Susan De La Cruz
Dr. Susan De La Cruz is a Wildlife Biologist with the U.S. Geological Survey's Western Ecological Research Center.
She has over 20 years of wildlife research experience in San Francisco Bay Delta and along the Pacific and Central Flyways and as the senior researcher at the San Francisco Bay Estuary Field Station, she oversees and directs research activities. With Federal, State, University, non-profit, and local partners, she is actively involved in designing, funding, implementing and publishing research on foraging and migration ecology, winter habitat use, survival and contaminant effects in nearshore avian species. Her Ph.D. research focused on how changes in benthic prey resources in the estuary influence winter body condition, subsequent spring migration and cross-seasonal reproduction in surf scoters (Melanitta perspicillata), a declining sea duck species that winters in along the Pacific coast. Other current research includes modeling effects of sea-level rise and geomorphic change on avian foraging ecology and carrying capacity, evaluating the effects of water traffic on avian habitat use and behavior, measuring post-oil spill survival and behavior, determining the value of natural and restored intertidal and subtidal habitats for waterbirds and tidal marsh endemics, assessing impacts of dredge operations on benthic communities, and assessing the effectiveness of sediment augmentation (sediment subsidies) on tidal marsh resiliency.
HIGHLIGHTED PUBLICATIONS
Harris, M.C., Pearce, J.M., Prosser, D.J., White, C.L., Miles, A.K., Sleeman, J.M., Brand, C.J., Cronin, J.P., De La Cruz, S., Densmore, C.L., Doyle, T.W., Dusek, R.J., Fleskes, J.P., Flint, P.L., Guala, G.F., Hall, J.S., Hubbard, L.E., Hunt, R.J., Ip, H.S., Katz, R.A., Laurent, K.W., Miller, M.P., Munn, M.D., Ramey, A.M., Richards, K.D., Russell, R.E., Stokdyk, J.P., Takekawa, J.Y., and Walsh, D.P. 2016. U.S. Geological Survey science strategy for highly pathogenic avian influenza in wildlife and the environment (2016–2020): U.S. Geological Survey Open-File Report 2016–1121, 38 p., http://dx.doi.org/10.3133/ofr20161121.
Mills, K.L., J.K. Gaydos, C.G. Fiorello, E.R. Whitmer, S.E.W. De La Cruz, D.M. Mulcahy, L.I. Vilchis, and M.H. Ziccardi. 2016. Post-release survival and movement of Western Grebes (Aechmophorus occidentalis) implanted with intracoelomic satellite transmitters. Waterbirds 39(2):175-186. http://dx.do
Education and Certifications
University of California, Davis: Ph.D., Ecology, Ecotoxicology Emphasis, December 2010
Dissertation title: Habitat, Diet, and Contaminant Relationships of Surf Scoters Wintering in San Francisco
Texas A&M University: M.S., Wildlife and Fisheries Sciences, December 1998
Thesis title: Screening for Endocrine Disrupting Effects of Xenobiotics in Wildlife Using Oxbow Lakes and Settling
University of California, Davis: B.S., Biological Sciences, December 1992
Science and Products
Selenium Cycling in Salton Sea Wetlands
Avian Influenza Prevalence Correlated to Mercury Concentrations in Wild Waterfowl
New Technologies for Wildlife Tracking
Mercury Accumulation in Waterbirds (Black Rails) Related to Sediment Chemistry in San Francisco Bay Wetlands
Assessing the Benefits and Vulnerability of Current and Future Potential Ecosystem Services of the Nisqually River Delta and other Puget Sound Estuaries
Suisun Marsh Waterfowl and Wildlife Studies
Avian Ecology and Multi-Species Habitat Use in Pacific Coast Estuaries
Wetland Restoration in the San Francisco Bay Delta and Pacific Northwest
Pacific Coast Fisheries GIS Resource Database
San Francisco Bay Benthic Macroinvertebrate Atlas
San Francisco Bay Estuary Field Station
Food Web and Invertebrate Ecology Studies in Pacific Coast Estuaries
Tracking Data for Lesser Scaup (Aythya affinis)
Carbon, Nitrogen, and Sulfur Stable Isotopes from Primary Producers, Invertebrates, and Fish at the Nisqually River Delta, Washington from 2011, 2012, and 2015
Data describing habitat use and availability for wild waterfowl in California, USA
Biofilm Percent Cover Maps in San Francisco Bay, 2020-2022
Data describing infection status and movement ecology of North American waterfowl
Data measuring avian influenza infection, mercury concentration, and body condition in wild waterfowl
Aquatic Prey Resources in Response to Estuary Restoration in Willapa Bay, Washington (2014-2015)
