The persistent impacts of trace metals from mining on floodplain grass communities along Soda Butte Creek, Yellowstone National Park
Stoughton, J.A. and Marcus, W.A
Environmental Management, Vol. 25 Issue pp. 305
During a large flood event in 1950, a mine-tailings impoundment dam failed, and elevated levels of trace metals were observed subsequently in floodplain soils along Soda Butte Creek within Yellowstone National Park. In this study, the metal effects on floodplain grasses were examined. Four meadow study sites were selected, representing varied elevations and downstream distances from the tailings source. Trace metals were analyzed, and soil pH, soil electrical conductivity, and percent clays were measured. Grass species density was also measured for various perennial species. Results showed that vegetation diversity, density, and biomass varied widely up to a certain trace-metal level, at which the values of all three parameters declined significantly. Soil pH was also important, as values below 6.5 caused similar declines in vegetation density and biomass.