Dr. Eagles-Smith is a Research Ecologist with the Corvallis Reseach Group in Corvallis, Oregon. His research focuses on the interactions among ecological processes, contaminant bioaccumulation, and effects on wild populations. His work specifically focuses on (1) the ecological factors regulating contaminant bioaccumulation and trophic transfer, with an emphasis on food web processes and contaminant cycling, (2) land use practices and ecosystem restoration effects on contaminant cycling through food webs, and (3) the sublethal effects of contaminants on individuals and contaminant-induced impairment to reproduction in the wild. Dr. Eagles-Smith's research is broadly applied across taxa (primarily fish and waterbirds) and habitat types (including lakes, freshwater wetlands, agricultural fields, and estuarine habitats).
Education
Ph.D. Ecology. University of California, Davis (2006)
B.S. (Magna Cum Laude) Env. Resource Sciences.
University of California, Davis (2000)
Professional Experience
Supervisory Research Ecologist, USGS, FRESC, Corvallis Research Group (8/07-3/2010).
Wildlife Biologist, USGS, WERC, UC Davis Field Station (8/07-3/2010).
Senior Biologist, US Fish and Wildlife Service, Sacramento (2/07-8/07).
Staff Biologist, US Fish and Wildlife Service, Sacramento (2/03-2/07).
Doctoral Research, Dept. of Wildlife, Fish and Cons. Biology, UC Davis (9/00-11/06).
Staff Research Assistant, Dept. of Wildlife, Fish and Cons. Biology, UC Davis (2/98-9/00).
Research Interests
Stable isotope applications to ecosystem energetics, food web ecology, fish and avian foraging ecology, mercury bioaccumulation in aquatic food webs, mercury effects on waterbirds, mercury bioaccumulation in waterbirds, avian reproductive ecology.
In a comprehensive overview, scientists explain that human and wildlife exposure and toxicological responses to mercury are dependent on factors that operate across global, individual, and molecular scales. They provide a roadmap for unified research to facilitate a better understanding of human and wildlife health risks from mercury exposure.
In a study designed to help resource managers when considering mercury exposure risk, scientists determined that sulfur cycling—a process closely related to mercury methylation rates—and ecological conditions that influence exposure are important factors affecting fish mercury concentrations in estuarine wetlands.
Proposed new coal export terminals in Washington and Oregon could increase rail traffic through the Northwest and potentially increase unintended release of coal dust to the environment.
The FRESC Contaminant Ecology research program evaluates the distribution, movement, and ecological effects of environmental contaminants across the landscape and strives to provide relevant science in support of natural resource conservation, management, and decision making.
Mercury contamination is a serious issue that impacts both ecosystem and human health on a global scale. In its organic (methylmercury) form, mercury is highly bioaccumulative and is among the most toxic compounds commonly found in the environment. Mercury is a relatively distinctive contaminant in the sense that the risk of deleterious environmental effects is more strongly related to...
The distribution and occurrence of contaminants and the associated biological exposure in ecological systems are driven by complex interactions between contaminant sources and mobilization pathways that are overlaid upon the habitat requirements of at-risk organisms. Moreover, landscape structure and land uses can strongly influence the driving processes of contaminant cycling, as well as the...
Whereas the other themes of the Contaminant Ecology Research Program focus on where, why, and how contaminants cycle and bioaccumulate in ecological systems, this theme is focused on determining what happens at environmentally relevant concentrations.
This is a broad theme representing the largest component of the Contaminant Ecology Research Program, acting as a bridge between the “Habitat and Land Use Influences” and “Ecological Effects” themes. “Contaminant Bioaccumulation” focuses on quantifying the transfer or movement of contaminants through food webs, and identifying the primary landscape factors and ecological mechanisms that are...
Body symmetry of Forster's terns (Sterna forsteri) in San Francisco Bay was related to blood and feather mercury concentrations. Body asymmetry can affect a bird's fitness by reducing flight efficiency, thus increasing energetic costs (especially during migration) and interrupting normal feeding and breeding behaviors.
A creative combination of radiography and techniques borrowed from meat processing and gold prospecting led to a better method for determining the lead content in ground squirrels shot by hunters to evaluate potential exposure risk to avian scavengers such as golden eagles (Aquila chrysaetos).
The unique combination of natural processes and human activities present in western North America can strongly affect the exposure of fish and birds to methylmercury, the most toxic form of mercury (Hg).
