The EPA has recognized the need for a rational approach to the incorporation of ecological impact information into power facility siting decisions in the northern great plains. Research funded by the Colstrip, Coal-fired Power Plant Project is a first attempt to generate methods to predict the bioenvironmental effects of air pollution before damage is sustained. Pre-construction documentation of the environmental characteristics of the grassland ecosystem in the vicinity of Colstrip, Montana began in the summer of 1974. Since then, key characteristics of the ecosystem have been monitored regularly to detect possible pollution impacts upon plant and animal community structure. In the summer of 1975, field stressing experiments were begun to provide the data necessary to develop dose-response models for SO2 stress on a grassland ecosystem. These experiments involve continuous stressing of one acre grassland plots with measured doses of SO2 during the growing season (usually April through October). Results of the 1976 and 1977 field seasons' investigations are summarized in this publication. The six-year project will terminate in 1980 and a final report will be published after data analyses are complete.

"Terrestrial Systems Division, Corvallis Environmental Research Laboratory." "April 1979." "EPA 600-3-79-044." Cover title. Includes bibliographical references. Interim ;