Sagebrush, Common and Uncommon, Palatable and Unpalatable

I read with interest Jim Brunner's recent view point article' where he briefly traced the recognition of palatable forms of sagebrush. Jim's keen sense of differences in sagebrush taxa were first published more than 3 decades ago.2 Jim's comments stimulated some thoughts of my own about the recognition, distribution, and palatability of sagebrush taxa. I'm sharing some of those thoughts here. Sagebrush is an icon of the American West.3 However, it is a symbol that stirs a range of emotions among rangeland managers.4-7 An appreciation for the values of sagebrush ecosystems has been a long time coming and, unfortunately, is juxtaposed with a fragmentation of that resource over much of its historic range.4'5 That is not to say that there are areas that may not need management, including reduction of sagebrush density, but more often, in my opinion, the weightier need is for restoration and enhancement. Sagebrush ecosystems are varied and rich in indigenous and multitudinous forms of life. Some forms are obligate to their sagebrush habitat, eg, greater sage-grouse, Gunnison sage-grouse, pygmy rabbits, sage thrasher, and sage sparrow.4'5 Brunner' pointed out that sagebrush is diverse in form and in its acceptance as forage for animals (palatability). Some taxa are common; others are not. Big sagebrush is the central and most important species to the group that forms its own portion of the large genus Artemisia-the subgenus Tridentatae (Table 1). This group is composed of wholly western North American endemics, although Artemisia in general, through representation of its other subgenera, occurs widely around the world. I believe there are 6 kinds (subspecies) of big sagebrush. Three of these are common throughout the distributional range of the subgenus and species, which is nearly the same. The geographic range of the subgenus is only slightly larger than that of big sagebrush itself, to the northeast by silver sagebrush (Artemisia cana) and to the southeast by Bigelow sagebrush (A. bigelovii).A The common subspecies are basin, mountain, and Wyoming b g sagebrushes, respectively, the subspecies tridentata, vaseyana, and wyomingensis. These subspecies each have distinctive morphological differences and habitat preferences but can be distributed in close proximity.9 The distribution of basin big sagebrush in particular is highly fragmented because the deep, well-drained soils that it prefers are prime agricultural and urban lands. Mountain big sagebrush is sometimes divided into 2 varieties based on the number of flowers per head. The common mountain big sagebrush east of the Cascade-Sierra axis is sometimes termed variety paucifora to contrast it with the plants with larger flower heads that occur at higher elevations and latitudes (variety vaseyana of ssp. vaseyana). Both are quite similar, and I am comfortable in calling both "mountain big sagebrush." The recognition of Wyoming big sagebrush has expanded widely during my career. It was not described until 1965.10 I well remember my introduction to bona fide Wyoming big sagebrush. It was at the field trip of the 1973 Wyoming Shrub Ecology Workshop held in Pinedale. Alan Beetle, who with his student Alvin Young had described the subspecies, led the field trip to the type location. Before that time, my experience with what I thought was Wyoming big sagebrush had been with what has subsequently been formally described as Lahontan low sagebrush (A. arbuscula ssp. longicaulis).11 My mentor Perry Plummer had many accessions of sagebrush growing at the Snow Field Station in Ephraim, Utah, among which were accessions of Lahontan low sagebrush, which had been collected as seedling transplants from northwestern Nevada as "widelobe" with the sobriquet "an ecotype of Wyoming big sagebrush" from Alan Beetle through Jim Brunner. After I had learned what typical Wyoming big sagebrush was really like at the Wyoming Shrub Ecology Workshop, I saw that it was widely distributed, but previously unrecognized, in many locations. Others have recognized this wide distribution as well; published studies recognize it in 11 states."2'13 It is always tetraploid (has 4 sets of chromosomes), whereas basin and mountain big sagebrush are usu-