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Project Summary Sheet

U.S. Geological Survey, Greater Everglades Priority Ecosystems Science (GE PES) Initiative

Fiscal Year 2007 Study Summary Report

Study Title: Synthesis of South Florida Ecosystem History Research
Study Start Date: 10/1/04 Study End Date: 9/30/07
Web Sites: and
Location (Subregions, Counties, Park or Refuge): Everglades NP, Biscayne NP, Big Cypress Preserve, Ten Thousand Islands NWR, Loxahatchee NWR, WCA 2, 3; Broward, Collier, Dade, Monroe, Lee and West Palm Beach Counties.
Funding Source: USGS Greater Everglades Priority Ecosystems Science (PES) Initiative
Annual Costs: FY05: (50/50 split between tasks); FY06 (50/50 split between tasks); FY07 (Task 1; Task 2).
Principal Investigator(s): G. Lynn Wingard and Debra A. Willard
Study Personnel: T. Cronin, C. Holmes, D. Willard, L. Wingard, USGS. J. Hudley, Contractor.
Supporting Organizations: South Florida Water Management District, ACOE, NOAA, Everglades National Park, Biscayne National Park, Big Cypress Preserve, Ten Thousand Islands NWR, Loxahatchee NWR, Florida Fish & Wildlife Conservation Commission
Associated / Linked Studies: Interrelation of Everglades Hydrology and Florida Bay Dynamics (Ecology Component), Tides and Inflows in the Mangrove Ecotone (TIME) Model Development, Ecosystem History of the Southwest Coast-Shark River Slough Outflow Area, Paleosalinity as a Key for Success Criteria in South Florida Restoration, Historical Changes in Salinity, Water Quality and Vegetation in Biscayne Bay

Overview & Objective(s): Everglades restoration planning requires an understanding of the impact of natural and human-induced environmental change in shaping the current ecosystem. Recent and ongoing research in the wetlands and estuaries is documenting biotic responses to specific environmental changes in specific parts of the greater Everglades ecosystem (tree islands, sawgrass ridges, sloughs, marl prairies, mangroves) and throughout Florida and Biscayne Bays. Data generated in these projects are being evaluated in the context of possible restoration strategies to improve prediction of future ecosystem response. This project is intended to synthesize all data generated to date on the history of the Greater Everglades ecosystem and the response of various components to climatic and anthropogenically derived change. This will provide land managers with a concise summary of the most current information on ecosystem history for South Florida and it will identify gaps in information needs for additional work.

Status: All ecosystem history data for Biscayne Bay and Florida Bay have been compiled, standardized, and verified to original records; database version 1 was released April 2006 and version 2 April 2007 (available at The molluscan data were extracted from the standardized dataset and statistically analyzed to produce a reliable modern proxy data set that correlates to salinity (correlation value 0.8). All age data from cores in Biscayne Bay and Florida Bay have been compiled, standardized, and comparable age models produced; open file report released Summer 2007. These two steps serve as the basis for all additional core interpretations which will roll over into Task 7 in FY08.

Summaries of a qualitative assessment of the spatial and temporal changes in the estuaries have been completed and presented at GEER, NCER and several meetings with the land management agencies. These data are currently being used to develop target salinity values for the estuaries. We have continued to collaborate with the Southern Estuaries Sub-team of RECOVER, and have provided all data and information available on historical salinities to them. In addition, the modeler working with RECOVER has successfully used our data in his linear regression models to hindcast historical flow conditions in the terrestrial Everglades.

Pollen data are posted on the North American Pollen Database (at the World Data Center for Paleoclimatology in Boulder, CO ( and at the US Geological Survey South Florida Information Access (SOFIA) site ( as publications are released.

Recent Products:
Bernhardt, C.E. and Willard, D.A., 2006. Marl prairie vegetation response to 20th century hydrologic change. U.S. Geological Survey Open-File Report 2006-1355.

Willard, D.A., Bernhardt, C.E., Holmes, C.W., Landacre, B., and Marot, M., 2006. Response of Everglades tree islands to environmental change. Ecological Monographs 76 (4): 565-583.

