Analysis of the Benthic Macroinvertebrate Community Structure for Assessment of Water Quality of the Des Moines River
Westphal, Richard Leonard
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The problem. An evaluation of the water quality of the Des Moines River in the Des Moines, Iowa area was accomplished by sampling and analyzing the benthic macroinvertebrate community. Procedure. Artificial substrates at five stations collected macroinvertebrates. Community structure was analyzed using species diversity indices. Species diversity (D) and redundancy (R) values were used to calculate standardized distance (S.D.) values. These indices were analyzed using standard statistical tests of significance. Findings. An analysis of variance for standardized distance (S.D.) values demonstrated significant difference for sampling dates and location of stations. When adjusted for current velocity, no significant difference was detected for station locations, but significance over time was retained. Mean value for species diversity was 2.19. Macroinvertebrate samples demonstrated seasonal distribution. Conclusions. Current velocity appeared to be a major factor controlling colonization of macroinvertebrates in this study. The mean species diversity value indicated the Des Moines River is mildly polluted. Standardized distance (S.D.) values appear to be more meaningful than species diversity (D) alone in assessing community structure. Recommendations. The main recommendation for future study is to compare benthos sampled with artificial substrates in different current velocities at the same location.
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