PROCEEDINGS: Index of Abstracts
EFFECTS OF ACIDIC PRECIPITATION ON LEAF DECOMPOSITION
RATES, MICROBIAL BIOMASS, AND LEAF PACK MACROINVERTEBRATES IN SIX
STREAMS ON THE ALLEGHENY PLATEAU OF WEST VIRGINIA
Erik S. Engstrom-1, Sean K. Meegan-1, Sue A. Perry-2, and William
1-Graduate Students, and Professor, respectively, Division of Forestry,
West Virginia University, Morgantown, WV 26506. 2-West Virginia
Cooperative Fish and Wildlife Research Unit, Division of Forestry,
West Virginia University, Morgantown, WV 26506-6125.
We studied the effects of acidification on leaf litter decomposition
in six headwater streams in the Monongahela National Forest. These
streams differed in underlying geology and mean baseflow pH (3.99,
4.24, 6.13, 6.47, 6.59, and 7.52). We placed 10-gram leaf packs
of white oak, red maple, and yellow poplar in each stream, and retrieved
them after two days, two weeks, and then at 4-week intervals from
November 1993 to February 1994. Leaf packs were analyzed to determine
changes through time in leaf decay rate, invertebrate composition,
density, and biomass, and microbial biomass (ATP concentration).
The mass loss rate coefficient, k, ranged from -0.0128 to -0.0052
for poplar, -0.0120 to -0.0047 for maple, and -0.0059 to -0.0018
for oak. The acidic streams had significantly lower decay rates.
The acidic streams had higher invertebrate densities but lower biomass
than the more alkaline streams. ATP concentrations were lower in
the acidic streams than in the more alkaline streams. In streams
that are vulnerable to acidification, pH depression may reduce energy
and material availability to stream macroconsumers.