projects > development and stability of everglades tree islands, ridge and slough, and marl prairies > project summary
Project Summary Sheet
Fiscal Year 2005 Study Summary Report
Study Title: Development and Stability of Everglades Tree Islands, Ridge and Slough, and Marl Prairies
Overview & Objective(s): Everglades restoration planning requires an understanding the impact of natural and human-induced environmental change on wetland stability. This project initially focused on tree-island development and trends and has expanded into two other systems: the sawgrass ridge and slough system and marl prairies. For each system, restoration targets are being proposed, even though little data exists on their predrainage extent and ecosystem dynamics. Initial goals of the project included: determine geologic and hydrologic controls on tree-island formation, development and sustainability; establish vegetational trends in tree-island development; determine the role of tree islands in the geochemical budget of nutrients; and investigate the use of sediment phosphorus as a tracer of historic bird populations in the Everglades.
Investigations of the Ridge and Slough system are directed to: determine the longevity of the features; document changes in spatial extent of sawgrass ridges and sloughs; determine past rates of peat accretion in ridges vs. sloughs; determine whether sawgrass ridges are analogs for sites of tree-island formation; and assess the response of ridges and sloughs to natural and anthropogenic hydrologic changes. Investigations of marl prairies are designed to determine whether the distribution and vegetational composition of marl prairies has changed over the last century.
Status: By the end of FY05, cores will have been collected on 39 tree islands in Loxahatchee NWR, WCA 2A, 3A, 3B, and Everglades National Park (Shark River Slough and Taylor Slough). Pollen and geochronologic data have been generated from 27 cores representing 15 tree islands. Six transects of cores were collected across "pristine" and altered sawgrass ridges and sloughs sites in WCA 3A. From these, pollen analysis is complete on surface samples and four transects, representing a total of 11 cores. In FY 04-05, field work included coring of strand and pop-up tree islands in Loxahatchee NWR and tree islands in the East Everglades Expansion Area of Everglades National Park. A long core (5 meters) also was collected in Deep Lake (BCP) to evaluate natural and anthropogenic patterns of change in an ancient sink-hole lake in a relatively pristine area of the Preserve. Analysis of sediment cores collected in marl prairies in the western Everglades as a pilot study indicated that pollen, plant macrofossil, and ostracode records all provide good records of vegetational and hydrologic change in marl-accumulating systems, and we intend to sample other such sites to document the timing of vegetational changes and correlate them with specific hydrologic events. In Loxahatchee, we collected cores on nine tree islands and nine marshes in the northern, central, and southern reaches of the Refuge to establish the original ecosystem structure and composition and evaluate changes in response to 20th century management changes. During the summer of FY05, four tree islands in the East Everglades Expansion Area of Everglades National Park will be cored in collaboration with archeological research conducted by park personnel.
Willard, D.A., Holmes, C.W., Korvela, M.S., Mason, D., Murray, J.B., Orem, W.H., and Towles, D.T., 2002. Paleoecological insights on fixed tree island development in the Florida Everglades: I. Environmental Controls. In Sklar, F.H., and van der Valk, A. (Eds.), Tree Islands of the Everglades: 117-152.
Orem, W.H., Willard, D.A., Werch, H.E., Bates, A.L., Boylan, A., and Corum, M., 2002, Nutrient geochemistry of sediments from two tree islands in Water Conservation Area 3B, the Everglades, Florida. In Sklar, F.H., and van der Valk, A. (Eds.), Tree Islands of the Everglades: 153-186.
Willard, D.A. and Orem, W.H. 2003, Tree-Islands of the Florida Everglades - A Disappearing Resource, U.S. Geological Survey Open-file Report 03-26: 2 pp.
Bernhardt, C.E., Willard, D.A., and Holmes, C.W., 2003, Development and Stability of the Everglades Ridge and Slough Landscape. U.S. Geological Survey Open-file Report 03-54: 128.
Willard, D.A., 2004, Tree Islands of the Florida Everglades Long-term Stability and Response to Hydrologic Change, U.S. Geological Survey Open-file Report 2004-3095: 4 pp.
Bernhardt, C.E., Willard, D.A. 2004. Influence of 20th century water management on plant communities in Everglades marl prairies. First National Conference on Ecosystem Restoration.
Willard, D.A., 2004. Impacts of land-cover and hydrologic change on vegetation of the south Florida coast. First National Conference on Ecosystem Restoration.
Bernhardt, C.E. and Willard, D.A., 2004. Development and Stability of the Everglades Ridge and Slough Landscape: Records from three transects in Water Conservation Area 3A. U.S. Geological Survey Open-file Report 2004-1448.
Willard, D.A., Bernhardt, C.E., Weimer, L.E., Cooper, S.R., Gamez, D., and Jensen, J., 2004. Atlas of pollen and spores of the Florida Everglades. Palynology 28: 175-227.
Bernhardt, C.E. and Willard, D.A., in prep. Influence of 20th century water management on plant communities in Everglades marl prairies. Fall 2005.
Orem W., Willard D., Lerch H., Corum M., Bates A., and Barnhardt C. (2005). Distributions of soil carbon and nutrients on tree islands in the Everglades. Open-File Report, U.S. Geological Survey. Fall 2005.
Orem W., Newman S., Lerch H., Corum M., Bates A., and Willard D. (2006) Biomarkers of wading bird populations on tree islands of the Everglades. Organic Geochemistry. Winter 2006.
Willard, D.A., Bernhardt, C.E., Holmes, C.W., Landacre, B., and Marot, M., in review. Tree Islands of the Everglades Ridge and Slough Region: Response to Environmental and Climatic Variability, Ecological Monographs.
Willard, D.A., Bernhardt, C.E., Holmes, C.W., and Marot, M., in prep. Everglades wetland response to hydrologic fluctuations: climatic vs. human impacts. In Jones, J.W. (Ed.), Topical Report on Everglades land surface history and process modeling. USGS Bulletin. Winter 2005.
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: http://sofia.usgs.gov/publications/reports/doi-science-plan/]:
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).
U.S. Department of the Interior, U.S. Geological Survey
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Last updated: 15 January, 2013 @ 12:43 PM(TJE)