Biological Tissue Data Used to Evaluate Selenium Hazards in the Salton Sea Ecosystem (1984-2020)
Sediment Biogeochemistry and Subsequent Mercury Biomagnification in Wetland Food Webs of the San Francisco Bay, CA (ver. 2.0, December 2023)
Western sandpiper diet composition in south San Francisco Bay, CA
Tidal marsh biomass field plot and remote sensing datasets for six regions in the conterminous United States (ver. 2.0, June 2020)
Temporal Viral Viability Data from Avian Influenza A Viruses Maintained in North American Wetlands Under Experimental and Environmental Conditions
Vulnerability to sea-level rise varies among estuaries and habitat types: Lessons learned from a network of surface elevation tables in Puget Sound
Potential use of poultry farms by wild waterfowl in California's Central Valley varies across space, times of day, and species: implications for influenza transmission risk
Allochthonous marsh subsidies enhances food web productivity in an estuary and its surrounding ecosystem mosaic
Contrasting migratory chronology and routes of Lesser Scaup: Implications of different migration strategies in a broadly distributed species
Evaluating conservation units using network analysis: A sea duck case study
Linking meso-scale spatial variation in methylmercury production to bioaccumulation in tidal marsh food webs
Evaluation of breeding distribution and chronology of North American scoters
Selenium hazards in the Salton Sea environment—Summary of current knowledge to inform future wetland management
Demographics and gross pathology of scoters and scaups killed by the Cosco Busan oil spill in California
Waterfowl recently infected with low pathogenic avian influenza exhibit reduced local movement and delayed migration
Avian influenza antibody prevalence increases with mercury contamination in wild waterfowl
Spatiotemporal changes in influenza A virus prevalence among wild waterfowl inhabiting the continental United States throughout the annual cycle
Science and Products
- Science
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Selenium Cycling in Salton Sea Wetlands
The effect of selenium toxicity on wildlife has been known for more than 50 years. This issue drew particular attention in the 1980s when embryo deformity and mortality was observed in birds at a wildlife refuge in California. Harmful effects from selenium were determined to be connected to irrigation drainage water. As a result, an effort began to monitor levels of selenium in irrigation drainage...Avian Influenza Prevalence Correlated to Mercury Concentrations in Wild Waterfowl
Low pathogenic avian influenza infections were directly correlated with blood mercury concentrations in wild waterfowl, indicating that mercury exposure may be related to pathogen susceptibility. Further study is needed to determine if and how mercury and other environmental contaminant exposures may affect disease susceptibility in wildlife.New Technologies for Wildlife Tracking
Next generation of wildlife tracking using light-weight, 3D printed, waterproof tags.Mercury Accumulation in Waterbirds (Black Rails) Related to Sediment Chemistry in San Francisco Bay Wetlands
The U.S. Geological Survey (USGS) assessed the effect of sediment chemistry, food web structure, and diet on mercury bioaccumulation in black rails in the San Francisco Bay watershed. Differences in mercury accumulation in the birds were related to differences in sediment chemistry in the wetlands.Assessing the Benefits and Vulnerability of Current and Future Potential Ecosystem Services of the Nisqually River Delta and other Puget Sound Estuaries
The Nisqually River Delta represents the largest wetland restoration in the Pacific Northwest. The restoration resulted in a 50% increase in potential salt marsh habitat. The Delta supports threatened salmon fisheries, large populations of migratory birds, and provides unique opportunities for recreation. The Delta also provides multiple ecosystem services, which are the benefits that wildlife orSuisun Marsh Waterfowl and Wildlife Studies
Suisun Marsh provides critical habitat for wintering and breeding waterbirds in California. USGS WERC collaborates with the California Department of Water Resources to examine trends in bird declines and to assess the habitat factors driving long-term survival of waterfowl, rails, and other birds in this important area.Avian Ecology and Multi-Species Habitat Use in Pacific Coast Estuaries
