Carl L. Wambolt

Crude terpenoid influence on mule deer preference for sagebrush.

Samples of current years growth of leaves and stems were collected in February 1983 from basin big sagebrush (Artemisia tridentata Nutt. tridentata), Wyoming big sagebrush (A.t. wyomingensis Beetle and Young), mountain big sagebrush (A.t. vaseyana [Rydb.] Beetle), and black sagebrush (A. nova Nels.) on a mule deer (Odocoikus hemionus hemionus) winter range near Gardiner, Montana. Samples were from both lightly and heavily used plants (form classes) within each taxon. Crude terpenoids were separated into 3 groups: headspace vapors, volatile, and nonvolatile crude terpenoids. Compounds in each group are thought to stimulate the sensory organs of mule deer. Individual compounds were identified and quantified for comparison with preference ranks among taxa and between utilization form classes. Seven compounds were selected by discriminant analysis as indicators among the 4 taxa, with methacrolein+ethanol, p-cymene, and the sesquiterpene lactones the most probable preference determinants. Seven other compounds were found useful for separating plants within taxa into form classes. Chemical differences between the 2 form classes, however, were less distinguishable than were those among the 4

An 18-year comparison of control methods for Wyoming big sagebrush in southwestern Montana.

Four Wyoming big sagebrush (A rtenmsiatridentatassp. wyomingensis Beetle and Young) control treatments: burning, spraying with 2,4-D, rotocutting, and plowing, along with no control (rest) were compared in southwestern Montana. Production data (excluding sagebrush) were collected 10 years and sagebrush canopy cover and understory basal cover were collected 8 years during the period 1963-1981. Sagebrush canopy was most effectively reduced by burning while plowing with seeding was least effective. Rest alone resulted in a 29%o reduction in sagebrush canopy during the study period. By 1981, burning provided the most production from the dominant forage species (bluebunch wheatgrass (Agropyron spicatum (Pursh) Scribn.) and important vegetal classes, although burning and spraying were equally successful when production was totaled for all years sampled. Understory basal cover did not prove useful to evaluate treatment effectiveness. Big sagebrush (Artemisia tridentata Nutt.) maintains an undeniably important role on rangelands in the Western United States. Big sagebrush occupies nearly 60 million hectares in this region (Beetle 1960). Relatively recent taxonomic advancements in the big sagebrush complex initiated by Beetle (1960) and Beetle and Young (1965) have encouraged research to expand our knowledge about the taxa in such diverse areas as further taxonomic refinement, ecological relationships, forage relationships, and manipulation of sagebrush ecosystems. Welch and McArthur (1979) emphasize the nature of big sagebrush by recognizing its aggressive, productive, and persistent habits which, along with its low preference for forage by cattle, are undoubtedly responsible for its having been the subject of many control projects. Blaisdell et al. (1982) emphasize that no one control technique will likely prove optimum under all conditions as big sagebrush control often is reported without consideration for inter-taxon variation. This complicates interpretation of many previous studies. In addition, few reports are available that follow vegetal reaction to big sagebrush control for more than a few years. This may partially explain apparent contradictions in the literature regarding effectiveness of various control and post-control techniques to suppress big sagebrush. The objective of this study was to compare the effectiveness of 4 brush control treatments and no-control (rest) for Wyoming big sagebrush over the period 1963-1981. Effectiveness is evaluated through comparisons among treatments for forage production, sagebrush canopy cover, and basal cover of understory species. Study Area and Methods The study site is located in southwestern Montana approximately 27 km west of Dillon and 3 km northeast of Bannack at an elevation of 1,890 m on the west flank of Badger Pass. The area is administered by the Bureau of Land Management (BLM) and has been grazed by domestic livestock since the mid-1800s. The topography is moderately rolling, varying in slope from 0-8%. The site comprises a Wyoming big sagebrush-bluebunch wheatgrass habitat type and has been dominated by those species throughout the study period. Although basin big sagebrush (Artemisia tridentata Nutt. ssp. tridentata) is found nearby, it occupies more mesic soils Authors are associate professor and professor emeritus, Animal and Range Sciences Department, Montana State University, Bozeman, 59717. The authors wish to express their appreciation to the Butte, Mont., District, Bureau of Land Management for the use and protection of the study site. Manuscript accepted 21 October 1985. resulting from drainage patterns and deeper soil development (Beetle and Young 1965, Barker and McKell 1983). Clay loams predominate in surface and subsurface soils with loams being less common. The solum extends 30 to 35 cm to a strongly calcareous C horizon. Erosion had thinned or completely removed the A horizon. The average annual precipitation is approximately 310 mm with peak