Julie Yee
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
Filter Total Items: 52
Changes in breeding population sizes of double-crested Cormorants Phalacrocorax auritus in the Humboldt Bay area, California, 1924–2017
To better understand recent population growth of the Double-crested Cormorant Phalacrocorax auritus along the Pacific coast of North America, we assessed long-term breeding population trends in the Humboldt Bay area, California, using aerial photographic survey data collected since 1989 as well as available prior data. The earliest documentations of breeding (but without nest counts) are from 1924
Authors
Phillip J. Capitolo, Harry R. Carter, Julie L. Yee, Gerard J. McChesney, Michael W Parker, Richard J Young, Richard T. Golightly, W Breck Tyler
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, location on the beach, habitat type, and distance into the marsh. D
Authors
Guthrie S. Zimmerman, Veronica Varela, Julie L. Yee
California sea otter (Enhydra lutris nereis) census results, spring 2018
The 2018 census of southern sea otters (Enhydra lutris nereis) was conducted from late April to mid-May along the mainland coast of central California and in April at San Nicolas Island in southern California. The 3-year average of combined counts from the mainland range and San Nicolas Island was 3,128, a decrease of 58 sea otters from the previous year. The 5-year average trend in abundance, inc
Authors
Brian B. Hatfield, Julie L. Yee, Michael C. Kenner, Joseph A. Tomoleoni, M. Tim Tinker
Body mass, wing length, and condition of wintering ducks relative to hematozoa infection
Waterfowl managers lack information regarding factors that may be reducing the positive response of waterfowl body condition to habitat improvements. Protozoan blood parasites (i.e., hematozoa) are commonly found in birds and have been related to reduced body mass, wing length, and body condition. We studied relationships between 12 measures of hematozoa infection and body mass, wing length, and b
Authors
Joseph P. Fleskes, Andrew M. Ramey, Andrew B. Reeves, Julie L. Yee
Prediction of fish and sediment mercury in streams using landscape variables and historical mining
Widespread mercury (Hg) contamination of aquatic systems in the Sierra Nevada of California, U.S., is associated with historical use to enhance gold (Au) recovery by amalgamation. In areas affected by historical Au mining operations, including the western slope of the Sierra Nevada and downstream areas in northern California, such as San Francisco Bay and the Sacramento River–San Joaquin River Del
Authors
Charles N. Alpers, Julie L. Yee, Joshua T. Ackerman, James L. Orlando, Darrell G. Slotton, Mark C. Marvin-DiPasquale
Increased body mass of ducks wintering in California's Central Valley
Waterfowl managers lack the information needed to fully evaluate the biological effects of their habitat conservation programs. We studied body condition of dabbling ducks shot by hunters at public hunting areas throughout the Central Valley of California during 2006–2008 compared with condition of ducks from 1979 to 1993. These time periods coincide with habitat increases due to Central Valley Jo
Authors
Joseph P. Fleskes, Julie L. Yee, Gregory S. Yarris, Daniel L. Loughman
Egg laying sequence influences egg mercury concentrations and egg size in three bird species: Implications for contaminant monitoring programs
Bird eggs are commonly used in contaminant monitoring programs and toxicological risk assessments, but intra-clutch variation and sampling methodology could influence interpretability. We examined the influence of egg laying sequence on egg mercury concentrations and burdens in American avocets, black-necked stilts, and Forster's terns. The average decline in mercury concentrations between the fir
Authors
Joshua T. Ackerman, Collin A. Eagles-Smith, Mark P. Herzog, Julie L. Yee, C. Alex Hartman
Sampling to estimate population size and detect trends in Tricolored Blackbirds
The Tricolored Blackbird (Agelaius tricolor) is a medium-sized passerine that nests in the largest colonies of any North American landbird since the extinction of the passenger pigeon (Ectopistes migratorius) over 100 years ago (Beedy and Hamilton 1999). The species has a restricted range that occurs almost exclusively within California, with only a few hundred birds scattered in small groups in O
Authors
Robert Meese, Julie L. Yee, Marcel Holyoak
Experimental enhancement of pickleweed, Suisun Bay, California
