Seed germination during unhospitable environmental conditions can be a major barrier to direct seeding efforts in dryland systems. In the sagebrush steppe, Artemisia tridentata Nutt. ssp. wyomingensis and Artemisia arbuscula are important shrub species that are being used in restoration, but seeding success is highly sporadic due to inter-annual and intra-seasonal weather variability. Altering and expanding the period of germination, as a form of bet-hedging, may improve plant establishment. Our objective was to determine if we could expand the period of germination using plant growth regulators (PGRs) applied in a conglomerated seed coating treatment. In a laboratory study, the seed was either left untreated, conglomerated separately with two concentrations of a germination inhibitor, abscisic acid (ABA), or with two different germination promoters, gibberellic acid (GA3) and 1-Aminocyclopropane carboxylic acid (ACC), a precursor to ethylene. Seeds were incubated in a loam soil at five constant temperatures (5-25 C) for approximately three months. Results indicate that seed treatments with PGRs can delay or speed germination. The greatest response to the seed treatments was observed at 5 C. For example, at this temperature PGRs delayed the time for 25% of the seeds to germinate by a maximum of 35 and 21 d and decreased this time by 5 and 25 d for A. t. ssp. Wyomingensis and A. arbuscula, respectively. Field studies are needed to determine if the bet-hedging strategy developed in this study will increase the likelihood that some seeds will germinate during periods that are more favorable for plant establishment.

Sagebrush (Artemisia spp.) is an important source of food and cover for many animals, especially during winter months. Understanding how wildlife species respond to sagebrush management actions can help improve conservation planning. Dixie harrow is a method of improving spring/summer habitat for many herbivores by reducing sagebrush cover to stimulate the growth of grasses and forbs. These treatments, however, may influence the quantity and quality of sagebrush available to greater sage-grouse (Centrocercus urophasianus; hereafter, sage-grouse) during winter. We evaluated the effects of Dixie harrow on sage-grouse resource selection during winter (Chapter 1) and on the nutritional value of sagebrush (Chapter 2). We were unsure what effect Dixie harrow would have on the nutritional value of sagebrush, but hypothesized that sage-grouse would select for untreated areas because they contained a higher quantity of food and cover. We captured 81 sage-grouse and fit them with GPS transmitters. Using 6,728 winter locations, we modeled third-order resource selection. Further, we collected samples of sagebrush plants that sage-grouse had eaten from (n = 54), samples of sagebrush plants passed by but not eaten from (n = 54), as well as samples from random locations inside (n = 60) and outside Dixie harrow treatments (n = 60). Contrary to our hypothesis, sage-grouse selected for Dixie harrow treatments during winter. We found that sage-grouse selectively browsed sagebrush plants with increased nutritional value, and that sage-grouse browsed plants inside treatments more frequently than outside the treatments, but Dixie harrow treatments had no measurable effect on the nutritional value of sagebrush. Based on our results, Dixie harrow treatments performed at the southern extent of the sage-grouse range will create habitat that sage-grouse prefer during winter, but we were unable to ascertain why sage-grouse select for Dixie harrow treatments during winter.

