PLANT LITTER DECOMPOSITION IN WETLANDS RECEIVING ACID-MINE DRAINAGE

The impact of acid mine drainage on the decomposition of wetland plant species of northern West Virginia was studied to determine if the potential exists for nutrient cycling to be altered in systems used to treat this drainage. There were two objectives of this study. First, decomposition of aboveground plant material was measured to determine species decomposition patterns as a function of pH. Second, decomposition of Litter from various pH environments was compared to assess whether litter origin affects decomposition rates. Species differences were detected throughout the study. Decomposition rates of woolgrass [Scirpus cyperinus (L.) Kunth] and common rush (Juncus effusus L.) were significantly lower than those of calamus (Acorus calamus L.) and rice cutgrass (Leersia oryzoides L.). Differences among species explained a large proportion of the variation in percentage of biomass remaining. Thus, differences in litter quality among species was important in determining the rate of decomposition. In general, significantly more decomposition occurred for all species in high pH environments, indicating impeded decomposition at low pH. While decomposition of some species litter differed depending on its origin, other species showed no effect. Cattail (Typha latifolin L.), in particular, was found to have lower decomposition rates occurring with material grown at low pH. Lower decomposition rates could result in lower nutrient availability leading to further reduction of productivity under low pH conditions.