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Assessing the condition of riverine systems using multimetric indices: An example from Oregon's Calapooia basin
Citation:
Massie, J., Joe Ebersole, D. Peck, A. Herlihy, AND S. Leibowitz. Assessing the condition of riverine systems using multimetric indices: An example from Oregon's Calapooia basin. Annual Meeting of the American Fisheries Society, Portland, OR, August 16 - 20, 2015.
Impact/Purpose:
Over the last few decades, quantitative methods have become an integral part of evaluating freshwater ecosystems in order to develop meaningful indicators of instream conditions that impact the development of aquatic communities. Multimetric indices (MMIs) that incorporate data on the biological and physical characteristics of freshwater systems can serve as useful tools for providing baseline data to monitor change over time. Evaluations such as EPA’s National Rivers and Streams Assessment (NRSA) have provided an estimate of condition at regional or national scales. To investigate the utility of MMIs at the local scale, we apply multiple existing methods for indicator development to a network of sites within the Calapooia River basin in Oregon’s Willamette Valley. The resulting trends are examined to provide insight into patterns occurring at smaller spatial scales that may not be captured by regional assessments. High-resolution application of indices can increase our understanding of how combinations of natural and anthropogenic stressors influence species distribution and could help guide management and restoration efforts. The format of this conference provides numerous concurrent symposia in which managers and researchers from academia, state, and federal agencies present new and innovative developments in fisheries science. This talk will present our results on fine-scale MMIs and offer attendees the opportunity to ask questions relevant to their research and offer recommendations for further application. The outcome of this presentation may foster collaborations between EPA and other agencies and increase the comparability of future watershed assessments based on similar methods.
Description:
Streams and rivers of the Western United States are susceptible to the combined influences of climate change and an expanding human population. Empirical tools for assessing instream conditions play a critical role in monitoring change, preventing degradation, and mitigating impacts to help ensure the resilience of our freshwater communities. Previous efforts have made notable progress towards integrating quantitative methods into multimetric indices (MMIs) developed for national and regional assessments, and provide a quantifiable view of varying conditions across the landscape. To explore how well the sparse distribution of sample sites used in large-scale assessments represent conditions that may be highly variable at finer spatial resolutions, we use data from various locations within Oregon’s Calapooia basin. We investigate multiple established methods for deriving MMIs using taxon-specific tolerances to disturbance and metrics developed for the Western mountains. We examine and compare spatial patterns in condition estimates based on different biological and physical characteristics (fish, macroinvertebrates, habitat). Applying MMIs at fine spatial resolution can provide a better understanding of both the natural landscape patterns in freshwater assemblages, and the anthropogenic effects influencing them. This understanding can help guide and prioritize restoration and management.