We developed ecological indicators of stream macroinvertebrates in two regions of the Midwestern USA dominated by row-crop agriculture. Indicators were identified in a hierarchical fashion. Reach-scale variables related to macroinvertebrate attributes were first identified, and then catchment-scale variables related to those reach-scale variables were identified. Reach-scale indicators common to both regions were % fine sediments, number of habitats, and width:depth ratio. SD of elevation and % commercial land use were selected as catchment-scale indicators in both regions. Our analyses revealed a multi-scale mechanistic relationship between macroinvertebrate attributes associated with degraded conditions (i.e., fewer taxa of Plecoptera and Trichoptera, and a higher proportion of chironomids, burrowers, and depositional taxa) and % fine sediments in stream reaches, which, in turn, was negatively related to catchment characteristics (i.e., SD of elevation) in one region. Understanding how natural variables such as topography influence channel shape and within-channel structure can help guide management options and expectations for different regions. We suggest that developing multi-scale indicators in a mechanistic fashion will be more effective than developing indicators at only one spatial scale for protecting and restoring stream structure and function.
Bibliographical noteFunding Information:
Roger Haro, Ahn Ly, Heather Malstrom, and Mark Prankus assisted in the collection of field data. Tom Hollenhorst and Connie Host prepared spatial databases and conducted GIS analyses. Jackie Pechin and John Ameel conducted many of the laboratory analyses. Jesse Schomberg calculated Manning's n. Although the research described in this article was funded wholly or in part by the United States Environmental Protection Agency Science to Achieve Results (STAR) program through grant number CR822043-01-0 and R825870-01-0 to Richards, Johnson, and Host, it has not been subjected to the Agency's required peer and policy review and therefore does not necessarily reflect the views of the Agency and no official endorsement should be inferred. This is publication no. 491 of the Center for Water and the Environment, Natural Resources Research Institute, University of Minnesota Duluth.
Copyright 2009 Elsevier B.V., All rights reserved.
- Macroinvertebrate attributes
- Midwestern USA