Since the main prey of mountain lions are deer, wherever deer are found across western North America, you are likely to find mountain lions as well. The human population is growing rapidly in areas like Southern California, where habitat is becoming increasingly fragmented.
Our studies show that mountain lions have large home ranges with an average of 125 square miles for adult males. Most at risk for human conflict are young males when they leave their mothers, because adult males will not tolerate young males in their territories. Many mountain lions have traveled tremendous distances in order to find new homes. In Southern California, that means crossing roads. Highways across southern California are major barriers and sources of mortality for this species, and are contributing in a substantial way to genetic restriction and the threat of local extinction for smaller isolated populations like those in the Santa Ana Mountains south of Los Angeles. Our research aims to increase understanding of current mountain lion connectivity across the major transportation corridors in the state that separate mountain lion subpopulations. GPS collar data can pinpoint focal locations where engineering interventions, such as new or improved wildlife crossings, can facilitate connections between populations. These crossings, when combined with appropriate fencing, can also reduce the incidence of lions killed by vehicle strike (roadkill), a key component to assuring long term population survival. Because of the increasing awareness of the negative effects of population fragmentation and isolation for mountain lions and other wildlife, we are using our current data, and will use data collected in the future, to advise Caltrans and others on the most effective highway crossing locations and designs.