Willard, D.A. and Cronin, T.M., 2007 (in press). Paleoecology and ecosystem restoration: Case studies from Chesapeake Bay and the Florida Everglades. Frontiers in Ecology and the Environment 5 (9): 8 pp.

Wingard, G.L., and project members, 2006, 2007, Ecosystem History Access Database, available at

Wingard, G.L., (with contributions by T.M. Cronin and W. Orem), Ecosystem History, chapter 3 of Nuttle, W. and Hunt, J., (eds.), Florida Bay Science Program: A Synthesis of Research on Florida Bay: Florida Fish and Wildlife Research Institute Technical Report TR-11, pp. 9-29.

Wingard, G.L., 2006, Defining Natural Freshwater Flow for Critical Ecosystems: A case study from South Florida: Geological Society of America, Abstracts, Special Meeting Sept. 2006, Managing Drought and Water Scarcity in Vulnerable Environments.

Wingard, G.L., Hudley, J.W., Holmes, C.W., Willard, D.A., and Marot, M., 2007, Synthesis of Age Data and Chronology for Florida Bay and Biscayne Bay Cores Collected for Ecosystem History of South Florida's Estuaries Projects: USGS Open File Report 2007-1203. (Directors approval 7/3/2007 - currently being converted to html in St. Pete for uploading to SOFIA)

Oral presentations have been given to the Southern Estuaries Sub-Team of the RECOVER Regional Evaluation Team (6-2005, 9-2006) Fish & Wildlife, South Florida Water Management District and ACOE personnel (8-2006), Southern Prairie Workshop (5/07), and Natural Systems Modeling workgroup (7/07). In addition, a workshop was organized on Paleoecology for the Greater Everglades Ecosystem Restoration Conference and National Conference on Ecosystem Restoration.

Planned Products:

Journal article to be submitted to Holocene or Quaternary Research: Working Title: Development of a salinity transfer function using molluscan assemblages: a tool for restoration. All analyses are complete and figures done. Write up 3/4 complete so should be in review this fall. Purpose of this paper was a "proof of concept" to illustrate how well the assemblage data predict the salinity by testing with modern samples.

Submission of article entitled “Climate variability and anthropogenic impacts on wetland development: the sawgrass ridge and slough landscape, Everglades, Florida” to Wetlands by winter, 2007. Manuscript ready for submission for USGS review.

Journal article to be submitted to Ecological Applications: Marl prairie response to 20th century hydrologic change. Anticipated submission spring, 2008.

Factsheet illustrating some of the changing patterns we have detected in Florida Bay and Biscayne Bay - based on presentations given at GEER and NCER - early winter FY08.

Policy paper on application of paleoecology to set targets for restoration.

Specific Relevance to Information Needs Identified in DOI's Science Plan in Support of Ecosystem Restoration, Preservation, and Protection in South Florida (DOI's Everglades Science Plan) [See Plan on SOFIA's Web site:]:

One of the primary 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 Synthesis of ecosystem history data from the wetlands and estuaries of South Florida will provide the necessary data to achieve this goal.

Task 1 of this study supports several of the projects listed in the DOI science plan, specifically: Arthur R. Marshall Loxahatchee NWR Internal Canal Structures; Water Conservation Area 3 Decompartmentalization and Sheetflow Enhancement; and Combined Structural and Operational Plan) by (a) documenting the timing of tree-island formation across the region; (b) establishes patterns of vegetation development and geochemical changes on the islands; (c) comparing development of different types of tree islands; (d) developing a model of tree-island formation that may be used in restoration of degraded islands and, possibly, creation of new islands; and (e) determining the duration of flooding or drought that tree islands can tolerate before changes in aerial extent occur.

