I am a Biologist with USGS, Western Ecological Research Center. My research focuses on estuaries, restoration research, and monitoring in the San Francisco Bay and Puget Sound ecosystems.
With over 10 years of experience leading the Wetland Restoration Program at USGS San Francisco Bay Estuary Field Station, I have been fortunate to have worked in amazing wetlands, including the Alaskan tundra, Mo'orea mangroves, Wisconsin lacustrine wetlands, and coastal and tidal marshes in San Francisco Bay and Puget Sound. At USGS, I have helped developed, implemented, and established new tools to track restoration change (i.e., remote sensing, RTK GPS mapping, bathymetry system, remote logger network) as well as establish the benthic ecology laboratory. As a cohesive team, we provide science support to land managers with assessments of early phase estuarine restorations within a long term monitoring framework (incorporating Climate Change and Blue Carbon data needs).
We work closely with Federal, Tribal, and State managers so that applied research addresses adaptive management priorities on a variety of topic areas such as: restoration effectiveness, USFWS Tidal Marsh Recovery Plan species and habitats, benthic invertebrate prey availability and carrying capacity for shorebirds, juvenile salmonid invertebrate prey within habitat mosaics within a restored estuary, benthic invertebrate colonization along elevation gradients, methylmercury in tidal marsh, food webs, and inundation and salinity effects on plants. The manuscript Woo and Zedler 2002 was selected as one of the top 30 papers in the past 30 years in the international journal Wetlands (http://www.springer.com/life+sciences/ecology/journal/13157?detailsPage=press)
I am also interested in outreach and education. I co-created an online repository of wetland monitoring www.nisquallydeltarestoration.org, and designed a practitioner’s online guide to monitoring methods http://tidalmarshmonitoring.net/. Our programs have benefitted from student interns (high school to graduate level students) through various internships (e.g., USGS NAGT, SISNAR, and Youth internships, Solano Community College Internships, and Benicia High School Ech2O Academy).
PAST PUBLICATIONS
Davis, M. J., Woo, I., Ellings, C. S., Hodgson, S., Beauchamp, D. A., Nakai, G. and De La Cruz, S. E. W. 2019. Freshwater Tidal Forests and Estuarine Wetlands May Confer Early Life Growth Advantages for Delta‐Reared Chinook Salmon. Trans Am Fish Soc, 148: 289-307. doi:10.1002/tafs.10134
Drexler, J. Z., Woo, I. , Fuller, C. C. and Nakai, G. 2019. Carbon accumulation and vertical accretion in a restored versus historic salt marsh in southern Puget Sound, Washington, United States. Restor Ecol. doi:10.1111/rec.12941
Holmquist, J.R., L. Windham-Myers, N. Bliss, S. Crooks, J.T. Morris, P.J. Megonigal, T. Trox
Science and Products
Recreational Birdwatching and Habitat
Fisheries and Fish Habitat
Marsh Elevation Change and Carbon Sequestration
An Ecosystem Services Assessment of the Nisqually River Delta, South Puget Sound, Washington
NASA-USGS National Blue Carbon Monitoring System
Assessing the Benefits and Vulnerability of Current and Future Potential Ecosystem Services of the Nisqually River Delta and other Puget Sound Estuaries
Wetland Restoration in the San Francisco Bay Delta and Pacific Northwest
Biofilm Percent Cover Maps in San Francisco Bay, 2020-2022
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)
Projected future habitat, elevation change, and carbon accumulation of coastal wetlands in the Nisqually River Delta, Washington
Western sandpiper diet composition in south San Francisco Bay, CA
Small mammal surveys from northern San Francisco Bay: 1998-2014
Historical Time-series Classification of Habitat for 1957, 1980 and 2015 in the Nisqually River Delta, Washington
Linking meso-scale spatial variation in methylmercury production to bioaccumulation in tidal marsh food webs
Selenium hazards in the Salton Sea environment—Summary of current knowledge to inform future wetland management
Assessing small-mammal trapping design using spatially explicit capture recapture (SECR) modeling on long-term monitoring data
Can coastal habitats rise to the challenge? Resilience of estuarine habitats, carbon accumulation, and economic value to sea-level rise in a Puget Sound estuary
A climate-mediated shift in the estuarine habitat mosaic limits prey availability and reduces nursery quality for juvenile salmon
Small shorebirds feast on green slime to fuel their long migration
Age‐ and sex‐related dietary specialization facilitate seasonal resource partitioning in a migratory shorebird
Impacts of periodic dredging on macroinvertebrate prey availability for benthic foraging fishes in central San Francisco Bay, California
Rediscovery of the horseshoe shrimp Lightiella serendipita Jones, 1961 (Cephalocarida: Hutchinsoniellidae) in San Francisco Bay, California, USA, with a key to the worldwide species of Cephalocarida
Carbon sources in the sediments of a restoring vs. historically unaltered salt marsh