Fire is an important disturbance mechanism in big sagebrush (Artemisia tridentata) communities, yet little is known about wildlife population dynamics during post-fire habitat succession. I estimated the abundance of small mammals and birds in relation to fire history in mountain big sagebrush (A.t. spp. vaseyana) communities on the Sheldon National Wildlife Refuge in the northwestern Great Basin, USA. I employed a chronosequence approach that took advantage of multiple wildfires that had occurred in similar plant communities between 7 to 20 years prior to sampling. Belding’s ground squirrel (Spermophilus beldingii) were approximately 10 times as abundant in burned areas relative to adjacent unburned habitat regardless of the number of years since a burn occurred. Deer mouse (Peromyscus maniculatus) was more abundant on more recently burned sites, but not at sites closer to full vegetation recovery. Great basin pocket mouse (Perognathus parvus), sagebrush vole (Lemmiscus curtatus), and least chipmunk (Tamius minimus) abundance did not vary as a function of fire history, but some variance was explained by habitat features such as rocky areas and the canopy characteristics of sagebrush. Bird diversity was higher in unburned habitats irrespective of the number of years of recovery out to 20 years. Nine of the 12 most widely occurring species of birds in the study have population densities influenced by fire or post-fire habitat succession to at least 13 to 20 years following a burn. Sage Sparrow (Amphispiza belli), Black-throated Sparrow (Amphispiza bilineata), and Spotted Towhee (Pipilo maculatus) occurred at relatively low densities and were nearly restricted to unburned habitats. Green-tailed Towhee (Pipilo Chlorurus), Gray Flycatcher (Empidonax wrightii), American Robin (Turdus migratorius), and Brown-headed Cowbird (Molothus ater) occurred at lower densities in burned areas than adjacent unburned areas although the relationship was not strong for the latter two species. The magnitude of the difference in density between burned and unburned sites within a landscape diminished with the number of years of vegetation recovery for Green-tailed Towhee. Brewer’s Sparrow (Spizella brewerii) occurred at lower densities relative to adjacent habitat in the most recent burn, but occurred at higher densities after 20 years of habitat succession, suggesting a positive response with a multiple decade lag period. Horned Lark (Eremophila alpestris) and Vesper Sparrow (Pooecetes gramineus) respond positively to fire, but densities were similar to unburned areas after 20 years of habitat succession. An ordination analysis captured 86% of the variation in 12 bird species with 3 orthogonal axes. My research demonstrates that strong community structure exists for birds associated with mountain big sagebrush habitats, and that fire influences community structure for multiple decades. / Graduation date: 2011 / Access restricted to the OSU Community at author's request from Dec. 22, 2010 - Dec. 22, 2011.

The sagebrush steppe is a particularly sensitive ecosystem that is easily disturbed by fires, oil and gas extraction, woody-plant encroachment, and overgrazing. The natural regeneration of native species following a disturbance within this system is typically slow and sporadic, which allows invasive grasses to occupy the landscape. Attempts to assist the recovery of these landscapes through direct seeding is commonly met with poor success rates, particularly in lower elevation, drier sites. Novel seed enhancement technologies and planting techniques that mitigate limiting factors impairing restoration efforts may improve the likelihood of restoring these degraded areas. For chapter 1, we evaluated a solid-matrix priming technique, where bluebunch wheatgrass (Pseudoroegneria spicata) and Lewis flax (Linum lewisii) were primed and then the priming matrix and seed were pelleted together. We evaluated primed seed that had been incorporated into pellets at two field sites against seed that was pelleted but been left unprimed, and untreated seed (control). These three seed treatments were planted in the spring (mid-march) in shallow (2-cm) and deep (15-cm) furrows, in a complete factorial design. We found that primed seeds generally produced higher plant densities than control seed at the beginning of the growing season; however, its influence diminished towards the end of the growing season. We also found that deep furrows increased plant density throughout the growing season and even into the following year. The combination of priming and deep furrows outperformed control seed in shallow furrows in all measured metrics. For chapter 2, we evaluated a seed conglomeration technique for improving Wyoming big sagebrush (Artemisia tridentata ssp. Wyomingensis) emergence and survival under fall and winter plantings. The trial was implemented at five sites across Utah and Nevada in a randomized complete block-split-split plot design, with site, and planting season, comprising the split-plot factors. Each site and season combination was seeded with conglomerated and control seed. We found that in most cases, a fall seeding of Wyoming big sagebrush was either the same or more successful compared to planting on the snow in the winter, which is the current suggested practice. Our results also demonstrated that seed conglomeration produced higher plant densities compared to control seed throughout the growing season. The higher density of plants produced from conglomerates combined with the improved seed delivery provided by the conglomeration technique was estimated to offset the cost in producing conglomerates and reduce overall restoration costs by 41%.

In 1979, a handful of Nevada state officials sparked a movement to transfer the large unappropriated domain to the western states. For two years what became known as the Sagebrush Rebellion swept across the American West like brushfire, engaging westerners of all stripes in a heated dispute over the question of the public lands. In Utah, as elsewhere in the West, public officials, rural ranchers, miners, developers, academics, environmentalists, and concerned citizens joined the debate and staked sides. This episode underscored western relationships between people and nature and featured contests over competing ideologies in the West. But it probably did more harm than good in solving the problems of the West and even further polarized westerners against themselves. After just two years in the limelight, the Sagebrush Rebellion unspectacularly faded into public memory, partly as a result of environmental opposition but mostly because Ronald Reagan's administration steered public land policy in a new direction. Interior Secretary James Watt took steps to appease disgruntled westerners by loosening federal regulations on the public lands, but he opposed any efforts for a large-scale transfer. Thus the Sagebrush Rebellion ultimately failed; but still today the sentiment and conflicts that propelled it persist, continuing to color the panorama that is the American West.

