Grantee Research Project Results
Final Report: Integrating Coral Reef Ecosystem Integrity and Restoration Options with Watershed-based activities in the Tropical Pacific Islands and the Societal Costs of Poor Land-use Practices
EPA Grant Number: R828008Title: Integrating Coral Reef Ecosystem Integrity and Restoration Options with Watershed-based activities in the Tropical Pacific Islands and the Societal Costs of Poor Land-use Practices
Investigators: Richmond, Robert H. , Hamnett, Michael , Wolanski, Eric
Institution: University of Guam , University of Hawaii at Honolulu , Australian Institute of Marine Sciences
EPA Project Officer: Packard, Benjamin H
Project Period: (Extended to July 31, 2004)
Project Amount: $795,249
RFA: Water and Watersheds (1999) RFA Text | Recipients Lists
Research Category: Watersheds , Water
Objective:
The objectives for this project were to: (1) characterize watershed discharges affecting coastal reefs chemically, temporally, and spatially; (2) determine the classes and concentrations of coastal pollutants of greatest concern to coral reef sustainability and provide quantitative data for revising local and regional water quality standards; (3) develop techniques to identify sublethal stress in corals before outright mortality occurs; (4) determine if coral reef recovery and restoration activities are practical following both anthropogenic and natural disturbances; (5) quantify the cultural and economic impacts of land-based developments that affect coastal resources and incorporate this information into the decisionmaking process; (6) develop educational materials for a variety of users and stakeholders; and (7) develop a set of recommendations to prevent damage to coral reef ecosystems, and when such occurs, mitigation measures that may be undertaken.
Summary/Accomplishments (Outputs/Outcomes):
As this was a multidisciplinary program, there have been a number of findings in each of the program areas of biological, physical, and social sciences.
Biological Sciences
The research on coral reproduction and recruitment demonstrated that there are at least six chemically mediated stages critical to the success of reef replenishment that are being affected by watershed discharges: (1) synchronization among conspecific corals during spawning events; (2) egg-sperm interactions; (3) fertilization; (4) embryological development; (5) settlement and metamorphosis (recruitment); and (6) acquisition of symbiotic dinoflagellates (zooxanthellae). Water-soluble pollutants were particularly a concern for stages 1,2,3,4, and 6, whereas lipophilic substances (e.g., organophosphate pesticides) were a documented problem for recruitment, as the pollutants tested appeared to block both metamorphic inducers and larval receptors.
Watershed discharges had a substantial effect on coral community composition, structure, and function. In one small watershed, these effects were apparent over a distance of 300 m from the land-sea interface. Four coral reef community transitions were documented over this distance.
Stress could be observed in corals affected by watershed discharges at sublethal levels using molecular biomarkers of exposure, and these tools are proving to be useful in identifying specific causes of coral reef decline. Six classes of response were assayed: (1) genomic integrity-the ability of the genomic process to maintain a functional state; (2) protein metabolic condition-the process of protein synthesis, maturation, and degradation; (3) xenobiotic detoxification-the process of preventing or reducing the adverse (toxic) effects of exposure to a pollutant; (4) metabolic integrity-the ability of a cell to maintain a differentiated state from its environment and functional metabolic pathways; (5) oxidative damage and response-the process of maintaining a viable condition in an oxygen-laden environment; and (6) membrane integrity-the ability of a membrane to act as a selectively permeable barrier.
Molecular biomarkers in corals were found to be able to identify exposure and subsequent effects of an oil spill associated with a ship grounding incident in Yap State, Federated States of Micronesia, and the data were presented in ongoing court proceedings. Biomarkers of exposure appear to be able to serve the needs of resource managers for both identifying specific causes of stress to corals at sublethal levels and to measure effectiveness of mitigation measures in reducing levels of stress.
