PARENT SESSION
Oral Session # 80: Urban Ecology II: Soils and Streams.
Presiding: J Ehrenfeld
Thursday, August 7. 1:30 PM to 5:00 PM, SITCC Meeting Room 105.

Impact of development on stream community structure and decomposition rates: Streams in piedmont North Carolina.

Reice, Seth¹, Geraci, Christy Jo², ¹ University of North Carolina, Chapel Hill, NC² Clemson University, Clemson, SC

ABSTRACT- The conversion of forested landscapes to urban and suburban land uses is the major threat to stream community health and dynamics. We analyzed the effect of urban/suburban development and loss of vegetated cover through comparisons between two dramatically different streams. The catchment of Bolin Creek has a moderate gradient of development, ranging from 74.5% forests and fields (combined) upstream to 54.9% downstream (ArcView GIS). Conversely, urban and suburban land uses increase downstream. Meeting of the Waters Creek (MOW) originates on the UNC-CH campus and is nearly 98% urbanized upstream, and gets progressively more vegetated (to 75%) as it flows off campus into the N.C. Botanical Garden. We sampled both streams for macrobenthos and leaf litter decomposition rates. The benthic communities changed in both streams, becoming less species rich as the vegetated proportion of the catchment declined. Leaf litter decomposition rates were not significantly different over the more narrow range of development in Bolin Creek. In MOW leaf litter decomposition rates increased significantly with increasing vegetated cover. So, urbanization degraded both biodiversity and decomposition processes. Species richness is a valid and reasonably sensitive instrument for ecological assessment. Leaf litter decomposition rates give a good estimate of the function of the stream ecosystem and should be included in the assessment of stream ecosystem health

Key words: macrobenthos, urbanization, species richness, leaf litter decomposition