Waterbirds such as shorebirds, waders, and ducks depend on healthy and productive estuaries to “fuel up” for long distance migrations along the Pacific Flyway. Estuarine ecosystems include a mosaic of managed, natural, and restoring wetlands , and provide critical stop-over and wintering areas for federally protected migratory bird species. USGS WERC’s Dr. Susan De La Cruz works with federal...Wetland Restoration in the San Francisco Bay Delta and Pacific Northwest
Estuaries and healthy coastal habitats are among the most productive ecosystems on Earth. They provide a variety of benefits, including habitat and food for fish and wildlife, flood and erosion protection, improved water quality, increased carbon sequestration, as well as beautiful scenery and opportunities for recreation. Along the U.S. Pacific Coast, both the San Francisco Bay estuary and the...Pacific Coast Fisheries GIS Resource Database
Pacific Coast fisheries information is currently available only from wildlife agencies in disparate databases. To maximize the value of these data, the Bureau of Ocean Energy Management, Regulation, and Enforcement and U. S. Geological Survey have combined data from several of these sources into a single, comprehensive database. This gives resource managers a tool to easily extract species or...San Francisco Bay Benthic Macroinvertebrate Atlas
Information on benthic macroinvertebrate populations is currently available from numerous agencies in disparate databases. To maximize the value of these data, San Francisco State University and the U. S. Geological Survey have combined data from several of these sources into a single comprehensive database. To request this database, please contact Dr. Susan De La Cruz (sdelacruz@usgs.gov)San Francisco Bay Estuary Field Station
The San Francisco Bay Field Station is the center of studies on recovering tidal wetland ecosystems and ongoing efforts to balance the restoration of local marshes and the needs of seabirds. Click on the "Science" tab for a comprehensive summary of this station and its research.Food Web and Invertebrate Ecology Studies in Pacific Coast Estuaries
Invertebrate communities provide food for several economically and ecologically important fish and waterbird species in coastal estuaries. Scientists at the WERC San Francisco Bay Estuary Field Station specialize in studying foraging ecology of waterbirds and fishes, general food web dynamics across estuaries, and the effects of habitat restoration and other factors on waterbird prey availability. - Data
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Tracking Data for Lesser Scaup (Aythya affinis)
These location data were collected from a free-ranging species of diving duck, the Lesser Scaup (Aythya affinis), using the Argos Satellite Telemetry System with platform transmitter terminals (PTTs) that were surgically implanted in ducks. Ducks were marked at two breeding areas: Yukon Flats National Wildlife Refuge in Alaska, USA at the northern extent of their distribution (66.51000 degrees N,Carbon, Nitrogen, and Sulfur Stable Isotopes from Primary Producers, Invertebrates, and Fish at the Nisqually River Delta, Washington from 2011, 2012, and 2015
This dataset consists of carbon, nitrogen, and sulfur stable isotope data from primary producers, invertebrates, and fish from the Nisqually River Delta, Washington from 2011, 2012, and 2015. Data were collected to determine food web structure in different habitat zones within the entire river delta. Data collection for primary producers and invertebrates were led by U.S. Geological Survey, whileData describing habitat use and availability for wild waterfowl in California, USA
These data describe the overlap of wild waterfowl and domestic poultry operations in California, USA. These data support a paired USGS publication.Biofilm Percent Cover Maps in San Francisco Bay, 2020-2022
This data release includes 9 GeoTIFF rasters that represent percent cover of intertidal microbial biofilm on the mudflats of South San Francisco Bay, CA between June 2020, and June 2022. Rasters follow the naming scheme biofilmPC_YYYYMMDD_10m.tif, where “biofilmPC” describes the dataset, YYYYMMDD is the date of the image, and 10m is the spatial resolution of the raster. Raster data products were dData describing infection status and movement ecology of North American waterfowl
