Tunnel and Fencing Options for Reducing Road Mortalities of Freshwater Turtles

This study was undertaken to investigate the relative effectiveness of experimental under-road passages and barriers for freshwater turtles as solutions to the problem of roadway mortality through a series of designed behavioral experiments. At outdoor laboratories, movements in response to varying light levels, and barrier opacity were examined for painted turtles (Chrysemys picta), Blanding’s turtles (Emydoidea blandingii), and spotted turtles (Clemmys guttata). Additionally, tunnel size and tunnel entrance design were examined for painted turtles only. A total of 886 painted turtles, 53 Blanding’s turtles, and 50 spotted turtles were used in factorial experimental designs to test for effects of (1) tunnel lighting and size, (2) artificial lighting, and (3) guidance structure characteristics. Behaviors of turtles were quantified both as binomial responses (success/fail), and continuous responses. As the amount of natural light transmitted through the tops of tunnels increased, successful completion of the trials increased. This relationship was also maintained when the lighting was artificial. All three tested species responded poorly to the 0% available light treatment. Guidance structure characteristics did not affect the willingness of turtles to enter passages. Turtles moved at a slower rate when traveling along a translucent barrier, compared to an opaque one. The authors' results indicate the importance of designing road passage structures for freshwater turtles that provide adequate tunnel lighting in combination with opaque and/or translucent barriers, as determined through evaluation of the wetland/roadway context in regards to protect objectives.


  • English

Media Info

  • Media Type: Digital/other
  • Edition: Final Report
  • Features: Figures; References; Tables;
  • Pagination: 87p

Subject/Index Terms

Filing Info

  • Accession Number: 01667215
  • Record Type: Publication
  • Report/Paper Numbers: SPRII.06.22, UMTC-12.02
  • Contract Numbers: 56460
  • Created Date: Apr 25 2018 11:14AM