Tuesday, May 27, 2008
340

Macroinvertebrate community structure in disturbed streams affected by excess storm water runoff

Jason M. Nelson1, Jason Drogowski2, Michelle Harju2, and Eric Snyder2. (1) Biology, Miami Univeristy, Ohio, Oxford, OH 45056, (2) Biology, Grand Valley State University, 212 Henry Hall, 1 Campus Dr., Allendale, MI 49401

Ravine tributary streams surrounding Grand Valley State University are variously affected by storm water runoff, representing a spectrum from severely impacted to pristine.  Quantitative macroinvertebrate samples taken from six streams in late June 2007, indicated that insect diversity was negatively correlated to total dissolved solids (p=0.037), % EPT was negatively correlated to iron (p=0.002), % chironomidae was negatively correlated to algal AFDM (p=0.039), and Ephemeroptera and Plecoptera abundance were negatively correlated to turbidity (p=0.025 in both) (stepwise multiple linear regression analyses).  Chironomidae represented a larger fraction of the community in a golf-course stream (Least Significant Difference) but had higher abundances in storm water-influenced streams vs. the control.  The Family Biotic Index (FBI), a metric devised to evaluate Family-level tolerance to disturbance, was positively correlated to ammonium-N concentration (p=0.049); concentrations in disturbed streams had more tolerant individuals (higher FBI score).  Macroinvertebrate abundance was highest in highly disturbed streams and lowest in the pristine control stream.  In summary, we found that (i) ravine streams with excess storm-water runoff had greater abundances of disturbance-tolerant taxa, (ii) these hydrological conditions play a role in determining macroinvertebrate community structure, and (iii) we established base-line conditions prior to the initiation of a storm-water abatement program.


Web Page: macroinverebrate community structure, ravine tributary streams, storm water runnoff, insect diversity, family biotic ind