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Use of survey data to develop sediment criteria for protecting aquatic vertebrates in mountain streams
Citation:
KAUFMANN, P. R., S. A. BRYCE, AND G. LOMNICKY. Use of survey data to develop sediment criteria for protecting aquatic vertebrates in mountain streams. Presented at 2009 Western Division, American Fisheries Society annual meeting, Albuquerque, NM, May 03 - 07, 2009.
Impact/Purpose:
We examined the relationship of aquatic vertebrate taxa abundances and an index of biotic integrity (IBI) to reachwide measures of areal percent streambed surficial fines (≤ 0.06 mm) and sand and fines (≤ 2 mm), based on data collected from 557 wadeable streams in the Western Mountain region of the U.S. as part of the recent National Wadeable Streams Assessment (NWSA) carried out by the U.S. EPA and States.
Description:
We examined the relationship of aquatic vertebrate taxa abundances and an index of biotic integrity (IBI) to reachwide measures of areal percent streambed surficial fines (≤ 0.06 mm) and sand and fines (≤ 2 mm), based on data collected from 557 wadeable streams in the Western Mountain region of the U.S. as part of the recent National Wadeable Streams Assessment (NWSA) carried out by the U.S. EPA and States. Four-person crews typically completed NWSA biotic assemblage and habitat sampling in 6 to 8 hours of field time per site. Quantile regression predicted a 5.3% decline in the potential maximum vertebrate IBI for each 10% increase in areal percent fines, and a 4.5% decline in potential IBI for each 10% increase in the combined percentage of sand and fines. To identify possible impairment thresholds along these continuous linear relationships, we examined 1) the range of areal percent fines and areal percent sand and fines values at 169 least-disturbed reference sites in our sample; 2) sediment tolerance values calculated for a selection of sediment-sensitive aquatic vertebrate taxa for both particle size classes; and 3) a literature review of the effects of sand and fines on the survival of salmonid eggs to hatching. Based on this combined information, we concluded that minimum-effect sediment thresholds for fines (≤ 0.06 mm) and sand and fines (≤ 2 mm) for the group of sediment-sensitive aquatic vertebrates were 5% and 13%, respectively. We offer these results as scientific guidance for the process of establishing sediment criteria.