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Communication at the NABS Annual meeting, Keystone, 2000
(286) EYEING THE AUFWUCHS AND GROPING THE GROWTH: A RAPID METHOD FOR ESTIMATING EPILITHIC PERIPHYTON ABUNDANCE IN STREAMS.
J.W. Feminella1 and C.P. Hawkins2. 1Department of Biological Sciences, Auburn University, Alabama USA 36849-5407, 2Department of Fisheries and Wildlife, Watershed Science Unit and Ecology Center, Utah State University, Logan, Utah USA 84322-5210
A major drawback to quantifying periphyton in streams at large spatial scales is that empirical measurements are slow and laborious, which often limit their use to only a few locations. We designed a semi-quantitative method (Algal Cover Index, ACI) that can be used in the field to rapidly estimate periphyton and algal biomass within clear-running streams. ACI is based on both visual and tactile assessments of the amount of periphyton, either as low-growing biofilm or upright filamentous algae, occurring on 10-30 stones within a riffle. Individual assessments are then subjectively combined into a single ACI score for that riffle. Field calibrations of ACI alongside traditional methods of periphyton quantification within several SW Washington streams (catchments of Clearwater Creek) revealed that ACI was effective in predicting periphyton (AFDM) and algal (Chlorophyll a) biomass, and weighted AFDM (WAFDM; = AFDM x chlorophyll), a measure of potential periphyton quality. ACI accounted for 85, 68, and 85% of the variation among replicates in chlorophyll, AFDM, and WAFDM, measured for individual stream stones, respectively. We also are currently evaluating the efficacy of the ACI within Piedmont and Appalachian streams of the southeastern United States, over a wide range of periphyton growth conditions.
Presented at 11:45 AM on Thursday, June 1, 2000 in Factors Affecting Algal and Macrophyte Growth II
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