2002 Progress Report: Pacific Estuarine Ecosystem Indicator Research (PEEIR) Consortium: Ecosystem Indicators Component

EPA Grant Number: R828676C001
Subproject: this is subproject number 001 , established and managed by the Center Director under grant R828676
(EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).

Center: Pacific Estuarine Ecosystem Indicator Research (PEEIR) Consortium
Center Director: Anderson, Susan L.
Title: Pacific Estuarine Ecosystem Indicator Research (PEEIR) Consortium: Ecosystem Indicators Component
Investigators: Morgan, Steven , Bennett, Bill , Hollibaugh, James T. , Nisbet, Roger M.
Current Investigators: Morgan, Steven , Bennett, Bill , Cherr, Gary N. , Green, Peter , Grosholz, Edwin , Judah, Linda , Kuivila, Katherine , Nelson, Douglas , Nisbet, Roger M. , Smalling, Kelly , Spilseth, Sarah , Vines, Carol , Visinitainer, Tammie
Institution: University of California - Davis , University of California - Santa Barbara , University of Georgia
Current Institution: University of California - Davis , U.S. Geological Survey , University of California - Santa Barbara
EPA Project Officer: Packard, Benjamin H
Project Period: March 1, 2001 through February 28, 2005
Project Period Covered by this Report: March 1, 2001 through February 28, 2002
RFA: Environmental Indicators in the Estuarine Environment Research Program (2000) RFA Text |  Recipients Lists
Research Category: Ecological Indicators/Assessment/Restoration , Water , Ecosystems


The overarching objective of this research project is to develop a suite of ecological indicators to rapidly assess the integrity and sustainability of wetlands in West Coast estuaries. This project involves the development of an integrated suite of indicators to evaluate the impacts of stressors across levels of biological organization, trophic structure, life stage, time, and space.

Progress Summary:

Four approaches were used by teams of investigators from the University of California-Davis and the University of California-Santa Barbara to determine the impacts of stress from nutrient loading, pollution, and exotic species on wetlands from northern and southern California: (1) physiochemical monitoring; (2) biological monitoring; (3) toxicity biomarkers; and (4) statistical analysis and modeling. Research was conducted in concert with the Biochemistry and Bioavailability (BBC) team to characterize the physicochemical environment including temperature, salinity, oxygen, submergence times, sediment grain size, nutrient inputs and toxic contaminant loads. The Biochemical Response to Contaminants (BRC) team conducted toxicity biomarker assays in the field and the Remote Sensing Component (RSC) team grounded truth measurements taken at the ecosystem level.

This year, study sites were located at seven sites in northern and southern California including Walker Creek and Toms Point in Tomales Bay, Stege Marsh and China Camp in San Francisco Bay, Morro Bay, Carpinteria Marsh, and Mugu Lagoon. Sites spanned biogeographic boundaries and the estuaries varied morphologically, which provided a good test of the reliability of the indicators to assess wetland integrity across diverse environments. This year, we: (1) censused the full spectrum of wetland communities including microbes, plants, invertebrates, fishes, birds, and parasites; (2) characterized sites for nutrient and toxic contaminants in collaboration with the BBC and BRC teams; and (3) developed modeling approaches that will enable us to determine whether our indicators responded significantly to measured stressors, the ability of indicators to distinguish between reference and impacted sites, and the effects of contaminants on individuals, populations, and ecosystems across space and time. Specifically, indicators are being developed by contrasting conditions at previously characterized reference and impacted sites, following nutrient gradients at all seven sites, and toxic contaminant gradients at three sites (Stege, Carpinteria, and Mugu).

The development of indicators critically depends on: (1) the initial establishment of an overarching sampling design that fully integrates the research of each of the five components of the project; (2) the vertical integration of investigations into the effects of contaminants on the wetland ecosystems beginning with their bioavailability and working up the levels of biological organization from the subcellular to the landscape level; and (3) the development of sophisticated statistical approaches and new models that integrate and make sense of the enormous and diverse array of information that will be obtained during this multifaceted, 4-year research project. Because ecosystems subsume lower levels of biological organization, our component has taken the lead, together with the Integration component, to ensure that these three essential criteria are met. We ensured that representatives from all of the research components participated in field sampling, and then we spent a great deal of time discussing the best way to fully integrate our project based on our initial results and experience. This effort led to the incorporation of a gradient design of contamination at the study sites. The teams returned to field sites to characterize the bioavailability and toxicity of contaminants along the gradient. Invertebrate and fish communities also were characterized along the gradient. A fully integrated sampling scheme was developed and deployed at multiple stations within each of the seven sites.

