Institute for Transportation

About the research

Roads pose several risks to wildlife due to several sources, including direct mortality from vehicle collisions, fragmentation of key habitat, and creating barriers to movement that result in isolated populations. For imperiled species, such threats can have an outsize impact on species persistence. Mitigation efforts such as wildlife crossings, fencing, roadside vegetation management, and retrofitting roads with wildlife-friendly design features have been shown to be effective at reducing the negative impacts of roads on wildlife.

This project seeks to identify priority sites in Iowa where road mitigation can provide the largest benefit to Species of Greatest Conservation Need (SGCN). The research will build upon ongoing work developing habitat suitability models for a suite of SGCN to predict statewide species’ occurrence under both current conditions and predicted future climate and land use change to develop a gridded biodiversity index. The research will use geospatial data on road configuration, traffic intensity, and wildlife mortalities to quantify road risk to identify sites with the highest combined biodiversity scores and road risk. Field surveys at these sites will be conducted in order to ground-truth model predictions, provide empirical estimates of species richness and density, and evaluate the feasibility and expected benefits of different mitigation efforts. Project deliverables include: (1) recommendations for road mitigations at 10 sites identified to be SGCN hotspots, (2) geospatial data layers of current and future predicted SGCN occurrence and road risk to prioritize future sites for mitigation, and (3) a proposed monitoring plan for evaluating mitigation measures post-implementation.

This project will help the Iowa DOT reduce negative impacts of roads, support conservation of Iowa’s wildlife, and provide a framework for prioritizing mitigation efforts that can serve as a model for other states in the Midwest.