Wildlife crossing structures are - usually in combination with wildlife fencing - aiming to reduce wildlife-vehicle collisions and facilitate wildlife movements across roads. Some sort of monitoring is often carried out immediately after construction of the crossing structures to assess whether they are used by the target species and what their crossing rates are. Various survey methods and sampling schemes are used, depending on e.g. the research question, the type of crossing structure, the target species and the available resources. Comparisons between research methods address the question which methods or sampling schemes are preferable over others, but such studies are rare. Partially based on the SAFEROAD project (www.saferoad-cedr.org), we evaluated four case studies that illustrate the importance of choosing proper monitoring methods. Case 1: comparison of the use of camera traps versus track beds in assessing crossing rates at two overpasses (Highway N524, Netherlands). Case 2: comparison of the use of one, two, or three track beds at two overpasses (Highway N524, Netherlands). Case 3: comparison of the use of ink track plates at one or at both entrances of seven underpasses (Highway A50, Netherlands). Case 4: comparison of different durations of monitoring at an overpass (Highway A27, Netherlands). Based on the results of these case studies we will provide practical guidelines for selecting appropriate survey techniques and sampling schemes to evaluate wildlife use of crossing structures.
road mitigation; de-fragmentation; wildlife fences; wildlife crossing structures; monitoring; track beds; track plates; camera traps; guidelines