National Park Service

South Florida/Caribbean I&M Network (SFCN)

Coastal Geomorphology Monitoring

Collecting soil elevation data in Biscayne National Park.
Collecting soil elevation data in Biscayne National Park.

Monitoring Reports

Journal Articles & Publications

Protocol

The SFCN Soil Elevation Table Monitoring Protocol is currently under development.

For more information contact:
Kevin R. T. Whelan, Ph D.

Importance/Issues

Soil dynamics (the build up or loss of sediment) is a basic process that can have far reaching impacts on an ecosystem. This process is especially important in mangroves, mudbanks, and salt ponds where small changes in elevation can have large changes in hydroperiod, tidal inundation, flushing and circulation. These in turn impact coastal vegetation and marine life in associated water bodies. Everglades restoration of regional hydrology, changes in water deliveries, large storm events, and sea level rise could all affect these soil dynamics and have implications for long-term changes in coastal wetlands. In the U. S. Virgin Islands, sediment filling of ephemeral guts and salt ponds from upland development is another important factor. Larger scale questions involve whether mangrove forest elevations will keep pace with sea level rise and what will be the effects of sea level rise on Florida Bay's berms, embankments, and mud banks.

Monitoring

  • What are the status and trends in soil dynamics (accretion, subsidence and erosion) in mangroves, mud-banks, and salt ponds, especially in relation to changes in hydrology (quality, quantity, timing and duration) sea-level, storms/hurricanes, and upland erosion?
  • Where do berms, embankments and mud banks in Florida Bay change in location?

Status and Trends

SFCN Monitoring in Biscayne National Park (BISC), Virgin Islands National Park(VIIS) and Salt River Bay National Historical Site and Ecological Preserve (SARI)

Figure 1. Sampling  Surface Elevation Table monitoring site in BISC, EVER, SARI and scouting sites in VIIS.
Figure 1. Sampling Surface Elevation Table monitoring site in BISC, EVER, SARI and scouting sites in VIIS.

In 2013, we sampled the two soil elevation monitoring sites in BISC and one site in SARI twice this year, and assisted with sampling five sites in EVER once this year. We were able to scout locations of potential sites in Virgin Islands National Park (VIIS) in April 2013. Scouting site selection was constrained by history of mangrove forest presence, forest tree size, intertidal location, influences from road bed runoff and an attempt to minimize vandalism (Figure 1). The SFCN was supposed to establish two soil elevation monitoring sites in VIIS this year; however, due to sequestration there was insufficient funds for travel and purchase of installation supplies. We have a protocol in draft form which builds upon the NPS protocol Monitoring Salt Marsh Elevation Cape Cod National Seashore and the Louisiana Department of Natural Resources Coastal Restoration Division. We are delaying the completion of the SFCN protocol until VIIS sites have been installed and the NPS protocol for measuring and understanding wetland elevation change (Lynch et al.) is completed since this is referenced extensively in the SFCN protocol and will be the guiding SET protocol in the nation. The SFCN spent 240 person hours in the field working on this vital sign.

Figure 2. X-ray computed tomography scan (CTscan) of the coronal image of the top of soil sample 6A to assess compaction and plant structures (Smithsonian Institution).
Figure 2. X-ray computed tomography scan (CTscan) of the coronal image of the top of soil sample 6A to assess compaction and plant structures (Smithsonian Institution).

Additionally, we collaborated with Dr. Marguerite Toscano (Smithsonian Institution) and Dr. Juan Gonzalez (University of Texas-Pan American) to sample mangrove peat cores in BISC in 2012 (FY12). We collected 10 basal peat samples over a surveyed depth range of -4.6 to -0.6 m MSL (relative to mean sea level) and two full (>4.6-6 m) cores for radiocarbon dating and other analyses. In 2013 (FY13) the peat cores have been described, photographed in field and lab, XRF scanned (U of Miami; 10kV- lighter elements (Al to Fe); 30 kV - heavier elements (Ni to Bi)), sampled for 18 AMS radiocarbon dates (completed/obtained), CT scanned to assess compaction and plant structures (Smithsonian) (Figure 2), sampled and analyzed for water content, bulk density and loss on ignition (UTPA). The deepest basal peat was collected from -4.6 m MSL, while a deeper core reached -6.41 m MSL without contacting bedrock. A Holocene sea level analysis is complete and will be published pending completion of the CT scanning and image interpretation, which provides the information needed to quantify peat density and structural changes down core and whether the peat sequence accurately tracks sea level as compared to previous coral-based and geophysical sea level models.

IN 2014, we will establish two SET sites in VIIS. We will finish adapting the SFCN SET protocol. We will continue biannual monitoring of the existing SET sites. We will continue to collaborate with Drs. Toscano and Gonzalez investigating the paleohistory of peat cores in BISC.

Everglades National Park

CERP RECOVER 2009 System Status Report has a summary of "Mangrove Forest Soil Accretion/Subsidence" in its RECOVER: 2009 System Status Report for the Greater Everglades: Everglades Coastal Wetlands Results.

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Approach

Soil Elevation Table (SETs) in Biscayne National Park (BISC), Virgin Islands National Park(VIIS) and Salt River bay National Historical Site and Ecological Preserve (SARI)

SFCN is adapting a "Soil Elevation" protocol for installing and monitoring soil elevation tables in mangroves at a number of the parks (BICY, BISC, SARI, VIIS) and in salt ponds at BUIS and VIIS. Soil Elevation Table (SET) monitoring involves establishing permanent select sites in mangrove forests and is designed to measure changes in soil surface elevation, accretion and erosion.

Mangrove SET sites must be typical mangrove forests with significant peat depth accumulation, limited access by the public, low trash buildup, and uniformity of vegetative cover. At each site three deep-rod Soil Elevation Table benchmarks are installed following National Geodetic Survey guidelines to enable measuring changes in elevation. Three feldspar marker horizons plots are established per benchmark and are used to measure vertical accretion and erosion. Data collection involves placing a SET "arm" of nine fiberglass pins on top of the benchmark pipe. Distance of all nine pins to the soil surface is measured at four SET "arm" positions per benchmark. Feldspar plots are cored at each sampling date to determine rate of accretion or erosion.

The SET sites in Biscayne National Park are complimentary to the SET monitoring project initiated by the US Geological Survey in Everglades National Park, allowing a more wide-scale look at the ecological processes shaping the geomorphology of the coastal mangrove ecosystem in south Florida.

Soil Elevation Table (SETs) in Everglades National Park

SFCN will link to existing reporting of EVER monitoring, i.e., the southwestern mangroves being conducted by Thomas J. Smith III of the U. S. Geological Survey (USGS), and the Taylor River mangroves sites being conducted by the Fred Sklar of South Florida Water Management District (SFWMD) in conjunction with the Florida Coastal Everglades Long term Ecological Research sites (FCE-LTER). SFCN staff also occasionally provides assistance with data collection and site maintenance at the USGS sites.

Mapping of mud banks in Florida Bay

This element is currently deferred due to insufficient funding and staff time.

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Last Updated: March 27, 2017 Contact Webmaster