These data, which support a USGS authored manuscript, describe how active and previous previous infection with avian influenza impacts the movement ecology of several wild waterfowl species that overwinter in California. Results varied by species and demonstrate that the relationships between avian influenza infection and wild bird movements are context- and species-dependent.Data measuring avian influenza infection, mercury concentration, and body condition in wild waterfowl
These data represent mercury contamination, influenza infection, and body condition in 11 species of dabbling and diving ducks in the Pacific Flyway. These data support a USGS lead scientific publication.Aquatic Prey Resources in Response to Estuary Restoration in Willapa Bay, Washington (2014-2015)
The ongoing restoration of more than 200 hectares of estuarine habitat at Willapa National Wildlife Refuge, southwestern Washington, is expected to benefit a variety of species, including salmonids that use estuarine and tidal marshes as rearing and feeding areas as well as migratory waterbirds. During March through June 2014 and 2015, this study was initiated to assess aquatic prey resources. WeBiological Tissue Data Used to Evaluate Selenium Hazards in the Salton Sea Ecosystem (1984-2020)
In response to the rapidly evolving conditions at the Salton Sea with the emergence of both newly formed wetland habitat and increasing hazards to wildlife, the U.S. Bureau of Reclamation and U.S. Geological Survey have funded a re-evaluation of data gaps regarding selenium concentrations in biota the region. As part of this work, selenium concentrations in biological tissue samples were compiledSediment Biogeochemistry and Subsequent Mercury Biomagnification in Wetland Food Webs of the San Francisco Bay, CA (ver. 2.0, December 2023)
Methylmercury (MeHg) is a globally pervasive contaminant that biomagnifies in food webs and can reach toxic concentrations in consumers at higher trophic levels, including wildlife and humans. The production of MeHg, and its subsequent entry and biomagnification in food webs, is governed by a complex suite of biogeochemical, physical, and ecological processes, resulting in spatial variation in theWestern sandpiper diet composition in south San Francisco Bay, CA
Diet composition can be influenced by age- and sex-related factors including an individual's morphology, social status, and acquired skills; however, specialization may only be necessary when competition is intensified by high population densities or increased energetic demands. The western sandpiper is a small (22-35 grams) migratory shorebird that exhibits female-biased sexual size dimorphism wiTidal marsh biomass field plot and remote sensing datasets for six regions in the conterminous United States (ver. 2.0, June 2020)
Remote sensing based maps of tidal marshes, both of their extents and carbon stocks, have the potential to play a key role in conducting greenhouse gas inventories and implementing climate mitigation policies. Our objective was to generate a single remote sensing model of tidal marsh aboveground biomass and carbon that represents nationally diverse tidal marshes within the conterminous United StatTemporal Viral Viability Data from Avian Influenza A Viruses Maintained in North American Wetlands Under Experimental and Environmental Conditions
Data sets containing: (1) sample collection and influenza A virus (IAV) screening information for wild ducks, (2) water temperature data for six North American wetlands, (3) water quality measurement from those wetlands, (4) laboratory-based study of viral viability using Minnesota wetland water, (5) naive mallards challenged experimentally with IAVs identified from the field experiment, and (6) g - Publications
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Vulnerability to sea-level rise varies among estuaries and habitat types: Lessons learned from a network of surface elevation tables in Puget Sound
