Interactions among vegetation, climate, and herbivory control greenhouse gas fluxes in a subarctic coastal wetland

Journal of Geophysical Research: Biogeosciences
By: , and 

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Abstract

High-latitude ecosystems are experiencing the most rapid climate changes globally, and in many areas these changes are concurrent with shifts in patterns of herbivory. Individually, climate and herbivory are known to influence biosphere-atmosphere greenhouse gas (GHG) exchange; however, the interactive effects of climate and herbivory in driving GHG fluxes have been poorly quantified, especially in coastal systems that support large populations of migratory waterfowl. We investigated the magnitude and the climatic and physical controls of GHG exchange within the Yukon-Kuskokwim Delta in western Alaska across four distinct vegetation communities formed by herbivory and local microtopography. Net CO2 flux was greatest in the ungrazed Carex meadow community (3.97 ± 0.58 [SE] µmol CO2 m−2 s−1), but CH4 flux was greatest in the grazed community (14.00 ± 6.56 nmol CH4 m−2 s−1). The grazed community is also the only vegetation type where CH4 was a larger contributor than CO2 to overall GHG forcing. We found that vegetation community was an important predictor of CO2 and CH4 exchange, demonstrating that variation in regional gas exchange is best explained when the effect of grazing, determined by the difference between grazed and ungrazed communities, is included. Further, we identified an interaction between temperature and vegetation community, indicating that grazed regions could experience the greatest increases in CH4 emissions with warming. These results suggest that future GHG fluxes could be influenced by both climate and by changes in herbivore population dynamics that expand or contract the vegetation community most responsive to future temperature change.

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Additional publication details

Publication type Article
Publication Subtype Journal Article
Title Interactions among vegetation, climate, and herbivory control greenhouse gas fluxes in a subarctic coastal wetland
Series title Journal of Geophysical Research: Biogeosciences
DOI 10.1002/2016JG003546
Volume 121
Issue 12
Year Published 2016
Language English
Publisher American Geophysical Union
Contributing office(s) Alaska Science Center Biology WTEB
Description 16 p.
First page 2960
Last page 2975
Country United States
State Alaska