You are here:
INTERREGIONAL COMPARISON OF NUTRIENT UPTAKE RATES IN MANAGED AND OLD-GROWTH WATERSHEDS
Citation:
McCormick, F H. AND B H. Hill. INTERREGIONAL COMPARISON OF NUTRIENT UPTAKE RATES IN MANAGED AND OLD-GROWTH WATERSHEDS. Presented at Interagency Conference on Research in the Watersheds, Benson, AZ, October 28-30, 2003.
Impact/Purpose:
The purpose of this research project is to provide methods, tools and guidance to Regions, States and Tribes to support the TMDL program. This research will investigate new measurement methods and models to link stressors to biological responses and will use existing data and knowledge to develop strategies to determine the causes of biological impairment in rivers and streams. Research will be performed across multiple spatial scales, site, subwatershed, watershed, basin, ecoregion and regional/state.
Description:
We compared nutrient uptake rates to examine the effect of timber harvest on streams. From 1999-2002, nutrient additions were conducted in 50 stream reaches in 4 ecoregions (southern Blue Ridge, NC, Ouachita Mountains, AR, Cascade Mountains, OR, and the redwood forests of the Coast Range, CA). Nutrient uptake was measured, along with the Cl-tracer, by depletion over stream distance. Streams draining logged watersheds had smaller dominant substrate size, more open canopies, and more sand and fine sediments in the channel. Phosphate uptake lengths were not significantly different when comparing streams draining old-growth or harvested watersheds or ecoregions. Ammonium uptake lengths were significantly longer in old-growth compared to harvested watersheds but were not different among ecoregions.