As mitigation for habitat impacted by the expansion of a pier on Suisun Bay, California, two vehicle parking lots (0.36 ha and 0.13 ha) were restored by being excavated, graded, and contoured using dredged sediments to the topography or elevation of nearby wetlands. We asked if pickleweed (Sarcocornia pacifica L, [Amaranthaceae]) colonization could be enhanced by experimental manipulation on these
Authors
A. Keith Miles, Dirk H. Van Vuren, Danika C. Tsao, Julie L. Yee
The precarious persistence of the endangered Sierra Madre yellow-legged frog Rana muscosa in southern California, USA
We conducted surveys for the Endangered Sierra Madre yellow-legged frog Rana muscosa throughout southern California to evaluate the current distribution and status of the species. Surveys were conducted during 2000–2009 at 150 unique streams and lakes within the San Gabriel, San Bernardino, San Jacinto, and Palomar mountains of southern California. Only nine small, geographically isolated populati
Authors
Adam R. Backlin, Cynthia J. Hitchcock, Elizabeth A. Gallegos, Julie L. Yee, Robert N. Fisher
The critical role of islands for waterbird breeding and foraging habitat in managed ponds of the South Bay Salt Pond Restoration Project, South San Francisco Bay, California
The South Bay Salt Pond Restoration Project aims to restore 50–90 percent of former salt evaporation ponds into tidal marsh in South San Francisco Bay, California. However, large numbers of waterbirds use these ponds annually as nesting and foraging habitat. Islands within ponds are particularly important habitat for nesting, foraging, and roosting waterbirds. To maintain current waterbird populat
Authors
Joshua T. Ackerman, C. Alex Hartman, Mark P. Herzog, Lacy M. Smith, Stacy M. Moskal, Susan E.W. De La Cruz, Julie L. Yee, John Y. Takekawa
Distance to human populations influences epidemiology of respiratory disease in desert tortoises
We explored variables likely to affect health of Agassiz's desert tortoises (Gopherus agassizii) in a 1,183-km2 study area in the central Mojave Desert of California between 2005 and 2008. We evaluated 1,004 tortoises for prevalence and spatial distribution of 2 pathogens, Mycoplasma agassizii and M. testudineum, that cause upper respiratory tract disease. We defined tortoises as test-positive if
Authors
Kristin H. Berry, no longer USGS Ashley A. Coble (formerly Emerson), Julie L. Yee, Jeremy S. Mack, William M. Perry, Kemp M. Anderson, Mary B. Brown
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Filter Total Items: 52
Changes in breeding population sizes of double-crested Cormorants Phalacrocorax auritus in the Humboldt Bay area, California, 1924–2017
To better understand recent population growth of the Double-crested Cormorant Phalacrocorax auritus along the Pacific coast of North America, we assessed long-term breeding population trends in the Humboldt Bay area, California, using aerial photographic survey data collected since 1989 as well as available prior data. The earliest documentations of breeding (but without nest counts) are from 1924AuthorsPhillip J. Capitolo, Harry R. Carter, Julie L. Yee, Gerard J. McChesney, Michael W Parker, Richard J Young, Richard T. Golightly, W Breck TylerDetection 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, location on the beach, habitat type, and distance into the marsh. DAuthorsGuthrie S. Zimmerman, Veronica Varela, Julie L. YeeCalifornia sea otter (Enhydra lutris nereis) census results, spring 2018
The 2018 census of southern sea otters (Enhydra lutris nereis) was conducted from late April to mid-May along the mainland coast of central California and in April at San Nicolas Island in southern California. The 3-year average of combined counts from the mainland range and San Nicolas Island was 3,128, a decrease of 58 sea otters from the previous year. The 5-year average trend in abundance, incAuthorsBrian B. Hatfield, Julie L. Yee, Michael C. Kenner, Joseph A. Tomoleoni, M. Tim TinkerBody mass, wing length, and condition of wintering ducks relative to hematozoa infection
Waterfowl managers lack information regarding factors that may be reducing the positive response of waterfowl body condition to habitat improvements. Protozoan blood parasites (i.e., hematozoa) are commonly found in birds and have been related to reduced body mass, wing length, and body condition. We studied relationships between 12 measures of hematozoa infection and body mass, wing length, and bAuthorsJoseph P. Fleskes, Andrew M. Ramey, Andrew B. Reeves, Julie L. YeePrediction of fish and sediment mercury in streams using landscape variables and historical mining
