Microhabitat use by blackbanded (Percina nigrofasciata), turquoise (Etheostoma inscriptum), and tessellated (Etheostoma olmstedi) darters in a piedmont stream
Henry, Brent E.
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We quantified factors affecting microhabitat use for three darter species in a 116m reach of a Piedmont stream, via underwater observation and macroinvertebrate benthos samples during 2001-2002. The 12 month period of sample collections, and the previous 12 months were the first and second driest years on record, respectively. PCA indicated that in Spring 2002, a season with higher amounts of habitat availability, there existed fewer significant differences in darter microhabitat use, whereas in Autumn 2001 and Summer 2002 all darters used significantly different microhabitats. In general, turquoise darters used more scour areas, tessellated darters more depositional, and blackbanded darters utilized intermediate habitats. During Autumn 2001, large blackbanded darters (> 55mm) occurred in faster microhabitats with more erosional substrata than smaller specimens, and used a greater variety of depths. In Autumn 2001, large turquoise darters ( > 40mm) used deeper microhabitats with higher velocities and more erosional substrata than smaller individuals, whereas the opposite was true for Autumn 2002. Blackbanded darters used microhabitats with significantly less macroinvertebrate biomass and abundance in Autumn 2001, but with higher percentages of Dipterans. In Spring 2002, all three darters occurred in microhabitats with significantly lower macroinvertebrate biomass and numerical abundance (blackbanded and tessellated only) than found at random. We observed no interspecific differences in biomass, numbers, or percent Dipteran composition, nor any size related differences in macroinvertebrate abundance in microhabitats occupied by darters.