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E&S Home > Vol. 14, Iss. 2 > Art. 7 > Abstract Open Access Publishing 
Wildlife Tunnel Enhances Population Viability

Rodney van der Ree, Australian Research Centre for Urban Ecology, Royal Botanic Gardens Melbourne
Dean Heinze, Department of Primary Industries and Water
Michael McCarthy, Australian Research Centre for Urban Ecology
Ian Mansergh, Department of Sustainability and Environment


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Roads and traffic are pervasive components of landscapes throughout the world: they cause wildlife mortality, disrupt animal movements, and increase the risk of extinction. Expensive engineering solutions, such as overpasses and tunnels, are increasingly being adopted to mitigate these effects. Although some species readily use such structures, their success in preventing population extinction remains unknown. Here, we use population viability modeling to assess the effectiveness of tunnels for the endangered Mountain Pygmy-possum (Burramys parvus) in Australia. The underpasses reduced, but did not completely remove, the negative effects of a road. The expected minimum population size of a “reconnected” population remained 15% lower than that of a comparable “undivided” population. We propose that the extent to which the risk of extinction decreases should be adopted as a measure of effectiveness of mitigation measures and that the use of population modeling become routine in these evaluations.

Key words

barrier effect; Burramys; population-level impacts; population viability analysis; road ecology; underpass; wildlife crossing structure
Ecology and Society. ISSN: 1708-3087