UNDERPASS SYSTEMS FOR AMPHIBIANS

The spotted salamander (Ambystoma maculatum) is found throughout the eastern United States and southeastern Canada. The life history of the spotted salamander is representative of many species of amphibians in New England. Essentially terrestrial animals, these amphibians must migrate to wetland breeding sites and, after breeding, move back into upland non-breeding habitats. In areas where roads or highways separate breeding ponds from upland, non-breeding habitat, road mortality can be a serious threat to amphibian populations. Incidences of high amphibian mortality associated with roadways have attracted the attention of the general public and has resulted in a number of amphibian tunnel projects, most of them in Europe. In 1987, North America's first salamander tunnels were constructed at a site in Amherst, Massachusetts. The tunnels were monitored during the spring migration in 1988. This study found that the tunnels were successful at moving salamanders across the road. At a minimum 75.9% of animals that reached the tunnel entrances successfully passed through them. Of the remaining 24.1%, it is not known whether these animals abandoned their migration, bypassed the fence system or passed through the tunnels on a subsequent night. As many of the salamanders appeared hesitant to enter the tunnels, an investigation was made to determine the possible cause. Preliminary results indicate that the absence of light is a factor responsible for tunnel hesitation. Future tunnels should be designed to maximize the amount of ambient light inside the tunnels. An additional concern is that amphibians typically require wet conditions for their migrations. Some mechanism must be found for allowing rain to moisten the substrate within the underpasses. More research is needed to determine whether amphibians will travel through a long culvert or underpass necessary to traverse a major highway, or whether shorter tunnels with an intermediate habitat island in the median strip would be more effective.

Language

  • English

Media Info

  • Features: References;
  • Pagination: p. 224-227

Subject/Index Terms

Filing Info

  • Accession Number: 00745667
  • Record Type: Publication
  • Report/Paper Numbers: FHWA-PD-96-041
  • Files: TRIS, USDOT, STATEDOT
  • Created Date: Feb 2 1998 12:00AM