Quantifying the Road-Effect Zone: Threshold Effects of a Motorway on Anuran Populations in Ontario, Canada

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 Ale...

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Main Authors: Felix Eigenbrod, Stephen J. Hecnar, Lenore Fahrig
Format: Article
Language:English
Published: Resilience Alliance 2009-06-01
Series:Ecology and Society
Subjects:
Online Access:http://www.ecologyandsociety.org/vol14/iss1/art24/
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author Felix Eigenbrod
Stephen J. Hecnar
Lenore Fahrig
author_facet Felix Eigenbrod
Stephen J. Hecnar
Lenore Fahrig
author_sort Felix Eigenbrod
collection DOAJ
description 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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spelling doaj.art-8e4acf26d9e94f5aba87d5337394776c2022-12-21T18:37:22ZengResilience AllianceEcology and Society1708-30872009-06-011412410.5751/ES-02691-1401242691Quantifying the Road-Effect Zone: Threshold Effects of a Motorway on Anuran Populations in Ontario, CanadaFelix Eigenbrod0Stephen J. Hecnar1Lenore Fahrig2Geomatics and Landscape Ecology Research Laboratory, Department of Biology, Carleton University, Ottawa, CanadaDepartment of Biology, Lakehead University, Thunder Bay, Ontario, CanadaGeomatics and Landscape Ecology Research Laboratory, Department of Biology, Carleton University, Ottawa, Ontario CanadaThe 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.http://www.ecologyandsociety.org/vol14/iss1/art24/accessible habitatamphibian declineanuran populationsecological thresholdsforestsfragmentationhabitat losspiecewise regressionroad ecology.
spellingShingle Felix Eigenbrod
Stephen J. Hecnar
Lenore Fahrig
Quantifying the Road-Effect Zone: Threshold Effects of a Motorway on Anuran Populations in Ontario, Canada
Ecology and Society
accessible habitat
amphibian decline
anuran populations
ecological thresholds
forests
fragmentation
habitat loss
piecewise regression
road ecology.
title Quantifying the Road-Effect Zone: Threshold Effects of a Motorway on Anuran Populations in Ontario, Canada
title_full Quantifying the Road-Effect Zone: Threshold Effects of a Motorway on Anuran Populations in Ontario, Canada
title_fullStr Quantifying the Road-Effect Zone: Threshold Effects of a Motorway on Anuran Populations in Ontario, Canada
title_full_unstemmed Quantifying the Road-Effect Zone: Threshold Effects of a Motorway on Anuran Populations in Ontario, Canada
title_short Quantifying the Road-Effect Zone: Threshold Effects of a Motorway on Anuran Populations in Ontario, Canada
title_sort quantifying the road effect zone threshold effects of a motorway on anuran populations in ontario canada
topic accessible habitat
amphibian decline
anuran populations
ecological thresholds
forests
fragmentation
habitat loss
piecewise regression
road ecology.
url http://www.ecologyandsociety.org/vol14/iss1/art24/
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