| Brook trout (Salvelinus fontinalis) are the only salmonids native to eastern North America and the southern Appalachian strain has declined markedly since 1900. The Great Smoky Mountains National Park (GSMNP) restored southern Appalachian brook trout to 2.7 km of LeConte Creek and stream habitat and aquatic macroinvertebrate populations were characterized within LeConte Creek as brook trout were restored. Aquatic macroinvertebrate communities were also examined in two post-restoration brook trout streams and one rainbow trout (Oncorhynchus mykiss) stream.; Resolution among stream communities, as assessed by discriminant analysis, increased when members of the family Chironomidae were identified to genus versus pooling them at the family-level. Therefore, all chironomids were identified to the genus-level. Samples collected from riffle habitat during September 1998 from LeConte Creek were used to investigate the identification of distinct stream “zones” based on shifts in aquatic insect community structure. No shifts in community structure were identified based on stream chemistry changes. However, a distinct change in large-scale habitat characteristics produced responses in aquatic insect communities. Functional feeding group representations indicated the large-scale habitat break corresponded to a change in functional characteristics of the stream community. The macroinvertebrate community within the stream containing rainbow trout was studied to detect temporal changes in functional characteristics, and it was determined that community function and structure did not change seasonally. However, differences were observed between seasons at the taxa density scale of community description. Evaluation of natural inter-annual variation in the aquatic macroinvertebrate community of the rainbow trout stream indicated that aquatic insect order densities and functional feeding group densities were similar between years within each season. Although taxa richness was similar between years, taxonomic composition and taxa density varied considerably. Analysis of data from all study streams indicated that no consistent or clear pattern existed within the macroinvertebrate community that could be attributed to brook trout restoration efforts. Therefore, results indicated that trout predation and brook trout restoration in GSMNP had no detectable effect on macroinvertebrate communities, or that natural inter-annual changes dilute any signal of trout effects on these macroinvertebrate communities. |
