The fisher is a forest-dwelling carnivore of conservation concern in the southern Sierra Nevada. In recent years, drought followed by extensive tree mortality has dramatically altered the forest in this region. Between 2007 and 2018, we located fisher scat using detection dog teams twice a year in a standardized grid, providing information on fisher space and habitat use prior to and during these climate-induced disturbance events. We found that fisher space-use was positively correlated with live forest prior to the drought, and live forest was strongly associated with areas where fishers persisted during and after disturbance. Fishers persisted in areas with tree mortality if they were already present, but they were unlikely to colonize new areas with tree mortality. The presence of California black oak had a positive influence on space-use at the start of the study and was positively associated with areas where fishers persisted and colonized over time. Fishers were less likely to occur in areas farther from streams. Overall, the proportion of the study area used by fishers declined over time. Our results highlight the value of live forest stands and California black oaks on the landscape if fishers are to persist in this region.