Habitat of the endangered salt marsh harvest mouse (Reithrodontomys raviventris) in San Francisco Bay
Disentangling the effects of habitat biogeochemistry, food web structure, and diet composition on mercury bioaccumulation in a wetland bird
Science and Products
- Science
Recreational Birdwatching and Habitat
Thousands of visitors flock to the Billy Frank Jr. Nisqually National Wildlife Refuge every year to look for birds both rare and common. Birdwatching activities contribute to economic activity for the Nisqually area and play a role in the broader outdoor-loving culture of the Pacific Northwest.Fisheries and Fish Habitat
The estuarine habitat of the Delta is critical to the production of salmon, which supports recreational, commercial, and subsistence fishing. The combination of shaded pools, shallow reaches, and a rich prey population provide excellent feeding grounds for juvenile fish. Fishing also holds great importance in the cultural practices of the Nisqually Tribe.Marsh Elevation Change and Carbon Sequestration
Tidal marsh vegetation grows in a narrow elevation zone between sea level and the upland behind it. These plant communities have evolved to accumulate sediment over time and maintain their relative elevation with gradual rates of change in sea level. It is uncertain which marsh vegetation communities will be able to accumulate sediment at a rate that keeps pace with accelerated sea level rise.An Ecosystem Services Assessment of the Nisqually River Delta, South Puget Sound, Washington
Overview of Nisqually River Delta ecosystem services modelingNASA-USGS National Blue Carbon Monitoring System
The NASA-USGS National Blue Carbon Monitoring System project will evaluate the relative uncertainty of iterative modeling approaches to estimate coastal wetland (marsh and mangrove) C stocks and fluxes based on changes in wetland distributions, using nationally available datasets (Landsat) and as well as finer scale satellite and field derived data in six sentinel sites.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 orWetland 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... - Data
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 dAquatic 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 compiledProjected future habitat, elevation change, and carbon accumulation of coastal wetlands in the Nisqually River Delta, Washington
This dataset consists of raster geotiff outputs from modeling habitat change, marsh vertical accretion, and carbon accumulation in the Nisqually River Delta, Washington, USA. These rasters represent projections of future habitat type, change in surface elevation above Mean Sea Level, and total sediment carbon accumulation since 2011 in coastal wetland habitats. Projections were generated in 20-yeaWestern 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 wiSmall mammal surveys from northern San Francisco Bay: 1998-2014
This datasets summarizes small mammal trapping efforts that USGS San Francisco Bay Estuary Field Station has led, co-led, or supervised, to detect and monitor the endangered salt marsh harvest mouse (Reithrodontomys raviventris) in the northern reaches of San Francisco Bay from 1998-2014. As the salt marsh harvest mouse is listed as endangered under the Endangered Species Act, sensitive locationHistorical Time-series Classification of Habitat for 1957, 1980 and 2015 in the Nisqually River Delta, Washington
This USGS Data Release represents geospatial and tabular data for the Nisqually River Delta historical habitat mapping. The data release was produced in compliance with the new 'open data' requirements as a way to make the scientific products associated with USGS research efforts and publications available to the public. The dataset consists of 9 separate items: 1. Forest Change (raster datase - Publications
Filter Total Items: 33
Linking 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 CruzSelenium 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. AntoninoAssessing small-mammal trapping design using spatially explicit capture recapture (SECR) modeling on long-term monitoring data
Few studies have evaluated the optimal sampling design for tracking small mammal population trends, especially for rare or difficult to detect species. Spatially explicit capture-recapture (SECR) models present an advancement over non-spatial models by accounting for individual movement when estimating density. The salt marsh harvest mouse (SMHM; Reithrodontomys raviventris) is a federal and CalifAuthorsChase M. Freeman, Laureen Barthman-Thompson, Robert C. Klinger, Isa Woo, Karen M. ThorneCan coastal habitats rise to the challenge? Resilience of estuarine habitats, carbon accumulation, and economic value to sea-level rise in a Puget Sound estuary