The study supports the Arthur R. Marshall Loxahatchee NWR Internal Canal Structures project (LNWR; p. 39) as it (1) provides data about historic hydrologic and ecological conditions on the refuge (p.40) and (2) helps understand the ecological effects of hydrology and water quality on refuge resources (p. 40) The study supports the Water Conservation Area 3 Decompartmentalization and Sheetflow Enhancement project (DECOMP; p. 66) as it (1) helps understand the linkages among the geologic, hydrologic, chemical, and biological processes that shaped the predrainage Everglades (p. 68); (2) helps understand the critical factors for sustaining tree islands, ridge and slough habitats, and marl prairies (p. 68); and (3) helps understand the effects of different hydrologic regimes and ecological processes on restoring and maintaining ecosystem function (p. 69).

This study supports the Combined Structural and Operational Plan project (CSOP and Mod Waters; p. 70) as it (1) generates information that will improve ecological models and make them more suitable for application of the Natural Systems Model (p. 71).

Task 2 of this study directly supports the needs of the Southern Estuaries Sub-Team (SET) of the Regional Evaluation Team (RET) of RECOVER. The SET is interested in potential data generated by this project to help set performance measures (PMs) for the southern estuaries. 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 primary tool for setting the PMs for the southern estuaries.

In addition, this study supports the Florida Bay and Florida Keys Feasibility Study Project, the Additional Water for Everglades National Park and Biscayne Bay Feasibility Study Project, the Biscayne Bay Coastal Wetlands Project, the Southern Golden Gate Estates Hydrologic Restoration, and the Southwest Feasibility Study Projects. This study supports these projects by 1) synthesizing research to understand the predrainage hydrology, including the amount, timing and seasonality of freshwater delivered to the estuaries of south 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

This study supports the Florida Bay and Florida Keys Feasibility Study Project by addressing the questions 1) What are the links between impediment to circulation created by the causeway and the ecology of Florida Bay . . .?” (DOI Science Plan, p. 64), “What are the links between freshwater inflows to Florida Bay and the ecology of the bay?” (p. 65), and “What is the ecological response to hydrologic change?” (p. 66). 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 and Taylor Sloughs and Biscayne Bay 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 Biscayne Bay Coastal Wetlands Project by addressing the questions “How much freshwater, and in what seasonal patterns, was delivered historically to Biscayne Bay?” (DOI Plan, p. 63), “What are the links between hydrology and ecology in the Biscayne Bay coastal wetlands?” (p. 64), and “What are the key indicators of natural ecological response . . .” and “what are the baseline conditions of the indicators?” (p. 66). The data generated by this project are particularly valuable because they provide 100 to 500 years worth of data on changes to the system. 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). 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).

Key Findings:
Results from the qualitative summary of the estuarine data indicate the following:

  • Changes were occurring in the system prior to 1900 - at most sites there is a gradual increase in salinity over time. These changes are consistent with sea level rise.
  • HOWEVER - the rate of change has increased in the 20th century at many sites.
  • Homogenization of the estuarine environment seems to be taking place in the later part of the 20th century. Euryhaline, lower diversity environments are found in areas that were polyhaline and more diverse around 1900.

Quantitative analysis of modern molluscan faunal assemblage data has demonstrated that it serves as an accurate proxy for salinity, with a correlation value of 0.8.

Pollen-based reconstruction of Everglades hydrologic variability over the past 2000 years indicates that the system fluctuates between severe droughts and wet conditions. During droughts, deep-water slough vegetation was replaced by drought-tolerant species and moderate hydroperiod marshes (such as during the MWP). In some cases, the system was resilient enough to recover to pre-drainage states within a few decades, but in others, droughts triggered long-term development of different communities, such as tree islands and sawgrass ridges.

Everglades pollen data generally indicate that pre-drainage hydroperiods were longer and water depths greater than in the modern wetland. This translated into greater delivery of freshwater and lower salinities in the estuaries before the onset of water management, documented by molluskan and benthic foraminiferal assemblages from Florida Bay and the freshwater-saltwater ecotone near Biscayne Bay. The conflict between proxy-based estimates of pre-drainage salinity and hydroperiod with predictions from ecosystem models (which consistently predict higher salinity and shorter hydroperiod than the paleoecological data) has highlighted the necessity of using paleoecological data to calibrate and verify models used to establish restoration targets.

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