Carol McIvor
<http://www.nrel.colostate.edu/brd_global_change/proj_29_florida_mangroves.html>
The data generated by this project is being used in models (hydrological and ecological) for gauging restoration success. The data are also being used in the formulation of Performance Measures. For example, spatial data on the movement of the mangrove / marsh ecotone (derived from the digital historical aerial photographs) will be used to provide a pre-drainage baseline of the Everglades ecosystem and metrics of success in restoration.
Smith, Thomas J., III
Ewel, K. C. Keeland, B. D. Tara, T. Smith, T. J., III
Genereux, David P. Saiers, James E.
Saiers, James E.
Hurricane damage to mangrove forests is most often followed by seedling recruitment, tree growth and forest recovery. Occasionally, however, recovery fails to occur over some affected areas, likely because of site-specific changes in sediment loss and character. Such sediment-related changes in pockets along mangrove-forested creeks in the Big Cape Sable Creek (BSC) complex have resulted in a mosaic of mangrove forests and either adjacent or partially enclosed mudflats of a range of sizes. Our goal is to take advantage of this situation to ask: “ what is the consequence of long-term habitat conversion from mangrove forests to pocket mudflats - with a concomitant increase in the amount of edge - following hurricane landfall?”
During FY2002, the seven major creeks of the BSC complex were exhaustively explored for three creeks that would meet the following criteria: suitable forest and mudflat sites occurred along a single creek; sites were approachable by research boat but were removed from areas most frequently used by the boating public; replicate creeks were available with both habitat types; mudflats were of a size that could be sampled with existing gear (intertidal rivulet nets) used along the Shark River transect. We were delayed in April 2002 in building necessary researcher walkways along intertidal rivulets at the 3 mudflat sites because of a change in ENP policy about compliance with the Wilderness Act and the possible need for NEPA review. We currently (June 2002) have detailed documentation into permitting channels at ENP regarding choice of safe environmental materials, but have been stymied in our efforts to obtain a valid research permit for this portion of the work. Efforts are continuing.
The degree and duration of tidal flooding appears to greatly affect the suite of species capable of routinely using the intermittently available flooded mangrove forest floor. Similarly, the amount of variability in physicochemical parameters, specifically salinity, appears to be another “filter” for species capable of surviving wide ranges in variability in exchange for expanded habitats exploited.
Fish sampling stations have been established at three sites along the salinity (and flooding) gradient to test this hypothesis. Samples have been, and will continue to be taken every two months from replicate nets and two methods at each site. The objectives in the next fiscal year are to quantify the micro-drainage basins draining into each of 9 intertidal nets, and to begin integrating biological and physicochemical data to partition the variance due to the multiple factors affecting fish productivity.
Fire appears to play a crucial role in the maintenance of the coastal marine prairies within Everglades National Park and elsewhere in far south Florida. Occurrence of marsh fires may impact the ability of mangrove forests to invade marsh areas. The objective of this task is to understand the effect of fire on controlling the spatial extent of mangrove expansion into upstream coastal marine prairies.
A transect has been established across a mangrove marsh ecotone adjacent to the Harney River for detailed study. A series of permanent vegetation plots have been set up to measure mangrove tree growth and seeding recruitment. Replicate sediment porewater sampling wells are monitored near each vegetation plot. Mangrove seedling transplants have been established to assess the ability of mangroves to grow under a sawgrass canopy. In conjunction with ENP Fire Cache, a controlled burn was conducted to assess fire impacts on the vegetation along the ecotone. Sampling of the burn area will continue. Available data on the location of historical fires will be entered into a GIS system for comparison with overlays of the movement of the ecotone with time.
Measure changes in the position of the mangrove – marsh ecotone over recent time (1920s to present). Relate movement of the ecotone to measurable environmental factors such as recent sea level variation and freshwater inflow. Estimate decadal and greater term variation via down core analyses of long cores taken at sites SH1-5.
Assist with scanning historical aerial photographs of the coastal regions of Everglades NP and south Florida. Photos will be scanned at 800dpi, mosaiced and georeferenced for use in conventional GIS packages. Position of the mangrove / marsh ecotone will be determined by photo interpretation and changes maps developed. The scanned photos will be compiled into CD / DVD sets for distribution to clients as USGS Open File Reports. Sediment cores from sites SH1-5 will be collected by vibracoring. Cores will be returned to the lab for processing by collaborating USGS scientists.
Seventeen hydrological sampling stations have been established across the mangrove marsh ecotone at four locations in Everglades National Park (downstream of the C-111 canal, Shark River Slough, Lostmans River and the Chatham River). Each station consists of at least two sampling wells, one for groundwater and one for surface water. Subsets of stations are instrumented to sample soil water and measure rainfall. Data are collected at intervals ranging from every hour to every four hours depending on the ability to recharge batteries. Data are downloaded daily and archived for later QA/QC operations. In FY02 significant equipment upgrade is being carried out to standardize instrumentation across all sites. During FY03 and 04 the network will be operated and the data distributed to all parties, especially the TIME modeling group and the hydrology section at the South Florida Natural Resources Center.
U.S. Department of the Interior, U.S. Geological Survey, Center for
Coastal Geology
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