Effects of Urbanization and Habitat Fragmentation on Bobcats and Coyotes in Southern California

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Abstract
Urbanization and habitat fragmentation are major threats to wildlife populations, especially mammalian carnivores. We studied the ecology and behavior of bobcats (   Lynx rufus ) and coyotes ( Canis latrans ) relative to development in a fragmented landscape in southern California from 1996 to 2000. We captured and radiocollared 50 bobcats and 86 coyotes, determined home ranges for 35 bobcats and 40 coyotes, and measured their exposure to development ( “urban association” ) as the percentage of each home range composed of developed or modified areas. Both species occupied predominantly natural home ranges. Adult female bobcats had low levels of urban association, significantly lower than coyotes, adult male bobcats, and young female bobcats. Home‐range size was positively correlated with urban association for coyotes and adult male and young female bobcats, suggesting that human‐dominated areas were less suitable than natural areas in some important way. Animals more associated with non‐natural areas had higher levels of night activity, and both bobcats and coyotes were more likely to be in developed areas at night than during the day. Survival rates were relatively high and were not related to urban association, at least for animals>6–9 months of age. Mortality rates from human‐related causes such as vehicle collisions and incidental poisoning were also independent of urban association. In this region, even the few animals that had almost no human development within their home range were vulnerable to human‐related mortality. Carnivore conservation in urban landscapes must account for these mortality sources that influence the entire landscape, including reserves. For bobcats, preserving open space of sufficient quantity and quality for adult females is necessary for population viability. Educating local residents about carnivores is also critical for conserving populations in urban areas.