THE STREAM ENVIRONMENT 



AND MACROINVERTEBRATE COMMUNITIES: 



CONTRASTING EFFECTS OF MINING 



IN COLORADO AND THE EASTERN 



UNITED STATES 



JAMES V. WARD,* STEVEN P. CANTON,* and LAWRENCE J. GRAYt 

 *Department of Zoology and Entomology, Colorado State University, 

 Fort Collins, Colorado, and tDepartment of Zoology, Arizona State University, 

 Tempe, Arizona 



ABSTRACT 



Studies were conducted year-round on a Colorado stream that receives drainage 

 from a coal mine to assess the potential response of macroinvertebrate 

 communities to mining activities in the western United States. Species 

 composition, diversity, and standing crop were examined, and results are 

 compared with similar studies conducted in eastern states. Generally low values 

 of sulfate and iron, highly-buffered waters, and low levels of toxic substances 

 characterized the Colorado stream and applied, in general, to many streams in 

 the western energy-development region. Moderate inputs of soluble salts 

 increased ' abundance of macroinvertebrates without significant changes in 

 community structure or other discernible indications of stressed conditions. This 

 is attributed to the relatively soft waters above the mine and the protection 

 afforded by a buffer strip between the mine spoils and the stream. Increased 

 salinity, sedimentation, and water depletion are major problems, but, with 

 proper environmental considerations, mining in the West may not have the 

 severe impacts on stream biota which characterize many eastern mining regions. 



The western United States has vast expanses of coal. Kauffman and 

 Schaefer (1977) indicated that "70 percent of all known, high-grade, 

 low-sulphur, strippable coal deposits are located in this area, as are all 

 of the country's major high-grade oil shale reserves." They estimated 

 that the next 10 to 25 years will be a developmental period for the 

 energy resources of the western United States. 



Coal-bearing strata underlie 28% of the state of Colorado 

 (Landis, 1964). Coal deposits are of the Upper Cretaceous and early 

 Tertiary periods, as are the majority of surface mineable coal reserves 



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