EFFECT OF PEATLAND DRAINAGE, HARVESTING, AND RESTORATION ON ATMOSPHERIC WATER AND CARBON EXCHANGE

Abstract

There is a limited understanding of the hydrological and microclimatic processes from drained, harvested, or restored peatlands, and by extension the nature of the carbon balance is uncertain. However, understanding the symbiotic processes governing water and gas exchange is essential to the development of appropriate management plans for peatland restoration. In this paper, we highlight and contrast the suite of processes governing the atmospheric exchange of water and carbon on natural, harvested, and restored peatlands. Evapotranspiration from harvested sites is important throughout the spring and summer, and is not greatly different from the adjacent natural bog. On cutover peatlands, strong capillary water movement compensates for the lack of vascular plants, which on the natural bog become increasingly important as the capillary water movement within drying Sphagnum decreases. Methane emissions from cutover bogs are an order of magnitude lower than in natural sites, however, carbon dioxide (CO2) emissions are approximately three times greater. Peatland restoration enhances CO2 sequestration, although restoration (at least in the short term) does not restore the net carbon sink function to that in natural bogs. A conceptual model highlighting these changes in the atmospheric exchange of water and carbon from a natural bog through drainage, harvesting, abandonment, and restoration is presented. [Key words: peatlands, restoration, hydrology, climatology, evaporation, carbon dioxide, methane, harvested peatlands.]