This study examined winter habitat use and nesting ecology of greater sage grouse (Centrocercus urophasianus) in Strawberry Valley (SV), Utah located in the north-central part of the state. We monitored sage grouse with the aid of radio telemetry throughout the year, but specifically used information from the winter and nesting periods for this study. Our study provided evidence that sage grouse show fidelity to nesting areas in subsequent years regardless of nest success. We found only 57% of our nests located within the 3 km distance from an active lek typically used to delineate critical nesting habitat. We suggest a more conservative distance of 10 km for our study area. Whenever possible, we urge consideration of nest-area fidelity in conservation planning across the range of greater sage grouse. We also evaluated winter-habitat selection at multiple spatial scales. Sage grouse in our study area selected gradual slopes with high amounts of sagebrush exposed above the snow. We produced a map that identified suitable winter habitat for sage grouse in our study area. This map highlighted core areas that should be conserved and will provide a basis for management decisions affecting Strawberry Valley, Utah.

Population growth for species with long lifespans and low reproductive rates (i.e., K-selected species) is influenced primarily by both survival of adult females and survival of young. Because survival of adults and young is influenced by habitat quality and resource availability, it is important for managers to understand factors that influence habitat selection during the period of reproduction. My thesis contains two chapters addressing this issue for K-selected species in Utah. Chapter one evaluates habitat selection of greater sage-grouse (Centrocercusurophasianus) on Diamond Mountain during the critical nesting and brood-rearing period. Chapter two address selection of birth sites by bison (Bison bison) on Antelope Island, Utah. We collected micro-habitat data for 88 nests and 138 brood locations of greater sage-grouse from 2010-2012 to determine habitat preferences of nesting and brooding sage-grouse. Using random forests modeling techniques, we found that percent sagebrush, percent canopy cover, percent total shrubs, and percent obscurity (Robel pole) best differentiated nest locations from random locations with selection of higher values in each case. We used a 26-day nesting period to determine an average nest survival rate of 0.35 (95% CI = 0.23 – 0.47) for adults and 0.31 (95% CI = 0.14 – 0.50) for juvenile grouse.Brood sites were closer to habitat edges, contained more forbs and less rock than random locations. Average annual adult female survival across the two-year study period was 0.52 (95% CI= 0.38 – 0.65) compared to 0.43 (95% CI= 0.28 – 0.59) for yearlings.Brooding and nesting habitat at use locations on Diamond Mountain met or exceeded published guidelines for everything but forb cover at nest sites. Adult and juvenile survival rates were in line with average values from around the range whereas nest success was on the low end of reported values. For bison, we quantified variables surrounding 35 birth sites and 100 random sites during 2010 and 2011 on Antelope Island State Park. We found females selected birth sites based on landscape attributes such as curvature and elevation, but also distance to anthropogenic features (i.e., human structures such as roads or trails). Models with variables quantifying the surrounding vegetation received no support.Coefficients associated with top models indicated that areas near anthropogenic features had a lower probability of selection as birth sites. Our model predicted 91% of observed birth sites in medium-high or high probability categories. This model of birthing habitat, in cooperation with data of birth timing, provides biologists with a map of high-probability birthing areas and a time of year in which human access to trails or roads could be minimized to reduce conflict between recreation and female bison.

No description available.

