Citation:

Massie, J., Joe Ebersole, D. Peck, A. Herlihy, M. Snyder, AND S. Leibowitz. APPLYING MULTIMETRIC INDICES AT HIGH RESOLUTION: AN INVESTIGATION OF SPATIAL PATTERNS AND TEMPORAL VARIATION WITHIN AN OREGON WATERSHED. Oregon Chapter of the American Fisheries Society (ORAFS) Annual Meeting, Bend, OR, February 28 - March 03, 2017.

Impact/Purpose:

Multimetric indices (MMIs) that incorporate data on the biological and physical characteristics of freshwater systems and provide meaningful indicators of instream conditions can serve as important tools for monitoring change over time, identifying sensitive habitats, and prioritizing management and restoration efforts. Evaluations such as EPA’s National Rivers and Streams Assessment (NRSA) and the Environmental Monitoring and Assessment Program (EMAP) use such indices to provide important insights into the status and trends in condition of the Nation’s waters, but do not tell us as much about variation in condition within individual watersheds at local scales. To investigate this local variability, we apply two existing indices to high density sampling data from the Calapooia watershed in Oregon’s Willamette Basin. The high degree of variation in biotic condition among sites within this basin provide insight into patterns occurring at smaller spatial scales and increase our understanding of how the combination of natural and human stressors influence condition. We also found that indices of condition for streams that flow year-round tended to be similar whether sampled in spring or summer, indicating that sampling conducted at any one time throughout the spring-summer period may provide a reliable index of condition. These results will help local watershed councils, landowners and agencies better understand what locations are in best and worst condition, and plan stream and riparian restoration activities accordingly. This abstract contributes to SSWR 1.1B.

Description:

Like many inland waters worldwide, streams and rivers of the Western U.S. are faced with a multitude of challenges stemming from past land use practices and changing future conditions. To address these issues, the USEPA has developed empirical tools for evaluating instream conditions and monitoring the status of our freshwater resources over time. These efforts have made substantial progress in integrating quantitative methods into multimetric indices (MMIs) used for national and regional assessments and have provided an enhanced understanding of condition patterns across the broader landscape. To examine the extent of spatial and temporal variability not captured by the sparse distribution of sample sites used in these large-scale assessments, we applied two existing MMIs to inter-seasonal fish and macroinvertebrate data from the Calapooia Basin in Oregon’s Willamette Valley. Our chosen indices revealed a high degree of variation in biotic condition within our study area. With notable exceptions, indices were seasonally robust, indicating potential flexibility for scheduling sampling. An increased understanding of condition patterns occurring at fine spatial scales and the natural and anthropogenic effects influencing them can help guide and prioritize restoration and management.

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