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Greenhouse gas emission response to global change may be limited by vegetation community shifts
Citation:
Martin, R. AND S. Moseman-Valtierra. Greenhouse gas emission response to global change may be limited by vegetation community shifts. Society of Wetland Scientists (SWS) Annual Meeting, Corpus Christi, TX, June 01 - 03, 2016.
Impact/Purpose:
This abstract submission is for an invited talk at the annual Society of Wetland Scientists meeting in June 2016. The talk will be presented at a symposium on interactions of global change impacts on coastal marsh carbon and nitrogen cycling.
Description:
Coastal marshes experience a confluence of global changes including climate change, sea level rise, exotic species invasion, and eutrophication. These changes are likely to exert new abiotic stressors and affect interspecific interactions that influence vegetation community structure. Plant communities drive carbon and nutrient cycling, including fluxes of greenhouse gases (GHGs) that may affect the role coastal marshes play in mediating climate. To elucidate marsh functional responses to global change scenarios, stressors must be tested in combination and future vegetation community composition must be considered. In a space-for-time approach, field experiments were performed to characterize differences in GHG fluxes between current high marsh communities dominated by Spartina patens and potential future states characterized by encroaching low marsh Spartina alterniflora and upland edge Phragmites australis. To infer potential responses of GHG fluxes associated with different vegetation communities to global change, manipulative mesocosm experiments were performed. Responses of S. patens and S. alterniflora marsh GHG fluxes to sea level rise and eutrophication-driven algal bloom deposition, and of S. patens and P. australis GHG fluxes to nitrogen pollution and simulated climate change (warming and elevated atmospheric CO2), were tested. Results of these experiments suggest that while eutrophication and climate change may stimulate increased emission of the greenhouse gases methane (CH4) and (N2O), these may be countered by increased CO2 uptake (of up to orders of magnitude) by a shift in vegetation communities from S. patens to Phragmites and S. alterniflora.