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projects > sediment elevation and accumulation in response to hydrology, vegetation and disturbance in the southwest coastal everglades > work plan

Project Work Plan

Department of Interior USGS GE PES
Fiscal Year 2014 Study Work Plan

Study Title: Sediment Elevation and Accumulation in Response to Hydrology, Vegetation and Disturbance in the southwest Coastal Everglades
Current Study Start Date: 1 October 2013 Current Study End Date: 30 September 2014
Location (Subregions, Counties, Park, or Refuge): Everglades NP, Miami-Dade and Monroe Counties
Funding Source: USGS
Funding History: Initially, the project was funded by the USACOE as part of CERP. The project was picked up in FY13 by GEPES.
FY14 USGS Funding:
Principal Investigator: T.J. Smith III
USGS Project Officer: T.J. Smith III
USGS Technical Officer: B. Turrentine
Supporting Organizations: Everglades NP and the South Florida - Caribbean Inventory and Monitoring Unit occasionally provide personnel to assist with sampling.

Overview & Objectives: Sea level has been rising at Key West, FL for over 100 years at a rate of approximately 2.24 mm•yr-1 (Maul and Martin 1993, and see: ). The rate at which sea level is rising is expected to increase in the coming years and may approach 20 mm•yr-1 (Donoghue 2011). An important question for resource managers at the local, state and federal level is: "Will coastal wetlands (e.g. mangrove forests and salt marshes) keep pace with SLR?" This "keeping pace" may take the form of the wetland accreting vertically by building peat and / or migrating upstream along coastal river channels (Smith et al. 2009). Sediment accretion has been identified as a key component for monitoring of the Everglades' restoration (Comprehensive Everglades Restoration Plan (CERP) Monitoring and Assessment Plan 2009, pages 3-88 and 3-112). Over the past 15 years, the U.S. Geological Survey, Southeast Ecological Science Center, has developed a network of sediment elevation monitoring sites in the southwest coastal portions of Everglades National Park (ENP, see Fig. 1). Sediment elevation change is monitored by the use of a Surface Elevation Table or SET (described below). Another factor that influences coastal wetlands is disturbance. This may be in the form of storm surges and wind damage from tropical cyclones, and fire and freeze events (Smith et al. 2013). A storm surge may have positive benefits by depositing sediments, thus raising elevation, or it could cause erosion of the sediments, thus lowering elevation. Hurricane winds, however, may destroy large tracks of the mangrove forest, which do not necessarily recover (Smith et al. 2009). Thus, long-term monitoring of wetland elevation and vegetation dynamics is necessary to gauge restoration success in the coastal Everglades.

Specific objectives:

Specific Relevance to Major Unanswered Questions and Information Needs Identified:

This work addresses specific goals for the Greater Everglades Module, Monitoring and Assessment Plan: Mangrove forest community dynamics and soil accretion / subsidence.
(See: Page 3-112, 113)

map showing site locations Figure 1. Study site locations along the Shark (SH) and Lostmans (LO) Rivers and at Big Sable Creek (BSC). [larger image]


Planned Products for FY14: Datasets for USGS Data Series reports and at least one peer reviewed journal publication.

Work Plan

1) Task Title: Re-measure sediment surface elevation tables and feldspar marker horizons
Task Leaders: T.J. Smith III
Phone: 727-502-8130
FAX: 727-502-8001
Task priority: High
Task Personnel: G. Tiling-Range, Contracted through CNTS

