Ecological Monitoring of Healthy and Unhealthy Salt Marsh Sites

to Reach Educational, Research and Management Objectives M. Carla CurranM. Carla Curran11, Dionne Hoskins, Dionne Hoskins1,21,2, Carol Pride, Carol Pride11, Joseph Richardson, Joseph Richardson11 and Mary Sweeney-Reeves and Mary Sweeney-Reeves33

11Savannah State University, Savannah State University, 2 2 National Marine Fisheries Service, NOAA, National Marine Fisheries Service, NOAA, 33University of Georgia, Marine Extension ServiceUniversity of Georgia, Marine Extension Service

METHODS“Dead Marsh” Sites

The initial study will focus on several on Talahi Island, Oatland Island, and the Isle of Hope to be monitored by SSU undergraduates, graduate students, and Adopt-a-Stream/Adopt-a-Wetland groups, respectively. The latitude and longitude of each site has been determined by GPS and coordinates will be supplied to the GA DNR for ground-truthing of aerial photographs. The most thorough array of analyses will initially be carried out at the Talahi Island site, which will be sampled at 1-month intervals from mid-February through mid-April by SSU undergraduate marine ecology students. Sampling at one or two of the sites will continue throughout the year through a combination of SSU internship projects and a graduate student thesis project.

Expansion/Regrowth of Impacted AreasFlagged stakes will be placed along the borders of

“dead marsh” regions so that any expansion or reduction of the impacted area through time can be determined. In addition, the investigators and nearby residents are documenting changes in the marsh through periodic photos of affected regions.

The density of Spartina alterniflora will be quantified using a 0.5 m2 quadrat along 2 transects of healthy marsh and 2 transects of dead marsh at each site (Figures 2 and 3). Number of live and dead shoots will be tabulated separately.

Erosion/AccretionStakes will be placed at each cite with cm markings

both above and below the sediment surface to monitor sediment erosion/accretion throughout the study.

Water QualityWater quality parameters (DO, temperature, salinity,

turbidity, and concentrations of orthophosphates and nitrogenous compounds) will be monitored at each study site in adjacent tidal creeks and/or within the healthy and dead marsh regions during high tide.

Pore watersPore waters will be sampled at select healthy and dead

sites for salinity determinations.

MeiofaunaMeiofauna from the top 3 cm of sediment will be

identified to major taxa and enumerated. Benthic foraminifera will be identified from samples representing the upper 20 cm of sediment. Results will be compared between live and dead marsh.

MacrofaunaSnail and crab hole densities will be determined at

intervals along the transects.

OBJECTIVES To assist the Coastal Resources Division of the Georgia Department of Natural Resources in making management decisions regarding salt marsh regions experiencing dieback.

To determine the ecological impact of salt marsh dieback in the Savannah, GA region.

To monitor environmental factors that may contribute to the dead marsh phenomenon.

To have undergraduate marine science majors and graduate students take a lead role in collecting and analyzing data, and documenting their findings.

To involve high school Adopt-a-Stream/Adopt-a-Wetland groups in ecological studies through the monitoring of shoot densities, epifauna, and water quality parameters at designated “dead marsh” sites.

To provide a collaborative research project for Savannah State University faculty and colleagues at the University of Georgia.

Figure 2. Transect line through healthy marsh starting at die-backmargin (foreground)

ABSTRACTIn the spring of 2003 the “dead marsh” phenomenon

in the Savannah, GA area will be examined by a multi-investigator team consisting of the Marine Ecology Lab class at Savannah State University (SSU), a high school Adopt-a-Stream/Adopt-a-Wetland group, and 4 SSU marine sciences program faculty. Since the issue of “dead marsh” areas in coastal Georgia is of interest to the GA DNR, we will prepare a report for this agency. Both healthy marsh and marsh areas experiencing Spartina alterniflora die-off will be studied. The surface area of dying marsh will be monitored for change over the course of the semester. Health of the salt marsh ecosystem will be gauged by determining the density of live and dead S. alterniflora shoots, the density of snails and crab holes, and the density and diversity of benthic fauna, including agglutinated foraminifera. Transects will be performed and samples taken three times during the spring semester. Physical/chemical properties that could be impacting the health of the system will also be monitored. The properties to be measured include pore water salinities at each transect site and the temperature, salinity, pH, [DO], [NO3

-], [PO43-],

and turbidity of adjacent tidal creeks.

INTRODUCTION“Dead marsh” is an area with little or no live above-

ground vegetation (Figure 1). It has been documented in LA, TX, FL, GA, SC, and NY. Reasons for the dieback are unclear but may be related to drought/increased salinity, biogeochemistry, changes in organismal composition and density, or anthropogenic disturbances. The purpose of this study is to determine differences in water quality, macrofauna, meiofauna, and shoot density between live and dead marsh. We will involve undergraduate students, graduate students, and volunteer citizens with the ultimate goal of elucidating this phenomenon and distributing information to the scientific and lay communities, and GA DNR.

Figure 1. Discrete “square” area of dead marsh

OUTCOMES An environmental database and archival documents will be maintained at the Asa Gordon library available for public use, undergraduate instruction, and postgraduate research

A series of reports on marsh conditions that are appropriate for a variety of stakeholders (managers, educators, citizens, politicians, scientists)

Undergraduate research and reports

Postgraduate theses

Community involvement in habitat assessment and increased public awareness of coastal habitat quality

Increased collaboration among Savannah State University, the University of Georgia, and the Georgia Department of Natural Resources in terms of establishing sampling protocol, collecting data, and analyzing the results of our study

Information that will assist in the development of potential marsh restoration projects

Figure 3. Students counting Spartina shoots in a quadrat areaalong a transect line.

ACKNOWLEDGMENTSThe authors would like to express their gratitude to Adopt-a-Stream, Adopt-a-Wetland, and Oatland Island Educational Center.