The Texas ocelot, an endangered species, is facing threats from historic hunting, habitat loss, inbreeding, and traffic collisions. Only 50-80 ocelots remain in the US, exclusively in Willacy and Cameron counties in southern Texas, which are isolated from the larger population in northwestern Mexico by highways and urban development.
A study in Frontiers in Ecology and Evolution found that a range of species, including middle-sized carnivores like bobcats and coyotes, successfully use wildlife exits, a new mitigation structure specifically designed for the US endangered ocelot.
The Texas Department of Transportation designed novel exits in 2018 to encourage ocelots to leave highways back into nature. The study tested if the wildilfe exits are correctly used by medium-sized carnivores in Texas, using an 11.9-km-long stretch of State Highway 100 between Los Fresnos and Laguna Vista.
In 2018, 10 wildlife exits were installed along the stretch, with two automatic wildlife cameras installed at each exit. The cameras were regularly checked and their images were downloaded and categorized into different species.
A study at a university found that wildlife exits on Texas highways were used by 10 mammal species, including ocelots, bobcats, and coyotes. The exits were designed to prevent wildlife from using them in the wrong direction, but ongoing research aims to improve them.
The study found that ocelots have not been photographed using the exits, but coyotes and bobcats use them correctly, suggesting they are likely to do so. The largest local species, such as white-tailed deer, nilgai, and javelina, were unable to use the exits, and additional mitigating structures like tunnels and crossing grids are installed.
The authors suggest that while highway exits function as intended, ongoing research is focused on improving them to prevent wildlife from using them in the wrong direction. They suggest that wildlife collision mitigation is more cost-effective during construction than retrofitting. The focus should be on endangered species.