Task Summary and Objectives:
We will resample a network of SETs and marker horizons that was established in the Everglades beginning in 1998. There are base and support pipes that remain permanently at the various study sites. The SET itself is a portable device that fits into the base pipe and is moved from support to support. The SETs are both the "original" design (Boumans and Day 1993) and the newer shallow and deep rod designs (Cahoon et al. 2002a, b). The shallow rod SETs measure the dynamics of the root zone. Deep rod SETs are driven into the limestone base below the peat layer and sample the entire sediment body. For each SET design, measurements are made at four directions from the base pipe. At each direction, nine pins are lowered to the sediment surface and measured. Thus, 108 measurements are made for each type of SET (3 SETs x 4 directions x 9 pins = 108). Marker horizons consist of feldspar (a white colored, clay-like mineral). This is spread on the sediment surface in a known location (marked with PVC stakes) near the SETs. The thickness of material on top of the horizons is measured at each sampling. Changes in the thickness of the layer over time are calculated. A positive change is termed accretion, and a negative change is erosion. By comparing measured elevation and accretion (or erosion), subsidence / expansion of the sediment body can be determined (Whelan et al. 2005, 2009). The SET and marker horizon sites are on two transects, one along the Shark River (SH) and one along the Lostmans River (LO, Fig. 1). There are six sites on the SH transect (SH1 - SH5) and a site at Big Sable Creek (BSC, on the northwest corner of Cape Sable). The LO transect has three sites (LO1-3). There are three SETs of each type at each site. The SETs have been surveyed to the NAVD88 vertical datum and so the sediment surface elevations are also be reported in this datum.

Specific Task Products:

Product: Data on sediment surface elevation change in the southwest coastal Everglades added to the long-term database.

Delivery Date: August - September 2014

2) Task Title: Upgrading and expanding a spatially explicit geodatabase for the project's data
Task Leaders: T.J. Smith III
Phone: 727-502-8130
FAX: 727-502-8001
Task priority: High
Task Personnel: Ginger Tiling-Range, Contracted through CNTS

Task Summary and Objectives:
A geodatabase for serving various types of data for the coastal Everglades was initiated several years ago (Tiling et al. 2008). This original database was intended to allow for the entry and analysis of the long-term vegetation plot data. We will upgrade the database by entering the site mean SET data for all sites and sampling dates. Additionally, we will add the historical coastal charts and aerial photos for the project study sites (Smith et al. 2002a, b). Finally, we will compile information for sediment cores collected by other researchers over the years within Everglades National Park. Many of the scientists published core logs showing detailed lithology for their collected material (e.g. Dolsen & Riegel 1966, Cohen & Spackman 1977). These will be scanned and entered into the database.

The database was initiated in MS Access and has a Graphical User Interface (GUI) for ease of use (Tiling et al. 2008). As new data layers are added we will expand the GUI to include them. The system will be constructed such that users can "point and click" to see the data layers for each of the SET sites and download the data if desired. The geodatabase will be posted online, most likely on the SOFIA website. A user's manual will be written and posted with the geodatabase. Together these tools will allow for easy access for data viewing, quality control, sharing and distribution.

Product: Geodatabase of sediment surface elevation and marker horizon data for the SET sites.

Delivery Date: September 2014

Product: User's manual for the SET geodatabase.

Delivery Date: September 2014

3) Task Title: Analyses of the SET data for the 1998 - 2013 period of record.
Task Leaders: T.J. Smith III
Phone: 727-502-8130
FAX: 727-502-8001
Task priority: High
Task Personnel: Nathaniel Plant, Coastal and Marine Geology, St. Petersburg
Ginger Tiling-Range, Contracted through CNTS

Task Summary and Objectives:
We will undertake an extensive analysis of the SET data accumulated to date (1998 - 2013). The analyses will include the use of simple statistics (i.e. means, variances) to compare data between stations, along river transects, and between the two river systems. Regression analysis will also be employed and results compared across sites. Patterns of sediment elevation change will be related to variation in surface and ground water levels that have been recorded at stations collocated with the SETs. These analyses will be undertaken for three time periods: 1) the entire period of record; 2) the pre-Wilma period (1998 - 09/2005); and 3) the post-Wilma period (10/2005 - 2013).

