Mountain Lions Transform Ecosystem at Jasper Ridge

A recent Stanford University study published on September 17, 2026, in Ecology and Evolution revealed that visiting mountain lions transformed an entire ecosystem at the Jasper Ridge Biological Preserve, located about 45 miles south of San Francisco. Researchers combined motion-activated camera records from 2015 to 2020 with vegetation surveys to analyze how top predators influence small protected habitats. The study demonstrated that increased mountain lion presence triggered trophic cascades, causing deer activity to drop and young oak trees to flourish. Furthermore, mid-sized predators such as coyotes and bobcats decreased their activity to avoid the apex predators, while fox populations increased and subsequently suppressed rabbit activity. Senior author Elizabeth Hadly and lead author Chinmay Sonawane emphasized that small preserves, which make up about 82 percent of protected areas smaller than 5 square kilometers in the United States, still possess significant ecological value when connected to large wilderness areas like the Santa Cruz Mountains. The findings highlight the importance of maintaining fully functioning ecosystems containing top predators, even in suburban or urbanized settings, despite the pervasive influence of human activity acting as the ultimate apex predator.