Research overview: fencing and funnel effects at wildlife crossings

A wildlife crossing works only if animals are guided to it, and this overview examines the critical role of fencing in funneling wildlife toward structures while keeping them off the road. Exclusion fencing alongside highways reduces direct mortality and channels movement to designated crossings, but gaps, fence ends, and jump-outs create vulnerabilities, and poorly designed fencing can trap animals on the wrong side. The overview discusses how monitoring evaluates whether fencing successfully concentrates use at crossings, the importance of fence-end treatments, and the trade-offs between exclusion and the barrier effect of impermeable fencing. For felids, effective funneling can dramatically increase the conservation return on a crossing structure. The overview frames fencing not as an afterthought but as an integral, make-or-break component of any road-mitigation system.