Highway Crossing Rates of Wild Felids Before, During, and After Wildlife Crossing Structure Installation

• Published in: Ecology and evolution 2024-12, Vol.14 (12), p.e70703-n/a
• Main Authors: Lehnen, Sarah E., Sternberg, Mitch A., Swarts, Hilary M., Young, John H., Hanley, Victoria, Kline, Richard J.
• Format: Article
• Language: English
• Subjects: Animals; Applied Ecology; Behavioural Ecology; bobcat; Collars; Collision mortality; Conservation Ecology; Construction; Endangered species; Environmental protection; Habitat improvement; Habitat preferences; Habitats; Installation; Ketamine; Leopardus pardalis; Lynx rufus; Mortality; Movement Ecology; Nighttime construction; ocelot; Roads; Roads & highways; Speed limits; Time of use; Traffic control; Vehicles; Wildlife; Wildlife conservation; wildlife crossing structure; wildlife–vehicle collisions
• ISSN: 2045-7758; 2045-7758
• DOI: 10.1002/ece3.70703

ABSTRACT In an environment increasingly dominated by roads, wildlife crossing structures (WCS) have been installed to decrease wildlife mortality and improve habitat linkages. In South Texas, vehicle collisions have been a major mortality source for the endangered ocelot (Leopardus pardalis). To mitigate threats to this species, eight WCS, along with associated fencing, were strategically placed along Farm‐to‐Market Road 106 (FM106), which passes through ocelot habitat. We assessed the rate of on‐roadway crossings and WCS use by GPS‐collared animals before, during, and after WCS installation using camera traps to verify WCS use. Because of the rarity of ocelots in this region, we supplemented ocelot data with data from bobcats (Lynx rufus), a similarly sized felid with slightly more general habitat preferences. Thirty‐five animals, 30 bobcats, and 5 ocelots were tracked using GPS collars between 2013 and 2021. We observed a decline in the total number of crossings and on‐roadway crossings of FM106 for both ocelots and bobcats over the duration of the study, despite controlling for factors such as an individual animal's proximity to FM106. There were 37 documented crossings using WCS by GPS‐marked bobcats while their collars were active. However, the rate of on‐roadway crossings during the post‐construction period was still higher than the WCS use rate for both species. Animals were more likely to make on‐roadway crossings during nighttime especially during unusually bright nights. While controlling for other factors, both species moved more quickly when making on‐roadway crossings compared to WCS crossings or noncrossing intervals but moved more slowly when traffic levels were higher than expected for that time of day. Animals may take years to acclimate to the presence of WCS, suggesting that the use of these structures may increase over time. Additional fencing could further help limit high‐risk road encounters by ocelots in this region. In South Texas, eight wildlife crossing structures (WCS) were installed to mitigate vehicle collisions and improve habitat connectivity for the endangered ocelot and other wildlife. GPS tracking of 35 animals (30 bobcats and 5 ocelots) from 2013 to 2021 showed a decline in total and on‐roadway crossings, and, although WCS were used, they were still used less frequently than on‐roadway crossings. The study suggests that animals may need time to acclimate to WCS, and additional fencing could further reduce high‐risk road e