Build it and They Will Come: Response of the California Red-Legged Frog (Rana Draytonii) to Habitat Restoration in Baja California

Abstract

The California red-legged frog (Rana draytonii) is a large frog native to California, USA and northern Baja California, Mexico that predominantly inhabits slower-moving permanent water sources such as streams, lakes, marshes, ponds, and ephemeral drainages in valley bottoms and foothills, as well as adjacent upland habitats. However, range-wide population decline of the species has been substantial, and today it is estimated that the species occupies less than 30% of its historical range. In Mexico, California red-legged frog populations are declining dramatically, primarily from anthropogenic stresses, including ground-water mining, habitat conversion, and spread of exotic species. To improve habitat conditions for the species in the Sierra San Pedro Martir mountain range, a local non-profit conservation organization, along with international partners, created new pond and wetland habitat, and enhanced habitat along an existing stream with California red-legged frogs in 2018, and annual wetland management has occurred since then. Annual field surveys for California red-legged frogs and their egg masses were conducted from 2013 to 2023 at multiple locations. The annual population surveys suggest California red-legged frog populations have been increasing at the restoration site since 2018. From these data, I found that habitat restoration and maintenance may effectively increase local populations of California red-legged frog in Baja California. These observations suggest that funding from international partners to support conservation efforts like this one may be an effective means of positively impacting threatened species over a relatively short period of time.