Net Ecosystem Production and Carbon Greenhouse Gas Fluxes in Three Prairie Wetlands

作者：Bortolotti Lauren E^*; St Louis Vincent L; Vinebrooke Rolf D; Wolfe Alexander P

来源：Ecosystems, 2016, 19(3): 411-425.

DOI：10.1007/s10021-015-9942-1

• carbon dioxide
• ecosystem metabolism
• ecosystem restoration
• greenhouse gas emissions
• methane
• net ecosystem production
• prairie pothole wetlands

In central North America, prairie wetlands provide many important ecosystem services including attenuating floods, improving water quality, and supporting biodiversity. However, over half of these wetlands have been drained for agriculture. Relatively little is known about the functioning of these ecosystems either in their natural state or restored after drainage. We characterized net ecosystem production and carbon greenhouse gas (GHG) fluxes (carbon dioxide [CO2] and methane) in the open-water zones of three prairie wetlands over two ice-free seasons. These wetlands included a natural site and sites restored 3 and 14 years prior to study (hereafter "recently restored" and "older restored"). We also assessed how two techniques for estimating metabolic status, the diel oxygen method (used to measure NEP) and net CO2 fluxes, compared. The diel oxygen method suggested that the restored wetlands were net heterotrophic across years, whereas the natural wetland was net heterotrophic in 1 year and net autotrophic in the other. Similar conclusions arose from quantifying net CO2 fluxes, although this technique proved to be relatively insensitive for understanding metabolic status at a daily temporal scale owing to the influence of geochemical processes on CO2 concentrations. GHG efflux was greatest from the recently restored wetland, followed by the older restored and natural wetlands. Overall, GHG flux rates were high and variable compared with other inland aquatic ecosystems. Although restoration may progressively return wetland functioning to near-natural states, our results highlight the necessity of preventing wetland drainage in the first place to preserve ecosystem functions and services.

• 出版日期2016-4