Dr. Michael (Mike) Wolfe is a Professor in the Department of Wildland Resources with primary research interests in the area of ecology and management of wild ungulates and their principal predators.  He also served as Mammals Coordinator for the Utah Division of Wildlife Resources. 

Email: michael.wolfe@usu.edu

Abstract:

Sagebrush Steppe Restoration and Wild Ungulates

Michael L. Wolfe, Utah State University, Logan, UT and Rick Danvir, Deseret Land and Livestock, Woodruff, UT 84086

Sagebrush (Artemisia spp.) steppe communities provide in varying degrees winter or summer habitat principally for elk (Cervus elaphus), mule deer (Odocoileus hemionus), and pronghorn (Antilocapra americana). Habitat functions include forage and to a lesser degree security cover (especially for fawns of the latter species). The relative value of these habitats depends upon the plant species composition of the communities (shrub vs. herbaceous components), food preferences of the ungulates using them and, in the case of winter range, stature of the sagebrush in relation to snow depth. Although sagebrush may not be the most preferred browse species, it assumes particular importance under severe winter conditions, when snow may cover other more palatable species. Palatability of sagebrush varies among species and subspecies as well as by ecotypes and the maturity of individual plants. Historically, sagebrush treatments focused on large-scale removal and conversion to grasslands. More progressive contemporary treatments are oriented toward emulation of natural disturbances and/or restoration of functionality in sagebrush steppe communities and are of greater potential benefit to big game animals. These typically involve spectrum of procedures to reduce the canopy cover of decadent or over-mature sagebrush stands and encourage the diversity and growth of herbaceous understory vegetation frequently supplemented with planting of additional species. The projected benefits for big game animals of sagebrush restoration efforts are improved quantity, diversity and nutritional quality of forage and putatively elevated nutritional plane and fitness of the animals in question, presumably with population responses of greater fecundity and survival rates and possibly numbers. As with other species of vegetation conversion programs sagebrush restoration projects often demonstrate increased levels of utilization of treated areas and in some cases improved palatability and nutrient levels of the vegetation. Moreover, there exists considerable empirical evidence linking ungulate body condition with reproductive performance and possibly survival rates. However, actual benefits likely vary with scale and method of treatment as well as post-treatment management. Thus, while the expectation of positive population level responses is rational, empirical documentation of such responses is limited, largely due to the logistical problems of measuring body condition and demographic parameters on a meso- or management unit scale. In some instances the confounding influences of environmental variables such as drought and severe winter conditions may obscure treatment benefits. Some case histories of successful programs and strategies to maximize potential benefits for the three ungulates are discussed.