In more advanced analyses, we will use empirical orthogonal functions (EOFs) to examine how elevation changes are correlated in time and space (Plant et al. 2008, Keshtpoor et al. 2013). The EOFs will allow the determination of modes of correlation in the data, identify processes operating at different time scales, and filter out noise. The first step in this process is to interpolate all SET elevations to a common time series (that does not need to be equally spaced in time). This will allow comparison to physical process drivers, such as water level. In the second step, the means are removed from the respective time series, leaving the variance. In the third step, the EOFs are calculated for the variances and decomposed in modes (in the sense of spectral analysis a time series can have variation at several time spans: monthly, yearly, decadal, etc.). In this analysis each site will serve as a variable, so there are potentially 10 EOFs. However, the first EOF explains the largest percentage of the overall variance, the second EOF explains the second largest portion of the variance, and so on. It is anticipated that only the first 4 or 5 of the EOFs will explain significant portions of the overall variance. Finally, for each variable (site), a weighting factor is calculated for each EOF. This indicates how important the EOF is for that site. The analysis will be repeated for the same time periods defined above.

Refereed journal publications describing the results of the SET analyses and providing interpretation and relevance for the Everglades will be produced. The papers will be posted on the SOFIA website.

Product: Refereed publications discussing results of analyses and interpretation and meaning for the GE PES.

Delivery Date: September 2014

4) Task Title: Analyze mangrove forest permanent plot data.
Task Leaders: T.J. Smith III
Phone: 727-502-8130
FAX: 727-502-8001
Task priority: High
Task Personnel: Ginger Tiling-Range

Task Summary and Objectives:
Permanent mangrove forest vegetation plots were established beginning in the months following Hurricane Andrew (Smith et al. 1994). The plots are circular with a permanent center stake. The plots have different diameters ranging from 5 - 16 m. The diameter was determined at plot establishment based on an initial survey of stem density. All stems over 1.5 m in height have been tagged with an aluminum tree tag, identified to species, and mapped in space. The mapping involves measuring the distance from the center stake to the stem, and measuring the direction from the center to the stem in degrees. The stems diameters at breast height (DBH, at approximately 1.4 m above the soil) have been measured eight or nine times over time, depending on when the plot was established (Ward et al. 2006). During each census, recruitment of new stems into the plot, and the death of old stems, was recorded. Additionally, allometric equations (Niklas 1994) have been developed for each of the three mangrove species to allow the calculation of plant biomass from the DBH measurements (Smith and Whelan 2006). SETs are located at some, but not all, of the permanent plots. Those sites with SETs and permanent plots include: SH2, SH3, SH4, SH5, BSC-F and LO3.

We will conduct an analysis of the population dynamics of the mangroves in each plot by examining survival, recruitment, mortality, and growth statistics. Total biomass for each species, in each plot, for each survey, will be calculated. Biomass data will standardized across the plots to a value of kilograms per 0.1 hectare. Differences among plots will be examined by looking at those environmental factors that vary across the landscape. These factors include salinity and flooding frequency (Ward et al. 2006), and disturbances such as hurricanes and the occurrence of fire (Smith et al. 2009). Finally, the spatial pattern of the stem-mapped trees will be examined using point-pattern analysis (Moeur 1993). Point-pattern analysis can reveal changes in the pattern (clumped, random or uniform) across different spatial scales. A species can be clumped at short distances (4-6 m) but random at longer distances (10 m). Changes in these patterns over time have been used to infer both intra- and interspecific competitive interactions in forest trees (Moeur 1997). It is anticipated that several publications will arise from this work, one for the population dynamics aspect, one for biomass changes and one for the competitive interactions.

Product: Refereed publications discussing the analyses of the permanent plot data.

Delivery Date: September 2014

Literature Cited

Boumans, R.M. and Day, J.W. 1993. High precision measurements of sediment elevation in shallow coastal areas using a sedimentation-erosion table. Estuaries, 12: 260-268.

Cohen, A.D. and Spackman, W. 1977. Phytogenic organic sediments and sedimentary environments in the Everglades-mangrove complex, Part II. The origin, description and classification of the peats of southern Florida. Palaeonographica, 162, Part B: 71-114.

Donoghue, J.F. 2011. Sea level history of the northern Gulf of Mexico coast and sea level rise scenarios for the near future. Climatic Change, 107: 17-33.

Cahoon, D.R., Lynch, J.C., Hensel, P., Perez, B.C., Boumans, R.M. and Day, J.W. 2002a. High-precision measurement of wetland sediment elevation: I. Recent improvements to the sedimentation-erosion table. Journal of Sedimentary Research, 72: 30-33.

