ARS | Publication request: WILD AND PRESCRIBED FIRE EFFECTS TO WYOMING BIG SAGEBRUSH STEPPE, EASTERN OREGON

Submitted to: Ecology and Management of Pinyon Juniper Communities Within The Interior W
Publication Type: Abstract
Publication Acceptance Date: May 1, 2005
Publication Date: May 16, 2005
Citation: Bates, J.D., Miller, R., Sharp, R.N. 2005. Wild and prescribed fire effects to Wyoming big sagebrush steppe, Eastern Oregon [abstract]. Ecology and Management of Pinyon Juniper Communities Within The Interior W. Paper No. 31.

Technical Abstract: Fire remains a management tool for increasing herbaceous diversity and structural complexity in large, intact Wyoming big sagebrush communities such as found in eastern Oregon and northern Nevada. However, there is limited information available on Wyoming sagebrush community dynamics following fire and the potential risks for weed invasion after fire disturbance. In this study we evaluated Wyoming sagebrush community dynamics following prescribed burning and wildfire. Both fires removed sagebrush from the community. The prescribed fire was of low intensity and there were no measurable differences in herbaceous composition between burned and unburned treatments 2 years after fire. The wildfire was of high intensity and produced variable effects dependent on the plant association. Wyoming big sagebrush/Thurber¿s needlegrass associations were severely impacted by the wildfire, causing high mortality of perennial grasses and mat-forming forbs. Cheatgrass has increased slowly. Because of the reduction in the perennial grass component much of the area in the Thurber¿s needlegrass association remains open to further annual grass colonization. Wyoming big sagebrush/bluebunch wheatgrass associations though severely impacted did not suffer high mortality of perennial grasses, thus, perennial herbaceous composition recovered or exceeded pre-burn levels by the 3rd year post-fire. However, bluebunch wheatgrass and Thurber¿s needlegrass associations are often found in a mosaic on the landscape. Efforts should be made to limit severe wildfire disturbances in these plant associations in eastern Oregon and elsewhere because of the risk of weed invasion. If burning is prescribed, prescriptions should probably be limited to periods when conditions produce fires of lower severity.