Western Fence Lizard
The Western fence lizard (Sceloporus occidentalis) is a relatively common and widespread lizard in Southern California. It is larger and prefers less open habitat than the related side-blotched lizard, yet USGS and National Park Service biologists are finding signs of genetic isolation in both species. As urban development fragmented the Santa Monica Mountains scrubland into isolated "habitat islands", wildlife populations have also become genetically isolated as individuals are unable cross urban barriers to breed with neighboring members of their own species. Genetic isolation and loss of genetic diversity can lead to greater risk of a species' extinction.