Carbon dioxide and methane fluxes in variably-flooded riparian forests

The water quality protection function of riparian buffers is widely recognized, but much less is known regarding the dynamics of greenhouse gases in these ecosystems. Carbon dioxide (CO2) and methane (CH4) fluxes were monitored at 6 riparian sites along a 4th-order segment of the White River (Indiana, USA) to assess the effect of vegetation and flood frequency on gas fluxes. The study sites included shrub/grass, young (80years) riparian forests that were either flood-protected (FP), occasionally flooded (OF) or frequently flooded (FF). No significant effect of vegetation type on either CO2 or CH4 flux was noted. While CH4 level was sometimes high (up to 120μLL−1) in the deep soil layers, concentration near the soil surface (1.28μLL−1) was generally lower than in the litter layer (2.35μLL−1). In addition to this pattern, the negative relationship (r2: 0.23, P