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Quantifying the road effect zone: threshold effects of a motorway on anuran populations in Ontario, Canada

Eigenbrod, Felix, Hecnar, Stephen J. and Fahrig, Lenore (2009) Quantifying the road effect zone: threshold effects of a motorway on anuran populations in Ontario, Canada Ecology and Society, 14, (1), 24-[18pp].

Record type: Article


The negative effect of roads on wildlife is recognized as a major contributor to the global biodiversity crisis, with anurans being among the most vulnerable groups overall. The “road-effect zone,” i.e., the extent of significant ecological effects from the edge of a road (Forman and Alexander 1998), has important management implications, but has never been quantified for anurans. In the first study of its kind, we measured the extent and type of relationship underlying the road-effect zones of a motorway with a high proportion of heavy-truck traffic, particularly at night (Highway 401) for anuran species richness and relative abundance. We surveyed 34 ponds located 68–3262 m from the edge of the motorway, and used piecewise and linear regressions to determine if road-effect zones were clearly delineated by ecological thresholds. We found road-effect zones of 250–1000 m delineated by ecological thresholds for four of seven species and species richness, and road-effect zones of well beyond 1000 m best described by linear regressions for two species. The negative effect of Highway 401 was unexpectedly strong for four of seven species suggest that, in addition to road mortality, very high nighttime truck traffic can actually lead to reduced use of breeding habitat near the motorway either by acting as a barrier to forest habitat on the other side of the highway and/or because of traffic noise. Our results show that most anurans are likely to have reduced abundances near motorways, but that both the extent of the effect of this type of road and the underlying relationship vary considerably between species. Furthermore, the noise and/or barrier effect of very high nighttime traffic volumes can lead to negative effects of motorways even on species that are relatively unaffected by direct road mortality

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Published date: 2009
Keywords: accessible habitat, amphibian decline, anuran populations, ecological thresholds, forests, fragmentation, habitat loss, piecewise regression, road ecology


Local EPrints ID: 181359
ISSN: 1708-3087
PURE UUID: 5be81f5a-d84f-40bc-a1b1-839e4ec30bcc

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Date deposited: 15 Apr 2011 14:34
Last modified: 18 Jul 2017 11:59

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Author: Felix Eigenbrod
Author: Stephen J. Hecnar
Author: Lenore Fahrig

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