Some of the most pressing conservation concerns involve declining populations of species with low fecundity and highly specialized foraging and reproductive requirements. Yet, we often lack a functional understanding of how individuals of those species interact with their environment, specifically how their movement is affected by human-induced changes. In order...
A fundamental objective of ecology and population biology is to identify factors that drive population dynamics and determine the population-level consequences of their interaction with the environment. Studies of reproductive performance can illuminate population dynamic processes, including the links between organismal biology, the environment, and life history theory. A central...
After a 40-year absence from Oregon’s landscape, expanding gray wolf (Canis lupus) populations are reestablishing elements of interspecific competition with sympatric large carnivores, like cougars (Puma concolor). This presents new challenges for management of large carnivores and their ungulate prey populations (e.g., elk, Cervus canadensis nelsoni; mule deer, Odocoileus hemionus)...
Following European-American colonization of North America and associated landscape changes, barred owls (Strix varia) underwent a dramatic expansion of their historical range. The barred owl expanded across the previously tree-less Great Plains that had limited their distribution, and into the forests along the west coast. In these western forests they...
The greater sage-grouse (Centrocercus urophasianus; hereafter, sage-grouse) is a ground nesting gallinaceous bird that requires large contiguous patches of sagebrush. Sage-grouse populations have declined, especially in the Great Basin where changes in wildfire regimes and the invasion of annual grasses have contributed to habitat loss and fragmentation. During the last...
Osteoporosis is characterized by low bone mineral density (BMD), bone fragility, and an increased risk of osteoporotic fracture. The disease is systemic in nature but potential solutions include exercises prescriptions that target the clinically relevant sites of osteoporosis (hip and spine) to improve bone mass. The aim of this dissertation...
The agricultural industry across the United States is experiencing a shortage of qualified and interested young professionals who aspire to enter the agricultural sector. Internships have largely been used as an effective hands-on learning tool, exposing college students to an array of occupational skills and expectations in hopes of creating...
Karl Jordan (1861-1959) was an extraordinarily productive entomologist who influenced the development of systematics, entomology, and naturalists' theoretical framework as well as their practice. He has been a figure in existing accounts of the naturalist tradition between 1890 and 1940 that have defended the relative contribution of naturalists to the...
Faculty-led short-term programs are the most popular type of study abroad experience for undergraduate students in the United States. The rise of the FLST model has created new challenges for institutions and faculty. This study undertakes a critical analysis of the practice of faculty-led short-term (FLST) study abroad at U.S....
The expansion of native, woody plants is a global phenomenon with characteristics and effects that are often indistinguishable from exotic invasions. These expansions have largely been driven by altered fire regimes and favorable climatic conditions. In the Great Basin of western North America, expansion of conifers such as western juniper...
Agriculture teachers, in comparison to other high school teachers, work in more varied and demanding work environments (Terry & Briers, 2010; Torres, Ulmer, & Aschenbrener, 2008). The body of literature studying the impacts of more varied and demanding work environment on early career agriculture teachers (ECATs) is commonly limited to...
The California Current Large Marine Ecosystem (CCLME), located on the eastern boundary of the North Pacific Ocean, is highly dynamic, with variable conditions driven by seasonal upwelling, regional oceanography, and broad scale climate patterns. In the last decade, the northeast Pacific Ocean has experienced several marine heatwaves (MHWs), prolonged periods...
In grasslands, grazing by large ungulates can influence vegetation structure, composition, primary productivity, and ultimately, ecosystem functioning. While grazing represents a complex disturbance, grazing intensity largely determines the effects of
grazing on vegetation. Structural and compositional changes in the plant community caused by grazing could have bottom-up effects on species...
Caspian terns (Hydroprogne caspia) and double-crested cormorants
(Phalacrocorax auritus) nest in large colonies on East Sand Island in the Columbia
River estuary, the largest known colonies for the two species in the world. Both
species of piscivorous colonial waterbirds have been identified as predators with a
significant impact on the...
The multifaceted role of the environment in regulating the structure and dynamics of biological communities has long fascinated ecologists and motivated much debate and research. Now, in a time of accelerated global changes due to human impacts, the need to understand how the environment shapes communities has gained new urgency....
The causes of the global biodiversity crisis are varied and complex. Anthropogenic threats may act in isolation, or interact additively or synergistically with each other or with natural stressors to affect sensitive taxa. The recent emergence of many infectious diseases in wildlife has brought attention to the role of disease...
Chronic truancy and absenteeism are two considerable issues currently facing our youth at increasing rates nationwide. Quantitative research supporting chronic truancy and absenteeism as national problems is abundant (Hendricks, Sale, Evans, McKinley, and Delozier Carter, 2010). Research indicates that students who identify as truant during the middle school grades and...
The phytopathogen Phytophthora ramorum (Werres, DeCock & Man in't Veld), causal agent of Sudden Oak Death (SOD) of oaks (Quercus spp.) and tanoaks (Notholithocarpus densiflorus syn. Lithocarpus densiflorus), is established in coastal forests of the western United States. Since the discovery of SOD in the Douglas-fir / tanoak forests of...
This dissertation focuses on the predator-prey relationship between two species of avian predators, Caspian terns (Hydroprogne caspia) and double-crested cormorants (Phalacrocorax auritus), and one of their important prey types, juvenile salmonids (Oncorhynchus spp.), in the Columbia River estuary of Oregon and Washington states during the period 1998 – 2007. I...
Investigation into how animals move within the landscape is important for both understanding of ecological processes and conservation management. Animal movement is important in shaping life history transitions, demographics, individual fitness, and species distributions. However, as landscapes become increasingly affected by human activities, movement becomes important as species navigate landscapes...