Possible Relationships Between Surface Water Chemistry and Aquatic Plants in the Northern Great Plains

The possibility of establishing relationships between surface water chemistry and the occurrence of certain aquatic plant species was investigated on 281 wetland sites throughout the northern Great Plains. Ninety-seven species of aquatic plants were selected for the study, selection being based on the direct association of plants with water and on the number of sites at which the plants were found. The ranges and means of surface water conductivity, total alkalinity and pH values were determined on a species by species basis. Of the three chemical parameters measured, conductivity of surface water appeared to have the greatest influence on the presence or absence of certain aquatic plants. Five species were found strictly in fresh water while eleven others were found to tolerate subsaline conditions. Most species tolerated great variation in alkalinity, while 22 species were found strictly in highly alkaline waters. Little relationship was found between pH and aquatic plant occurrence, although the highest pH readings occurred in subsaline waters and the lowest readings in fresh waters