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publications > open file report > OFR 2004-1448
U.S. Department of the Interior
U.S. Geological Survey
OFR 2004-1448
Anthropogenic and Natural Variation in Ridge and Slough Pollen Assemblages
Bernhardt, C.E.1, Willard, D.A.1, Marot, M.2, and Holmes, C.W.2
1U.S. Geological Survey, Eastern Earth Surface Processes Team, 926A National Center, Reston, VA 20192
2U.S. Geological Survey, Center for Coastal and Marine Geology, 400 6th Street South, St. Petersburg, FL 33701
Abstract
We present pollen evidence documenting the response of sawgrass ridge and slough systems of the Florida Everglades to hydrologic changes during the last 3,500 years. Sediment cores and surface samples were collected in three transects across sawgrass ridges and sloughs in Water Conservation Area 3A to determine the age of the features, long-term variability in plant community composition, stability of sawgrass ridge and slough size, and their response to 20th century changes in hydrology. Statistically significant differences in abundance of Cladium pollen in surface samples collected throughout the system allow differentiation of these communities in the sedimentary pollen record. Analysis of pollen in cores from the three transects indicates that the general distribution of ridges and sloughs has remained distinct through time. There is evidence the vegetation has responded to past global-scale climate events, such as the Medieval Warm Period, as well as the 20th century anthropogenic alterations to the natural hydrology. The ridge community is more responsive and susceptible to perturbations in hydrology than the slough community. In contrast, the slough plant community is more stable and less likely to demonstrate long-term changes after perturbations to hydrology. Regardless, these data indicate that the ridge and slough landscape is resilient to changes in hydrology and posses the potential to return to a natural state with the return of natural hydrologic conditions.
Introduction >
December, 2004
NOTE: Report not reviewed for consistency and standardization by USGS
Related information:
SOFIA project: Development and Stability of Everglades Tree Islands, Ridge and Slough, and Marl Prairies
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