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Land cover effects on benthic macroinvertebrate community structure in Orange County, NC.
Geraci, Christy*,1, 2, 1 University of North Carolina at Chapel Hill, Chapel Hill, NC, USA2 Clemson University, Clemson, SC, USA
ABSTRACT- This study examined the relationship between land cover and benthic macroinvertebrate community structure in the Little Creek and Morgan Creek Watersheds of Orange County, North Carolina. Rootwad and riffle habitats were sampled at 18 sites along five creeks using D-frame sweep nets and kick nets. Land cover percentages in the upstream drainage basin and 60m riparian corridor of each site were calculated from classified Enhanced Thematic Mapper (ETM) imagery of the Chapel Hill Area from July 1999 (Row 35, Path 16). Linear regression models showed stronger relationships between land cover and benthic macroinvertebrate community structure in rootwads than in riffles. At the upstream drainage basin scale, percent forest cover and percent urban land cover were both strong predictors of taxa richness, Shannon diversity, and abundance in rootwads, but were only weakly related to taxa richness and diversity in riffles, and were not related to abundance in riffles. Similar results were found at the 60m riparian corridor scale. The results of this study suggest that 1) the benthic macroinvertebrate community in rootwads is more reflective of altered hydrology and non-point source pollution than the riffle communities in these watersheds, and 2) land use planning techniques that preserve forest patches throughout the watershed are equally important to preserving aquatic biodiversity as those that restrict development only within a specified distance from stream channels.
Key words: land cover, benthic, macroinvertebrate, community structure