PROCEEDINGS: Index of Abstracts

LEAF LITTER DECOMPOSITION AND ELEMENTAL CHANGE IN THREE APPALACHIAN MOUNTAIN STREAMS OF DIFFERENT PH

Steven W. Solada-1, Sue A. Perry-2, and William B. Perry-1

1-Division of Forestry, West Virginia University, Morgantown, WV 26506. 2-West Virginia University, National Biological Service, West Virginia Cooperative Fish and Wildlife Research Unit, PO Box 6125, Morgantown, WV 26506-6125.

The decomposition of leaf litter provides the primary nutrient source for many of the headwater mountain streams in forested catchments. An investigation of factors affected by global change that influence organic matter decomposition, such as temperature and pH, is important in understanding the dynamics of these systems. We conducted a study of leaf litter elemental change during decomposition in three headwater mountain streams within or near the Fernow Experimental Forest, Monongahela National Forest, West Virginia. Three leaf species, placed in individual leaf bags, were placed in three streams that had mean pH values of 4.2, 6.2, and 7.5. Nitrogen, expressed as percent of initial concentration, was conserved in leaf litter in all three streams. Nitrogen concentrations were not significantly different in the acidic stream as compared with the more neutral streams. In contrast, phosphorus was lost more rapidly from the leaf detritus in the acidic stream (45.9 percent), than in the more neutral streams (52.0 percent and 63.1 percent). The rates of decomposition for white oak and red maple were significantly lower (k = 0.0062 for red maple) in the acidic stream as compared with the more neutral streams, WSH and HSH (k = 0.0128 and 0.0072, respectively). Although no differences in final nitrogen content were observed, detrital decomposition, microbial biomass, and the accumulation of phosphorus, calcium, and magnesium were inhibited in the low pH stream. These results suggest that acidification may significantly reduce the rate of leaf detrital breakdown, which may result in a reduction of the nutrient base for aquatic consumers.