PROCEEDINGS: Index of Abstracts

LEAF LITTER PROCESSING IN WEST VIRGINIA MOUNTAIN STREAMS: EFFECTS OF TEMPERATURE AND STREAM CHEMISTRY

Jacquelyn M. Rowe-1, William B. Perry-1, and Sue A. Perry-2

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

Climate change has the potential to alter detrital processing in headwater streams, which receive the majority of their nutrient input as terrestrial leaf litter. Early placement of experimental leaf packs in streams, one month prior to most abscission, was used as an experimental manipulation to increase stream temperature during leaf pack breakdown. We studied leaf litter processing in three second-order, mid-Appalachian streams along a pH gradient (mean pH = 4.2, 6.5, 7.5). Leaf pack processing rate coefficients (k) were calculated for single species leaf packs of red maple, white oak, and yellow poplar retrieved from each stream at regular intervals over two 12-week study periods: October to January, average total degree days = 442.0; and November to February, average total degree days = 271.3. Processing rates for all leaf species in both study periods were highest in the most alkaline stream. Within each stream, processing rates were not significantly higher during either study period. Invertebrate density was higher during the earlier, warmer study period, but shredder biomass showed no significant trends. ATP concentrations on leaf material were generally higher during the earlier study period, indicating higher microbial biomass. Overall, leaf litter processing in this study was influenced by a combination of factors including temperature, water chemistry, invertebrate community, and microbial processing.