Sea-level rise (SLR) and obstructions to sediment delivery pose challenges to the persistence of estuarine habitats and the ecosystem services they provide. Restoration actions and sediment management strategies may help mitigate such challenges by encouraging the vertical accretion of sediment in and horizontal migration of tidal forests and marshes. We used a process-based soil accretion model (AuthorsMonica Mei Jeen Moritsch, Kristin B. Byrd, Melanie J. Davis, Anthony J. Good, Judith Z. Drexler, James T. Morris, Isa Woo, Lisamarie Windham-Myers, Eric E. Grossman, Glynnis Nakai, Katrina L. Poppe, John M. RybczykA climate-mediated shift in the estuarine habitat mosaic limits prey availability and reduces nursery quality for juvenile salmon
The estuarine habitat mosaic supports the reproduction, growth, and survival of resident and migratory fish species by providing a diverse portfolio of unique habitats with varying physical and biological features. Global climate change is expected to result in increasing temperatures, rising sea levels, and changes in riverine hydrology, which will have profound effects on the extent and compositAuthorsMelanie J. Davis, Isa Woo, Christopher S. Ellings, Sayre Hodgson, David Beauchamp, Glynnis Nakai, Susan E. W. De La CruzSmall shorebirds feast on green slime to fuel their long migration
Shorebirds wade in shallow waters along shorelines searching for food. More than a million shorebirds visit the San Francisco Estuary each year during their migration to feast on the insects, worms, clams, and crabs that live on or under the surface of the sand or mud. The abundant food in the Estuary provides shorebirds with the energy they need to migrate thousands of kilometers, between their bAuthorsLaurie Anne Hall, Susan E. W. De La Cruz, Isa Woo, Tomohiro Kuwae, David Mcgovern Nelson, John Y. TakekawaAge‐ and sex‐related dietary specialization facilitate seasonal resource partitioning in a migratory shorebird
Dietary specialization is common in animals and has important implications for individual fitness, inter‐ and intraspecific competition, and the adaptive potential of a species. 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 byAuthorsLaurie Anne Hall, Susan E. W. De La Cruz, Isa Woo, Tomohiro Kuwae, John Y. TakekawaImpacts of periodic dredging on macroinvertebrate prey availability for benthic foraging fishes in central San Francisco Bay, California
BackgroundBecause of its importance for species covered under Federal Fishery Management Plans (FMPs), the San Francisco Bay (SFB) estuary has been designated as Essential Fish Habitat (EFH) under the Magnuson-Stevens Fishery Conservation and Management Act (MSA; 16 United States Code §18559b). Within this estuary, benthic macroinvertebrate communities provide important prey resources for many ecoAuthorsSusan E. W. De La Cruz, Isa Woo, Laurie Hall, Alison Flanagan, Hannah MittelstaedtRediscovery of the horseshoe shrimp Lightiella serendipita Jones, 1961 (Cephalocarida: Hutchinsoniellidae) in San Francisco Bay, California, USA, with a key to the worldwide species of Cephalocarida
Lightiella serendipitaJones, 1961 was first discovered in San Francisco Bay, California in 1953, but it had not been observed since 1988. In 2017, a total of 13 adult L. serendipita specimens were found as part of a study in central San Francisco Bay, nearly doubling the total number of specimens ever collected. We measured vertical distribution of macroinvertebrates and environmental variables, iAuthorsCrystal Garcia, Isa Woo, D. Christopher Rogers, Alison M Flanagan, Susan E. W. De La CruzCarbon sources in the sediments of a restoring vs. historically unaltered salt marsh
Salt marshes provide the important ecosystem service of carbon storage in their sediments; however, little is known about the sources of such carbon and whether they differ between historically unaltered and restoring systems. In this study, stable isotope analysis was used to quantify carbon sources in a restoring, sparsely vegetated marsh (Restoring) and an adjacent, historically unaltered marshAuthorsJudith Z. Drexler, Melanie J. Davis, Isa Woo, Susan E.W. De La CruzHabitat of the endangered salt marsh harvest mouse (Reithrodontomys raviventris) in San Francisco Bay
Understanding habitat associations is vital for conservation of at‐risk marsh‐endemic wildlife species, particularly those under threat from sea level rise. We modeled environmental and habitat associations of the marsh‐endemic, Federally endangered salt marsh harvest mouse (Reithrodontomys raviventris, RERA) and co‐occurrence with eight associated small mammal species from annual trap data, 1998–AuthorsBruce G. Marcot, Isa Woo, Karen M. Thorne, Chase M. Freeman, Glenn R. GuntenspergenDisentangling the effects of habitat biogeochemistry, food web structure, and diet composition on mercury bioaccumulation in a wetland bird
Methylmercury (MeHg) is a globally pervasive contaminant with known toxicity to humans and wildlife. Several sources of variation can lead to spatial differences in MeHg bioaccumulation within a species including: biogeochemical processes that influence MeHg production and availability within an organism’s home range; trophic positions of consumers and MeHg biomagnification efficiency in food websAuthorsLaurie Anne Hall, Isa Woo, Mark C. Marvin-DiPasquale, Danika C Tsao, David P. Krabbenhoft, John Y. Takekawa, Susan E. W. De La Cruz - News