precipitation occurring in May and June. We utilized a randomized complete block design of 4 replicates in the experiment. Treatment plots were 27 m X 46 m in 2 replicates and 31 m X 46 m in the other 2 replicates. Most treatment plots were separated by roadways seeded to crested wheatgrass (Agropyron cristatum (L.) Gaertn.) Analysis of variance was used to evaluate relationships among measured factors. Livestock grazing was excluded from the study site by an exclosure fence after May, 1963. Chemical, plow, and rotocut treatments were applied on 18-19 June, 22 June, and 6 July 1963, respectively. The burn treatment was accomplished after 4 September 1964 after being attempted in the autumn of 1963 when fuel conditions prohibited burning. Chemical treatment consisted of an application of 2,4-D ester in water at the rate of approximately 1.68 kg/ha with a surfactant from a ground sprayer. Plowing was accomplished with a disc plow similar to the popular Brushland plow of the era (Larson 1982) which Blaisdell et al. (1982) considered very effective. Plowed plots were broadcast seeded with approximately 9 kg/ ha of bluebunch wheatgrass seed from a local source, a practice considered necessary with this severe treatment (Blaisdell et al. 1982). The rotary cutter used was similar to the Bush Hog (Larson 1982). Burning was difficult due to a barely adequate fuel base (Beardall and Sylvester 1976) and some sagebrush plants had to be burned individually. witnin each treatment replicate, 6 permanent 15.24-m transect lines (Canfield 1941) were randomly established to determine Wyoming big sagebrush crown cover by line intercept. Data were taken in tenths of feet (approximately 3 cm units). Openings in the live canopy larger than 3 cm (0.1 ft.) were recorded as nonsagebrush intercepts. It should be emphasized that this method gives lower values than those obtained by line intercepts of sagebrush plant perimeters or by the Daubenmire (1959) method. Intercepts of such perimeters ignore open spaces and dead branches within the perimeter. This is important in comparing other research results with ours and when reading such publications as Britton and Ralphs (1979) which set cover standards for sagebrush control operations. We believe our method accurately measures changes in live sagebrush cover, significant in considering the ecological status of big sagebrush through time. It is unfortunate that most management publications set sagebrush cover standards without defining the measurement basis. Along each of the 15.24-m transects, 2 permanent 1.22-m transects were randomly selected to read basal cover of all plants. These data were recorded in hundredths of feet (approximately 3-mm units) of line intercept by species, litter, rock, and bare ground. Production data in each treatment replicate were obtained by clipping 5 circular plots of 0.5 m2 randomly spaced on a diagonal line beginning and ending no closer than 6 meters from the treatment corners. During the randomization process, the centers of the 0.5-M2 plots were located at least 2.13 m apart to avoid disturbance of plants when clipping adjacent plots. In each year when production data were collected, the diagonal sampled in the rectangular 314 JOURNAL OF RANGE MANAGEMENT 39(4), July 1986 This content downloaded from 40.77.167.87 on Sun, 17 Apr 2016 07:01:45 UTC All use subject to http://about.jstor.org/terms treatment was alternated to minimize effects of previous sampling. Plant material was oven dried at 650 C for 1 week before weighing. All measurements were taken as close to the peak of standing crop production as practical. Thus, grass and shrub phenology were similar each year at the time data were taken. Canopy and basal cover were recorded 8 years and production 10 years during the 18-year study. Results and Discussion Wyoming big sagebrush canopy cover provides a partial basis for evaluation of treatment effectiveness throughout the study period (Figures 1 and 2). The homogeneity of the sagebrush cover in the 1963 pretreatment data is evident by the lack of statistical significance among the treatment means. There was a significant reduction in sagebrush canopy cover the first year after application of the sagebrush control treatments (1965 for burn and 1964 for other treatments). The longevity of this reduction has varied considerably among the treatments. The 18 years of the study allowed ample opportunity for sagebrush reoccupation under a variety of weather conditions. Burning completely destroyed the stands of Wyoming big sagebrush. There was essentially no re-establishment of sagebrush through 1970, 6 years after burning, in spite of the availability of sagebrush seeds from rest (untreated) plots and plants growing outside the study exclosure. Up to 1967, only the spray technique had been as effective as burning in sustaining reductions of sagebrush canopy. From 1970 on, burned plots had significantly less sagebrush canopy than any other treatment. Although some reoccupation of sagebrush on the burned plots was evident by 1981, its canopy cover was still less than 2% compared to 10.5-16% in the other treatments. The apparent success of burning in this study may agree with the observations and data of Harniss and Murray (1973), who REST (no treatment) o2 a a a 15.6 14.9 16.116.7 a a b b 16 15 I4~~ 13.3 12.9 b0. b1

