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NUTRIENT UPTAKE LENGTH, CHANNEL STRUCTURE, AND TRANSIENT STORAGE IN STREAMS DRAINING HARVESTED AND OLD GROWTH WATERSHEDS
Citation:
Hill, B. H., F H. McCormick, B. C. Harvey, AND S. L. Johnson. NUTRIENT UPTAKE LENGTH, CHANNEL STRUCTURE, AND TRANSIENT STORAGE IN STREAMS DRAINING HARVESTED AND OLD GROWTH WATERSHEDS. Presented at 86th Annual Meeting of the Ecological Society of America, Madison, WI, August 5-12, 2001.
Description:
Channel structure and transient storage were correlated with nutrient uptake length in streams draining old-growth and harvested watersheds in the Cascade Mountains of Oregon, and the redwood forests of northwestern California. Channel width and riparian canopy were measured at 10 equally spaced intervals along each 50-m to 100-m study reach. Stream depth was measured at 1-m intervals along the study reaches. No significant differences were found in stream width and depth between streams draining old-growth and harvested watersheds, but streams draining harvested watersheds had more open riparian canopies. Transient storage (A) was calculated as differences in area under the curves for predicted and actual Cl-transport through the study reaches. Few differences in A were measured between streams draining old-growth and harvested watersheds. Nutrient uptake was measured along with the Cl-tracer, by depletion over stream distance. Phosphate (P) uptake lengths were not significantly different among streams draining old-growth or harvested, and were significantly correlated with riparian canopy cover. Ammonium uptake lengths were significantly longer in old-growth compared to harvested watershed, and were significantly correlated with riparian canopy cover and stream channel area. The opposing correlations of P and N uptake with riparian canopy and A suggest differences in uptake processes.