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SENSITIVITY OF ZOOPLANKTON INDICATORS IN REGIONAL MONITORING
Citation:
Stemberger, R. S., D P. Larsen, AND T. M. Kincaid. SENSITIVITY OF ZOOPLANKTON INDICATORS IN REGIONAL MONITORING. CANADIAN JOURNAL OF FISHERIES AND AQUATIC SCIENCES. NRC Research Press, Ottawa, Canada, 58:2222-2232, (2001).
Description:
This study describes an approach for assessing and selecting ecological indicators for regional monitoring of northeastern US lakes. We analyze the components of variance for indicators of zooplankton richness and abundance in the context of the spatial and temporal sampling design of the U. S. EPA's Environmental Monitoring and Assessment Program (EMAP) pilot study. The components of variance include spatial or lake variance, year variance, local or interaction (lake X year) variance, and within-year sample variance. We evaluated indicators for their ability to meet monitoring goals such as status estimation and trend detection with respect to spatial scale. We compared sensitivity of candidate indicators for region-wide estimates and for underlying geographic subregions. Subregions were defined by landscape features and post-glacial drainage history. Region-wide estimates of sensitivity for richness indicators did not differ greatly from estimates based on subregions. However, abundance-based indicators showed much greater sensitivity, increasing more than 20 fold for some indicators in specific subregions. Abundance of calanoid copepods were the most sensitive indicators having up to 69% and 95% of total variance attributed to the lake component in regional and subregional estimates, respectively. Rotifers, cyclopoid copepods, large and small cladocerans, and minor zooplankton groups had low sensitivity irrespective of spatial scale. This analysis suggests that performance of indicators can be increased with regional spatial partitioning that reflects natural biogeographic and landscape features.