Revegetation of Roadcut Slopes in Mesa Verde National Park, U.S.A.

The geology of Mesa Verde National Park (MVNP) poses unique problems to road construction and maintenance. Major geologic formations of the Park consist of an overlying resistant sandstone cap underlain by highly erodable shales. Once this sandstone cap is removed, the shales are easily eroded away, creating the notable mesas of the region. In many places, road construction has removed the sandstone layer and vegetation resulting in unaesthetic barren slopes that require continual maintenance and have proven difficult to revegetate. An experiment was conducted to evaluate the effectiveness of several cultural techniques combined with seeding and transplanting indigenous plants for revegetation of these roadcut slopes. Techniques evaluated were fertilization, mulching, soil pitting, and polyacrylamide amendments. Replicated test plots were established at three roadcut sites in MVNP to evaluate these techniques by measuring percent plant cover by species over a 4-year period. A combination of seeding grasses and transplanting forbs and shrubs appeared to be the optimal way to maintain species diversity and structure on the road-cuts while accomplishing the goal of revegetating these difficult sites. The perennial forb Aster glaucodes and the shrub Artemisia ludoviciana showed high survival when transplanted in the experimental roadcut sites. These species, as well as the perennial grass Pascopyrum smithii, also established well from seed. The addition of an organic fertilizer, in combination with mulch, proved to be the most effective method of improving vegetation cover for these and other transplanted species.