Temporal Trends and Drivers of Mountain Lion Depredation in California, USA

Increasing human populations and expanding development across the globe necessitate continual progress in understanding and mitigating human–wildlife conflict. California, USA has the largest human population and at least half of the state is suitable mountain lion (Puma concolor) habitat. The juxtaposition of high human abundance within and adjacent to mountain lion habitat make California relevant for understanding human–large carnivore conflict. We compiled 7,719 confirmed incidents of mountain lions depredating domestic animals over a 48-year period (1972–2019) to examine temporal trends in mountain lion depredations as well as factors influencing annual depredation rates at the county level. Linear regressions demonstrated that the overall number of depredation events and those involving pets (e.g., dogs [Canis lupus familiaris] and cats [Felis catus]) and small hoofstock (primarily sheep [Ovis aries] and goats [Capra aegagrus hircus]) have increased significantly over time with small hoofstock comprising the majority of depredations. Poisson regression models revealed human density and agricultural productivity were negatively associated with increasing depredation rates while amount of suitable habitat and number of mountain lions removed in the previous year were positively associated with increasing depredation rates. In general, our results point to smaller-sized hoofstock operations in areas of suitable mountain lion habitat as key factors in predicting mountain lion depredations in California. Further, the permanent removal of offending individuals appears to increase the potential for conflict in the following year. Broadly speaking, improving husbandry standards for pets and small hoofstock living in areas occupied by large carnivores may be the most effective way to reduce human–predator conflict in California and elsewhere