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LANDSCAPE INFLUENCES ON IN-STREAM BIOTIC INTEGRITY: USE OF MACROINVERTEBRATE METRICS TO IDENTIFY LANDSCAPE STRESSORS IN HEADWATER CATCHMENTS
Daniel, F B., M. B. Griffith, J M. Lazorchak, AND M E. Troyer. LANDSCAPE INFLUENCES ON IN-STREAM BIOTIC INTEGRITY: USE OF MACROINVERTEBRATE METRICS TO IDENTIFY LANDSCAPE STRESSORS IN HEADWATER CATCHMENTS. Presented at Society of Environmental Toxicology and Chemistry, Salt Lake City, UT, November 18-22, 2002.
This project has three overall goals: 1) To develop efficacious methods for quantitative assessment of riparian resources at a both local and watershed scales; 2) to examine land use elements, at various scales as regulators of both water quality and biological integrity in freshwater streams, and 3) to elucidate the potential of riparian corridors to ameliorate various stressor impacts from the surrounding catchment.
-FY00 Activities The field sampling conducted in the first year will be repeated for all of the sub-watershed sites in the second year. Using the sub-watershed boundaries determined via the hydrologic models the landscape metrics for each sub-watershed will be developed. Likewise the high resolution land cover data for the riparian corridors will be developed from the digitized aerial photography.
-FY01 Activities The field sampling conducted in the years one and two will be repeated for all of the sub-watershed sites in year three. The field data from all three years will be combined to develop the indices of water quality and biotic integrity for the sub-watersheds. The stream quality and land cover data from the watershed catchment area and the riparian corridor will be correlated using a series of step-wise, multistage, linear regression models. Individual features of stream quality will be related to various riparian land cover parameters and other land use elements in the watershed as a whole. Statistical analysis will be completed.
-FY02 Activities Final reports and manuscripts for submission to the peer reviewed scientific literature will be prepared.
The biotic integrity of streams is profoundly influenced by quantitative and qualitative features in the landscape of the surrounding catchment. In this study, aquatic macroinvertebrate metrics (e.g., relative abundance of Ephemeroptera, Trichoptera, and/or Plecoptera taxa, or the relative abundance of non-insects, oligochaetes, tolerant, intolerant, or facultative taxa, and Hilsenhoff's Biotic Index, etc.) were measured over three successive seasons (1999-2001) in 35 headwater streams (sub-watersheds) located in the Little Miami River (Ohio) watershed. These sub-watersheds are spread across three Omernik Level IV ecoregions (Darby Plains, Loamy, High Lime Till Plains and Pre-Wisconsin Drift Plains) and they exhibit variations in the landscape features of their catchments including land cover (e.g., 23-91% row crop agriculture), geophysical (e.g., drainage density 1.1-3.6 km-1), and soil types (e.g., 27-36% soil clay content). Using stepwise multi-regression, relationships between measures of in-stream measures (as dependent variables) and various classes of landscape features (as independent variables), were examined at three spatial scales: the sample reach, the riparian corridor, and the entire catchment. The goal of this effort was to generate models for various in-stream stressor gradients (e.g., substrate embeddedness, canopy cover, and nutrient loads), based on landscape measures. In turn, these stressors influence in-stream water quality and biotic integrity. Accordingly, in these sub-watersheds, several of the macroinvertebrate metrics exhibited significant correlations with the stressor, substrate embeddedness (percent fines and sand). In addition, the landscape features measured at the catchment scale were more significantly correlated to embeddedness than the anaolgous features measured at the riparian corridor scale.