The Influence of Aspen Chemistry and the Nutritional Context on Aspen Herbivory

Herbivory is one major force accelerating aspen decline in North America, but it is unclear why herbivores prefer certain aspen stands over others, or over other plant species in the understory. In this dissertation, I determined the influence of nutrients and plant secondary compounds (PSC), physiological state, chemical composition, and prior experience on aspen preference by sheep in controlled pen experiments. In addition, I explored the relationship between herbivory, regeneration, recruitment, and other landscape elements for specific aspen stands within Wolf Creek Ranch in northern Utah using biomass and chemical composition of the understory and chemical defenses of juvenile aspen trees (i.e., the foodscape). Aspen intake was enhanced when lamb diets contained a high crude protein to energy ratio or when the basal diet contained a low density of energy. Intake was depressed as concentrations of PG (phenolic glycosides) increased in aspen leaves or when lambs were fed a high energy to protein ratio. The effects of nutrients on aspen intake were greater when phenolic glycosides in aspen were present at low concentrations. However, when given a choice between aspen leaves of high or low PG content, lamb preference depended more on aspen nutrient and mineral availability, or on prior diet, than on defense chemistry. On the landscape, I found that stands at low elevations with low abundance of nutrients in the understory are more likely to experience less regeneration and recruitment than those growing within nutrient-rich sites. Aspen browsing was negatively correlated with PG content in aspen stands, and elk presence (measured via fecal pellets) was negatively correlated with abundance of understory protein. In conclusion, aspen herbivory appears to be controlled by the interplay between types and amounts of nutrients offered by the landscape and the chemical composition of aspen stands. A clear assessment of these variables on the landscape, i.e., the foodscape, will aid in the development of novel management strategies aimed at providing nutrients (e.g., through supplements, introduced forages) at strategic locations in order to reduce aspen herbivory within at-risk aspen stands

16th Wildland Shrub Symposium Threats to Shrubland Ecosystem Integrity 2010 May 18-20 Logan, UT

Abstract: The 29 papers in this proceedings are divided into the main organized sessions of the 16th Wildland Shrub Symposium, including the plenary session to introduce the theme of threats to shrubland ecosystem integrity, impacts of energy development and reclamation on ecosystem function, invasive plant ecology. wildlife habitats: impacts and restoration opportunities, historical perspectives in shrublands, ecosystem threats due to fire in the Mojave Desert, and modeling and monitoring of shrubland ecosystems. An overarching goal of the symposium was to make linkages between research and management

American Bison Ecology and Bison-Cattle Interactions in an Isolated Montane Environment

As bison are considered to be ecologically extinct, and negative interactions between bison and cattle are perceived to limit bison restoration and cattle production, I designed a series of studies to test for potential competition between bison (Bison bison) and cattle (Bos taurus) for forage on the Henry Mountains in southern Utah. These studies provide insight into key information gaps previously identified by the Utah Division of Wildlife Resources (UDWR), Bureau of Land Management, and the local grazing association. The results indicate that bison and cattle are not strong competitors for forage on the Henry Mountains. Jackrabbits (Lepus californicus) emerged as the strongest competitive threat to cattle, consuming more than twice the amount of forage consumed by bison. Further, bison habitat preferences did not match with cattle habitat needs as reported by a survey of the local ranching community. This suggests that negative impacts on cattle due to bison have been overstated. Still, any potential negative impacts of bison will be felt by a small group of local individuals. This prompted me to design a new management scheme, which has the potential to increase the number of bison on the Henry Mountains while also compensating local ranchers for reducing the number of cattle they graze in the area. This system should be mutually beneficial for the local ranching community and the UDWR, and easily implemented by taking advantage of the currently exiting conservation license program

Sharing Common Ground on Western Rangelands: Proceedings of a Livestock/Big Game Symposium

This proceedings includes 37 papers and posters presented at the Sharing Common Ground symposium. The information represents the progress made in livestock/big game management since the 1991 symposium with the theme of Seeking Common Ground. The broad range of topics includes the rangeland resource, the science of livestock/big game interactions, the human dimension, and the success stories from the seeking common ground partnership demonstration projects

Information and tools to conserve and restore Great Basin ecosystems

Keywords: Ecosystem health, Great Basin, Conservation of Natural Resource

Effects of Fire in the Northern Great Plains

This publication is a review of selected literature about prescribed burning in the Northern Great Plains for management of wildlife. It discusses the effect of fire on soil nutrients and minerals, upland grasses and forbs, undesirable species, shrubs, trees, certain plant species, emergent vegetation in prairie wetlands, insects, nongame birds, upland game birds, waterfowl, shorebirds, small mammals, and livestock

Technical reference: Seventh biennial conference of research on the Colorado Plateau

Seventh Biennial Conference of Research on the Colorado Platea

A Functional Framework for Improved Management of Western North American Aspen (Populus tremuloides Michx.)

Quaking or trembling aspen (Populus tremuloides Michx.) forests occur in highly diverse setting across North America. However, management of distinct communities has long relied on a single aspen to-conifer successional model. We examine a variety of aspen dominated stand types in the western portion of its range as ecological systems; avoiding an exclusive focus on seral dynamics or single species management. We build a case for a large-scale functional aspen typology based on existing literature. Aspen functional types are defined as aspen communities that differ markedly in their physical and biological processes. The framework presented here describes two “functional types” and seven embedded “subtypes”: Seral (boreal, montane), Stable (parkland, Colorado Plateau, elevation and aspect limited, terrain isolated), and a Crossover Seral-Stable subtype (riparian). The assessment hinges on a matrix comparing proposed functional types across a suite of environmental characteristics. Differences among functional groups based on physiological and climatic conditions, stand structures and dynamics, and disturbance types and periodicity are described herein. We further examine management implications and challenges, such as human alterations, ungulate herbivory, and climate futures, that impact the functionality of these aspen systems. The functional framework lends itself well to stewardship and research that seeks to understand and emulate ecological processes rather than combat them. We see advantages of applying this approach to other widespread forest communities that engender diverse functional adaptations