In recent years southern Sierra Nevada (SSN) forests have experienced rapid environmental change including drought, widespread tree mortality, and mega fires burning over 700,000 acres in 2020-2021 alone. We analyzed 13 years of monitoring data from the US Forest Service’s Sierra Nevada Carnivore Monitoring Program to assess the impacts of these changes on the endangered SSN fisher population and three co-occurring carnivore species (marten, grey fox, ringtail). We used a hierarchical, multi-species occupancy analysis to estimate annual occupancy and detection probabilities incorporating covariates for forest structure tree mortality, fire severity, and climate. We summarized annual occupancy patterns across three regions and three elevation strata. Across the SSN occupancy for fisher and marten fluctuated annually but was relatively stable in some regions but declined significantly for both species on the Sequoia National Forest by 2023. Conversely, by 2022 grey fox occupancy more than doubled compared to the first 3 years of the study. Fisher occupancy also varied across elevation strata with occupancy declining most strongly at low elevations. Fisher occupancy decreased after fire across all fire severity levels, with the greatest decline in areas of high severity fire. However, response to fire varied across species with marten occupancy also declining but grey fox and ringtail occupancy increasing in high severity fire areas. Our results illustrate the value of long-term monitoring data in evaluating the impact of environmental change on wildlife species.