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projects > ecosystem history of the southwest coast-shark river slough outflow area
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Project Work Plan
Department of Interior USGS GE PES
Fiscal Year 2009 Study Work Plan
Study Title: Ecosystem History of the Southwest Coast-Shark River Slough Outflow Area
Overview & Objective(s): One of the primary goals of the Central Everglades Restoration Plan (CERP) is to restore the natural flow of water through the terrestrial Everglades and into the coastal zones. Historically, Shark River Slough, which flows through the central portion of the Everglades southwestward, was the primary flow path for freshwater moving through the Everglades Ecosystem. However, this flow has been dramatically reduced over the last century as construction of canals, water conservation areas and the Tamiami Trail either retained or diverted flow from Shark River Slough. The reduction in flow and changes in water quality through Shark River have had a significant effect on the freshwater marshes and the associated coastal ecosystems. Additionally, the flow reduction may have shifted the balance of fresh to salt-water inflow along coastal zones, resulting in an acceleration of the rate of inland migration of mangroves into the freshwater marshes. The objectives of this study are to document impacts of changes in salinity, water quality, coastal plant and animal communities and other critical ecosystem parameters on a sub-decadal to centennial scale in the southwest coastal region (from Whitewater Bay, north to the Ten Thousand Islands), and to correlate these changes with natural events and resource management practices. Emphasis will be placed on 1) determining the amount, timing and sources of freshwater influx (groundwater vs. runoff) into the coastal ecosystem prior to and since significant anthropogenic alteration of flow; and 2) determining whether the rate of mangrove and brackish marsh migration inland has increased since 20th century water diversion and what role sea level rise might play in the migration.
Specific Relevance to Major Unanswered Questions and Information Needs Identified: (Page numbers below refer to DOI Science Plan.)
One of the primary DOI activities discussed in the DOI Science Plan is to "ensure that hydrologic performance targets accurately reflect the natural predrainage hydrology and ecology" (DOI Science Plan, p. 14). The primary goal of the Ecosystem History of the Southwest Coast-Shark River Slough Outflow Area study is to determine the predrainage hydrology and ecology of the southwest coastal environment. The Southern Estuaries Sub-Team (SET) of the Regional Evaluation Team (RET) of RECOVER is interested in potential data generated by this study to help set performance measures (PMs) for the Whitewater Bay area. This team includes clients from DOI-NPS, DOI-F&WS, NOAA, ACOE, and SFWMD. Recent data obtained by SET through the simulations run for the Initial CERP Update (ICU) have returned salinity values far in excess of any anticipated; they have therefore turned to our paleosalinity data as the potential primary tool for setting the PMs for the southern estuaries.
Additionally, this study supports the Additional Water for Everglades National Park, the Southern Golden Gate Estates Hydrologic Restoration, and the Southwest Feasibility Study Projects, and it provides information relevant to Landscape Modeling, Invasive Exotic Plant Detection, and Monitoring and Aquatic Exotic Animals Projects. This study supports these projects by 1) conducting research to understand the predrainage hydrology, including the amount, timing and seasonality of freshwater delivered to southwest Florida historically; 2) examining the historical environmental conditions, including the linkage between hydrology (water quality and quantity), ecology, and habitats; 3) providing the modelers with data on historic conditions in order to set targets and performance measures that reflect natural hydrologic patterns; 4) providing long-term historical data on trends and cycles within the biological component of the ecosystem that can be forecasted to predict the effects of implementation of hydrologic restoration on the ecology of coastal communities; and 5) by determining the timing of introduction and spread of exotics in the southwest ecosystem and the coincident changes in the native species.
This study supports the Additional Water for Everglades National Park and Biscayne Bay Feasibility Study by addressing the questions "What were the physical and ecological conditions in . . . Shark River Slough . . .prior to drainage and modification . . ." (DOI Plan p. 63), "What are the hydrologic targets needed to mimic historic flows . . . ? (p. 63).
