Nitrogen Loading Leads To Increased Carbon Accretion In Both Invaded And Uninvaded Coastal Wetlands
Carbon pools, Carbon storage, Eutrophication, Great Lakes, Hydroperiod, Invasive species, Phragmites australis, Typha × glauca
Gaining a better understanding of carbon (C) dynamics across the terrestrial and aquatic landscapes has become a major research initiative in ecosystem ecology. Wetlands store a large portion of the global soil C, but are also highly dynamic ecosystems in terms of hydrology and N cycling, and are one of the most invaded habitats worldwide. The interactions between these factors are likely to determine wetland C cycling, and specifically C accretion rates. We investigated these interactions using MONDRIAN, an individual-based model simulating plant growth and competition and linking these processes to N and C cycling. We simulated the effects of different levels of (1) N loading, (2) hydroperiod, and (3) plant community (natives only vs. invasion scenarios) and their interactions on C accretion outcomes in freshwater coastal wetlands of the Great Lakes region of North America. Results showed that N loading contributed to substantial rates of C accretion by increasing NPP (net primary productivity). By mediating anaerobic conditions and slowing decomposition, hydroperiod also exerted considerable control on C accretion. Invasion success occurred with higher N loading and contributed to higher NPP, while also interacting with hydroperiod via ecosystem-internal N cycling. Invasion success by both Typha × glauca and Phragmites australis showed a strong nonlinear relationship with N loading in which an invasion threshold occurred at moderate N inputs. This threshold was in turn influenced by duration of flooding, which reduced invasion success for P. australis but not for T. × glauca. The greatest simulated C accretion rates occurred in wetlands invaded by P. australis at the highest N loading in constant anaerobic conditions. These model results suggest that while plant invasion may increase C storage in freshwater coastal wetlands, increased plant productivity (both native and invasive) due to increased N loading is the main driver of increased C accretion.
Department of Biology
Original Publication Date
DOI of published version
UNI ScholarWorks, Rod Library, University of Northern Iowa
Martina, Jason P.; Currie, William S.; Goldberg, Deborah E.; and Elgersma, Kenneth J., "Nitrogen Loading Leads To Increased Carbon Accretion In Both Invaded And Uninvaded Coastal Wetlands" (2016). Faculty Publications. 1034.