Sediment particles from terrigenous sources, specifically lateritic red clay and mud particles, were found to serve as nuclei for bacterial and microfaunal aggregations that resulted in the formation of “marine snow.” This material, organically-rich clumps, settle on the reef substrata, smothering coral recruits and contributing to the biological oxygen demand along reef surfaces at night. Field data collected on benthic algal cover and sediment resuspension rates in the absence of rain and additional watershed discharges demonstrated that overfishing of herbivorous fishes contributes to sediment accumulation and chronic impacts of sediment from land-based sources. Following periods of increased wave action, more than 50 percent of suspended sediment particles came from material trapped in benthic algae. As such, mitigation measures need to include both improving erosion control on land, as well as reducing benthic fleshy and filamentous algal cover.
Physical Sciences
Coastal Water and Substratum Quality. The physical oceanographic and sedimentation research focused on three bays, two in Palau and one in Guam. Airai Bay (Palau) is fed by the Ngerikiil River and receives discharges from a watershed heavily impacted by human activities (road and home construction; farming). Ngardorch Bay (Palau) has a smaller watershed catchment with lower levels of human activities. Fouha Bay, on the southern coast of Guam, is open to oceanic influences including direct wave energy and lacks a coastal mangrove community. Each of the three bays studied demonstrated differences in the magnitude of response based on the specific characteristics of the adjacent watershed and the receiving water characteristics.
Fouha Bay is a 400 m long, 10 m deep, funnel-shaped, coral-fringed embayment on the southwest coast of Guam. It drains a small catchment area (5 km2) of steeply sloping, highly erodible lateritic soils. River floods are short-lived and the sediment load is very large, with suspended sediment concentration exceeding 1,000 mg l-1. The resulting river plume is about 1 m thick and is pulsing in a series of 1-2 hour long events, with outflow velocity peaking at 0.05 m s-1. Turbulent entrainment results in an oceanic inflow at depth into the bay. As soon as river flow stops, the plume floats passively and takes 5 days to be flushed out of Fouha Bay. In calm weather, about 75 percent of the riverine mud settles out of the river plume into the underlying oceanic water where it forms a transient nepheloid layer. This mud ultimately settles and is trapped in Fouha Bay. Under typhoon-driven swell waves, the surface plume is at least 7 m thick and bottom entrainment of mud results in suspended sediment concentrations exceeding 1,000 mg l-1 for several days. The data from this bay support the premise that successful management of fringing coral reefs adjacent to high islands may not be possible without proper land use management in the surrounding watersheds.
A comparative study was undertaken of the fate of fine sediment in the Ngerikiil and Ngardorch mangrove-fringed estuaries in Babeldaob Island, Palau, Micronesia. The sediment yield is 10-19 times higher in the Ngerikiil River watershed, which has been extensively cleared and farmed, whereas much of the Ngardorch River catchment was still pristine in 2002. The mangroves comprised 3.8 percent of each estuarine area, and in both systems they trapped about 30 percent of the riverine sediment. The mangroves were an important buffer, protecting fringing coral reefs from excessive sedimentation.
Airai Bay, Palau, is a small (3 km2), semi-enclosed, mangrove-fringed, meso-tidal, coral lagoon on the southeast coast of Palau fed by the Ngerikiil River. It drains a small watershed area (26 km2) of highly erodible soils in an area with high annual rainfall (3.7 m). River floods are short-lived and the sediment load is very large, with suspended fine sediment concentrations exceeding 1,500 mg l-1. The resulting river plume is about 2 m thick. Brackish water is only flushed out of Airai Bay during ebb tides. The brackish water residence time is about 7 days; during this period, the plume remains a distinct surface feature even after river runoff has ceased. About 98 percent of the riverine fine sediment settles in Airai Bay, of which about 15-30 percent is deposited in the mangroves during river floods. This mud remains trapped in Airai Bay because the bay is protected from ocean swell and because the tidal currents and locally generated wind-waves are too small to resuspend the mud in quantity. The mud is smothering coral reefs, creating a phase shift from coral to fleshy algae dominance, as well as changing habitats by creating mud banks. The persistence of Airai Bay marine resources will not be possible without improved soil erosion control within the watershed. Sedimentation rates in the Ngardorch estuary were a fraction of those observed in Airai Bay, attributed to the lower levels of land-based clearing and development activities within the watershed.