This study supports the Southern Golden Gate Estates Hydrologic Restoration Project by providing long-term (100-500 years) data on natural hydrologic patterns that can be used to set targets for freshwater inflows (p. 50). In addition, information on long-term changes in the biota and ongoing studies to develop our modern proxy database (used for core interpretation) will provide baseline data on the ecological responses of communities and species (p. 51).
This study supports the Southwest Feasibility Study Project by providing predrainage hydrologic and ecologic conditions that can be used to set the hydrologic targets (p. 50). The results of the core analyses will provide data on temporal and spatial patterns within the estuaries and the linkage between hydrologic conditions and ecological responses; this information can be used by the modelers (p. 50) and to determine what faunal or floral species might be used as key indicators (p. 51).
In addition, the study contributes to the Landscape Modeling project by providing historical ecological data on trends and cycles that can be forecasted to predict the effects of implementation of hydrologic restoration on the ecology of coastal communities. This addresses questions of the impact of increased flow (p. 63), and expected faunal and floral responses (p. 64, p. 79, p. 80). The study also contributes to the Invasive Exotic Plant Detection and Monitoring and Aquatic Exotic Animals Projects by determining the temporal and spatial distribution of exotics and changes in native species coincident with introduction (p. 118).
Specific Relevance to USGS Mission:
This project is directly related to the USGS Science Strategy (USGS Circ. 1309) - Understanding Ecosystems and Predicting Ecosystem Change. We are investigating the causes and consequences of ecological change and are developing and providing methods for protecting and managing the South Florida Ecosystem - methods which can be applied to other ecosystems around the country and around the world. We are interpreting for the land managers and policy makers how current and future rates of change will affect the natural resources and societal infrastructure of South Florida. In addition, the project contributes significantly to the Climate Variability and Change Science Strategy by examining the effects of climate and sea level rise on the South Florida ecosystem over historically significant time periods. Using historical records, we can project future states under various IPCC scenarios and how those scenarios may affect restoration planning.
Status: Analysis of faunal and floral remains, geochemistry and geochronology of three cores forming a transect up Shark River Slough have been completed and are currently being compiled for a journal article. Age models for all transect cores collected in 2004 and 2005 were developed in FY08 following the same method used for the synthesis of age data on Florida Bay and Biscayne Bay cores by combining carbon-14 and lead-Pb analyses into a calibration model; thus, all age data across south Florida for our estuarine cores can ultimately be compared. In FY08, we focused field and lab efforts on building the southwest coast modern analogue proxy dataset, because the organisms in the southwest vary significantly from Florida Bay, with the exception of the Whitewater Bay region. These new proxy data will improve our interpretation of the downcore data. A key indicator species for the fresh/saline transition zone was identified in the modern environment that will be instrumental in interpreting the cores and potentially for mapping future migration of this critical zone. It was determined in FY08 that the pre-existing wetlands/terrestrial cores collected in the late 1990s are not suitable for analyses. This component of research will be moved to the Salinity Targets project and new sites determined to help address the questions of sea level rise in the southwest coastal area. In FY08, the bulk of our efforts were focused on the Salinity Targets project, but the progress in that area will significantly benefit our knowledge of the southwest coast ecosystem history. Coupled paleoecology/linear regression models developed in collaboration with Dr. Frank Marshall were developed and tested for Florida Bay, but ultimately these same methods will be applied to the southwest cores in the Shark, Harney and Lostmans transects.
NOTE for FY09 all tasks were collapsed into one as we synthesize and wrap up the data and results from this project.
Work to be undertaken during the proposal year and a description of the methods and procedures:
In 2009 we will complete all faunal and floral analyses necessary to interpret the environmental changes occurring temporally and spatially in the transects up the Shark River, Harney and Lostmans River systems. These data will be compiled, reports produced and results presented at meetings. We will begin to collaborate with the RECOVER Southern Estuaries Sub-team members to utilize the southwest data from these cores for the Linear Regression Models. This work will be completed under the Salinity Targets Project.
U.S. Department of the Interior, U.S. Geological Survey
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Last updated: 04 September, 2013 @ 02:09 PM(KP)
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