Land use change driven by human population expansion continues to impact the integrity and configuration of riparian corridors worldwide. Wildlife viability in semi-arid regions depends heavily on the connectivity of riparian washes, since water is a major limiting resource. In Sonora, Mexico, developments such as the expansion of Federal Highway 2 and the construction of the US-Mexico border wall are constricting wildlife movement throughout the region and disconnecting essential habitat within the Madrean Archipelago biodiversity hotspot. We used camera traps to assess species occupancy, species abundance, and the related environmental variables impacting the use of washes as movement corridors by mammals in the semi-arid woodlands of Cuenca Los Ojos (CLO). CLO is a conservation ranch in Sonora, Mexico located ~5 km south of the border and ~3 km south of Federal Highway 2. From October 2018 to April 2019, we deployed 21 camera traps in four washes along the Cajon Bonito River. We used single-season occupancy models and Royal Nichols abundance models to explore which environmental variables guide the selection of washes as movement corridors by mammals of conservation concern within this region.
Results/Conclusions
Twenty-one mammal species were recorded in the study area, including jaguar (Panthera onca), American black bear (Ursus americanus), white-tailed deer (Odocoileus virginianus), and beaver (Castor canadensis). Washes narrower in width were more important for some species, while most species used sites further from Federal Highway 2. Mountain lion (Puma concolor) had an occupancy probability of 0.95 ± 0.08 in our system, and the top model included wash width, water presence, and distance to river. This relationship was negative but not significant. Bands of coati (Nasua narica) had a similarly high occupancy probability (.998 ± 0.02) with NDVI, distance to road, and elevation all present in the top model. Vertical structure, wash width, water presence, and distance to river were important for coati abundance. These results confirm the importance of protecting a diversity of wash habitats for wildlife use in semi-arid regions. Our data identifies a greater need for the placement of funnel fencing, over- or under-passes, and other forms of mitigation along the highway and border wall to facilitate wildlife connectivity. More research is needed to further explore information about species of conservation concern like jaguar, ocelot, and black bear and how connectivity loss will impact their populations.