A model was developed to explain coral and algal abundance on coastal coral reefs as a function of spike-like natural disturbances from tropical storms/typhoons and turbid river floods, followed by long recovery periods where the rate of reef recovery depends on ambient water and substratum quality. The model includes competition for space between corals and algae, coral recruitment, and reef connectivity. The model is applied to a 400 km stretch of Australia’s Great Barrier Reef and to the 200 m long reef tract at Fouha Bay, in Guam, Micronesia. For these two sites and at these two scales, the model appears successful at reproducing the observed distribution of algae and coral. For both sites, it is suggested that the reefs have been degraded by human activities on land and that they will recover provided remedial measures are implemented on land to restore the water and substrate conditions. We suggest ways to improve the model and to use the model to guide future ecological research and management efforts on coastal coral reefs (Wolanski, et al., 2003).
The following relationship between turbidity (associated with terrestrial runoff) and herbivorous fish populations (Figure 1) was determined and published in the Journal of Marine Systems as referenced in the publications/presentations section of this report.
Figure 1. The Relationship Between Turbidity and Herbivorous Fish Populations
Watershed Modeling
Basic Model Information. Name of model(s) used:
- HOME (Hydrology, Oceanography, Meteorology, Ecology)
- Fine sediment budgets in: (1) mangroves and (2) coral reefs
- Flocculation models (marine snow)
Whether existing, newly developed, or newly modified under this grant:
- HOME is a new model, developed in 2002 and modified and improved under this grant.
- The fine sediment budgets follow the methodology of Wolanski and Spagnol (2000) and Wolanski (2001). In Airai Bay, Palau, it was the first time that they were applied to simultaneously coral reefs and mangroves.
- The riverine sediment inflow in Fouha Bay was taken from U.S. Geological Survey river and sediment concentration data.
Type of model(s) (e.g., distributed, lumped, statistical):
- The HOME model is a distributed ecohydrological model.
- Fine sediment budgets are lumped models.
- Flocculation models are process-based.
Grid size of model(s):
- HOME model: 1 mesh=1 reef
- Sediment budgets: subdivide the ecosystems into eco-units (e.g., mangroves and zones of coral reefs)
- Flocculation: mm to mm size
Spatial extent for which model applied(s):
- HOME: 400 km
- Sediment budgets: hundreds of m
- Flocculation models: microns to cm
Time period and time-step for model simulation:
- HOME: years and weeks
- Sediment budgets: weeks to 1 year
- Flocculation models: minutes
Model variables and sources of data to parameterize the models:
- HOME: river water and sediment discharge, wind, typhoon tracks, coral, and algal cover
- Sediment budgets: advective fluxes and settling fluxes
- Flocculation models: floc size
Processes/endpoints predicted by model(s) (e.g., mass balances, water quality constituents, amount, and timing of discharge) and the locations for which these are predicted (e.g., pour point of watershed, river nodes, averages for individual grids, averages for subwatersheds)
- HOME: model predicts coral reef health.
- Sediment budgets: model predicts the fate of fine sediments in various ecotones.
- Flocculation models: model predicts floc size and amount of material flocculated and its settling velocity.
How hydrological models are linked (if more than hydrological model is employed in the study):
- HOME: the model links hydrology (muddy river plumes computed by a three-dimensional river plume baroclinic hydrodynamic model driven by river flood hydrographs and water turbidity data), oceanography (connectivity between reefs through exchange of coral planulae), meteorology (tracks and intensity of typhoons), and ecology (competition for space between corals and algae).
- Sediment budgets: link hydrodynamic data with suspended sediment fluxes data.
- Flocculation models: no links.
Testing and validation of the model:
- HOME: The HOME model was successfully tested against 10 years of reef health data from a long-term monitoring data set that was made available to the investigators. The ‘calibration’ constants were pre-set (and not adjusted to better fit the model) from data on coral cover of reefs surveyed immediately before and after impacts by typhoons or river floods.
