Wildlife Use of Drainage Structures Under 2 Sections of Federal Highway 2 in the Sky Island Region of Northeastern Sonora, Mexico

Roads and highways are 1 of the most significant obstacles affecting wildlife movement by fragmenting habitat, altering wildlife migration and use of habitat, while also being a danger to wildlife and humans caused by wildlife-vehicle interactions. To mitigate wildlife mortality on highway sections and to minimize death and injury to motorists as well, road ecologists have proposed structures adapted for the safe passage of wildlife across roads. In this study, photographic sampling was conducted using trail cameras to quantify wildlife activity and use of existing culverts, bridges, and drainages within 2 separate sections of Mexico Federal Highway 2 where previous field assessment had observed high levels of activity. These sections are important areas for the conservation of wildlife, and they are known to be biological corridors for rare species of concern such as jaguar, black bear, and ocelot. The trail cameras were operated for 1 year to document the annual cycle of wildlife movement through the area. With the photographs obtained, a database was created containing the information from each wildlife-culvert interaction. Prior to sampling, an inventory of existing culverts was conducted that measured height, width, volume, and surrounding habitat to assign a hypothesized use quality index. After testing for significant differences in use index among culverts, we recognized that all culverts were equally important for moving wildlife, and that there were no significant differences in the use of culverts by the quality index.