Consequences of Treating Wyoming Big Sagebrush to Enhance Wildlife Habitats

Abstract Sagebrush (Artemisia L.) taxa historically functioned as the keystone species on 1 090 000 km2 of rangeland across the western United States, and Wyoming big sagebrush (Artemisia tridentata Nutt. ssp. wyomingensis Beetle and Young) is or was dominant on a substantial amount of this landscape. Wyoming big sagebrush provides habitat for numerous wildlife species. Nevertheless, Wyoming big sagebrush communities are commonly manipulated to decrease shrub cover and density and increase the productivity and diversity of herbaceous plants. We examined relationships between management-directed changes in Wyoming big sagebrush and greater sage-grouse (Centrocercus urophasianus), elk (Cervus elaphus), pronghorn (Antilocapra americana), and mule deer (Odocoileus hemionus), species commonly associated with these ecosystems. We focused on herbicide applications, mechanical treatments, and prescribed burning, because they are commonly applied to large areas in big sagebrush communities, often with the goal to improve wildlife habitats. Specifically, our objective was to identify treatments that either enhance or imperil sagebrush habitats for these wildlife species. The preponderance of literature indicates that habitat management programs that emphasize treating Wyoming big sagebrush are not supported with respect to positive responses by sage-grouse habitats or populations. There is less empirical information on ungulate habitat response to Wyoming big sagebrush treatments, but the value of sagebrush as cover and food to these species is clearly documented. A few studies suggest small-scale treatments (≤ 60-m width) in mountain big sagebrush (Artemisia tridentata ssp. vaseyana [Rydb.] Beetle) may create attractive foraging conditions for brooding sage-grouse, but these may have little relevance to Wyoming big sagebrush. Recommendations or management programs that emphasize treatments to reduce Wyoming big sagebrush could lead to declines of wildlife species. More research is needed to evaluate the response of sagebrush wildlife habitats and populations to treatments, and until that time, managers should refrain from applying them in Wyoming big sagebrush communities. Resumen Sagebrush (Artemisia L.) históricamente ha funcionado como un especie clave en 1 090 000 km2 de pastizales a través del oeste de los Estados Unidos y Wyoming big sagebrush (A. tridentata Nutt. ssp. wyomingensis Beetle and Young) es o fue dominante en una gran área de este paisaje. En Wyoming big sagebrush provee hábitat para una gran cantidad de especies de fauna silvestre. Sin embargo, en Wyoming las comunidades de big sagebrush son comúnmente manipuladas para disminuir su cobertura y densidad para incrementar la productividad y diversidad de plantas herbáceas. Se examinó la relación entre los cambios debidos al manejo dirigido en Wyoming big sagebrush y las especies de sage-grouse (Centrocercus urophasianus), elk (Cervus elaphus), berrendo (Antilocapra americana) y venado mula (Odocoileus hemionus), comúnmente asociadas con estos ecosistemas. Nos enfocamos en la aplicación de herbicidas, tratamientos mecánicos, y fuego prescrito, ya que ellos son se aplican comúnmente en áreas extensas de comunidades de big sagebrush, frecuentemente con la meta de mejorar el hábitat para fauna silvestre. Específicamente, nuestro objetivo fue identificar los tratamientos que mejoran o ponen en riesgo los hábitats de sagebrush para estas especies silvestres. La preferencia de la literatura indica que los programas de manejo de hábitat que enfatizan el tratamiento de big sagebrush en Wyoming no están apoyados con respecto a las respuestas positivas por los hábitats o poblaciones de sage-grouse. Existe información menos empírica acerca de la respuesta del hábitat de ungulados a los tratamientos de Wyoming big sagebrush, pero el valor de sagebrush como fuente de cobertura y alimentación para estas especies está claramente documentada. Pocos estudios sugieren tratamientos a pequeña escala (≤ 60 m ancho) en mountain big sagebrush (A. t. ssp. vaseyana [Rydb.] Beetle) podrían crear condiciones atractivas forrajeras para el anidamiento de sage-grouse, pero éstas podrían tener poca relevancia para Wyoming big sagebrush. Recomendaciones o programas de manejo que enfoquen sus tratamientos en la reducción de Wyoming big sagebrush podrían conducir a la reducción de especies silvestres. Más investigación es necesaria para evaluar en mejor manera la respuesta de los hábitats de sagebrush para fauna silvestre y sus poblaciones a estos tratamientos y hasta entonces, manejadores deben abstenerse de aplicarlas en las comunidades de big sagebrush en Wyoming.