- Sediment budgets: The sediment budgets were not predictive; they were calculated from extensive oceanographic and sedimentology field data to assess the flow-through and the retention of mud through various marine ecotones.
- Flocculation models: These budgets were not predictive; they were calculated from field and laboratory studies on the speed and efficiency of the formation of muddy marine snow.
- The new watershed model HOME has a predictive capability that should be very useful to both watershed managers and reef managers in quantifying the link between land use activities and the health of coral reefs.
Social Sciences
The social science component of this research program provided insight into the application of scientific data and the implementation of policies designed to meet management and hence stakeholder needs. The two primary sites for this program included Guam, a U.S. territory and highly “westernized” society (urbanized, fast-food chains, conspicuous resort and hotel development), and the Republic of Palau, which is far less developed, with limited levels of construction activities and lower-impact tourism focused on SCUBA diving, kayaking, and enjoyment of the natural environment. Socially, Guam has a western political system of an elected governor, legislature, and an independent judiciary, whereas Palau has both elected leaders and traditional leaders, including Chiefs and the influence of well-organized women’s groups within a matrilineal society.
A key understanding reached early by the principal investigators (PIs) and the advisory committee was that “coral reef management” is a misnomer, in that is not really possible to manage coral reefs, but rather, the key deliverables need to focus on the management of human activities as they affect coral reefs. As such, there was recognition of the importance of the social science component in the application of the data collected from the biological and physical oceanographic studies.
The watersheds selected for the studies were chosen both on the basis of the physical characteristics, as well as the willingness and interest of the adjacent human communities to participate in the activities and take ownership of the results. In Guam, regular meetings were held in Umatac Village, with the mayor, the municipal planning council, and interested community members. A member of the community was hired as a facilitator and served as a continuous conduit between the scientists and the village. Input on the project was continually solicited from the community, and feedback was provided on the progress. The mayor provided office space in his facility to support some of the experiments. Students from the local elementary school were involved in outreach activities and painted a number of murals in the village on watershed issues. The community leaders agreed to take on the major problem of fires set by hunters to improve access to feral pigs and deer by dealing with the individuals known to family members. The involvement of the school children provided additional peer pressure, as many were nieces and nephews of the hunters. The community municipal planning council also agreed to consider requesting the Guam Legislature to enact legislation to establish a Marine Protected Area in Fouha Bay to ban fishing of the herbivorous (algae-eating) fish for 1 to 2 years in support of studies to determine if this could reduce sediment accumulation. Additional funding for this project received from the National Oceanic and Atmospheric Administration (NOAA) will allow this effort to continue.
In Palau, the first site was chosen with the input of the local conservation society and community, and the second site, based on the watershed attributes. A door-to-door community outreach effort was undertaken by the staff of the Palau International Coral Reef Center (PICRC) as well as a number of meetings held with the local Chiefs and fishers, facilitated by a well-respected Palauan congressional delegate and past Executive Director of the Palau Conservation Society. The most striking outcome of this project in terms of policy implementation followed a PowerPoint presentation by the two Palauan researchers (in the Palauan language) in the Airai Village traditional meeting house (called a Bai) for the chiefs, fishers and interested community members. Six weeks after the data analysis and presentation, a moratorium on cutting and filling of mangroves was implemented around the bay under study. Two years later, the ban was still in place and no additional damage had occurred to the mangrove ecosystem. Additional education materials (watershed information sheets and a calendar) that reached all villages in Palau were developed through the Palau Conservation Society with support from the U.S. Environmental Protection Agency (EPA) Science To Achieve Results (STAR) grant.
Continued efforts in the translation of science into policy are ongoing with the NOAA grant support.
