Projects

Effects of fire on water quality, plant production, and biogenic accretion in a Juncus roemerianus d

End Date: 02/1/10

Abstract

Coastal wetlands provide a number of goods and services to human communities, including storm abatement, flood mitigation, and biodiversity for recreational activities and coastal economies. The long-term stability of these valuable ecosystems is threatened by habitat loss, habitat degradation, over-exploitation of natural resources, and climate change, especially sea-level rise. 

Management and restoration of these ecosystems should not only restore critical habitat for ecologically and economically important species, but maintain long-term marsh stability by enhancing accretion as a means of combating relative sea-level rise. 

Prescribed burning is a common management practice employed in coastal marshes and adjacent pine hammocks of the United States to maintain habitat, preserve native biodiversity, promote survival of fire-dependent species, increase food availability for wildlife, and decrease fuel loads that contribute to catastrophic wildfires. However, the effects of fires on nutrient availability, productivity, and accretion of organic matter (biogenic accretion) in Juncus roemerianus marshes of the Gulf Coast are poorly understood. 

Because fires may alter water quality, plant productivity, and ultimately, biogenic accretion within marshes, prescribed burning may be a useful tool for enhancing elevation gain in marshes threatened by submergence due to sea-level rise. In addition, prescribed burning may be a useful tool for removal of hurricane-related debris and restoration of coastal marshes following severe storms. 

This project will elucidate the effects of fire in a J. roemerianus marsh at Grand Bay National Estuarine Reserve in Mississippi by quantifying changes in water quality and nutrient availability, plant production, biogenic accretion, and hurricane-debris removal before and after a prescribed burn. 

Results from this research will increase knowledge of the relative importance of ecological processes for maintenance of marsh ecosystems, provide insight to the resiliency of coastal marshes following disturbance, contribute to our understanding of factors influencing water quality and nutrient cycling in marshes, inform management practices, aid in the conservation of habitat that is important for local fisheries and recreation industries, and address the need for debris removal following coastal storms.  Thus, this study will address the “Health and Restoration of Coastal Habitats” MAGSG priority area and will provide important scientific, economic, and social benefits to communities.

Objectives

Year 1:

  1. Determine field site locations within Grand Bay NERR
  2. Characterize and map debris accumulation within experimental blocks
  3. Implement experimental design including establishment of 18 experimental plots and installation of marker horizons
  4. Determine baseline characteristics of water quality, plant production, and accretion for all experimental plots and of water quality in adjacent bayous
  5. Conduct prescribed burning of marsh
  6. Implement post-burn data collection at all experimental plots and in adjacent bayou

Year 2:

  1. Complete post-burn data collection at all experimental plots and in adjacent bayou and analyze data
  2. Test fire effects on organic debris removal by re-surveying blocks for presence of debris
  3. Test hypotheses of fire effects on water quality, plant production, and biogenic accretion
  4. Provide workshops as part of education and outreach 
  5. Provide oral presentations of research findings to scientific community, resource managers, and public at conferences
  6. Provide written descriptions of research findings in reports and peer-reviewed manuscripts

Methodology

This project will investigate the effects of fire on the water quality, plant production, and biogenic accretion of a Juncus roemerianus marsh at Grand Bay National Estuarine Research Reserve in Mississippi.  The methods to be used for data collection and analysis include:

  1. Prescribed fire: in conjunction with fire managers at the Mississippi Sandhill Crane National Wildlife Refuge
  2. Soil and porewater physicochemistry: redox potential, bioavailable nutrients, and sulfide concentrations as described in Patrick et al., 1996; McKee et al., 1988; Robertson et al., 1999, respectively
  3. Porewater physicochemistry: pH and salinity using YSI meters
  4. Belowground plant production: implanted mass technique as described in Symbula & Day, 1988
  5. Aboveground plant production: paired-clip plots as described in Lomnicki et al., 1968
  6. Plant percent cover: aerial estimation of cover within 1 m x 1 m plots
  7. Biogenic accretion: feldspar marker horizons (see http://www.pwrc.usgs.gov/set/installation/markers.html)
  8. Percent combustion of organic debris: comparison of debris abundance before and after burn using GPS-generated maps of debris locations within the marsh

Rationale

The proposed research will address the “Health and Restoration of Coastal Habitats” MAGSG priority area by investigating how prescribed fire affects physicochemistry, plant production, and biogenic accretion in a coastal marsh at Grand Bay National Estuarine Research Reserve (NERR), Mississippi.  Grand Bay marshes are important habitat for threatened and endangered species, recreationally important species, and economically important species, and appropriate management and restoration of these marshes will not only improve habitat but maximize opportunities for revenue and jobs associated with eco-tourism along the Gulf Coast.  The data from this project will provide a variety of scientific, economic, and social benefits.

For example, data can be used to evaluate the benefits and potential costs of prescribed burning as a management practice in a J. roemerianus dominated marsh, as well as to identify the effects of burning on nutrient availability and transport between the marsh and the surrounding bayous.  These data will provide key insights into the effectiveness of prescribed burning as a management strategy, and the relative importance of biogenic accretion for the maintenance of valuable marsh habitat.  In addition, these data can be used to evaluate the effectiveness of fire for removal of debris after severe storms.

For More Information Contact: the MASGC Research Coordinator, Loretta Leist (Loretta.leist@usm.edu).

Please reference the project number R/CEH-27.