SEASONAL VARIATION IN MACROINVERTEBRATES AFFECTED BY ACID MINE DRAINAGE
Many streams in Appalachia are affected by acid mine drainage (AMD) from historical coal extraction practices. The responses of the summer macroinvertebrate communities to AMD have been well-documented. However, the composition of macroinvertebrate assemblages varies between seasons, and the sensitivity of spring and fall macroinvertebrate assemblages to AMD impairment has not been as well-studied. We tested the hypothesis that AMD chemical stressors have a weaker influence on macroinvertebrate communities in spring and fall compared to summer. We used mixed model ANOVA’s to compare N=11 impaired and N=9 unimpaired sites in which riffle habitat was sampled over consecutive seasons (spring-summer or summer-fall) to test for effects of season, AMD and interactions between season and AMD. AMD reduced overall taxa richness (p=0.001) and abundance (p=0.043) as well as scraper grazer richness (p=0.003) and abundance (p=0.003). Seasonal effects on taxonomic and functional composition of the riffle community were modest, indicating high overall redundancy. Contrary to our hypothesis, the only interaction between season and impairment was on total taxonomic richness (p=0.001), which increased from spring to fall at impaired sites but not unimpaired.
Andrew Travers ( Co-Presenter/Co-Author), Ohio University, email@example.com;
Kelly Johnson (Primary Presenter/Author), Ohio University, firstname.lastname@example.org;