Species Diversity of Benthic Macroinvertebrates in the Des Moines River, Iowa

Abstract

Problem. Evaluation of the water quality of the Des Moines River. Iowa by sampling and analyzing the benthic macroinvertebrate community. Procedure. Artificial substrates at four stations were used to collect benthic macroinvertebrates. Community structure was analyzed with species divorsity indices. Species diversity (D) and redundancy (R) values were used to calculate standardlzed distance (SD) values. The indices were analyzed statistically. Findings. The average D values ranged from 1.62 to 1.94. Mean standardized distance (SD) values were lowest immediately above the metropolitan Des Moines area and highest immediately downstream from the metropolitan Des Moines area. Conclusion. According to species diversity (D) values, the entire Des Moines River in the study area exhibited mild pollution. Differences in: community structure do exist in the river. Differences in standardized distance (SD) values are attributed to influences that the metropolitan area had on the river. Red Rook Reservoir showed no statistically significant effects on the station immediately downstream. Recommendations. Recommendations for further study are: (1) Follow-up species diversity and productivity studies after Saylorville Reservoir is impounded. (2) Follow-up study with more sample sites between stations 2 and 3 incorporating chemical analysis of water to pinpoint the site of most drastic water quality change.