Potential methane production and oxidation in wetland plant communities: Investigating a diversity-function relationship

Our goal was to understand how plant diversity affects potential methane production and oxidation in freshwater wetland soils from central Ohio. Wetlands were divided into two areas (fringe and central) based on degree of flooding and plant community composition. Two natural and two created wetlands were selected and plots were established across a range of plant diversity within both areas of each wetland. Soils from each plot were incubated in the lab to measure methane production and oxidation potentials. In the fringe areas, mean methane production potential was 4.56 ng CH₄ g soil^-1 hr^-1 in the natural wetlands and 0.08 ng CH₄ g soil^-1 hr^-1 in the created, while mean oxidation potential was 8.63 ng CH₄ g soil^-1 hr^-1 in the natural wetlands and 1.68 ng CH₄ g soil^-1 hr^-1 in the created. In the central areas, mean methane production potential was 16.97 ng CH₄ g soil^-1 hr^-1 in the natural wetlands and 1.90 ng CH₄ g soil^-1 hr^-1 in the created, while mean oxidation potential was 15.06 ng CH₄ g soil^-1 hr^-1 in the natural wetlands and 3.71 ng CH₄ g soil^-1 hr^-1 in the created. There was no relationship between plant diversity and methane oxidation or production potential in these soils; however, we cannot rule out the possibility that this relationship may be masked by concomitant soil conditions (moisture, pH, and organic matter content) which varied considerably between natural and created wetlands.