FLORISTICS AND COMMUNITY ECOLOGY OFAQUATIC VEGETATION OCCURRING IN SEVEN LARGE SPRINGS AT OZARK NATIONAL SCENIC RIVERWAYS, MISSOURI (U.S.A.), 2007-2012

摘要

We studied the aquatic vegetation communities of seven large springs located at Ozark National Scenic Riverways, Missouri, 2007-2012. This study provides a baseline for assessing the impacts of anthropogenic and natural disturbances on the ecologicalintegrity of springs. Vegetation was assessed quantitatively along sample cells located on multiple transects in each spring. We list 69 distinct taxa with substantial overlap of species occurrences among springs, including 6 families, 6 genera, and 6 species of algae, and 9 families, 12 genera, and 19 species of mosses and liverworts. Among angiosperms, we report 10 families, 13 genera, and 20 species of monocots, and 16 families, 23 genera, and 24 species of dicots. Some species previously reported from the springs are no longer present, which may be due to long-term changes in watershed condition. Individual sample cells typically contained four to six taxa, although Welch Spring generally had only two to three taxa represented. Effective numbers ofspecies were generally consistent among years for all springs, but the various species did not occur in equal abundance in the community within or among sample years. Taxa richness was slightly higher than Simpson's Diversity Index effective number (De)and Shannon's Diversity Index effective number (He) for all years among springs. He ranged from 1.34 to 3.76 among sampling years and springs with values for Alley and Blue springs of approximately 3 while those for Big, Pulltite, Round, and Welch springs were closer to 2. De ranged from 1.25 to 3.86 among sampling years and springs. Few non-native plant species occurred in the springs, and they accounted for <15% of the foliar cover across transects.