Valuing Wildlife Crossings: Generating Mitigation Credit for the Inclusion of Wildlife Crossings Within the SR 40 Corridor in Marion, Lake, and Volusia Counties, Florida

Roads can have negative impacts on wildlife, most notably through habitat fragmentation and genetic isolation. Vehicle traffic on roads can lead to wildlife-vehicle collisions and roadkill, which may imperil local wildlife populations. Improved habitat connectivity, road permeability, and deterrents onto roads are all important factors when developing mitigation strategies for wildlife on future road projects. However, transportation agencies have not explored whether such mitigation strategies for wildlife can be applied to and provide compensation for federal permits which authorize the dredge or fill of waters of the United States. In 2013, we discussed the need to determine the value of mitigation strategies for wildlife on State Road (SR) 40, as part of our presentation to the International Conference on Ecology and Transportation. Here, we provide an update to that presentation, describe the methodology we used to value certain mitigation strategies for wildlife, discuss our permitting with the U.S. Army Corps of Engineers (ACOE), and implications on future projects in Florida and across the United States.SR 40 bisects large tracts of undeveloped natural habitats under public ownership and conservation easements, including the Ocala National Forest, Silver Springs State Park, and the Heart Island Conservation Area, among others. These habitats support many wildlife species, a number of which are listed by federal and state agencies as endangered, threatened, or species of special concern. However, SR 40 acts as a semi-permeable barrier for the north-south passage of wildlife, particularly small, less mobile species. Unsurprisingly, SR 40 experiences some of the highest numbers of wildlife-vehicle collisions in Florida, and extremely high numbers of roadkill among Florida black bears, amphibians, and reptiles.
We designed the two-to-four lane widening of a 7.6-mile segment of SR 40 in Volusia County that incorporated one dedicated wildlife crossing structure and three pairs of wildlife shelves, as well as wildlife fencing where feasible. This design would impact numerous wetlands, requiring compensation for the lost values of those wetlands as part of the federal permitting process. In Florida, these values are determined with the Uniform Mitigation Assessment Method (UMAM). We used the UMAM to determine the values lost due to the proposed direct wetland impacts, but also to estimate the enhanced values from wildlife crossing structures and wildlife fencing on the habitats adjacent to SR 40. We relied on the spatial requirements for semi-aquatic and wetland dependent wildlife species in various habitats around central Florida to determine the potential assessment area that would be improved by the wildlife crossing features. Ultimately, our analysis determined that the wildlife crossing features would provide enhancement and reduce our compensatory mitigation requirement by an equal amount. Our analysis was approved by the ACOE in 2017.