|Shields Jr, Fletcher|
Submitted to: North American Benthological Society Bulletin
Publication Type: Abstract Only
Publication Acceptance Date: May 1, 1997
Publication Date: N/A
Technical Abstract: In an effort to evaluate habitat rehabilitation criteria for unstable warmwater streams, a one-kilometer reach in an incised stream (Goodwin Creek) was modified to create greater water depth with riffle-pool sequences using small weirs and spur dikes of quarry stone. Riparian zone recovery was augmented using living willow (Salix nigra) posts. Physical and invertebrate characteristics at Goodwin Creek were compared to a similar incised creek which did not receive modifications (Bobo Bayou) and to a non-incised stream used as a reference (Toby Tubby Creek) for two years prior and three years following rehabilitation. Physical changes due to rehabilitation at Goodwin Creek included a 148% increase in mean water depth and a 67% decrease in mean velocity. Pool habitat increased from 20% to 66% of stream area due to treatment. Following rehabilitation, number of taxa for Goodwin Creek increased to approximate that of the reference stream, and during the third year after modifications, increased in Goodwin Creek though both the control and reference streams showed sharp decreases. Filtering-collector densities in Goodwin Creek increased sharply after rehabilitation, roughly paralleling densities in the reference stream, while densities in the comparison incised stream remained low. Shredder feeding group densities in Goodwin Creek also increased greatly following rehabilitation, exceeding both the reference and incised streams. The rehabilitated stream also exhibited a distinct decrease in density of the tolerant and nuisance populations of midges (Diptera: Chironomidae: Polypedilum illinoiense and Dicrotendipes nervosus groups) found there.