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: 55
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
Behavioural cues surpass habitat factors in explaining prebreeding resource selection by a migratory diving duck
Prebreeding habitat selection in birds can often be explained in part by habitat characteristics. However, females may also select habitats on the basis of fidelity to areas of previous reproductive success or use by conspecifics. The relative influences of sociobehavioural attributes versus habitat characteristics in habitat selection has been primarily investigated in songbirds, while less is kn
Authors
Shawn T. O'Neil, Jeffrey M. Warren, John Y. Takekawa, Susan E. W. De La Cruz, Kyle A. Cutting, Michael W. Parker, Julie L. Yee
Protection benefits desert tortoise (Gopherus agassizii) abundance: the influence of three management strategies on a threatened species
We surveyed an area of ∼260 km2 in the western Mojave Desert to evaluate relationships between condition of Agassiz's Desert Tortoise populations (Gopherus agassizii) and habitat on lands that have experienced three different levels of management and protection. We established 240 1-ha plots using random sampling, with 80 plots on each of the three types of managed lands. We conducted surveys in s
Authors
Kristin H. Berry, Lisa M. Lyren, Julie L. Yee, Tracy Y. Bailey
Comparative microhabitat characteristics at oviposition sites of the California red-legged frog (Rana draytonii)
We studied the microhabitat characteristics of 747 egg masses of the federally-threatened Rana draytonii (California red-legged frog) at eight sites in California. our study showed that a broad range of aquatic habitats are utilized by ovipositing R. draytonii, including sites with perennial and ephemeral water sources, natural and constructed wetlands, lentic and lotic hydrology, and sites surrou
Authors
Jeff A. Alvarez, David G. Cook, Julie L. Yee, Michael G. van Hattem, Darren R. Fong, Robert N. Fisher
Net primary productivity of subalpine meadows in Yosemite National Park in relation to climate variability
Subalpine meadows are some of the most ecologically important components of mountain landscapes, and primary productivity is important to the maintenance of meadow functions. Understanding how changes in primary productivity are associated with variability in moisture and temperature will become increasingly important with current and anticipated changes in climate. Our objective was to describe p
Authors
Peggy E. Moore, Jan W. Van Wagtendonk, Julie L. Yee, Mitchel P. McClaran, David N. Cole, Neil K. McDougald, Matthew L. Brooks
Multiple factors affect a population of Agassiz's desert tortoise (Gopherus agassizii) in the Northwestern Mojave Desert
Numerous factors have contributed to declines in populations of the federally threatened Agassiz's Desert Tortoise (Gopherus agassizii) and continue to limit recovery. In 2010, we surveyed a low-density population on a military test facility in the northwestern Mojave Desert of California, USA, to evaluate population status and identify potential factors contributing to distribution and low densit
Authors
Kristin H. Berry, Julie L. Yee, Ashley A. Coble, William M. Perry, Timothy A. Shields
Whole-body concentrations of elements in three fish species from offshore oil platforms and natural areas in the Southern California Bight, USA
There is concern that offshore oil platforms off Southern California may be contributing to environmental contaminants accumulated by marine fishes. To examine this possibility, 18 kelp bass (Paralabrax clathratus Girard, 1854), 80 kelp rockfish (Sebastes atrovirens Jordan and Gilbert, 1880), and 98 Pacific sanddab (Citharichthys sordidus Girard, 1854) were collected from five offshore oil platfor
Authors
Milton S. Love, Michael K. Saiki, Thomas W. May, Julie L. Yee
Mercury assessment and monitoring protocol for the Bear Creek Watershed, Colusa County, California
This report summarizes the known information on the occurrence and distribution of mercury (Hg) in physical/chemical and biological matrices within the Bear Creek watershed. Based on these data, a matrix-specific monitoring protocol for the evaluation of the effectiveness of activities designed to remediate Hg contamination in the Bear Creek watershed is presented. The monitoring protocol document
Authors
Thomas H. Suchanek, Roger L. Hothem, James J. Rytuba, Julie L. Yee
Flightless and post-molt survival and movements of female mallards molting in Klamath Basin
Flightless and post-molt survival and movements were studied during August-May, 2001-2002, 2002- 2003 and 2006-2007 for 181 adult female Mallards (Anas platyrhynchos). Birds were radiotagged just before or early in their flightless period on four wetlands that differed in size on Klamath Basin (KB) National Wildlife Refuge complex. Flightless survival varied among years but was higher on two large
Authors
Joseph P. Fleskes, David M. Mauser, Julie L. Yee, David S. Blehert, Gregory S. Yarris
Factors influencing the at-sea distribution of Cassin's Auklets (Ptychoramphus aleuticus) that breed in the Channel Islands, California
We used radiotelemetry to evaluate at-sea habitat use by Cassin's Auklets (Ptychoramphus aleuticus) that bred at Prince Island, off southern California, from 1999 through 2001. We used logistic regression to compare paired radiotelemetry (presence) with random (pseudo-absence) location-associated habitat variables derived from (1) satellite remote-sensing of sea surface temperature and chlorophyll
Authors
Josh Adams, John Y. Takekawa, Harry R. Carter, Julie L. Yee
