Tuesday, June 5, 2007
102

(Talk Moved To Poster Session At Presenter's Request) Changes In Substrate Composition (And Fish Assemblage) Following Road-Stream Crossing Improvements On Pine Creek, Manistee County, Mi

Kristofor N. Nault1, Jason DeBoer1, J. Marty Holtgren2, Stephanie Ogren2, and Eric B. Snyder1. (1) Biology, Grand Valley State University, 1 Campus Drive, Allendale, MI 49401, (2) Conservation, Little River Band of Ottawa Indians, Manistee, MI 49660

Accumulation of sediments can degrade aquatic habitat, resulting in reduced biodiversity and fitness of aquatic organisms.  Management actions have been taken on Pine Creek (2nd order) to reduce sediment loading and provide a more natural flow regime by replacing faulty road-stream crossings.  Comparisons above and below restoration sites of sediment, organic matter, invertebrate, and fish populations were conducted pre and post restoration.  At the first reach, results indicated that downstream, gravel has increased while coarse, fine, and ultrafine sand has decreased.  Fish species diversity (Shannon’s index) remained stable (range 1.35-1.49).  At the second reach, only pre-restoration data is available, and substrate composition is variable.  Fish species diversity ranged from 0.85–1.70 and 1.04–1.92 at upstream and downstream sites, respectively, and tended to increase at upstream sites from year 1 to 3.  At the third reach, sediments that were flushed downstream decreased available gravel and increased fine, coarse, and ultrafine sand at the lower sites.  This may be correlated to a decrease in fish diversity at the lower-most site (1.15-0.69).  At the remaining sites, fish species diversity has remained stable or has increased.  Overall, significant responses in the fish community to restoration haven’t been observed.