Taxonomy and Ecology of Sagebrush in Oregon

C 4 Taxonomy and Ecology of Sagebrush in Oregon Station Bulletin 642 May 1980 Agricultural Experiment Station Oregon State University, Corvallis Contents Abstract 5 Introduction Taxonomy 6 Ecology 6 Scabland sagebrush 6 Black sagebrush 6 Low sagebrush 7 Cleftleaf sagebrush 7 Early sagebrush 7 Three-tip sagebrush 7 Bolander silver sagebrush 7 Mountain silver sagebrush 7 Wyoming big sagebrush 12 Basin big sagebrush 12 Mountain big sagebrush 12 Subalpine sagebrush 13 Diagramatic Key 8 Key to Artemisia (Section Tridentatae) in Oregon 10 Management Alternatives 13 Literature Cited 15 AUTHOR: A. H. Winward, Associate Professor, Rangeland Resources Program, Oregon State University, Corvallis, Oregon 97331. 3 Taxonomy and Ecology of Sagebrush in Oregon A. H. Winward ABSTRACT ally arise as to where or how much sagebrush is Twelve important sagebrush taxa form an needed for food or cover for native animals and important component of the vegetation on at birds. Should it be controlled or reduced, thereby least 19 million acres in Oregon. Each kind of releasing associated grasses and forbs for live- sagebrushhasitsown morphology,genetic stock and wildlife feed? If so, how should it be make-up, and ecologicalrequirements. Those reducedwith chemicals, by fire,or mechani- acquainted with these 12 taxa find them useful in cally? What was the ecological status of sage- recognizing range sites and understanding site brush during the presettlement period and how potential. This bulletin provides an update on information used toidentify these 12 taxa. A has this changed? What factors are responsible general description of their geographic distribu- for this change? tionis included, along with important features While arguments continue, scientists are gath- about their ecology and value as cover or forage. ering facts about sagebrush that will help answer these questions. For several years, scientists have been refin- INTRODUCTION ing sagebrush taxonomy. What was once de- The genus Artemisia (sagebrush) is known on scribed as a few separate species have been found most continents of the world. In the United States to be complexes of many subtaxa, each with its it occupies at least 96 million acres (Tisdale et al., own morphology, genetic make-up, and ecological 1969) and is found primarily in the steppe areas of requirements. Those acquainted withthe new the 11 western states. classification system find it easier to understand In the Pacific Northwest and Intermountain re- the ecology of each taxon and can better predict gions there are 20-plus recognized species, sub- responses to particular land management prac- species, and forms of woody sagebrush, plus at tices. least 15 herbaceous species. This paper covers The objectives of this paper are to: only the woody taxa which have perfect flowers Provide an update of the kinds of sagebrush (Tribe Anthemideae). Twelve representatives from in Oregon. this tribe are common in Oregon (Table 1). These Provide information necessary to recognize 12 taxa form an important component of the vege- each important taxon in Oregon. tation on at least 19 million acres in Oregon. A considerable amount of controversy about Stress the importance of keeping up with the value of sagebrush exists. Questions continu- the new sagebrush classification system. Table 1.Important woody Artemisia taxa in Oregon1 Standard Scientific name Common name abbreviation Artemisia rigida Scabland or stiff sagebrush Arri Artemisia nova Black sagebrush Arno2 Artemisia arbuscula ssp. arbuscula Low sagebrush Arara Artemisia arbuscula ssp. thermo p0/a Cleftleaf sagebrush Arart Artemisia Ion giloba Early sagebrush Arlo2 Art emisia tripartita ssp. tripartita Three-tip sagebrush Artrt2 Art emisia cana ssp. bolanderi Bolander silver sagebrush Arcab Artemisia cana ssp. viscidula Mountain silver sagebrush Arcav Artemisia tridentata ssp. wyomingensis Wyoming big sagebrush Artrw Artemisia tridentata ssp. trident ata Basin big sagebrush Artrt Artemisia tridentata ssp. vase yana Mountain big sagebrush Artrv Artemisia tridentata form spiciformis Subalpine big sagebrush Artrs 1 Common names and standard abbreviations from Garrison et al., 1976. 