wolf Canis lupus (4) and Eurasian lynx Lynx lynx (1). A similar range of species was recorded on the two other overpasses that were not designed as green bridges (see paper for data). A new highway was constructed in 1998–2004, with 2.1-m barrier fencing. Along a 9-km section, a 100-m-wide green bridge and two overpasses (742 and 835 m wide) above road tunnels, were monitored. Tracks (in snow, mud or sand) and other animal signs were counted 64 times at the green bridge and eight and 23 times at the two other overpasses, in January 1999–January 2001. One of the overpasses was also monitored using a camera trap.

(Summarised by Rebecca K. Smith)

Install barrier fencing and underpasses along roads Terrestrial Mammal Conservation

A study in 1999–2001 along a road through beech and fir forest in Gorski kotar, Croatia (Kusak et al. 2009) found that an underpass below a section of road on a viaduct, and separated from the road by barrier fencing, was used by medium to large-sized mammals. Tracks were recorded of roe deer Capreolus capreolus (total 20 tracks), red deer Cervus elaphus (12) wild boar Sus scrofa (1), brown bear Ursus arctos (4), grey wolf Canis lupus (1) and Eurasian lynx Lynx lynx (1). However, the underpass had five times fewer mammal crossings/day than did three overpasses (100–835 m wide). A new highway was constructed in 1998–2004 with 44 wildlife crossings and 2.1-m barrier fencing along a 9-km section. An underpass (569 m wide, below a 25-m-high road viaduct) was monitored. Tracks (in snow, mud or sand) and other animal signs were counted 23 times in January 1999–January 2001.

(Summarised by Rebecca K. Smith)