A review of ecological factors promoting road use by mammals

Roads have numerous negative impacts for mammals, but may also serve as attractants due to altered vegetation or provisioning of resources. We reviewed the use of roads and their associated features by mammals, in order to understand the ecological factors contributing to road use. We documented 129 studies that recorded road use by 116 mammalian species, spanning 15 orders and 35 families, in six continents. Carnivora was the most common order (40 species, 34% of all 116 species), followed by Artiodactyla (24 species, 20%) and Rodentia (21 species, 18%). The species were placed in the IUCN categories Least Concern (88 species, 76% of all 116 species), Vulnerable (11 species, 9%), Near Threatened (9 species, 8%), Endangered (6 species, 5%), and Critically Endangered (2 species, 2%). We assigned road use to five ecological categories, reflecting the reason for it, with subcategories where appropriate: (1) communication; (2) foraging (subcategories: anthropogenic food, herbivory, predation, salt, scavenging, water); (3) movement (subcategories: bridges, environmental alterations, habitat connectivity); (4) refuge (subcategories: avoidance, burrowing and denning, cover, roosting); and (5) thermoregulation. Foraging, movement, and refuge were the most common uses. Roads provide a variety of resources to mammals, but road use is highly dynamic in time and space. We suggest that the use of roads by mammals is extensive, both geographically and taxonomically. Road use is likely to influence mammalian ecology while contributing to the risk of collisions with vehicles.

Automated summary

Roads have both negative impacts and attractants for mammals due to altered vegetation and resource provision. Mammals use roads for communication, foraging, movement, refuge, and thermoregulation, with foraging, movement, and refuge being the most common reasons. The use of roads by mammals is extensive and diverse, potentially influencing mammalian ecology and increasing the risk of collisions with vehicles.