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 pot ential exists for nutrient cycling to be altered in systems used to tr eat this drainage. There were two objectives of this study. First, dec omposition of aboveground plant material was measured to determine spe cies 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 d etected throughout the study. Decomposition rates of woolgrass [Scirpu s cyperinus (L.) Kunth] and common rush (Juncus effusus L.) were signi ficantly lower than those of calamus (Acorus calamus L.) and rice cutg rass (Leersia oryzoides L.). Differences among species explained a lar ge proportion of the variation in percentage of biomass remaining. Thu s, differences in litter quality among species was important in determ ining the rate of decomposition. In general, significantly more decomp osition occurred for all species in high pH environments, indicating i mpeded decomposition at low pH. While decomposition of some species li tter 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 dec omposition rates could result in lower nutrient availability leading t o further reduction of productivity under low pH conditions.