Multi-scale relationship between peatland vegetation type and dissolved organic carbon concentration

Dissolved organic carbon (DOC) is a key component of the carbon cycle and has significant impacts on aquatic ecosystems and potable water treatment. Upward trends in river and lacaustrine DOC concentrations have been observed and a number of key drivers have been proposed. Here, we present DOC concentration data from plot scale pore waters at one site and surface water from artificial drains sampled within a national survey which demonstrate a significant correlation between peatland vegetation type and DOC concentration. Calluna dominance was associated with the highest DOC concentration, Molinia and Sphagnum dominance with lower concentrations, and sedge dominance with intermediate concentrations. Water sampled from drains dominated by Calluna had greater DOC concentrations than water sampled from pore waters in plots dominated by Calluna. In contrast DOC concentrations from plots dominated by sedges were greater than those sampled from drains dominated by sedges. We discuss these findings in relation to plant functional traits and their influence on the physical and biotic conditions that regulate DOC concentrations. Given the known effects of management activities and climate change on peatland vegetation composition there is potential to manage plant community composition to ameliorate the observed rising DOC concentration.