HR: 16:45h
AN: H32H-04    [PDF]
TI: Hydrologic Controls on Everglades Landscape Form and Function: Physical, Chemical and Biotic Interactions
AU: * Mitchell-Bruker, S
EM: Sherry_Mitchell@nps.gov
AF: Everglades National Park, 950 N. Krome Ave, Homestead, FL 33030 United States
AB: In the Florida Everglades, the natural landscape has evolved over thousands of years to sustain a delicately balanced ecosystem. The annual cycle of wetting and drying controls a variety of chemical, biological and physical processes. Human developments have interrupted this annual cycle by causing changes in water levels that lead to changes in hydroperiod . Relatively small changes in water level cause major shifts in hydroperiod, initiating a cascade of changes that drastically shift the ecosystem out of balance. Soil oxidation, soil formation and shifts in vegetation lead to changes in water chemistry, soil type and habitat value. Losses of soil result in losses in water storage, amplifying the effects of drainage. Keystone species that shape or maintain the landscape are eliminated as habitat value decreases, leading to further degradation of the landforms. To restore Everglades hydrology and ecology, it is necessary to restore the landscape form and function. Restoration of water levels does not necessarily coincide with restoration of hydroperiods, since in many cases soil loss or gain has changed the form of the landscape. Soils that are destroyed by fire in a matter of hours may take decades to rebuild. Sloughs that were maintained by flow and biotic activity have filled in, causing changes in vegetation and increased resistance to flow. To understand restoration it is necessary to identify the critical links between biotic and abiotic communities. Knowledge of current and past responses to hydrologic change can be used to formulate individual metrics that characterize the response of soils, vegetation and fauna to changes in water levels. These individual metrics can be combined and "calibrated" using current and historical soil and vegetation data to produce landscape performance measures. These performance measures are formulated in terms of hydroperiod return frequency to account for inter-annual variability. Application of these performance measures to hydrologic model output allows for quantification of the predicted spatial extent of a given landscape type.
DE: 1030 Geochemical cycles (0330)
DE: 1615 Biogeochemical processes (4805)
DE: 1831 Groundwater quality
DE: 1871 Surface water quality
DE: 1890 Wetlands
SC: Hydrology [H]
MN: 2003 Fall Meeting