Mercury (Hg) is a serious environmental problem that is impacting ecological and human health on a global scale. However, local and regional processes are largely responsible for producing methylmercury, which drives ecological risk. This is particularly true in western North America where the combination of diverse landscapes, habitat types, climates, and Hg sources may disproportionally...
In order to document potential environmental health risk in Cosumnes River Preserve wetlands due to mercury, we analyzed dragonfly larvae, western mosquitofish, and tree swallow eggs collected from wetlands and rice fields of the Preserve from 2011 to 2013.
The dataset includes the bird species, sex, mercury concentration in breast feathers and whole blood, and the composite measure of fluctuating asymmetry. Statistical models were developed for each species to analyze the relationship between mercury exposure in either breast feathers or whole blood and the composite measure of fluctuating asymmetry, while accounting for the sex of each bird....
The dataset includes specifics on fragments of bullets recovered from shot Belding's ground squirrels from Oregon and California. Ground squirrels were radiographed and then we used ImageJ software to count and measure the area of those bullet fragments.
This dataset contains data on the length, mass, and muscle total mercury concentration of Brown Trout (Salmo trutta) and Rainbow Trout (Oncorhynchus mykiss) collected from the Colorado River in Glen Canyon National Recreation Area (GLCA) and Grand Canyon National Park (GRCA), and Bright Angel Creek in GRCA.
Timber harvest has many effects on aquatic ecosystems, including changes in hydrological, biogeochemical, and ecological processes that can influence mercury (Hg) cycling. Although timber harvest’s influence on aqueous Hg transformation and transport are well studied, the effects on Hg bioaccumulation are not. We evaluated Hg bioaccumulation,...
Willacker, James; Eagles-Smith, Collin A.; Kowalski, Brandon M; Danehy, Robert J; Jackson, Allyson K.; Adams, Evan M.; Evers, David C.; Eckley, Chris S.; Tate, Michael T.; Krabbenhoft, David P. Although feathers are commonly used to monitor mercury (Hg) in avian populations, their reliability as a sampling matrix has not been thoroughly assessed for many avian species, including most songbirds (Order Passeriformes). To better understand relationships between total Hg (THg) concentrations in feathers and other tissues for birds in the...
Low, Katherine E.; Ramsden, Danielle K.; Jackson, Allyson K.; Emery, Colleen; Robinson, W. Douglas; Randolph, Jim; Eagles-Smith, Collin A. Mercury (Hg) loading and methylation in aquatic systems causes a variety of deleterious effects for fish and wildlife populations. Relatively little research has focused on Hg movement into riparian food webs and how this is modulated by habitat characteristics. This study characterized differences in Hg exposure in aquatic invertebrates and...
Jackson, Allyson K.; Eagles-Smith, Collin A.; Emery, Colleen Methylmercury (MeHg) bioaccumulation in freshwater aquatic systems is impacted by anthropogenic stressors, including climate change and nutrient enrichment. The goal of this study was to determine how warmer water temperatures and excess nutrients would alter zooplankton communities and phytoplankton concentrations, and whether those changes would...
Jordan, Meredith P; Stewart, Robin; Eagles-Smith, Collin A.; Stracker, Angela L Land-use activities can alter hydrological and biogeochemical processes that can affect the fate, transformation, and transport of mercury (Hg). Previous studies in boreal forests have shown that forestry operations can have profound, but variable effects on Hg export and methylmercury (MeHg) formation. The Pacific Northwest is an important...
Eckley, Chris S.; Eagles-Smith, Collin A.; Tate, Michael T.; Kowalski, Brandon M; Danehy, Robert; Johnson, Sherri L; Krabbenhoft, David P. Mercury (Hg) and lead (Pb) are widespread contaminants that pose risks to avian scavengers. In fact, Pb exposure is the primary factor limiting population recovery in the endangered California condor (Gymnogyps californianus) and Hg can impair avian reproduction at environmentally relevant exposures. The Pacific Northwest region of the...
Herring, Garth; Eagles-Smith, Collin A.; Varland, Daniel E. Mercury is a global pollutant released into the biosphere by varied human activities including coal combustion, mining, artisanal gold mining, cement production, and chemical production. Once released to air, land and water, the addition of carbon atoms to mercury by bacteria results in the production of methylmercury, the toxic form that...
Chen, Celia Y.; Driscoll, Charles T.; Eagles-Smith, Collin A.; Eckley, Chris S.; Gay, David A.; Hsu-Kim, Heileen; Keane, S.E.; Kirk, Jane L.; Mason, Robert; Obrist, Daniel; Selin, Henrik; Selin, Noelle; Thompson, Marcella R.