Influence of sagebrush terpenoids on mule deer preference

The effect on mule deer (Odocoileus hemionus hemionus Rafinesque) preference of compounds in mountain big sagebrush [Artemisia tridentata Nutt. ssp.Vaseyana (Rydb.) Beetle], Wyoming big sagebrush (A. t. ssp.Wyomingensis Beetle and Young), basin big sagebrush (A. t. ssp.Tridentata), and black sagebrush (A. nova Nels.) was compared using a two-choice preference test. Compounds tested included:p-cymene, 1,8-cineole, methacrolein (two concentrations), and the nonvolatile crude terpenoid fraction (NVCTF) from each taxon. The compounds were tested by applying them to chopped alfalfa hay at concentrations similar to those found in nature. The intake of the treated hay was compared with that of an untreated control. Eight deer were used as test animals in an 8 − 8 Latin-square design. All compounds tested significantly deterred ingestion (P < 0.05). Compound influence on preference, in order of increasing deterrence, was as follows: 50% methacrolein, mountain big sagebrush NVCTF, methacrolein, basin big sagebrush NVCTF,p- cymene, Wyoming big sagebrush NVCTF, black sagebrush NVCTF, and 1,8-cineole. Methacrolein appears to be an important preference determinant among big sagebrush subspecies, andp-cymene between black sagebrush and big sagebrush. The NVCTFs containing sesquiterpene lactones as one of their constituents were closely related to the preference of all four taxa. Future studies of animal preference for sagebrush should consider all of the potential defensive chemicals in the foliage.

Crude terpenoid influence on in vitro digestibility of sagebrush.

The infiuence of crude terpenoid content on in vitro organic matter digestibility (IVOMD) was determined for basin big sagebrush (ArteMia trident& Nutt. ssp. tridentata), Wyoming big sagebrush (A.t. ssp. wyomingensis Beetle and Young), mountain big sagebrush (A.t. ssp. vaseyana [Rydb.] Beetle), and black sagebrush (A. nova Nels.). IVOMD was determined using mule deer (OdocoiIeus hemionus hemionus), sheep (Ovis ammon a&s), and steer (Bos taurus) rumen inocula with current year’s growth collected from the 4 taxa at a common site on 1 Jan., 15 Feb., and 1 Apr. 1981. All inocuia had similar digestive efficiency. Extracting crude terpenoids from foliage increased IVOMD by an average of 12.3% overall. Few differences in IVOMD among taxa and dates were evident in foliage after crude terpenoids had been extracted. Order of increasing digestibility among taxa without crude terpenoids extracted was black sagebrush, mountain, Wyoming, and basin big sagebrushes, respectively. IVOMD generally Increased from January to April as crude terpenoids decreased. Crude terpenoid concentrations were lowest in mountain big sagebrush, intermediate in black sagebrush and Wyoming big sagebrush, and greatest in basin big sagebrush.

Mule deer and,elk foraging preference for 4 sage- brush taxa

A 10 year study under natural winter conditions at 2 sites tested the hypothesis that mule deer (Odocoileus hemionus hemionus) and elk (Cervus elaphus nelsoni) forage equally on 4 sagebrush (Artemisia L.) taxa. Each year approximately 2,500 available leaders on 244 plants on the Northern Yellowstone Winter Range were examined for browsing. Browsing levels increased with winter severity, reaching 91% of leaders browsed for mountain big sagebrush (A. tridentata ssp. vaseyana [Rydb.] Beetle), the preferred taxon (p< 0.05) that averaged 56.1% at the 2 sites. Wyoming big sagebrush (A.t. ssp. wyomingensis Beetle and Young) was narrowly preferred (38.6%) over basin big sagebrush (A.t. Nutt. ssp. tridentata) (30.3%). Black sagebrush (A. nova Nels.) was least preferred (17.0%). Differences in preference among taxa were smallest during the severest winters when more elk were present thereby increasing total sagebrush utilization. Mule deer diets averaged 52% sagebrush over the study. Many sagebrush plants were damaged and even killed by heavy browsing during the study. Promoting sagebrush productivity should be a management objective on similar winter game ranges.

