Popis: |
This study was an attempt to evaluate the effects on ten Rocky Mountain streams from management activities on U.S. Forest Service lands. Macroinvertebrate and water chemistry data were collected. Data analysis methods included: three diversity indices, a numerical taxonomy system of multivariate statistical analysis, numbers and biomass per selected taxa, percent composition per order, and total numbers and biomass. None of the methods of analysis were found to be adequate if used alone, but by using a combination of dendograms, biomass, and numbers data in addition to the diversity indices (SCI and d) stream stress could be detected. Although organic water pollution generally did not reach levels of concern, other forms of stress, such as siltation and altered flows, became evident upon data analysis. In general, stream insect communities studied showed quick recovery from short-term stresses but definite negative responses to chronic stresses. |