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INVERTEBRATE ASSEMBLAGES FROM HEADWATER STREAMS WITH DIFFERENT FLOW PERMANENCE
Citation:
FRITZ, K. M. AND B. R. JOHNSON. INVERTEBRATE ASSEMBLAGES FROM HEADWATER STREAMS WITH DIFFERENT FLOW PERMANENCE. Presented at North American Benthological Society, Anchorage, AK, June 04 - 09, 2006.
Impact/Purpose:
The goal of this research is to develop methods and indicators that are useful for evaluating the condition of aquatic communities, for assessing the restoration of aquatic communities in response to mitigation and best management practices, and for determining the exposure of aquatic communities to different classes of stressors (i.e., pesticides, sedimentation, habitat alteration).
Description:
Headwater streams are the most abundant and widespread of our nation's surface waters, yet few ecological assessments are specifically targeting these resources. Natural drying has a strong influence on the biological communities and can confound the use of traditional stream assessment tools. The study goal was to identify biological assemblage shifts associated with flow permanence in minimally altered headwater streams. This information can then be used to better separate the effects of periodic drying and anthropogenic impacts in headwater streams. Invertebrates were sampled from depositional and erosional habitats in 43 reaches along 17 headwater streams and across four forests in Indiana, Kentucky and Ohio. Assemblage composition differed significantly between intermittent and perennial reaches, however assemblages showed stronger overall differences among forests. Among environmental variables, water temperature and dissolved oxygen showed the strongest correlations to ordination axes. Invertebrate taxa individually accounted for low percentages of the overall dissimilarity between intermittent and perennial reaches, where 90% of the dissimilarity was accounted for by 169 taxa. Invertebrate assemblage differences appeared to be primarily driven by physiographic region and secondarily by flow permanence at the reach scale.