Study

A literature review of the effects of roads on amphibians and reptiles and the measures used to minimize those effects

  • Published source details Jochimsen D.M., Peterson C.R., Andrews K.M. & WhitfieldGibbons J. (2004) A literature review of the effects of roads on amphibians and reptiles and the measures used to minimize those effects. Idaho Fish and Game Department and USDA Forest Service report, 79pp.

Actions

This study is summarised as evidence for the following.

Action Category

Install barriers and crossing structures along roads/railways

Action Link
Reptile Conservation

Install barrier fencing along roads

Action Link
Amphibian Conservation

Install culverts or tunnels as road crossings

Action Link
Amphibian Conservation
  1. Install barriers and crossing structures along roads/railways

    A review of studies investigating culverts and road barriers in the USA (Jochimsen et al. 2004) found that some species used culverts and in some cases road casualties were reduced. Nine alligators Alligator mississippiensis used four fenced wildlife underpasses. Desert tortoise Gopherus agassizii and shovel-nosed snake Chionactis occipitali road casualties reduced after a barrier fence, 24 culverts and three bridges were installed and tortoises were recorded using the culverts. Although red-sided garter snakes Thamnophis sirtalis infernalis used tunnels, snake road casualties remained high during autumn migrations and only two timber rattlesnakes Crotalus horridus were recorded using a culvert in the two years following its construction. See original paper for details of each study.

    (Summarised by: Katie Sainsbury)

  2. Install barrier fencing along roads

    A study of drainage culverts modified with diversion fencing in Texas, USA (Jochimsen et al. 2004) found that fencing reduced road-kills in its vicinity, but aggregations of dead toads were recorded at the barrier endpoints. No Houston toads Bufo houstonensis used the culverts, which became impassable when flooded. Short sections of steel diversion fencing were added to existing drainage culverts to guide toads from known migration routes into the culverts.

  3. Install culverts or tunnels as road crossings

    A review of studies investigating culverts in Texas and near New York, USA (Jochimsen et al. 2004) found mixed results. Two tunnels with barrier walls decreased amphibian road deaths by 90%. Eight of the 20 known species were recorded using the tunnels. In contrast, no Houston toads Bufo houstonensis used modified drainage culverts and athough diversion fencing reduced road-kills in its vicinity, groups of dead toads were recorded at the ends. Short sections of steel diversion fencing were added to existing drainage culverts to guide toads from known migration routes into the culverts. The culverts were not designed for amphibians and became impassable when flooded. Two concrete tunnels with box openings (1.2 x 1.2 m) and wooden barrier walls were installed along a road adjacent to wetlands in 1999.

     

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