Widespread mercury (Hg) contamination of aquatic systems in the Sierra Nevada of California, U.S., is associated with historical use to enhance gold (Au) recovery by amalgamation. In areas affected by historical Au mining operations, including the western slope of the Sierra Nevada and downstream areas in northern California, such as San Francisco Bay and the Sacramento River–San Joaquin River DelAuthorsCharles N. Alpers, Julie L. Yee, Joshua T. Ackerman, James L. Orlando, Darrell G. Slotton, Mark C. Marvin-DiPasqualeIncreased body mass of ducks wintering in California's Central Valley
Waterfowl managers lack the information needed to fully evaluate the biological effects of their habitat conservation programs. We studied body condition of dabbling ducks shot by hunters at public hunting areas throughout the Central Valley of California during 2006–2008 compared with condition of ducks from 1979 to 1993. These time periods coincide with habitat increases due to Central Valley JoAuthorsJoseph P. Fleskes, Julie L. Yee, Gregory S. Yarris, Daniel L. LoughmanEgg laying sequence influences egg mercury concentrations and egg size in three bird species: Implications for contaminant monitoring programs
Bird eggs are commonly used in contaminant monitoring programs and toxicological risk assessments, but intra-clutch variation and sampling methodology could influence interpretability. We examined the influence of egg laying sequence on egg mercury concentrations and burdens in American avocets, black-necked stilts, and Forster's terns. The average decline in mercury concentrations between the firAuthorsJoshua T. Ackerman, Collin A. Eagles-Smith, Mark P. Herzog, Julie L. Yee, C. Alex HartmanSampling to estimate population size and detect trends in Tricolored Blackbirds
The Tricolored Blackbird (Agelaius tricolor) is a medium-sized passerine that nests in the largest colonies of any North American landbird since the extinction of the passenger pigeon (Ectopistes migratorius) over 100 years ago (Beedy and Hamilton 1999). The species has a restricted range that occurs almost exclusively within California, with only a few hundred birds scattered in small groups in OAuthorsRobert Meese, Julie L. Yee, Marcel HolyoakExperimental enhancement of pickleweed, Suisun Bay, California
As mitigation for habitat impacted by the expansion of a pier on Suisun Bay, California, two vehicle parking lots (0.36 ha and 0.13 ha) were restored by being excavated, graded, and contoured using dredged sediments to the topography or elevation of nearby wetlands. We asked if pickleweed (Sarcocornia pacifica L, [Amaranthaceae]) colonization could be enhanced by experimental manipulation on theseAuthorsA. Keith Miles, Dirk H. Van Vuren, Danika C. Tsao, Julie L. YeeThe precarious persistence of the endangered Sierra Madre yellow-legged frog Rana muscosa in southern California, USA
We conducted surveys for the Endangered Sierra Madre yellow-legged frog Rana muscosa throughout southern California to evaluate the current distribution and status of the species. Surveys were conducted during 2000–2009 at 150 unique streams and lakes within the San Gabriel, San Bernardino, San Jacinto, and Palomar mountains of southern California. Only nine small, geographically isolated populatiAuthorsAdam R. Backlin, Cynthia J. Hitchcock, Elizabeth A. Gallegos, Julie L. Yee, Robert N. FisherThe critical role of islands for waterbird breeding and foraging habitat in managed ponds of the South Bay Salt Pond Restoration Project, South San Francisco Bay, California
The South Bay Salt Pond Restoration Project aims to restore 50–90 percent of former salt evaporation ponds into tidal marsh in South San Francisco Bay, California. However, large numbers of waterbirds use these ponds annually as nesting and foraging habitat. Islands within ponds are particularly important habitat for nesting, foraging, and roosting waterbirds. To maintain current waterbird populatAuthorsJoshua T. Ackerman, C. Alex Hartman, Mark P. Herzog, Lacy M. Smith, Stacy M. Moskal, Susan E.W. De La Cruz, Julie L. Yee, John Y. TakekawaDistance to human populations influences epidemiology of respiratory disease in desert tortoises
We explored variables likely to affect health of Agassiz's desert tortoises (Gopherus agassizii) in a 1,183-km2 study area in the central Mojave Desert of California between 2005 and 2008. We evaluated 1,004 tortoises for prevalence and spatial distribution of 2 pathogens, Mycoplasma agassizii and M. testudineum, that cause upper respiratory tract disease. We defined tortoises as test-positive ifAuthorsKristin H. Berry, no longer USGS Ashley A. Coble (formerly Emerson), Julie L. Yee, Jeremy S. Mack, William M. Perry, Kemp M. Anderson, Mary B. Brown - News