Highlights of the preliminary analyses of data for the Ecosystems Indicator Component are itemized below. However, it should be reiterated that all sampling is fully integrated with the other project components.

Nutrient Cycling. We found that: (1) dissolved inorganic nitrogen concentration was orders of magnitude greater at Carpinteria than any other site and it was twice as great at Stege than the rest of the sites; (2) delta15N values of macroalgae and selected consumers spatially and temporally vary within the study marshes; (3) crabs and snails may be useful “indicator” species because they are present year round at most stations; and (4) delta15N values appear correlated with salinity, suggesting the incorporation of land-derived N in marsh food webs (see Figure 1).

Figure 1. Crabs, Snails, and Microalgae During Winter and Summer 2002 at Mugu Lagoon

Primary Productivity and Trophic Support. The dominant vegetation of marshes on the west coast, Salicornia, is smaller, greener, and denser where conditions are saltier and less toxic. In contrast, Salicornia has greater biomass, but most of it consists of brown stems, and plants are less dense where conditions are most toxic. Spartina was denser, taller, heavier, and had greater percent cover where conditions were less toxic than at our most toxic site (Stege). Furthermore, the percentage of flowering shoots was low at the most toxic site. Mats of cyanobacteria were prevalent at the most toxic site, unlike other sites. Ammonification rates, the first step in nutrient recycling, was highest at the most toxic site. Decomposition rates did not appear to be related to toxic exposure (see Table 1).

Table 1. Spartina Vegetation at China Camp and Stege Marsh

Spartina Vegetation
Mean +/- SD, n = 2 stations
China Camp
Stege Marsh
# Stems/m2
776 +/- 318
195 +/- 138
Canopy Height (cm)
870 +/- 310
460 +/- 140
% Cover
51 +/- 37
33 +/- 27
Biomass (kg/m2)
37.0 +/- 14.5
4.7 +/- 2.8
% Flowering Shoots
16 +/- 11
0.2 +/- 0.6

Microbial Communities. Total coliform concentration correlated with bacterial community composition and urbanization in the Santa Barbara area. Methods being developed appeared to accurately detect sources of contamination in laboratory-created “blind” samples. Dog, gull, and human sources appeared to contain different bacterial communities and the bacterial community in blind trials appeared to be human in origin. This study was coordinated by the Southern California Coastal Water Research Project (SCCWRP), and forges an important collaboration between SCCWRP and Pacific Estuarine Ecosystem Indicator Research (PEEIR).

Invertebrates. Abundance and diversity of infauna appeared to be related to toxic exposure. Amphipods appeared to be particularly sensitive indicators of stress. Amphipods, especially Corophium, were much less abundant at our most toxic site and may vary with contaminant exposure within Stege and Walker. However, one species of amphipod (Lysanassidae) was far more abundant at our most toxic site and it was found where contaminant exposure was greatest within the marsh. Contaminant exposure was greater in the marsh, where amphipods were most abundant, than in the channel, which may explain why amphipods were more susceptible to toxic exposure than other infauna. Several other potential indicators that were investigated appear to show less promise including the prevalence of invasive species, fluctuating asymmetry in crabs, and imposex in snails. Detritivore abundance holds considerable promise as an indicator.

Fishes. Fish size showed greater variation at our two most contaminated sites (Stege and Mugu) relative to other sites. Fish livers were larger at contaminated sites than at our reference site at Toms Point. Validation of growth rates from otoliths of our model fish species were accomplished and are being used to determine variation in growth rates with toxic exposure (see Figure 2).

Figure 2. Differences in Fish Size at Contaminated Sites

Parasites and Birds. Trematode richness varied with bird richness and may be an effective indicator of community diversity. Trematode frequency and richness are associated with general habitat quality when restoration sites were compared with natural marshes. It also appeared to be greatest at the most contaminated southern site (Mugu), intermediate at Carpinteria, and least in Morro Bay. Fish ciliates had insufficient spatial variation to be used as indicators at this time and need to be compared with fish toxicology data.

We concluded that our field sites are appropriate, working at them is feasible, and our target species are sufficiently abundant. We detected significant differences in microbial populations between these sites. We have determined that a combination of a gradient design nested within reference and impacted sites is the most powerful design to detect the effects of contaminants on wetland ecosystems. We also concluded that contaminants likely are most concentrated in channels and along the margins of tidal creek, and we are targeting these areas. Additional stations within sites have been incorporated to put the gradient in context of the larger ecosystem. Further discussions of scaling up indicators of plant stress to the level of the landscape using remote sensing revealed that the approach still looks promising. We are developing and validating this indicator in collaboration with the RSC and BBC.

