Sierra Nevada Carnivore Monitoring Program

A landscape photo of the southern Sierra Nevada Mountain range


The Region 5 Sierra Nevada Carnivore Monitoring Program is a long-term broad-scale population monitoring program to detect potential population declines in fisher (Pekania pennanti) and Pacific marten (Martes caurina) throughout National Forest lands in the Sierra Nevada, with a primary focus on the federally endangered southern Sierra Nevada fisher population.

This program systematically surveys monitoring units using remote sensor cameras, track-plate stations and genetic sampling to detect species and identify individuals. While originally designed to detect changes in occupancy, advances in survey methodology and analytical techniques have expanded the scope of the program to also include monitoring for changes in genetic diversity, population connectivity, species interactions and dietary composition over time.  Monitoring occurs over time at fixed locations and therefore changes in species presence can be correlated with changes in environmental conditions over time, such as wildfire, drought, and tree mortality.

Sierra Nevada Fisher visiting a monitoring stationPacific marten visiting a camera station from the Sierra Nevada Carnivore Monitoring Program












Accomplishments and Future Directions

Over the last 19 years of systematic surveys, the Sierra Nevada Carnivore Monitoring Program has completed >50,000 visits to monitoring stations across the Sierra Nevada.  These surveys provide scientifically defensible data to inform land management, listing decisions and conservation strategies, as well as provide valuable biological information about fisher, marten and other associated carnivore species such as [shown below, species names listed by row left to right] bobcat (Lynx rufus), mountain lion (Puma concolor), gray fox (Urocyon cinereoargenteus), coyote (Canis latrans), black bear (Ursus americana), ringtail (Bassariscus astutus) as well as a variety of small mammal species.

Bobcat visiting a camera station.

Mountain lion visiting a camera station.

Gray fox visiting a camera station.

Coyote visiting a camera station.

Bear visiting a camera station.

Ring-tailed cat visiting a camera station.

This long-term monitoring data provides a unique opportunity to investigate the effects of environmental change on mammalian species at a landscape scale which is especially important given the recent widespread drought, tree mortality, and wildfire in the southern Sierra Nevada.  It is one of the few sources of wildlife occurrence data spatially extensive enough to match the scale and scope of the tree mortality event and this will be a major focus of future work for the monitoring program.
Example of fisher tracks collected at a monitoring track-plate stationExample of fisher tracks collected at a box survey station.
Example of Pacific marten tracks collected at a monitoring track-plate stationExample of pacific marten tracks collected at a box survey station.

 Selected Publications

Tucker, J.M., King, C., Lekivetz, R., Murdoch, R., Jewell, Z.C. and Alibhai, S.K., 2024. Development of a non-invasive method for species and sex identification of rare forest carnivores using footprint identification technologyEcological Informatics79, p.102431.

Rich, L.N., Medel, I.D., Bangen, S., Wengert, G.M., Toenies, M., Tucker, J.M., Gabriel, M.W. and Davis, C.L., 2023. Integrating existing data to assess the risk of an expanding land use change on mammalsLandscape Ecology, pp.1-16.

Smith, G.B., Tucker, J.M. and Pauli, J.N., 2022. Habitat and drought influence the diet of an unexpected mycophagist: fishers in the Sierra Nevada, CaliforniaJournal of Mammalogy103(2), pp.328-338.

Pauli, J.N., Manlick, P.J., Tucker, J.M., Smith, G.B., Jensen, P.G. and Fisher, J.T., 2022. Competitive overlap between martens Martes americana and Martes caurina and fishers Pekania pennanti: a rangewide perspective and synthesisMammal Review52(3), pp.392-409.

Tucker, J.M., Moriarty, K.M., Ellis, M.M. and Golding, J.D., 2021. Effective sampling area is a major driver of power to detect long term trends in multispecies occupancy monitoringEcosphere12(5), p.e03519.

Davis, C.L., Rich, L.N., Farris, Z.J., Kelly, M.J., Di Bitetti, M.S., Blanco, Y.D., Albanesi, S., Farhadinia, M.S., Gholikhani, N., Hamel, S. Harmsen, B.J., J.M. Tucker et al., 2018. Ecological correlates of the spatial co‐occurrence of sympatric mammalian carnivores worldwide. Ecology letters.

Tucker, Jody M.; Allendorf, Fred W.; Truex, Richard L.; Schwartz, Michael K. 2017. Sex-biased dispersal and spatial heterogeneity affect landscape resistance to gene flow in fisher. Ecosphere. 8(6): e01839.

Rich, L.N., Davis, C.L., Farris, Z.J., Miller, D.A., Tucker, J.M., Hamel, S., Farhadinia, M.S., Steenweg, R., Di Bitetti, M.S., Thapa, K. and Kane, M.D., 2017. Assessing global patterns in mammalian carnivore occupancy and richness by integrating local camera trap surveys. Global Ecology and Biogeography. Global Ecology and Biogeography, 26(8), pp.918-929.

Zielinski, William J.; Tucker, Jody M.; Rennie, Kerry M. 2017. Niche overlap of competing carnivores across climatic gradients and the conservation implications of climate change at geographic range margins. Biological Conservation. 209: 533-545.

Ellis, Martha M.; Ivan, Jacob S.; Tucker, Jody M.; Schwartz, Michael K. 2015. rSPACE: Spatially based power analysis for conservation and ecology. Methods in Ecology and Evolution. Methods in Ecology and Evolution. doi: 10.1111/2041-210X.12369.

Tucker, Jody M.; Schwartz, Michael K.; Truex, Richard L.; Wisely, Samantha M.; Allendorf, Fred W. 2014. Sampling affects the detection of genetic subdivision and conservation implications for fisher in the Sierra Nevada. Conservation Genetics. 15(1): 123-136.

Zielinski, William J.; Baldwin, James A.; Truex, Richard L.; Tucker, Jody M.; Flebbe, Patricia A. 2013. Estimating trend in occupancy for the Southern Sierra fisher Martes pennanti population. Journal of Fish and Wildlife Management 4(1); e1944-687X. doi: 10.3996/012012-JFWM-002

Tucker, Jody M.; Schwartz, Michael K.; Truex, Richard L.; Pilgrim, Kristine L.; Allendorf, Fred W. 2012. Historical and contemporary DNA indicate fisher decline and isolation occurred prior to the European settlement of California. PLoS ONE. 7(12): e52803.

Spencer, Wayne; Rustigian-Romsos, Heather; Strittholt, James; Scheller, Robert; Zielinski, William; Truex, Richard. 2011. Using occupancy and population models to assess habitat conservation opportunities for an isolated carnivore population. Biological Conservation 144(2): 788-803

For more Forest Service publications, visit Treesearch.

Contact Information

Stephanie Eyes
Regional Carnivore Monitoring Program Leader

Forest Service, Pacific Southwest Region