Increasing native diversity of cheatgrass-dominated rangeland through assisted succession

Abstract

Increasing attention, resources and efforts are being focused on the conversion of weedy dominated rangelands back to perennial plant communities that resemble predisturbance communities in form, function and composition. A study was conducted in 1998 and replicated again in 1999 to determine whether native plants could be established through “assisted succession” - manipulating a cheatgrass-dominated area to perennial plant domination, then to native or near-native diversity. Cheatgrass dominated rangeland that had been successfully revegetated with crested wheatgrass (Agropyron cristatum [L.] Gaertner) was seeded with native species. Another area dominated by cheatgrass, but without crested wheatgrass, was also seeded. Four seedbed preparation methods were investigated: tilling, harrowing, application of a herbicide, and no treatment. Four different seeding methods were used in the 2 areas and 4 seedbed preparation techniques: drilling, broadcasting, a broadcast-cover method, and no seed. Seeding was done in February, and data were collected in mid-summer each year. Native grasses and shrubs emerged in greater numbers on treatments established on the crested wheatgrass matrix than on those established on the cheatgrass matrix. Perhaps in general, but especially in years with normal or below average precipitation, the assisted succession approach proved successful for restoration of native sagebrush-grassland steppe from cheatgrass range.