Sagebrush response to ungulate browsing in Yellowstone

Big sagebrush (Artemisia tridentata Nutt.) declined from ungulate browsing during the first half of the twentieth century on the Northern Yellowstone Winter Range. It was our objective to compare shrub parameters of Northern Yellowstone Winter Range sagebrush habitat types continually browsed or protected for 32 to 37 years. Measurements were taken in and out of exclosures for 19 environmentally paired, protected, and browsed sites. We found significant differences in development between protected and browsed shrubs. Big sagebrush canopy cover at the 19 sites averaged 19.7% with protection and 6.5% where browsed (P less than or equal to 0.0027), and plants were twice as numerous (P less than or equal to 0.0027) under protection. Winter forage production of individual big sagebrush plants was also greater under protection at 16 of the 19 paired sites (P less than or equal to 0.0027). Subdominant sprouting shrubs generally responded the same as big sagebrush. This ungulate induced decline of shrubs has implications for many Northern Yellowstone Winter Range values. Ultimately many organisms are sacrificed with the loss of quality big sagebrush habitat.

Effect of Method, Site, and Taxon on Line-Intercept Estimates of Sagebrush Cover

Abstract Sage-grouse (Centrocercus spp.) are arguably the best known of the many wildlife species that inhabit sagebrush (Artemisia spp.) ecosystems. Lack of standardization in the procedures used to assess sagebrush cover may contribute to inconsistencies in reported habitat requirements for sage-grouse and other wildlife. We compared 3 applications of the line-intercept method for 3 sagebrush taxa. We sampled 2 mountain big sagebrush (A. tridentata vaseyana) sites, 2 Wyoming big sagebrush (A. t. wyomingensis) sites, and 1 black sagebrush (A. nova) site to determine whether the results generated by the 3 methods differed. Percent cover as determined by agency methods was up to 2.6 times greater than that from research applications. Cover differences among techniques were influenced by taxa and site (P ≤ 0.001) because both affected shrub morphology. We believe it will be difficult to identify and achieve wildlife habitat guidelines for minimal sagebrush cover requirements if methodologies are not standardized.

Grazing effects on nutritional quality of bluebunch wheat-grass for elk.

We tested the hypothesis that nutrient content of bluebunch wheatgrass (Agropyron spicatum [Pursh] Scribn. &Smith) either cattle grazed in the spring, rested from cattle grazing for a full year, or given long term rest would all be equal during the given season at 1 location. A 3 pasture rest-rotation grazing system and an exclosure on the Mt. Fleece elk winter range in southwestern Montana were studied during 4 seasons over 3 years. Only nitrogen (N) and phosphorus contents were generally greater in the in the spring grazed regrowth pasture. However, regrowth from bluebunch wheatgrass grazed in the spring did not improve the species nutrient content for wildlife the following winter over nongrazed treatments. During winter when elk (Cervus elaphus nelsoni Bailey) are present, N, TDN, and IVDMD were not among the 3 treatments. Elk were determined unlikely to consume enough bluebunch wheatgrass to meet protein maintenance requirements during winter. Our findings resulted from analyses repeated over the 3 years for a complete cycle of a 3 pasture rest-rotation system: however, our hypothesis needs to be tested at other locations before assuming the same results elsewhere.

Black-Tailed Prairie Dog Effects on Montana's Mixed-Grass Prairie

Abstract Forty paired sites were examined on the mixed-grass prairie of northeastern Montana to compare the effects of black-tailed prairie dog (Cynomys ludovicianus) colonies on native range vegetation. Thirty 0.25-m2 quadrats were placed on colonized and uncolonized locations and matched by environmental conditions. Cover and standing crop biomass of each plant species was estimated using a double sampling procedure where every third plot was clipped and estimated. A total of 2 400 quadrats were estimated, whereas 720 quadrats were clipped during the months of May–August of 2000 and 2001. Crude protein, digestibility, neutral detergent fiber, and acid detergent fiber were determined on the basis of vegetative classes (cool-season grasses, warm-season grasses, standing dead grass, forbs, and dwarf shrubs). Pairwise comparisons were made using paired t tests and differences were declared significant at the 0.05 level. Plant biomass of colonized sites was dominated by fringed sagewort (Artemisia frigida Willd.) (42%), blue grama (Bouteloua gracilis [HBK] Lag. ex Steud) (16%), and western wheatgrass (Agropyron smithii Rydb.) (16%). Uncolonized sites were dominated by Wyoming big sagebrush (Artemisia tridentata ssp. wyomingensis Beetle and Young) (36%), western wheatgrass (13%), and blue grama (12%). Standing crop biomass, plant species richness, litter, standing crop crude protein, sagebrush canopy cover, and density were greater (P < 0.05) on uncolonized areas compared to colonized areas. Bare ground and crude protein concentration were greater (P < 0.05) on areas colonized by prairie dogs compared to uncolonized areas. Digestibility and fiber content of both areas were not different (P > 0.05). Activities associated with prairie dog colonies reduced plant productivity and plant species richness of the mixed-grass prairie by reducing cool-season perennial grasses and litter, increasing bare ground, and eliminating big sagebrush.