Future Activities:

Intensive discussions have been held to update our sampling plan for this year. Our plan consists of increasing the number of stations within two highly contaminated sites to increase our resolution of toxicant effects. Sampling will be continued at Stege Marsh, Carpinteria Marsh, and Walker Creek. Contaminant and toxicity exposure relative to population abundance and species richness will continue to be evaluated for multiple stations within each site in collaboration with the BRC and BBC. Outplant experiments will be conducted with crabs, fish, and clams at selected stations with sites to measure reproductive and growth performance, biomarker responses, and body burdens in collaboration with the BRC and BBC. Validation and initial field tests of plant stress relative to tissue burdens and bioavailability on the landscape level are being conducted in collaboration with the RSC and BBC. All other promising indicators described above will continue to be developed.

After intensive field work is completed this year, integration activities will include the synthesis of indicator data using both multivariate statistics and models. We will draft manuscripts reporting on the potential applicability of individual and aggregate indicators. Working teams will be initiated to formulate recommendations on: (1) plant indicators at multiple spatial scales; (2) indicators for model animals that relate stressor measurements to changes in fitness; and (3) appropriate integrative indicators related to nutrient cycling and bird populations.

Journal Articles on this Report : 3 Displayed | Download in RIS Format

Other subproject views: All 32 publications 14 publications in selected types All 13 journal articles
Other center views: All 139 publications 42 publications in selected types All 40 journal articles
Type Citation Sub Project Document Sources
Journal Article Huspeni TC, Lafferty KD. Using larval trematodes that parasitize snails to evaluate a saltmarsh restoration project. Ecological Applications 2004;14(3):795-804. R828676 (Final)
R828676C001 (2002)
R828676C003 (Final)
  • Full-text: University of California-San Diego-Full Text PDF
  • Abstract: ESA-Abstract
  • Journal Article Lafferty KD. Is disease increasing or decreasing, and does it impact or maintain biodiversity? Journal of Parasitology 2003;89(Suppl):S101-S105. R828676 (Final)
    R828676C001 (2002)
  • Full-text: Journal of Parasitology PDF
  • Journal Article Lafferty KD, Holt RD. How should environmental stress affect the population dynamics of disease? Ecology Letters 2003;6(7):654-664. R828676 (Final)
    R828676C001 (2002)
  • Full-text: CDLIB PDF
  • Abstract: Blackwell-Synergy Abstract
  • Supplemental Keywords:

    indicators, ecology, estuaries, wetlands, health, toxics, nutrients, exotic species, watersheds, ecological effects, bioavailability, ecosystem indicators, aquatic, integrated assessment, EPA Region 9., RFA, ENVIRONMENTAL MANAGEMENT, Water, ECOSYSTEMS, Ecosystem Protection/Environmental Exposure & Risk, estuarine research, exploratory research environmental biology, Ecosystem/Assessment/Indicators, Ecosystem Protection, Ecological Effects - Environmental Exposure & Risk, Aquatic Ecosystems, Terrestrial Ecosystems, Ecological Monitoring, Ecological Indicators, Risk Assessment, anthropogenic stresses, ecological risk assessment, wetlands, aquatic ecosystem, bioindicator, anthropogenic stress, ecosystem assessment, estuaries, wetland ecosystem, bioavailability, nutrients, trophic effects, ecosystem indicators, environmental indicators, coastal ecosystems, ecosystem restoration, aquatic ecology

    Progress and Final Reports:

    Original Abstract
  • 2001
  • 2003 Progress Report
  • Final Report

  • Main Center Abstract and Reports:

    R828676    Pacific Estuarine Ecosystem Indicator Research (PEEIR) Consortium

    Subprojects under this Center: (EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).
    R828676C000 Pacific Estuarine Ecosystem Indicator Research (PEEIR) Consortium: Administration and Integration Component
    R828676C001 Pacific Estuarine Ecosystem Indicator Research (PEEIR) Consortium: Ecosystem Indicators Component
    R828676C002 Pacific Estuarine Ecosystem Indicator Research (PEEIR) Consortium: Biological Responses to Contaminants Component: Biomarkers of Exposure, Effect, and Reproductive Impairment
    R828676C003 Pacific Estuarine Ecosystem Indicator Research (PEEIR) Consortium: Biogeochemistry and Bioavailability Component