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Adaptive Responses of Upland Coastal Marsh
Plant Communities to Climate Change
Objective:
- Determine how genetic responses to climate change may influence ecosystem processes
- Develop an integrative framework for assessing how coastal wetland ecosystems respond to climate change
Approach:
- Combine field and laboratory studies to determine the heritability and fitness costs of responses to increased salinity, inundation and elevated carbon dioxide in two dominant marsh species (Scirpus olneyi, Spartina patens)
- Determine whether spatiotemporal genetic variation observed at neutral and ecologically relevant loci are associated with adaptive responses
- Model the ecosystem consequences of genetic adaptation to climate change
Why This Research Is Needed:
Wetlands account for over 20% of the carbon stored in terrestrial soils, enough to increase the present atmospheric CO2 concentration by more than 50%. Therefore the cycling of carbon in these systems represents an important component in the global carbon cycle. In the past 100 years, the global carbon balance of wetlands may have shifted from being a sink for CO2 to a source, due to conversion and drainage of wetlands for agriculture and combustion of peat soil for fuel. These recent changes in wetland carbon cycles may therefore be contributing to rising atmospheric CO2 and global warming. However, the future role of wetlands as either sources or sinks of carbon will depend on how wetlands respond to global changes such as rising CO2, increasing temperatures and changes in hydrology. Since plants have the potential to adaptively respond to changing climate conditions, it is possible that natural selection for tolerant genotypes may involve indirect and unexpected consequences on ecosystem processes such as carbon sequestration. Because genetic adaptation of wetland plant species may alter community dynamics and carbon sequestration under predicted scenarios of future environmental conditions (i.e., increased atmospheric CO2, changes in salinity or sea level), research characterizing plants' evolutionary responses to changing climate conditions will improve models that predict ecosystem-wide impacts of global change.
Expected Outputs/Outcomes:
- Case studies on the heritability and fitness consequences of adaptation to elevated CO2, salinity and inundation
- Studies of genetic variation over time and space
- A model Improved understanding of how atmospheric, ecosystem and organismal processes interact will support the development and implementation of public policies related to climate change and conservation of coastal ecosystems
Partners:
US EPA ReVA Program, Duke University, The Smithsonian Environmental Research Center, Florida International University
Contact: Mike Blum (blum.mike@epa.gov) (Cincinnati, OH)