You are here:
INDICATORS OF ECOLOGICAL STRESS AND THEIR EXTENT IN THE POPULATION OF NORTHEASTERN LAKES
Citation:
Whittier, T R., S G. Paulsen, D P. Larsen, S A. Peterson, P R. Kaufmann, AND A. T. Herlihy. INDICATORS OF ECOLOGICAL STRESS AND THEIR EXTENT IN THE POPULATION OF NORTHEASTERN LAKES. Presented at Northeast Natural History Conference, Albany, NY, April 24-26, 2002.
Description:
The Environmental Monitoring and Assessment Program (EMAP) surveyed 345 northeastern lakes, during 1991-1996, in the first regional-scale survey to use a probability-based sampling design to collect biological assemblage data along with a broad range of physical and chemical indicators of stress to lakes. I focus on limnological topics, primarily, nutrient enrichment, acidification, and the extent and effect of impoundments, along with data on metals contaminants in fish, non-natives, and riparian disturbance. The results are presented as estimates of the extent to which the population of lakes in the Northeast were in impaired condition or subject to ongoing stress. Nearly half (47%) of the northeastern lakes were human-made impoundments; most of these were in the lowland ecoregions. Sediment diatom data indicate that natural lakes in the Northeast were rarely eutrophic in the past. In the 1990s, an estimated 24% of lakes and impoundments were eutrophic or hypereutrophic; 83% of these were impoundments. Of the stressors considered, acidification was the least extensive in the region, with 2% of lakes being acidic and another 12% being acid-sensitive. Fish in 24% of lakes had mercury concentrations exceeding 0.2 g/g, above which some agencies issue consumption advisories. Fish assemblages were extensively stressed by non-native species. Only 21% of lakes had no non-native fish, while 15% of lakes had more non-native species than natives. Shoreline alteration was fairly extensive, with 23% of lakes having visible evidence of human activity at half or more of the riparian assessment stations. Finally, I present a relative rankings of the extent of these stresses to Northeast lakes.