Linkages Among the Ecological, Physical, and Social Components of the Grant
Perhaps ironically, this project has benefited because there are only three PIs (one per discipline), each from institutions thousands of kilometers apart, who get along well with each other and are focused on the deliverables. Each of the Co-PIs has been able to take the lead in his particular area of expertise (ecology, physical science, and social science) to meet the project goals and objectives. In the case of this project, input from regional resource managers has provided continuous guidance, and the involvement of these individuals and additional stakeholders directly with the investigators during data collection has kept the project on track. Although publications have been among the deliverables from the research perspective, the goals have included providing adequate and accurate data to resource managers, policymakers, and stakeholders to support integrated watershed management practices as they affect coastal coral reefs and related marine resources and to move forward on policy implementation.
Both Guam and Palau have attributes that allowed the PIs to work with local communities and cooperate with regulatory agencies and legislative bodies with relative ease. As an example, data collected on coral reef health, sedimentation, and estuarine circulation patterns in Ngerikill Bay, Palau, in the morning were presented to members of the community the same evening. While biological and physical data were being presented, the participants were able to observe and evaluate the “social” reaction. In this specific case, local fishermen were already aware of the problems associated with poor land-use practices, but were now empowered by the validation of their observations and immediately began discussing actions needed to stop the environmental degradation. A key legislator was present who used this information to write a law on mangrove protection. This was an exercise in developing political will through the application of scientific data. While Guam is more Westernized, a similar effort in working with a local village municipal planning council yielded progress in addressing solutions. As the three PIs have focused on the conservation/management outputs, the integration of the three areas of research activity has occurred naturally.
Although there are many elements of this effort that require more work, especially in pursuing the land-based activities needed to reduce erosion and sedimentation, the project has made substantial progress through this interdisciplinary approach. The integration of the three disciplines is clearly reflected in a recently published paper in American Scientist that resulted from this project. In this paper, ecological and oceanographic data are interpreted within a policy context.
Although the data from each discipline may be in different forms and units, we have found the synthesis has provided much more than the sum of the parts in terms of addressing practical responses to poor watershed management practices. We believe this type of interdisciplinary approach to be effective and necessary if problems of environmental degradation are to be tackled in a practical manner.
As our questions are directed toward identifying and implementing activities that effectively reduce the impacts of poor land-use practices occurring within watersheds on coastal coral reefs, we have found all three components to be of equal value. Having adequate and accurate data does not solve problems but instead provides information upon which to make sound decisions. Without the social sciences, implementation would not occur. Our perspective includes the philosophy that science must go beyond documentation of environmental degradation and destruction and be used as a tool for managing human activities as they impact ecosystems. The social sciences are proving to be the key to the application of data to sound policy development and implementation.
Technological Developments
- Development and verification of the HOME ecohydrology model that predicts the combined impact on the health of coral reefs of both natural and human disturbances from land runoff.
- Development of a coral mud resuspender to quantify the amount of mud trapped on coral reefs as muddy marine snow and available for resuspension by waves even in the absence of river runoff.
- Development of a suite of biomarkers for identifying stress in corals.
Additional Deliverables
One of the significant additions to the program deliverables was the impact on the scientific training of Pacific Islanders, a highly underrepresented minority group in the natural sciences. All five of the theses resulting from the STAR grant were by minority students and four by Pacific Islanders. The two Palauan associate investigators have been senior authors on peer-reviewed journal articles, have trained other islanders throughout the region, and are continuing to serve as excellent role models.
Data from these studies were incorporated into invited testimony on coral reefs for both the Pew Ocean’s Commission and the U.S. Commission on Ocean Policy. The coral reproductive studies were used as the basis for a resolution accepted by the U.S. Coral Reef Task Force on protection of water and substratum quality around coral spawning times.
The results of this EPA STAR grant led to a new grant through NOAA for $1.38 million over 4 years to continue and expand aspects of the watershed studies.
