Open AccessNitrogen loading leads to increased carbon accretion in both invaded and uninvaded coastal wetlands
Author(s) -
Martina Jason P.,
Currie William S.,
Goldberg Deborah E.,
Elgersma Kenneth J.
Publication year - 2016
Publication title -
ecosphere
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.255
H-Index - 57
ISSN - 2150-8925
DOI - 10.1002/ecs2.1459
Subject(s) - wetland , phragmites , environmental science , cycling , ecology , ecosystem , accretion (finance) , carbon cycle , propagule , biology , geography , forestry , physics , astrophysics
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.