HR: 14:00h
AN: NB23B-03    [Abstracts]
TI: Assessment of Hydrological Variability on Habitat Stability and Macroinvertebrate Communities in an Intermittent Karst Ozark Stream
AU: * Carroll, T M
EM: tcarroll@drury.edu
AF: University of Kansas, 1450 Jayhawk Blvd, Lawrence, KS 66045 United States
AB: Research on the ecological effects of prolonged stream drying in karst systems has lagged far behind studies of continually flowing epigean systems. Macroinvertebrate community responses to hydrological variation in the South Dry-Sac River were examined over six seasons during 2003-2004. Stream permanence was quantified by measures of seasonal discharge, minimum discharge at summer baseflow, wetted riffle area-perimeter, and weekly bankfull percentages. Invertebrate community composition was determined by collecting three samples in each of ten riffles (180 samples) along a 1-km stretch of the stream located along a natural fault line in the Ozarks region of southwestern Missouri. Measures used to describe the invertebrate communities included measures of community composition (invertebrate density, richness, EPT taxa), and a series of diversity and similarity indices. Principal Components Analysis identified hydrological factors over physiochemical measures as being responsible for the greatest proportion of variation in abiotic factors among riffles. ANOVA techniques demonstrated that significant differences in invertebrate response variables existed among riffles when grouped by hydrological rather than seasonal parameters. Finally, a positive and linear relationship was evidenced between invertebrate response measures and riffle permanence. Results are discussed in relation to the role of hydrological variability in determining the biodiversity of karst instream communities.
DE: 9810 New fields (not classifiable under other headings)
DE: 9901 NABS Student Award - Basic Research
SC: North American Benthological Society [NB]
MN: 2005 Joint Assembly