Julie Yee
Biography
Dr. Julie Yee is a Research Statistician with the Western Ecological Research Center (WERC). Since 1997, she has used statistics and biometry for WERC to quantitatively analyze and interpret a variety of aspects of wildlife and plant population dynamics, such as recruitment, growth, survival, and wildlife movement. Her research has been applied to study the effects of renewable energy, contaminants, fire, and other influences on wildlife populations and ecosystems. She is currently a PI at the Santa Cruz field station where she supervises continued work on sea otter and nearshore research.
RESEARCH INTERESTS
- Frequentist and Bayesian statistical analysis
- Survival analysis
- Population dynamics
- Mark-recapture
- State-space modeling
- Integrated population modeling
- High performance computing
EDUCATION
- Ph.D., 1997, Statistics with Emphasis in Biostatistics, University of California, Davis.
- Dissertation Title: Asymptotic Approximations to Bayesian Posterior Distributions in Survival Problems with Incomplete Data
- M.S., 1993, Statistics, University of California, Davis
- B.S., 1991, Mathematics, California Institute of Technology
Science and Products
Population Biology and Behavior of Sea Otters
WERC's sea otter researchers are developing and utilizing a variety of methodological and analytical tools to understand the causes of biological and ecological trends in sea otter populations, and to predict the ecological consequences of management practices on these populations and their ecosystems.
California Sea Otter Surveys and Research
WERC collaborates with other research scientists to conduct annual population surveys of the southern sea otter -- a federally listed threatened species. In coordination with the California Department of Fish and Game and other institutions, ongoing surveys and research continues to inform the southern sea otter recovery plan for the U.S. Fish and Wildlife Service, and contributes to our...
Pacific Nearshore Project
Sea otters are crucial indicators of the health of our nearshore waters and coastal resources, from kelp forests to fisheries. What clues does the sea otter's decline hold for our knowledge of ecosystem and global change? WERC's sea otter team and U.S. and Canadian researchers have teamed together to investigate.
Relevance to USGS Missions:
This research project has direct...
California Sea Otter Stranding Network
The California Sea Otter Stranding Network is part of the USGS effort to monitor southern sea otters (Enhydra lutris nereis) and provide data to the U.S. Fish and Wildlife Service. WERC's sea otter team works with multiple institutions and partners to report, recover, and examine stranded sea otters. In addition, instructions on how to report a stranded sea otter are included in this webpage...
Santa Cruz Field Station
Scientists at the Santa Cruz Field Station study sea otters and seabirds in their environment. The USGS Western Ecological Research Center has two research missions based in the Santa Cruz region:
Annual California sea otter stranding data
The California Sea Otter Stranding Network is part of the USGS effort to monitor southern sea otters (Enhydra lutris nereis) and provide data to the U.S. Fish and Wildlife Service. Since 1985, stranded otters from throughout their California coastal range have been collected and analyzed to inform resource management on recovery and conservation of the species.
Annual sea otter survey data
WERC scientists conduct annual population surveys of the southern sea otter, a federally listed threatened species. Download annual survey data from 1985 to present.
Waterfowl use of wetland habitats informs wetland restoration designs for multi‐species benefits
Extensive global estuarine wetland losses have prompted intensive focus on restoration of these habitats. In California, substantial tracts of freshwater, brackish and tidal wetlands have been lost. Given the anthropogenic footprint of development and urbanization in this region, wetland restoration must rely on conversion of existing habitat...
Casazza, Michael L.; McDuie, Fiona; Jones, Scott; Lorenz, Austen; Overton, Cory T.; Yee, Julie L.; Feldheim, Cliff L.; Ackerman, Joshua T.; Thorne, Karen M. Body condition of wintering Pacific greater white-fronted geese
Extreme changes to key waterfowl habitats in the Klamath Basin (KB) on the Oregon–California border and the Sacramento Valley (SV) in California, USA, have occurred since 1980. The spatial distribution of Pacific greater white‐fronted geese (Anser albifrons sponsa; geese) has likewise changed among these areas and population size has grown from 79...
Skalos, Daniel A; Eadie, John M.; Yparraguirre, Daniel R; Weaver, Melanie L; Oldenburger, Shaun L.; Ely, Craig R.; Yee, Julie L.; Fleskes, Joseph P. Habitat features predict carrying capacity of a recovering marine carnivore
The recovery of large carnivore species from over‐exploitation can have socioecological effects; thus, reliable estimates of potential abundance and distribution represent a valuable tool for developing management objectives and recovery criteria. For sea otters (Enhydra lutris), as with many apex predators, equilibrium abundance is not constant...
Tinker, M. Tim; Yee, Julie L.; Laidre, Kristin L.; Hatfield, Brian; Harris, Michael D.; Tomoleoni, Joseph; Bell, Tom W.; Saarman, Emily; Carswell, Lilian P; Miles, A. Keith Feral burros and other influences on desert tortoise presence in the western Sonoran Desert
Across the globe, conflicting priorities exist in how land and resources are managed. In the American West, conflicts are common on public lands with historical mandates for multiple uses. We explored the impacts of multiple uses of land in a case study of Agassiz's Desert Tortoises (Gopherus agassizii), a federally threatened species, in the...
