In 2001 and 2004, AZGFD helped lead a pair of working groups that identified important areas of habitat connectivity around the state. Biologists identified the Santa Catalina Mountains–Tortolita Mountains linkage as one of several critical landscape connections within Pima County. Working group participants recognized that State Route 77 (SR77), a busy roadway north of Tucson, divided this critical linkage and severely restricted wildlife movements across the landscape. Over the next several years, AZGFD biologists collaborated with natural resource and transportation agencies, NGOs, and landowners to identify areas along SR77 with increased wildlife activity. These studies would help inform where wildlife crossing structures could improve the linkage while also alleviating wildlife-vehicle collisions along the roadway.
In 2009, Pima County Regional Transportation Authority (RTA) approved funding for a large wildlife overpass and underpass across SR77 with associated wildlife fence to guide wildlife to the structures. The Arizona Department of Transportation began upgrades to SR77 within the corridor in 2014, completing redevelopments and construction of the wildlife crossings in April 2016. On April 8th, 2016 AZGFD, with support from the RTA, installed trail cameras at both structures to monitor wildlife crossing trends over time and inform future wildlife crossing recommendations. Today, the wildlife crossing structures across SR 77 are helping to maintain the integrity of an important landscape linkage in the Sonoran Desert.
By the numbers:
More than 12,000 wildlife crossings by 20 species were documented using the crossing structures during the first five years of monitoring. These include:
5,211 mule deer crossings at the wildlife overpass
2,483 javelina crossings at the wildlife underpass
2,029 coyote crossings at the wildlife underpass
Other species commonly documented using the crossing structures include American badger, desert cottontail, white-nosed coati, Gambel’s quail, bobcat, and many more