Project: Vegetation Dynamics in Land-Margin Ecosystems: The Mangroves of South Florida

Web Site: http://www.fcsc.usgs.gov

Location: Southeast Coast, Southwest Coast; Miami-Dade, Monroe, Collier Counties

Principal Investigators: Thomas J. Smith III, Tom_J_Smith@usgs.gov, 305.348.1267

Project Personnel: Kevin Whelan, whelank@fiu.edu; Christa Walker, walkerc@fiu.edu

Other Supporting Organizations: National Park Service, Fish & Wildlife Service, Florida Department of Environmental Protection

Associated Projects: Hydrologic Variation and Ecological Processes in the mangroves Forests of South Florida: Response to Restoration (James E. Saiers & Thomas J. Smith III); Understanding and Predicting Global Climate Change Impacts on the Vegetation and Fauna of Mangrove Forested Ecosystems in Florida (Thomas J. Smith III & Carole C. McIvor)

Overview & Status: Land-margin ecosystems (mangroves, brackish marshes and coastal lakes / back bays) comprise some 40% of Everglades NP. Primary production in these ecosystems fuels the detrital foodweb which supports sport and commercial fisheries and numerous endangered species (e.g. manatee, wood stork, roseatte spoonbill). Freshwater inflow is critical in regulating the salinity and nutrient regimes of these systems and thus their productivity. In August 1992, the land-margin systems of south Florida were severely damaged by Hurricane Andrew. A great potential exists for water management (i.e. regulation of freshwater inlfow) to impact the natural recovery processes currently underway. The research discussed here asks several questions related to how the hydrologic restoration of the Everglades will affect land margin ecosystems, including: 1) How does freshwater inflow regulate primary productivity? 2) How does freshwater inflow interact with other factors (nutrients, soil type) to influence primary productivity? 3) Is there an affect of freshwater inflow on recovery from natural disturbance in these ecosystems? 4) Does freshwater inflow influence below-ground production, peat formation and soil accretion in mangroves? 5) Will the position of the mangrove / marsh ecotone respond to upstream water management? 6) What non-hydrological factors influence the position of the mangrove / marsh ecotone (e.g. soil type and depth, nutrients, fire)?

Needs & Products: This research addresses several important needs of the Greater Everglades Restoration including: 1) Mangrove primary productivity is a key indicator in the Mangrove Conceptual Model and forms the basis of the detrital foodweb that supports secondary production of estuarine fishes and crustaceans; 2) Secondary productivity in mangroves (e.g. commercially and recreationally important estuarine fisheries) is a key component of biological performance measures for restoration success and is used in the Mangrove Conceptual Models. Estuarine fish production is identified as a key Success Indicator. 3) Understanding processes of soil building, sediment accretion and erosion have been identified as critical to measuring restoration success. 4) Landscape level changes in the position of the mangrove / marsh ecotone indicate largscale vegetation change in the coastal zone. Vegetation change monitoring has been identified as a priority issue. 5) Data from the studies of primary productivity will be used in the ATLSS modeling program in the development of the mangrove community and landscape models. 6) Actual field measurements of sediment accretion / erosion will be vital to the development of models regarding soil dynamics.

Application to Everglades Restoration: These field data will be needed to calibrate landscape scale soil elevation models which are a CESI FY 2001 priority.