Intact sagebrush communities in the Great Basin are rapidly disappearing due to invasion of non-native plants, large wildfires, and encroachment of pinyon pine and juniper woodlands. Land management options include the use of prescribed fire, grazing, herbicides and mechanical treatments to reduce the potential for wildfire and restore plant communities. Land managers in the region face a complex and interrelated set of ecological, economic, and social challenges to the implementation of these management practices. Effective restoration strategies require consideration of citizens in the region and their acceptance of management practices, as well as their trust in the agencies that implement them. This longitudinal panel study (2006-2010) examines the social acceptability of management options for rangeland restoration and public trust in agencies to carry out these options in three urban and three rural regions of the Great Basin. Most similar studies in this region have been largely place-based and cross-sectional, focusing on communities at one point in time. Results from this study can be used to evaluate the success of management programs, predict support for different treatments, determine the impact of agency outreach efforts, and identify important factors for building trust between communities and agencies across the region. The study uses data from a mail-back questionnaire sent to residents in 2006 and again in 2010. Overall, 698 respondents comprise the panel of interest. Results suggest landscape scale events such as wildfire, as well as agency management and outreach programs, had little influence on respondents' perceptions of agencies or management options over the study period. Several key findings have persisted throughout the study: (1) acceptance is high for the use of prescribed fire, grazing, felling, and mowing, but low for chaining and herbicide use, though there are (2) low levels of public trust and confidence in agencies to implement these management options, and (3) there are salient differences between the region's rural and urban residents with important implications for agency communication strategies. Most changes in response over the study period were subtle, though the direction and strength of these changes highlight noteworthy trends: (1) Great Basin residents are becoming more aware of key threats facing rangelands, (2) they seem more interested in having a role in making management decisions, and (3) they are slightly more positive about their interactions with agency personnel. Finally, findings suggest many residents have had little experience with agency outreach programs. Trust and confidence in management agencies are key factors in garnering support for restoration activities. While knowledge of management activities and confidence in managers' ability to competently implement them certainly play a role, findings strongly suggest sincerity factors (e.g., good communication or the perception that agencies share citizens' goals, thoughts, or values) have the greatest influence on acceptance of management practices in the Great Basin. Results suggest it would be beneficial for agencies to take a more active role in building trust with residents across the region. Differing levels of knowledge and interest, as well as different concerns, found among rural and urban residents highlight the need to tailor outreach strategies for use in specific communities. / Graduation date: 2012

Juniper (Juniperus spp.) encroachment into sagebrush (Artemisia spp.) and bunchgrass communities has reduced understory plant cover and allowed juniper trees to dominate millions of hectares of semiarid rangelands. Trees are mechanically masticated or shredded to decrease wildfire potential and increase desirable understory plant cover. When trees are masticated after a major increase in tree population density and associated decrease in perennial understory cover, there is a risk that invasive annual grasses will dominate because they are highly responsive to the increased resource availability that commonly follows removal of the main resource user. To determine if tree mastication increases resource availability and subsequently favors invasive annual or perennial grasses, we compared soil temperature, water, and nutrient microenvironmental conditions and seedling establishment and growth. We used the major rangeland weed, cheatgrass (Bromus tectorum L.), to represent invasive annual grasses and Anatone bluebunch wheatgrass (Pseudoroegneria spicata (Pursh) A. Löve), a natural accession of native bluebunch wheatgrass, to represent the perennial grasses of the sagebrush-bunchgrass plant community. These comparisons were made between and within paired-adjacent masticated and untreated areas at three locations in Utah dominated by Utah juniper (Juniperus osteosperma (Torr.) Little). Juniper tree mastication generally increased resource availability with masticated areas having greater soil temperature, soil water availability, and soil N supply rates than untreated areas. Prior to juniper tree mastication litter mounds were not found to be resource islands probably because juniper trees themselves were using subcanopy soil water and nutrients. After juniper tree mastication and elimination of these predominant resource users, litter mounds served as resource islands with greater soil water availability and N supply rates than bare interspaces during the critical time for seedling establishment in spring. Plant growth followed in line with greater resource availability after tree mastication with masticated areas having more productive although fewer invasive-annual and perennial grass seedlings than untreated areas. These results suggest that increases in resource availability and warmer spring temperatures associated with mastication will not necessarily favor invasive annual over perennial grass seedling establishment. Resilience of the sagebrush-bunchgrass community to return to dominance after juniper control will likely be greatly influenced by how much of the sagebrush-bunchgrass community remains following tree control and the intensity of propagule pressure by invasive species. If only invasive annuals remain when the trees are treated then invasive annuals would be expected to dominate the post-treatment plant community especially with their ability to establish inside litter mounds unless they were also controlled and perennial grasses planted at the time of treatment.