The Cosumnes River watershed requires a 57–64 percent reduction in loads to meet the new Delta methylmercury (MeHg) total maximum daily load allocation, established by the Central Valley Regional Water Quality Control Board. Because there are no large point sources of MeHg in the watershed, the focus of MeHg load reductions will fall upon non-...
Marvin-DiPasquale, Mark C.; Windham-Myers, Lisamarie; Fleck, Jacob A.; Ackerman, Joshua T.; Eagles-Smith, Collin A.; McQuillen, Harry Lead (Pb) exposure in wildlife is a widespread management and conservation concern. Quantitative determination of Pb concentrations in wildlife tissues is the foundation for estimating exposure and risk. Development of low‐cost, portable instruments has improved access and cost‐effectiveness of determining Pb concentrations in blood samples, while...
Herring, Garth; Eagles-Smith, Collin A.; Bedrosian, Bryan; Craighead, Derek; Domenech, Robert; Langner, Heiko W.; Parish, Chris N.; Shreading, Adam; Welch, Alacia; Wolstenholme, Rachel Predators sample the available prey community when foraging; thus, changes in the environment may be reflected by changes in predator diet and foraging preferences. We examined Forster’s tern (Sterna forsteri) prey species over an 11-year period by sampling approximately 10,000 prey fish returned to 17 breeding colonies in south San Francisco Bay...
Peterson, Sarah H.; Ackerman, Joshua T.; Eagles-Smith, Collin A.; Herzog, Mark P.; Hartman, C. Alex Mercury (Hg) is a non-essential, toxic metal that is distributed worldwide. Mercury biomagnifies in food webs and can threaten the health of top predators such as seabirds. The Kittlitz's murrelet (Brachyramphus brevirostris) is a seabird endemic to Alaska and the Russian Far East and is a species of conservation concern in the region. We...
Kenney, Leah A.; Kaler, Robb S.; Kissling, Michelle L.; Bond, Alexander L.; Eagles-Smith, Collin A. Environmental mercury (Hg) contamination is an urgent global health threat. The complexity of Hg in the environment can hinder accurate determination of ecological and human health risks, particularly within the context of the rapid global changes that are altering many ecological processes, socioeconomic patterns, and other factors like...
Eagles-Smith, Collin A.; Silbergeld, Ellen K.; Basu, Niladri; Bustamante, Paco; Diaz-Barriga, Fernando; Hopkins, William A.; Kidd, Karen A.; Nyland, Jennifer F.
Land use change is an important driver of global mercury cycling. Timber harvest is a common land use that can alter associated aquatic ecosystems, yet little is known about how it affects mercury concentrations and associated food web changes.
Amphibian decline is a global conservation crisis driven by multiple interacting stressors, which often act at a local scale with global implications.
Although feathers are commonly used to monitor mercury in birds, their reliability has not been assessed for many avian species, including most songbirds.
The Willamette River basin in western Oregon is a system with legacy mercury contamination from both mining and reservoirs
Potential reintroduction of the endangered California Condor to parts of its historic range in the Pacific Northwest would benefit from information on possible threats that could challenge recovery efforts. Exposure to environmental contaminants is a key limiting factor for condor recovery in its southern range.
Mercury is a widespread pollutant that poses health risks to humans and wildlife at a global scale. Addressing these risks requires science-based integrated policy approaches.
The Cosumnes River watershed has seasonal, non-point source hotspots for total mercury and methylmercury production, which discharge to the Sacramento-San Joaquin River Delta in north-central California. To reduce mercury loads to the Delta, researchers created open-water deep cells at the downstream end of wetlands.
Lead exposure in wildlife is a widespread management and conservation concern. Low-cost, portable lead analyzers have improved access and cost-effectiveness of determining lead concentrations in animal blood samples, yet analytical bias and lack of quality-assurance–quality-control measures can confound results.
USGS author Collin Eagles-Smith led an invited synthesis paper as part of the plenary effort for the 13th International Conference on Mercury as a Global Contaminant.
Timber harvest is a significant driver of mercury releases in some parts of the world. Yet, the impact of forest harvest on mercury mobilization has not been directly studied in the Pacific Northwest despite being an important timber producing region that also receives high atmospheric mercury deposition.
Mercury contamination is widespread, at various levels across western North America in air, soil, sediment, plants, fish and wildlife.