Vegetation of roadcut slopes in the tundra of Rocky Mountain National Park,Colorado

Eight study-sites were chosen on road margins in the alpine tundra of Rocky Mountain National Park, Colorado. Seven of the sites were located about the middle of slopes created by filling, below the roads. The remaining site was above the road, and flat on bedrock. Mosaics of pioneer vegetation types are present on roadcut slopes. These appear to be correlated with altitude, exposure, substrate texture, and degree of slope. Forty to fifty years after denudation, succession plays only a minor role on roadcut slopes. Plant coverage after that time is approximately one-half that of cushion-plant communities on natural tundra. The most important pioneer plants under these conditions are ‘bunch type’ Gramineae, especially Agropyron scribneri and Poa fendleriana.