Date of Graduation

Spring 2010

Degree

Master of Science in Biology

Department

Biology

Committee Chair

John Havel

Abstract

This study examined the impact of road crossings on benthic macroinvertebrate communities in a wadeable Ozark river. I collected macroinvertebrates during winter and summer from four riffle locations (upstream, at crossing, downstream, and farther downstream) at each of five sites in the upper Current River (mean discharge 12 m3 s-1). Sixteen environmental variables were measured at each location to characterize sites. Using digital photographs from trail cameras, traffic frequencies were calculated and largely consisted of hikers and horses. Based on counts of 68,353 individuals from 111 macroinvertebrate taxa, I calculated four metrics (taxa richness, Shannon's index, EPT, biotic index) combined into the Stream Condition Index and assessed effects of stream crossings with a two-way nested ANOVA for each season. All metrics showed strong differences among sites but inconsistent effects among locations. Multivariate analyses (NMDS and a nested ANOSIM) also revealed strong differences in community composition among sites, as well as among locations. Taken together, the results indicate crossing disturbances during summer and winter 2009 were either too infrequent or small in intensity to impair benthic macroinvertebrate communities.

Keywords

benthic community, traffic, Stream Condition index, taxa richness, EPT richness, biotic index, Shannon's Diversity Index

Subject Categories

Biology

Copyright

© Rachel Lee Sine Heth

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