Science and Products
Filter Total Items: 55
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
Behavioural cues surpass habitat factors in explaining prebreeding resource selection by a migratory diving duck
Prebreeding habitat selection in birds can often be explained in part by habitat characteristics. However, females may also select habitats on the basis of fidelity to areas of previous reproductive success or use by conspecifics. The relative influences of sociobehavioural attributes versus habitat characteristics in habitat selection has been primarily investigated in songbirds, while less is kn
Authors
Shawn T. O'Neil, Jeffrey M. Warren, John Y. Takekawa, Susan E. W. De La Cruz, Kyle A. Cutting, Michael W. Parker, Julie L. Yee
Protection benefits desert tortoise (Gopherus agassizii) abundance: the influence of three management strategies on a threatened species
We surveyed an area of ∼260 km2 in the western Mojave Desert to evaluate relationships between condition of Agassiz's Desert Tortoise populations (Gopherus agassizii) and habitat on lands that have experienced three different levels of management and protection. We established 240 1-ha plots using random sampling, with 80 plots on each of the three types of managed lands. We conducted surveys in s
Authors
Kristin H. Berry, Lisa M. Lyren, Julie L. Yee, Tracy Y. Bailey
Comparative microhabitat characteristics at oviposition sites of the California red-legged frog (Rana draytonii)
We studied the microhabitat characteristics of 747 egg masses of the federally-threatened Rana draytonii (California red-legged frog) at eight sites in California. our study showed that a broad range of aquatic habitats are utilized by ovipositing R. draytonii, including sites with perennial and ephemeral water sources, natural and constructed wetlands, lentic and lotic hydrology, and sites surrou
Authors
Jeff A. Alvarez, David G. Cook, Julie L. Yee, Michael G. van Hattem, Darren R. Fong, Robert N. Fisher
Net primary productivity of subalpine meadows in Yosemite National Park in relation to climate variability
Subalpine meadows are some of the most ecologically important components of mountain landscapes, and primary productivity is important to the maintenance of meadow functions. Understanding how changes in primary productivity are associated with variability in moisture and temperature will become increasingly important with current and anticipated changes in climate. Our objective was to describe p
Authors
Peggy E. Moore, Jan W. Van Wagtendonk, Julie L. Yee, Mitchel P. McClaran, David N. Cole, Neil K. McDougald, Matthew L. Brooks
Multiple factors affect a population of Agassiz's desert tortoise (Gopherus agassizii) in the Northwestern Mojave Desert
Numerous factors have contributed to declines in populations of the federally threatened Agassiz's Desert Tortoise (Gopherus agassizii) and continue to limit recovery. In 2010, we surveyed a low-density population on a military test facility in the northwestern Mojave Desert of California, USA, to evaluate population status and identify potential factors contributing to distribution and low densit
Authors
Kristin H. Berry, Julie L. Yee, Ashley A. Coble, William M. Perry, Timothy A. Shields
Whole-body concentrations of elements in three fish species from offshore oil platforms and natural areas in the Southern California Bight, USA
There is concern that offshore oil platforms off Southern California may be contributing to environmental contaminants accumulated by marine fishes. To examine this possibility, 18 kelp bass (Paralabrax clathratus Girard, 1854), 80 kelp rockfish (Sebastes atrovirens Jordan and Gilbert, 1880), and 98 Pacific sanddab (Citharichthys sordidus Girard, 1854) were collected from five offshore oil platfor
Authors
Milton S. Love, Michael K. Saiki, Thomas W. May, Julie L. Yee
Mercury assessment and monitoring protocol for the Bear Creek Watershed, Colusa County, California
This report summarizes the known information on the occurrence and distribution of mercury (Hg) in physical/chemical and biological matrices within the Bear Creek watershed. Based on these data, a matrix-specific monitoring protocol for the evaluation of the effectiveness of activities designed to remediate Hg contamination in the Bear Creek watershed is presented. The monitoring protocol document
Authors
Thomas H. Suchanek, Roger L. Hothem, James J. Rytuba, Julie L. Yee
Flightless and post-molt survival and movements of female mallards molting in Klamath Basin
Flightless and post-molt survival and movements were studied during August-May, 2001-2002, 2002- 2003 and 2006-2007 for 181 adult female Mallards (Anas platyrhynchos). Birds were radiotagged just before or early in their flightless period on four wetlands that differed in size on Klamath Basin (KB) National Wildlife Refuge complex. Flightless survival varied among years but was higher on two large
Authors
Joseph P. Fleskes, David M. Mauser, Julie L. Yee, David S. Blehert, Gregory S. Yarris
Factors influencing the at-sea distribution of Cassin's Auklets (Ptychoramphus aleuticus) that breed in the Channel Islands, California
We used radiotelemetry to evaluate at-sea habitat use by Cassin's Auklets (Ptychoramphus aleuticus) that bred at Prince Island, off southern California, from 1999 through 2001. We used logistic regression to compare paired radiotelemetry (presence) with random (pseudo-absence) location-associated habitat variables derived from (1) satellite remote-sensing of sea surface temperature and chlorophyll
Authors
Josh Adams, John Y. Takekawa, Harry R. Carter, Julie L. Yee