Journal Articles on this Report : 11 Displayed | Download in RIS Format
Other project views: | All 65 publications | 17 publications in selected types | All 11 journal articles |
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Downs CA, Woodley CM, Richmond RH, Lanning LL, Owen R. Shifting the paradigm of coral-reef 'health' assessment. Marine Pollution Bulletin 2005;51(5-7):486-494. |
R828008 (Final) |
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Golbuu Y, Victor S, Wolanski E, Richmond RH. Trapping of fine sediment in a semi-enclosed bay, Palau, Micronesia. Estuarine, Coastal and Shelf Science 2003;57(5-6):941-949. |
R828008 (Final) |
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McKenna SA, Richmond RH, Roos G. Assessing the effects of sewage on coral reefs: developing techniques to detect stress before coral mortality. Bulletin of Marine Science 2001;69(2):517-523. |
R828008 (2001) R828008 (Final) |
Exit Exit |
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Richmond RH, Rongo T, Golbuu Y, Victor S, Idechong N, Davis G, Kostka W, Neth L, Hamnett M, Wolanski E. Watersheds and coral reefs: conservation science, policy, and implementation. Bioscience 2007;57(7):598-607. |
R828008 (Final) |
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Victor S, Golbuu Y, Wolanski E, Richmond R. Fine sediment trapping in two mangrove-fringed estuaries exposed to contrasting land-use intensity, Palau, Micronesia. Wetlands Ecology and Management 2004;12(4):277-283. |
R828008 (Final) |
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Wolanski E, Richmond RH, Davis G, Deleersnijder E, Leben RR. Eddies around Guam, an island in the Mariana Islands group. Continental Shelf Research 2003;23(10):991-1003. |
R828008 (Final) |
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Wolanski E, Richmond RH, Davis G, Bonito V. Water and fine sediment dynamics in transient river plumes in a small, reef-fringed bay, Guam. Estuarine, Coastal and Shelf Science 2003;56(5-6):1029-1040. |
R828008 (Final) |
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Wolanski E, Richmond R, McCook L, Sweatman H. Mud, marine snow and coral reefs-The survival of coral reefs requires integrated watershed-based management activities and marine conservation. American Scientist 2003;91(1):44-51. |
R828008 (Final) R825158 (Final) |
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Wolanski E, Boorman LA, Chicharo L, Langlois-Saliou E, Lara R, Plater AJ, Uncles RJ, Zalewski M. Ecohydrology as a new tool for sustainable management of estuaries and coastal waters. Wetlands Ecology and Management 2004;12(4):235-276. |
R828008 (Final) |
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Wolanski E, Colin P, Naithani J, Deleersnijder E, Golbuu Y. Large amplitude, leaky, island-generated, internal waves around Palau, Micronesia. Estuarine, Coastal and Shelf Science 2004;60(4):705-716. |
R828008 (Final) |
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Wolanski E, Richmond RH, McCook L. A model of the effects of land-based, human activities on the health of coral reefs in the Great Barrier Reef and in Fouha Bay, Guam, Micronesia. Journal of Marine Systems 2004;46(1-4):133-144. |
R828008 (Final) |
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Supplemental Keywords:
watersheds, ecological effects,sedimentation, erosion, sensitive populations, cumulative effects, ecosystem,indicators, restoration,, decision-making, community-based, cost benefit, conservation,Pacific Islands, EPA Region 9,, RFA, Scientific Discipline, Geographic Area, Water, Ecosystem Protection/Environmental Exposure & Risk, Ecology, Water & Watershed, Ecosystem/Assessment/Indicators, Ecosystem Protection, Environmental Chemistry, Chemistry, Ecological Effects - Environmental Exposure & Risk, Wet Weather Flows, Ecological Risk Assessment, International, Watersheds, coastal ecosystem, coral reef ecosystem, anthropogenic processes, water resources, aquatic ecosystem, anthropogenic stress, coral reefs, coastal watershed, valuation of watersheds, human activities, watershed, runoff, sediment, coral reef ecosystem restoration, coastal environments, socioeconomics, aquatic degradation, hydrology, Tropical Pacific Islands, societal costs, restoration, aquatic ecosystems, coral reef ecosystem integrity, human values, non-point sources, water quality, flow monitor, ecological indicators, Micronesia, ecology assessment models, outreach and education, ecological integrity, land use, restoration planning, watershed restorationRelevant Websites:
United States Coral Reef Task Force
Progress and Final Reports:
Original AbstractThe perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.