Estuarine systems that provide valuable ecosystem services to society and important foraging and rearing habitat for fish and wildlife species continue to undergo degradation. In Puget Sound, WA, as much as 70–80% of historic estuarine habitat has been lost to anthropogenic development, and continued losses are expected through the end of the twenty-first century due to rising sea levels. To evaluAuthorsMelanie J. Davis, Katrina L. Poppe, John M. Rybczyk, Eric E. Grossman, Isa Woo, Joshua W. Chamberlin, Michelle Totman, Todd Zackey, Frank Leonetti, Suzanne Shull, Susan E. W. De La CruzPotential use of poultry farms by wild waterfowl in California's Central Valley varies across space, times of day, and species: implications for influenza transmission risk
Interactions between wildlife and livestock can lead to cross-species disease transmission, which incurs economic costs and threatens wildlife conservation. Wild waterfowl are natural hosts of avian influenza viruses (AIVs), are often abundant near poultry farms, and have been linked to outbreaks of AIVs in poultry. Interspecific and seasonal variation in waterfowl movement and habitat use means tAuthorsClaire S. Teitelbaum, Michael L. Casazza, Cory T. Overton, Jeffery D. Sullivan, Elliott Matchett, Fiona McDuie, Austen Lorenz, Josh T. Ackerman, Susan E. W. De La Cruz, Diann ProsserAllochthonous marsh subsidies enhances food web productivity in an estuary and its surrounding ecosystem mosaic
Terrestrial organic matter is believed to play an important role in promoting resilient estuarine food webs, but the inherent interconnectivity of estuarine systems often obscures the origins and importance of these terrestrial inputs. To determine the relative contributions of terrestrial (allochthonous) and aquatic (autochthonous) organic matter to the estuarine food web, we analyzed carbon, nitAuthorsMelanie J. Davis, Isa Woo, Susan E. W. De La Cruz, Christopher S. Ellings, Sayre Hodgson, Glynnis NakaiContrasting migratory chronology and routes of Lesser Scaup: Implications of different migration strategies in a broadly distributed species
Migration allows birds to improve fitness by exploiting seasonal resource peaks and avoiding limitations. Migration strategies may differ among individuals within a species, but for all strategies, the benefit of increased fitness should outweigh the costs of migration. These costs can include increased mortality risk, time constraints in the annual cycle, and metabolic energy loss. We compared miAuthorsLaurie Anne Hall, Christopher J. Latty, Jeffrey M. Warren, John Y. Takekawa, Susan E. W. De La CruzEvaluating conservation units using network analysis: A sea duck case study
Conserving migratory wildlife requires understanding how groups of individuals interact across seasons and landscapes. Telemetry reveals individual movements at large spatiotemporal scales; however, using movement data to define conservation units requires scaling up from individual movements to species- and community-level patterns. We developed a framework to define flyways and identify importanAuthorsJuliet S. Lamb, Clara Cooper-Mullin, Scott Gilliland, Alicia Berlin, Timothy D. Bowman, Sean Boyd, Susan E. W. De La Cruz, Daniel Esler, Joseph R. Evenson, Paul L. Flint, Christine Lepage, Dustin Meattey, Jason Osenkowski, Peter WC Patton, Matthew Perry, Daniel H. Rosenberg, Jean-Pierre L. Savard, Lucas Savoy, Jason Schamber, David Ward, John Takekawa, Scott R. McWilliamsLinking meso-scale spatial variation in methylmercury production to bioaccumulation in tidal marsh food webs
Differences in sediment biogeochemistry among tidal marsh features with different hydrological and geomorphological characteristics, including marsh interiors, marsh edges, first-order channels, and third-order channels, can result in spatial variation in MeHg production and availability. To better understand the link between MeHg production in sediments and bioaccumulation in primary and secondarAuthorsLaurie Anne Hall, Isa Woo, Mark C. Marvin-DiPasquale, John Y. Takekawa, David P. Krabbenhoft, Donald Yee, Letitia Grenier, Susan E. W. De La CruzEvaluation of breeding distribution and chronology of North American scoters