Cahoon, D.R., Lynch, J.C., Hensel, P., Perez, B.C., Boumans, R.M. and Day, J.W. 2002b. High-precision measurement of wetland sediment elevation: II. The rod surface table. Journal of Sedimentary Research, 72: 734-739.

Dolsen, C.P. and Riegel, W. 1966. Phytogenic organic sediments and sedimentary environments in the Everglades-mangrove complex, Part I. Evidence for a transgressing sea and its effects on environments of the Shark River area of southwestern Florida. Palaeonographica, 117, Part B: 135-152.

Keshtpoor, M., Puleo, J.A. Gebert, J. and Plant, N.G. Beach response to a fixed sand bypassing system. Coastal Engineering, 73: 28-42.

Maul, G. and Martin, D. 1993. Sea level rise at Key West Florida, 1846 - 1992: America's longest instrument record? Geophysical Research Letters, 20: 1955-1958.

Moeur, M. 1993. Characterizing spatial patterns of trees using stem-mapped data. Forest Science, 39: 756-775.

Moeur, M. 1997. Spatial models of competition and gap dynamics in old-growth Tsuga heterophylla / Thuja plicata forests. Forest Ecology and Management, 94: 175-186.

Niklas, K.J. 1994. Plant allometry: The scaling of form and process. The University of Chicago Press, Chicago, IL, USA. 395 pp.

Plant, N.G., Holland, K.T. and Haller, M.C. 2008. Ocean wavenumber estimation from wave-resolving time series imagery. IEEE Transactions on Geoscience and Remote Sensing 46: 2644-2658.

Smith, T.J., III, Robblee, M.B., Wanless, H.R., & Doyle, T.W. 1994. Mangroves, hurricanes and lightning strikes. Bioscience, 44: 256-262.

Smith, T.J., III, Foster, A.M., Briere, P.R., Jones, J.W. and Van Arsdall, C. 2002. Conversion of historical topographic sheets (T-sheets) from paper to digital form: Florida Everglades and vicinity. USGS, Open-File Report 02-204.

Smith, T.J., III, Foster, A.M., Briere, P.R., Coffin, A.W., Jones, J.W., Van Arsdall, C. and Travers, L.J. 2002. Historical aerial photography for the greater Everglades of south Florida: The 1940, 1:40,000 Photoset. USGS, Open-File Report 02-237.

Smith, T.J., III and Whelan, K.R.T. 2006. Development of allometric relations for three mangrove species in south Florida for use in the Greater Everglades Ecosystem restoration. Wetlands Ecology and Management, 14: 409-419.

Smith, T.J., III, Anderson, G.H., Balentine, K., Tiling, G., Ward, G.A. and Whelan, K.R.T. 2009. Cumulative impacts of hurricanes on Florida mangrove ecosystems: Sediment deposition, storm surges and vegetation. Wetlands, 29: 24-34.

Tiling, G., Smith, T.J., III, Balentine, K., Anderson, G., Foster, A. and Ward. G. 2008. Development of a geodatabase for preserving, managing and analyzing information for the coastal Everglades. USGS Gulf Coast Science Conference and Florida Integrated Science Center Meeting: Proceedings with Abstracts. Open-File Report 2008-1329, pg 154.

Ward, G.A., Smith, T.J., III, Whelan, K.R.T. and Doyle, T.W. 2006. Regional processes in mangrove ecosystems: spatial scaling relationships, biomass, and turnover following catastrophic disturbance. Hydrobiologia, 569: 517-527.

Whelan, K.R.T., Smith, T.J., III, Cahoon, D.R., Lynch, J.C. and Anderson, G.H. 2005. Groundwater control of mangrove surface elevation: shrink and swell varies with depth. Estuaries, 28: 833-843.

Whelan, K.R.T., Smith, T.J., III, Anderson, G.H., and Ouelette, M.L. 2009. Hurricane Wilma's impact on overall soil elevation and zones within the soil profile in a mangrove forest. Wetlands, 29: 16-23.

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