| A forest riparian buffer is an area whose vegetation is trees which is located between a stream and the adjacent uplands. This study tested the efficacy of restored forest riparian buffers along streams in the Chesapeake Bay watershed by examining stream macrobenthic community structure. By conducting such a comparative analysis of streams with similar hydrologic and geological settings, but with differing ages of restored or natural forested buffer zones, I assessed the relative functionality of the restored forested wetland for re-establishing a stable, healthy aquatic ecosystem.; My research examined macrobenthic community structure in 30 streams with buffers ranging from 0 to greater than 50 years of age. Two separate benthic samples were analyzed from each stream (midreach, and downstream end of the forested buffer zone). Samples were identified to family, enumerated and entered into spreadsheets for statistical analysis. Metrics utilized included taxonomic richness, percent Ephemeroptera/Plecoptera/Trichoptera, % dominance, number of tolerant families present, % intolerant individuals, the Family Biotic Index, and several functional feeding group composition measures. Midreach water samples from each site were analyzed in the laboratory for ammonium nitrogen, nitrate nitrogen, total phosphorus, phosphate, total suspended solids and volatile suspended solids.; Results showed that habitat, water quality, and benthic macroinvertebrate metrics increase with age of restored buffer. Habitat scores appeared to stabilize between 10 and 15 years of age, were driven mostly by instream substrate availability and width and age of riparian buffer zones. Water quality parameters varied within buffer age groups depending on algal cover and age of surrounding forest vegetation. Benthic invertebrate taxa richness, % EPT, % Plecoptera, % Ephemeroptera, and the FBI all improved with age of buffer zone. Other metrics varied within age classes. Instream habitat quality, was the greatest driver of benthic macroinvertebrate community diversity and health, and appeared to peak within 10--15 years of restoration with noticeable improvements occurring within 5--10 years post restoration. (Abstract shortened by UMI.)... |
