1a. Objectives (from AD-416):
1) Determine what factors (management, site/environmental characteristic, etc) promote native plant recruitment in crested wheatgrass plant communities. 2) Determine if crested wheatgrass displaces native vegetation from plant communities.
1b. Approach (from AD-416):
Site Selection: To accomplish the first objective, we propose to sample 100 crested wheatgrass plant communities across the northern Great Basin to determine what factors promote native plant recruitment in crested wheatgrass plant communities. Private and public land managers will be contacted to locate near-monoculture of crested wheatgrass and crested wheatgrass with native vegetation recruitment. Sampling: Management history will be determined from historic records and personal knowledge of the land manager. Management history that will be collected includes year established, method of seeding, kind of brush control used, grazing history, and additional disturbances. Vegetation characteristics will be determined using 60 x 50 m plot to sample each site. Four 50 m transects will be deployed at 20 m intervals along the 60 m transect. Herbaceous vegetation cover and density will be visually estimated by species inside 40 x 50 cm frames located at 3 m intervals on each transect line (starting at 3 m and ending at 45 m), resulting in 15 frames per transect and 75 frames per plot. Shrub canopy cover by species will be measured by line intercept (Canfield 1941). Canopy gaps less than 15 cm will be included in the canopy cover measurements. Shrub density will be determined by counting all rooted individuals in five, 2 X 50 m belt transects at each plot. Soil texture, water holding capacity, pH, and profile description will also be collected at each site. Topographical position, aspect, elevation, and slope will be recorded at each site. To determine if crested wheatgrass displaces native vegetation, we will measure the densities and cover of perennial bunchgrasses in plots established in 1989 with specific densities of crested wheatgrass and seven native perennial bunchgrasses. Eight plots will be used to determine if crested wheatgrass density has increased and native perennial bunchgrass densities have decreased since the plots were established. Crested wheatgrass and native perennial bunchgrass cover will be measured in 15 randomly placed 0.2m2 frames in each plot. Density will measured across the entire plots to be able to compare to density in 1989.
3. Progress Report:
This project was terminated June 30, 2012 but will be extended another year. Research was completed on project objective 3 which relates to mechanisms of weed invasion and develop management strategies that can be used to restore rangelands that have been degraded by weeds or other disturbances. We sampled vegetation, site, and management characteristics at 50 crested wheatgrass stands to determine the effects of site and management factors on the recruitment of native vegetation into crested wheatgrass stands. We also identified over 50 more crested wheatgrass stands to sample in the future. Information gleamed from this study will help land managers restore and manage sagebrush steppe plant communities converted to crested wheatgrass stands.