Measuring Wildlife Linkage and Habitat Benefits Provided by Idaho's Existing Road and Highway Bridges

Focus Area

Wildlife & Ecosystems


Natural Resources






2-3 years

Research Idea Scope

The safety and maintainece of Idaho’s road and highway bridges is essential and their regular inspection, rennovation, and replacement is an important responsibility of the Transportation Department.   Incidently and unintentionally, many of these same road and highway bridges may provide for safe crossing of wildlife under rather than over roadways, reducing wildlife-vehcile collisions and provide bat roosting, maternity, or hibernacula habitats for Idaho’s native bat species.   Identifying which bridges provide either or both of these wildlife benefits is important as the Idaho Transportation Department moves ahead with projects  to modernize and maintain these bridges as well as expand or modify bridges in relation to transportation and highway system expansion.  This project will identify the unintended benefits to wildlife of Idaho’s road and highway bridges, assess the structural and spatial characteristics of inventoried bridges that contributed to their benefitting wildlife and help facilitate Idaho bridge improvements and safety by pre-emptively identifying bridge-specific conservation concerns as well as design features that should be protected or featured for wildlife benefit.   This project, in cooperation with state and local transportation Departments, will:  1) map and prioritize all Idaho road and highway bridges in terms of their proposed maintainence, inspection, and replacement schedules,  2) research and establish a bridge inventory protocol to capture relative wildlife underpass crossing capacity and use and bridge use and importance by species of Idaho bats, 3) site visit survey, inventory, and characterize bridges in decreasing order of priority and ability to make structural inspections for bat use, 4) analyze, model, and sum bridge underpass capacities for wildlife and bat habitat capacities and characteristics, 5) Report results in appropriate forums and incorporate metadata into Google Earth application and make available on Department web site, 6) Communicate and cooperate with transportation partners on the management implications of the project and provide benefit to transportation department bridge project schedules, budgets, and design.

Urgency and Payoff

Informs transportation department road and bridge maintainence and replacement schedules and budgets of important wildlife considerations in priority. Measures and quantifies benefit to wildlife and to public safety of existing transportation bridge system. Quantifies Idaho’s existing bridges in terms of species and site characteristics beneficial to wildlife. Provides an assessment of Idaho’s bridges and their beneficial characteristics to wildlife independent of transportation project schedules and budgets. Cooperative project increasing management information available to transportation and wildlife managers.

Suggested By

Gregg Servheen, Idaho Dept of Fish and Game