Urban landscape attributes affect occupancy patterns of the San Joaquin kit fox during an epizootic

Abstract

The federally endangered and California state threatened San Joaquin kit fox (Vulpes macrotis mutica) persists in relatively high density in the urban environment of Bakersfield, California, USA. Coyotes (Canis latrans), red foxes (V. vulpes), and gray foxes (Urocyon cinereoargenteus) are natural competitors of San Joaquin kit foxes, and their presence in Bakersfield potentially impacts kit foxes. We used annual camera survey data in 111 randomly selected 1-km2 grid cells to investigate the influence of landscape attributes and the presence of canid competitors on San Joaquin kit fox occupancy from 2015 to 2019 in Bakersfield. Of 59 candidate models, our results indicated that occupancy patterns of urban kit foxes were driven primarily by a selection for campuses (e.g. schools, churches, and medical centres), followed by an avoidance of paved roads. Presence of other canids was associated with kit fox presence during surveys but did not have a discernable effect on occupancy, possibly due to a relatively low number of detections. Kit fox occupancy was estimated to have declined by 40% in Bakersfield over the 5-year study, likely due to sarcoptic mange (canis variety skin mite, Sarcoptes scabiei) disease as evidenced by a 37–49% extinction probability as a result of mange. Despite mange, the San Joaquin kit fox population in Bakersfield is one of the largest remaining populations. Awareness of the selection for campuses and avoidance of paved roads by San Joaquin kit foxes can help to develop effective land management and mitigation policy for kit foxes affected by urban development.