Acid deposition effects on soil biodiversity and decomposition processes in Ohio Valley broadleaved forests.
LOUCKS, O.L.* 1, P.M.SUGG 2 and R.G.KUPERMAN 3
Miami University, Oxford, OH 45056 USA 1
University of Washington, Seattle WA 98101 USA 2
Edgewood Research, Development & Engineering Center, Aberdeen Proving Ground, MD USA 3
Studies of acid loadings, soil responses and diversity in species-rich insect families have been carried out along a gradient in cumulative deposition from southern Illinois to southern Ohio. Results show a direct, nearly linear response in soil chemical measures at carefully matched soil, forest cover and substrate geology types. The response correlates strongly with the magnitude of cumulative acidic inputs. The abundance and diversity of four insect groups is depressed in proportion to the decline in soil surface pH observed at the sites. The combined number of species in the Carabidae, Scarabaeidae, Staphylinidae, and Formicidae declined from 37 to 16 as the acid loading increased and soil pH declined. Three mechanisms comprising risks to survival of insect populations are evident, including the effects of H+ concentrations on the ion balance of young insect larvae, the effect of occasional toxic Al3+ flushing on soil insects during rain events, and the effect of nitrogen and ammonia enrichment throughout the soil decomposer food chain. Other data show that soil carbon processing and nutrient cycling have been diminished in proportion to the loss of soil fauna, leading to impaired ecosystem function and nutrient deficiencies.
This abstract is being presented at: 2:15 PM in session:
Oral Session #67: Decomposition Processes.