2007 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 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, 2007 through September 30, 2008
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
Our objective is to elucidate the effects of climate change on tidal salt marsh ecosystem services in Georgia and Louisiana, specifically to better understand how the ecosystem services of eutrophication control, carbon sequestration, sustainable habitat, and faunal support are influenced by climate change. Our goal is to determine how changes in plant density associated with increased drought severity alter these ecosystem services in salt marshes with tidal amplitudes ranging from microtidal (Louisiana) to meso-/macrotidal (Georgia).
Our approach has been to take advantage of severe drought events in salt marshes of both Louisiana and Georgia that resulted in large areas of sudden salt marsh dieback. Within each state, six salt marsh areas (blocks) were identified in which large (60 m2) permanent plots with boardwalks (to minimize sampling disturbance) were established in both severely-impacted dieback areas and adjacent, relatively unimpacted, reference marsh areas. Within the dieback areas, we artificially established (manually transplanted) Spartina alterniflora as a mechanism of controlling plant density as a treatment independently from the drought-induced dieback. Persistent drought conditions in Georgia have made obtaining the targeted plant densities difficult. Nonetheless, we successfully established a mosaic of 48 total permanent plots in Louisiana and Georgia that span a range of Spartina alterniflora plant densities from reference density, to high transplanted plant density, to low transplanted plant density, to bare plots in which alteration of ecosystem services (as described above) is being evaluated at several scales by our four research teams. Results to date indicate significant effects of geomorphic setting (Louisiana versus Georgia) and Spartina alterniflora plant density on a range of ecological processes that are serving as measurable indicators of ecosystem service.
Intensive early growing season (spring) and peak standing crop (fall) field sampling efforts will continue during the next reporting period. 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), belowground processes (belowground production, organic matter decomposition), aboveground processes (aboveground cover and productivity, instantaneous net CO2 assimilation, photosynthetic nutrient-use efficiency), sediment elevation and accretion, and invertebrate responses (infauna and epifauna inventories, predation rates, and food-web analyses). A research team coordination meeting will be scheduled to discuss data interpretation, data integration, and preparation for synthesis of the final report.