Berry, Kristin H.; Yee, Julie L.; Lyren, Lisa L.
Southern (California) sea otter population status and trends at San Nicolas Island, 2017–2020
The southern sea otter (Enhydra lutris nereis) population at San Nicolas Island, California, has been monitored annually since the translocation of 140 sea otters to the island was completed in 1990. Monitoring efforts have varied in frequency and type across years. In 2017, the U.S. Navy and the U.S. Fish and Wildlife Service initiated a sea...
Yee, Julie L.; Tomoleoni, Joseph A.; Kenner, Michael C.; Fujii, Jessica; Bentall, Gena B.; Tinker, M. Tim; Hatfield, Brian B. The distribution of woody species in relation to climate and fire in Yosemite National Park, California, USA
BackgroundThe effects of climate on plant species ranges are well appreciated, but the effects of other processes, such as fire, on plant species distribution are less well understood. We used a dataset of 561 plots 0.1 ha in size located throughout Yosemite National Park, in the Sierra Nevada of California, USA, to determine the joint effects of...
van Wagtendonk, Jan W.; Moore, Peggy E; Yee, Julie L.; Lutz, James A. Good prospects: High-resolution telemetry data suggests novel brood-site selection behavior in waterfowl
Breeding success should increase with prior knowledge of the surrounding environment, which is dependent upon an animal’s ability to evaluate habitat. Prospecting for nesting locations and migratory stop-over sites are well-established behaviors among bird species. We assessed whether ducks in Suisun Marsh, California, USA, a brackish marsh,...
Casazza, Michael L.; McDuie, Fiona; Lorenz, Austen; Keiter, David A.; Yee, Julie L.; Overton, Cory T.; Peterson, Sarah H.; Feldheim, Cliff L.; Ackerman, Joshua T. Assessing population-level consequences of anthropogenic stressors for terrestrial wildlife
Human activity influences wildlife. However, the ecological and conservation significances of these influences are difficult to predict and depend on their population‐level consequences. This difficulty arises partly because of information gaps, and partly because the data on stressors are usually collected in a count‐based manner (e.g., number of...
Katzner, Todd E.; Braham, Melissa A.; Conkling, Tara; Diffendorfer, James E.; Duerr, Adam E.; Loss, Scott R.; Nelson, David M.; Vander Zanden, Hannah B.; Yee, Julie L. An uncertain future for a population of desert tortoises experiencing human impacts
We evaluated the status of a population of Mojave Desert Tortoises (Gopherus agassizii), a threatened species, in the El Paso Mountains of the northwestern Mojave Desert in California, USA. The study area lies north of and adjacent to a designated critical habitat unit for the species, is adjacent to a state park, and is a short distance from the...
Berry, Kristin H.; Yee, Julie L.; Lyren, Lisa L.; Mack, Jeremy S Detection probabilities of bird carcasses along sandy beaches and marsh edges in the northern Gulf of Mexico
We estimated detection probabilities of bird carcasses along sandy beaches and in marsh edge habitats in the northern Gulf of Mexico to help inform models of bird mortality associated with the Deepwater Horizon oil spill. We also explored factors that may influence detection probability, such as carcass size, amount of scavenging,...
Zimmerman, Guthrie S.; Varela, Veronica; Yee, Julie L.
Trends in mammalian predator control trapping events intended to protect ground-nesting, endangered birds at Haleakalā National Park, Hawaiʻi: 2000–14
Predation and habitat degradation by non-native species are principal terrestrial threats to the federally endangered Hawaiian Petrel (ʻuaʻu, Pterodroma sandwichensis) and Hawaiian Goose (nēnē, Branta sandvicensis) within Haleakalā National Park (HALE), Maui, Hawaiʻi. Since 1981, HALE has maintained a network of live traps to control invasive...
Kelsey, Emily C.; Adams, Josh; Czapanskiy, Max F.; Felis, Jonathan J.; Yee, Julie L.; Kaholoaa, Raina L.; Bailey, Cathleen Natividad
California sea otter (Enhydra lutris nereis) census results, spring 2019
The 2019 census of southern sea otters (Enhydra lutris nereis), also known as California sea otters, was conducted from early May to early July along the mainland coast of central California and in April at San Nicolas Island in southern California. The range-wide index, defined as the 3-year average of combined counts from the mainland range and...
Hatfield, Brian B.; Yee, Julie L.; Kenner, Michael C.; Tomoleoni, Joseph A.
Annual Southern Sea Otter Census Cancelled Due to Health and Safety Concerns
In light of the ongoing COVID-19 pandemic, the USGS and partners at the California Department of Fish and Wildlife, Monterey Bay Aquarium, and the U.S. Fish and Wildlife Service have decided to cancel this year's annual rangewide southern sea otter census.
Learning From Real-World Experience to Understand Renewable Energy Impacts to Wildlife
A comprehensive analysis of how renewable energy facilities affect wildlife could inform efforts to predict and reduce these impacts. A team of researchers was asked to gain a better understanding of the actual environmental impacts of renewable energy generation on sensitive species and habitats in California.
Demographic Consequences of Human Stressors on Wildlife Populations
Predicting the ecological and conservation significances of human influences on wildlife populations is difficult. However, methodological developments can help make the transition from count-based field data on individuals to rate-based demographic estimates.