Sage-grouse groceries: forb response to pinon-juniper treatments

Authors: Bates, Jonathan - Jon; Davies, Kirk; HULET, APRIL - University Of Idaho; MILLER, RICHARD - Oregon State University; ROUNDY, BRUCE - Brigham Young University

Submitted to: Rangeland Ecology and Management
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/10/2016
Publication Date: 1/4/2017
Citation: Bates, J.D., Davies, K.W., Hulet, A., Miller, R.F., Roundy, B. 2017. Sage-grouse groceries: forb response to pinon-juniper treatments. Rangeland Ecology and Management. 70:106-115.

Interpretive Summary: In the western United States control of expansionary piñon-juniper woodlands by mechanical treatments and prescribed fire have been applied since the 1950’s to recover sagebrush steppe rangelands. The Sage Grouse Initiative has made conifer removal a major part of its program to recover sagebrush habitat for sage-grouse and other shrub steppe species. We analyzed data sets from previous and ongoing studies that provide cover response of perennial and annual forbs, utilized by sage-grouse in their diet, to mechanical and fire treatments. Site potential is a major determinant for gaining increases in perennial forbs utilized by sage-grouse following conifer control and the response of perennial forbs was similar regardless of conifer treatment (prescribed fire, clear-cutting and fuel reduction). Mechanical and low disturbance-fuel reduction conifer treatments not only produce similar perennial forb responses compared to fire, but maintain essential habitat characteristics of sagebrush steppe. Annual forbs favored by sage-grouse benefitted most from prescribed fire treatments with smaller increases following mechanical and fuel reduction treatments.

Technical Abstract: In the past 150 years, juniper (Juniperus spp. L.) and piñon (Pinus spp. L.) coniferous woodlands have increased 2 to 10-fold in 9 ecoregions spanning the Intermountain area of the western United States. Control of piñon-juniper woodlands by mechanical treatments and prescribed fire have been applied since the 1950’s to recover sagebrush steppe rangelands. Recently, the Sage Grouse Initiative has made conifer removal a major part of its program to recover sagebrush habitat for sage-grouse and other shrub steppe species. We analyzed data sets from previous and ongoing studies that provide cover response of perennial and annual forbs, utilized by sage-grouse in their diet, to mechanical and fire treatments. There were 11 sites in western juniper (Juniperus occidentalis Hook.) woodlands, three sites in singleleaf piñon (Pinus monophylla Torr. & Fr´em.) and Utah juniper (Juniperus osteosperma [Torr.] Little), two sites in Utah juniper, and two sites in Utah juniper and Colorado piñon (Pinus edulis Engelm). Western juniper sites were in NW California, eastern Oregon, and SW Idaho and were located in mountain big sagebrush steppe associations. Sites for the other woodlands were in eastern Nevada and western Utah and were located in Wyoming big sagebrush steppe associations. Site potential appears to be a major determinant for gaining increases in perennial forbs utilized by sage-grouse following conifer control. The response of perennial forbs was similar regardless of conifer treatment when comparing prescribed fire, clear-cutting and fuel reduction. For sage-grouse habitat, mechanical and low disturbance-fuel reduction conifer treatments not only produce similar perennial forb responses compared to fire, but maintain essential habitat characteristics of sagebrush steppe. Annual forbs favored by sage-grouse benefitted most from prescribed fire treatments with smaller increases following mechanical and fuel reduction treatments. Where large scale use of fire may not be a management option in sage-grouse habitat, the use of small-patchy fires to control conifers might offer opportunities to increase annual forbs used by sage-grouse and create a more diverse habitat for other species.