North America's scoter species are poorly monitored relative to other waterfowl. Black Melanitta americana, surf M. perspicillata, and white-winged M. deglandi scoter abundance and trend estimates are thus uncertain in many parts of these species' ranges. The most extensive source of waterfowl abundance and distribution data in North America is the Waterfowl breeding population and habitat surveyAuthorsKristin Bianchini, Scott G. Gilliland, Alicia Berlin, Timothy D. Bowman, W. Sean Boyd, Susan E. W. De La Cruz, Daniel Esler, Joseph R. Evenson, Paul L. Flint, Christine Lepage, Scott R. McWilliams, Dustin E. Meattey, Jason E. Osenkowski, Matthew Perry, Jean-François Poulin, Eric T. Reed, Christian Roy, Jean-Pierre L. Savard, Lucas Savoy, Jason L Schamber, Caleb S. Spiegel, John Takekawa, David H. Ward, Mark L. MallorySelenium hazards in the Salton Sea environment—Summary of current knowledge to inform future wetland management
Quaternary marine and continental shales in the western United States are sources of selenium that can be loaded into the aquatic environment through mining, agricultural, and energy production processes. The mobilization of selenium from shales through agricultural irrigation has been recognized since the 1930s; however, discovery of deformities in birds and other wildlife using agricultural habiAuthorsMichael R. Rosen, Susan E.W. De La Cruz, Krishangi D. Groover, Isa Woo, Sarah A. Roberts, Melanie J. Davis, Cristiana Y. AntoninoDemographics and gross pathology of scoters and scaups killed by the Cosco Busan oil spill in California
Unusual wildlife mortality events provide a unique opportunity to collect information on demographics, disease, and body condition in affected wildlife, which may be useful for informing oil spill damage assessments and future spill responses. In November 2007, the Cosco Busan Oil Spill occurred in San Francisco Bay, California, a globally important wintering area for waterfowl. The spill resultedAuthorsJessie Beck, Ryan D. Carle, HannahRose M. Nevins, Susan E. W. De La Cruz, Erica Donnelly-GreenanWaterfowl recently infected with low pathogenic avian influenza exhibit reduced local movement and delayed migration
Understanding relationships between infection and wildlife movement patterns is important for predicting pathogen spread, especially for multispecies pathogens and those that can spread to humans and domestic animals, such as avian influenza viruses (AIVs). Although infection with low pathogenic AIVs is generally considered asymptomatic in wild birds, prior work has shown that influenza-infected bAuthorsClaire S. Teitelbaum, Michael L. Casazza, Fiona McDuie, Susan E. W. De La Cruz, Cory T. Overton, Laurie Anne Hall, Elliott Matchett, Josh T. Ackerman, Jeffery D. Sullivan, Andrew M. Ramey, Diann ProsserAvian influenza antibody prevalence increases with mercury contamination in wild waterfowl
Environmental contamination is widespread and can negatively impact wildlife health. Some contaminants, including heavy metals, have immunosuppressive effects, but prior studies have rarely measured contamination and disease simultaneously, which limits our understanding of how contaminants and pathogens interact to influence wildlife health. Here, we measured mercury concentrations, influenza infAuthorsClaire Stewart Teitelbaum, Josh T. Ackerman, Mason A. Hill, Jaqueline M. Satter, Michael L. Casazza, Susan E. W. De La Cruz, Walter M. Boyce, Evan James Buck, John M. Eadie, Mark P. Herzog, Elliott Matchett, Cory T. Overton, Sarah H. Peterson, Magdalena Plancarte, Andrew M. Ramey, Jeffery D. Sullivan, Diann ProsserSpatiotemporal changes in influenza A virus prevalence among wild waterfowl inhabiting the continental United States throughout the annual cycle
Avian influenza viruses can pose serious risks to agricultural production, human health, and wildlife. An understanding of viruses in wild reservoir species across time and space is important to informing surveillance programs, risk models, and potential population impacts for vulnerable species. Although it is recognized that influenza A virus prevalence peaks in reservoir waterfowl in late summeAuthorsCody M. Kent, Andrew M. Ramey, Josh T. Ackerman, Justin Bahl, Sarah N. Bevins, Andrew S. Bowman, Walter Boyce, Carol Cardona, Michael L. Casazza, Troy D. Cline, Susan E. W. De La Cruz, Jeffrey S. Hall, Nichola J. Hill, Hon S. Ip, Scott Krauss, Jennifer M. Mullinax, Jacqueline M. Nolting, Magdalena Plancarte, Rebecca L. Poulson, Jonathan A. Runstadler, Richard D. Slemons, David E. Stallknecht, Jeffery D. Sullivan, John Y. Takekawa, Richard J. Webby, Robert G. Webster, Diann J. Prosser - News