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How effective is road mitigation at reducing road-kill? A meta-analysis.


How effective is road mitigation at reducing road-kill? A meta-analysis.

Rytwinski, Trina, Soanes, Kylie, Jaeger, Jochen A.G., Fahrig, Lenore, Findlay, C. Scott, Houlahan, Jeff, van der Ree, Rodney and van der Grift, Edgar A. (2016) How effective is road mitigation at reducing road-kill? A meta-analysis. PLoS ONE, 11 (11). pp. 1-25. ISSN 1932-6203

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Official URL: http://dx.doi.org/10.1371/journal.pone.0166941


Road traffic kills hundreds of millions of animals every year, posing a critical threat to the populations of many species. To address this problem there are more than forty types of road mitigation measures available that aim to reduce wildlife mortality on roads (road-kill). For road planners, deciding on what mitigation method to use has been problematic because there is little good information about the relative effectiveness of these measures in reducing road-kill, and the costs of these measures vary greatly. We conducted a meta- analysis using data from 50 studies that quantified the relationship between road-kill and a mitigation measure designed to reduce road-kill. Overall, mitigation measures reduce road- kill by 40% compared to controls. Fences, with or without crossing structures, reduce road- kill by 54%. We found no detectable effect on road-kill of crossing structures without fencing. We found that comparatively expensive mitigation measures reduce large mammal road-kill much more than inexpensive measures. For example, the combination of fencing and cross- ing structures led to an 83% reduction in road-kill of large mammals, compared to a 57% reduction for animal detection systems, and only a 1% for wildlife reflectors. We suggest that inexpensive measures such as reflectors should not be used until and unless their effectiveness is tested using a high-quality experimental approach. Our meta-analysis also highlights the fact that there are insufficient data to answer many of the most pressing ques- tions that road planners ask about the effectiveness of road mitigation measures, such as whether other less common mitigation measures (e.g., measures to reduce traffic volume and/or speed) reduce road mortality, or to what extent the attributes of crossing structures and fences influence their effectiveness. To improve evaluations of mitigation effectiveness, studies should incorporate data collection before the mitigation is applied, and we recom- mend a minimum study duration of four years for Before-After, and a minimum of either four years or four sites for Before-After-Control-Impact designs.

Divisions:Concordia University > Faculty of Arts and Science > Geography, Planning and Environment
Item Type:Article
Authors:Rytwinski, Trina and Soanes, Kylie and Jaeger, Jochen A.G. and Fahrig, Lenore and Findlay, C. Scott and Houlahan, Jeff and van der Ree, Rodney and van der Grift, Edgar A.
Journal or Publication:PLoS ONE
Date:21 November 2016
  • SAFEROAD project (www.saferoad-cedr.org), part of CEDR Transnational Road Research Programme Call 2013: Roads and Wildlife, which is funded by the national road administrations of Austria, Denmark, Germany, Ireland, Norway, Sweden, Netherlands and United
  • Natural Sciences and Engineering Research Council of Canada
  • Baker Foundation
  • ARC Centre for Excellence in Environmental Decisions
Digital Object Identifier (DOI):10.1371/journal.pone.0166941
Keywords:wildlife, mammals, roads, amphibians, meta-analysis, reptiles, death rates, transportation, mitigation, fence, crossing, wildlife passages, reflectors, effectiveness
ID Code:982015
Deposited On:28 Nov 2016 15:03
Last Modified:18 Jan 2018 17:54


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