Animal Vehicle Collision Reduction and Habitat Connectivity Pooled Fund Study – Literature Review

Abstract

This report contains a summary of past research and new knowledge about the effectiveness of mitigation measures aimed at reducing animal-vehicle collisions and at providing safe crossing opportunities for wildlife. The measures are aimed at terrestrial large bodied wild mammal species, free roaming large livestock species (e.g. cattle, horses), free roaming large feral species (e.g. “wild” horses and burros), and small animal species (amphibians, reptiles, and small mammals). While mitigation is common, it is best to follow a three-step approach: avoidance, mitigation, and compensation or “off-site” mitigation. If reducing collisions with large wild mammals is the only objective, the most effective measures include roadside animal detection systems, wildlife culling, wildlife relocation, anti-fertility treatments, wildlife barriers (fences),and wildlife fences in combination with wildlife crossing structures. If the objectives also include maintaining or improving connectivity for large wild mammals, then wildlife barriers (fences) in combination with wildlife crossing structures are most effective. Measures for large domestic mammal species are largely similar, though for free roaming livestock there are legal, moral and ethical issues. For small animal species, temporary or permanent road closure and road removal are sometimes implemented, but barriers in combination with crossing structures are the most common.