UTILIZING A MULTI - TECHNIQUE, MULTI -- TAXA APPROACH TO MONITORING WILDLIFE PASSAGEWAYS IN SOUTHERN VERMONT
Roadways affect wildlife habitat disproportionate to the area of land they occupy impacting wildlife through the loss and fragmentation of habitat, road mortality and disruption of movement. A variety of strategies have been used with mixed success to mitigate the impacts of transportation systems on wildlife. Underpasses are commonly used to facilitate movement of wildlife across roadways in Europe, Australia, Canada and the U.S. Through 2005, 460 terrestrial and 300 aquatic crossing structures have been identified throughout the United States but only a small portion of these crossings had monitoring incorporated into their project design. Most monitoring is limited to wildlife use of passage structures with little data collected on movement through the adjacent landscape. Data on the movement of individual animals through a passage structure is, at best, only an indirect measure of the success of a mitigation project. Mitigation success should be defined not only by what uses passage structures but also by assessing what animals fail to use the structures. Building on prior studies, this project takes a broad, multi--taxa approach to monitoring crossing structures on a newly constructed highway (the Bennington Bypass) in southern Vermont. We used a variety of techniques to assess movements of an array of species at two passage structures associated with the highway as well as in the surrounding landscape. Techniques used in our study include: small mammal trapping, track beds/plates, remote camera sensing, snowtracking and road kill surveys. By monitoring a wide variety of animal movements rather than focusing exclusively on the use of passages by wildlife we believe we can more accurately assess the effectiveness of the mitigation structures.