2005 Progress Report: Climate-Linked Alteration of Ecosystem Services in Tidal Salt Marshes of Georgia and LouisianaEPA Grant Number: R832221
Title: Climate-Linked Alteration of Ecosystem Services in Tidal Salt Marshes of Georgia and Louisiana
Investigators: Hester, Mark W. , Mendelssohn, Irving A. , Alber, Merryl , Joye, Samantha
Institution: University of New Orleans , Louisiana State University - Baton Rouge , University of Georgia
Current Institution: University of Louisiana at Lafayette , Louisiana State University - Baton Rouge , University of Georgia
EPA Project Officer: Packard, Benjamin H
Project Period: March 21, 2005 through September 30, 2009
Project Period Covered by this Report: March 21, 2005 through September 30, 2006
Project Amount: $749,457
RFA: Effects of Climate Change on Ecosystem Services Provided by Coral Reefs and Tidal Marshes (2004) RFA Text | Recipients Lists
Research Category: Ecosystems , Climate Change , Water , Aquatic Ecosystems , Ecological Indicators/Assessment/Restoration , Global Climate Change , Water and Watersheds
The objective of this research project is to elucidate the effects of climate change on tidal salt marsh ecosystem services in Georgia and Louisiana. Our goal is to better understand how the ecosystem services of eutrophication control, carbon sequestration, sustainable habitat, and faunal support are influenced by climate change. The goal of this research project is to determine how increased drought severity and associated changes in plant density alter these ecosystem services in salt marshes with tidal amplitudes ranging from microtidal (Louisiana) to meso/macrotidal (Georgia).
Site selection was initiated in March 2005 immediately after the lead university (University of New Orleans) received its contract. The site selection process in Louisiana occurred from late March 2005 through April 2005, followed by site selection in Georgia in May 2005. In both states, six sites were identified and research plot boundaries delineated. Permission from the appropriate land owner(s) for access and construction of research boardwalks has been obtained. All Louisiana access and treatment-plot boardwalks have been constructed and surface elevation tables (SETs) installed in odd-numbered blocks during this first reporting period. Because of the displacement of the University of New Orleans administrative personnel from the impact of Hurricane Katrina (August 29, 2005), finalization of subcontracts with the University of Georgia were delayed until late fall 2005. Therefore, the Georgia treatment-plot boardwalk construction will be initiated during the next reporting period.
Our proposed experimental design was to include reference Spartina alterniflora (smooth cordgrass) marsh stem densities and four S. alterniflora stem density treatments (bare, transplanted S. alterniflora at low stem density, transplanted S. alterniflora at high stem density, and naturally recolonizing S. alterniflora stem density). We were not able, however, to successfully locate this last treatment (naturally recolonizing S. alterniflora stem density) in the field in close proximity of large dieback sites where our other experimental treatments were required to be established in the same block. Therefore, our current experimental design does not include this vegetation treatment in the design. We did, however, increase the size of each of our 48 experimental research plots from the proposed 25 m2 per plot to the current size of 60 m2 (7.5 m x 8.0 m) per plot. As a result, the total area of our experiment in the field actually has increased substantially.
Construction of the treatment-plot boardwalks will commence at the Georgia (Sapelo Island) field site in spring 2006, immediately followed by the installation of SETs. After all boardwalks are in place in both states, we will implement our vegetation treatments by manipulating S. alterniflora stem densities in the dieback areas as follows: high plant density (30 cm plant spacings), low plant density (90 cm plant spacings), and bare (no transplants).
Once we successfully have established our transplants, the remaining plot setup will commence (insertion of litter bags, root ingrowth cores, interstitial wells, etc.). We will begin collecting data during summer 2006, with our first major seasonal sampling scheduled for fall 2006. Within each plot, a suite of abiotic and biotic response variables will be measured, including biogeochemical variables (soil physical properties, porewater and solid-phase inventories, sediment metabolism and denitrification, and benthic microalgal production), underground processes (underground production and organic matter decomposition), aboveground processes (aboveground cover and productivity, instantaneous net CO2 assimilation, and photosynthetic nutrient-use efficiency), sediment elevation and accretion, and invertebrate responses (infauna and epifauna inventories, predation rates, and food-web analyses).