5 4. Discuss the status of land management ECOLOGY practices based on the new system. Ecological features which influence where the sagebrush taxa grow include: TAXONOMY Elevation (as it affects temperature and soil moisture); Major morphological characteristics used to Soil depth, structure, drainage, and chem- classify sagebrush include: leaf shape, size, and i stry; color; shrub height and general form; branching of the inflorescence and number of seeds per Total yearly moisture and seasonal distri- flower head (see key). bution; and Since we deal with species, subspecies, and Other less defined features such as number forms, some characteristics are somewhat subtle. of cloud-free days per year and competing For this reason, several features often are used to vegetation. substantiate some separations. A few individual The following information is a general descrip- plants in most stands of sagebrush have unusual tion of the geographic distribution and ecology of oruncommon features.Generally,theseare sagebrush in Oregon. Specific areas where some caused by crossing of two taxa, "unnatural" envi- taxa have isolated or scattered occurrences may ronmental influences, or some other phenomenon not be mentioned. that alters a plant's natural appearance. In field work, however, problems from unusual individuals are minimal since we are dealing with full popula- Artemisia rigida (scabland sagebrush) tions, i.e., we are generally attempting to identify Scabland sagebrush occurs primarily in the sagebrush in an area versus an individual plant. north and northeastern part of the state.Itis In addition to using morphological features for found as far west as Wasco County, as far south classification, the number of chromosomes and as northern Harney County, and north and east chemical make-up have been used toidentify into Washington and Idaho.It grows on rocky, genetic variations of sagebrush. A useful chemical shallow soil areas from about 3,000 to 7,000 feet method to separate some sagebrush taxa is to elevation. The grass species most commonly as- place a few grams of leaf material in a clear glass sociated with scabland sagebrush under good con- bottle, add enough methanol or ethanol to thor- ditions is Sandberg's bluegrass (Poa sandbergii). oughly saturate the leaves, and allow the material Biscuitroots (Lomatium species) also are common to react for one-half hour (Winward and Tisdale, associates. Cheatgrass (Bromus tectorum) and 1969). The color of the fluorescing liquid can be other annual grasses and forbs become major increasers on disturbed sites of scabland sagebrush. Table 2.Fluorescent color of the sagebrush-methanol solution under long-wave, ultraviolet light (by taxon) Artemisia nova (black sagebrush) Group I.Fluoresce shades of creamish-blue Black sagebrush has been found in only three Artemisia arbuscula ssp. arbuscula southeastern Oregon countiesLake, Harney, and Artemisia arbuscula ssp. thermopola Malbeur. It extends in small patches as far north- Artemisia Ion giloba west as Christmas Valley but is more common in Artemisia tripartita ssp. tripartita the southern part of these three counties. It ap- Artemisia cana ssp. bolanderi pears to have some affinity to calcareous soils Artemisia cana ssp. viscidula with a high amount of surface rock or pavement. Artemisia tridentata ssp. vase yana It generally occurs above 4,000 feet elevation and Artemesia tridentata form spiciformis in some states has been found as high as 8,000 Group ILFluoresce shades of brownish-red feet. Several older range surveys describing black Artemisia tridentata ssp. wyomingensis sagebrush in other areas of Oregon apparently Artomisia tridentata ssp. tridentata are in error. Artemisia nova Vegetation commonly associated with this spe- Artemisia rigida cies under good conditions includes bluebunch wheatgrass (Agropyron spicatum), Indian ricegrass (OryzopsIs hymenoides), and, occasionally, needle- observed by shining a long-wave, ultraviolet light andthread grass (Stipa comata). Squirreltail(Si- on the bottle in a darkened room. The solution will tanion hystrix) and Sandberg's bluegrass are com- be shades of either creamish-blue or brownish- mon increasers. Under severely depleted condi- red. Colors which the sagebrush taxa fluoresce are tions, a large amount of bare ground becomes listed in Table 2. exposed on black sagebrush sites. 6 Artemisiasagebrush) arbuscula subsp. arbuscula (low tipArtemisia sagebrush) tripartita subsp. tripartita (three- thattheernless LowCascadesOregon. borderthan sagebrush 3,000 theIt exceptoccurs feetColumbia is elevation foundthein nearly northern River. in manyto all above Itcounties half isparts found of9,000 countiesof east east- fromfeet. of outcounties.onlyareas Inpositive. in Oregon,of Baker the Several state,Three-tip andthree-tip reports butnorthern none, sagebrushsagebrush have Harneyas recorded yet, canhas have and bebeen it Malheurchecked foundin foundother in shallow,areasWithdrought.longed few with spring unfracturedexceptions, an impermeableflooding bedrock.low and sagebrush "B"extensive It withstandshorizon is foundsummer or withpro- on allmanagementfuselysoilserate states aboveto after deep, that 3,800fire considerations. borderwell-drained, or feet clipping Idaho, elevation. loamyand itrequires It andgrows resprouts sandy on special mod- loam pro- onana).ensis),bunch Commonlylow

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