Endemic populations of pandora moths (Co/oradia pandora Blake), a defoliator of western pine forests, proliferated to epidemic levels in central Oregon in 1986 and increased dramatically through 1 994. Golden-mantled ground squirrels (Spermophilus lateralis Say) consume adult pandora moths, but reject nutritionally valuable eggs from gravid females. Feeding trials with...
Geocaching is an outdoor recreational activity where participants (geocachers) utilize a handheld Global Positioning System (GPS) receiver or smartphone to download coordinates in order to navigate to the location of a hidden container, a geocache. Since its inception in 2000 geocaching has grown exponentially. The potential ecological and recreation management...
Within the past two decades, the rise of nanotechnology has provided various technological and industrial sectors with avenues for significant growth and improvements to existing practices. With the inherent qualities which make materials on the nanoscale unique in behavior and function, there are limitless applications of nanotechnology. One of the...
I studied presence, relative abundance, and resource selection of bats in managed Douglas-fir (Pseudotsuga menziesii) forests in western Oregon from May through September, 1999–2001. Species richness was not related to elevation, density of snags, or length of edge or perennial streams in sampled landscapes. I captured bats more frequently in...
Gray wolves (Canis lupus) are the most socially polarizing species listed under the Endangered Species Act. Wildlife management practices at local, state, and federal levels include lethal control to resolve stakeholder and wolf conflicts as a last resort. There is little experimental evidence that lethal control is effective in this...
Red tree voles (Arborimus longicaudus) are a unique species of Arvicoline rodent found in western Oregon and northwest California. Their preferred habitat is mature and old-growth coniferous forest dominated by Douglas-fir (Pseudotsuga menziesii). Tree voles are an important prey item for northern spotted owls and many other predators, but are...
Density dependence is an ecological concept concerning the mechanisms of change in the size of a population. The inability to census ecological populations confounds approaches to identify and quantify the level of density dependence. Statistical tests which ignore the presence of measurement error tend to result in misspeci fied type...
My objectives were to: 1) develop a point count technique for estimating relative
abundance of band-tailed pigeons (Columbafasciata monilis), 2) determine the
availability, distribution, and interspersion of mineral sites, and nesting and foraging cover in relation to abundance of band-tailed pigeons in west-central Oregon, and 3) test the hypothesis that...
Following high-severity fire, forest succession may take alternate pathways depending on the pattern of the fire and any secondary disturbances during early stand development, with lasting consequences for ecosystem function. The objectives of this research were to quantify: (1) early postfire regeneration as influenced by the spatial pattern of a...
California's Central Valley agricultural landscapes provide several important wintering regions for Pacific Flyway sandhill crane (Grus canadensis) populations; however, the value of those regions is being compromised by urban expansion, other developments, and conversions to incompatible crop types. Greater (G. c. tabida) and lesser sandhill cranes (G. c. canadensis) both...
The main objectives of this study are to identify the nature of threats to protected areas and assess the effectiveness of protected area systems and management in Thailand, and to evaluate the use of conservation biology concepts in protected area management. The results from a survey of the heads of...
The Willamette River floodplain has been highly modified by urbanization, conversion of land to agriculture, construction of dams and revetments, and regulation of flow, all of which have reduced floodplain processes that provide valuable ecosystem services such as fish and wildlife habitat and flood storage. Efforts to protect and restore...
Nonparametric model-assisted estimators have been proposed to improve estimates of finite population parameters. More efficient estimators are obtained when the parametric model is misspecified due to the flexibility of nonparametric models. In this dissertation, we derive information criteria to select appropriate auxiliary variables to use in an additive model-assisted method....
Since the 1964 earthquake and geologic uplift, beavers (Castor canadensis) have expanded their historic range from the inland (outwash plain) Copper River Delta, Alaska to the once tidally influenced areas of the outer area (uplifted marsh). The uplift presents a unique opportunity to observe beaver expansion, habitat selection and influence...
Due to a general reduction in pavement program funding levels over the past decade, the current budget is not sufficient to maintain roadways at a high level of service with acceptable roughness levels. Rough roadways with poor ride quality increase drivers’ vehicle operating costs (fuel consumption, vehicle maintenance, and tire-wear)...
Missing data is one of the major methodological problems in longitudinal studies. It not only reduces the sample size, but also can result in biased estimation and inference. It is crucial to correctly understand the missing mechanism and appropriately incorporate it into the estimation and inference procedures. Traditional methods, such...
The concept of "adaptive governance" represents a spectrum of hybrid approaches to environmental governance employed to guide management of complex social-ecological systems under conditions of high uncertainty. While the concept of adaptive governance has benefited from over a decade of theoretical development, empirical examples of transitions towards adaptive governance are...
Breeding habitat of Harlequin ducks (Histrionicus
histrionicus) was studied in eastern Prince William Sound,
Alaska, during 1991 - 1993. Streams in Prince William
Sound were surveyed for Harlequin ducks and monitored with
mist nets. Physical characteristics of 24 Harlequin
breeding streams were compared to those of 24 streams not
used...
Denali National Park and Preserve (Denali) contains one of the highest densities of nesting Golden Eagles (Aquila cluysaetos) in North America. Productivity of this migratory population varies both temporally and spatially. Regardless of prey abundance, more fledglings are consistently produced at some nesting territories than others. In many raptor studies,...
I examined ecological relationships and mechanisms of coexistence for sympatric populations of Columbian white-tailed (Odocoileus virginianus leucurus) and black-tailed deer (Odocoileus hemionus columbianus) in Douglas County, Oregon, from September 1997 to August 1998. Horseback transects were used to describe spatial distributions, population overlap, and habitat use for both species. Behavioral...
Forest floor vertebrate species presence and abundance may be influenced by the volume and cover of coarse woody debris (CWD) in managed forests. I studied macro- and microhabitat associations of vertebrate species in 18 closed-canopy stands ranging in CWD volume from 14 to 859 m3/ha. Pitfall traps were used to...
The purpose of this dissertation was to define macrolichen community gradients in relation to succession, grazing and the environment. First, species scores indicating when macrolichen species appeared following disturbance were derived from the literature. Weighted averaging of these data with a community matrix created a successional score for each sample...
Regression calibration inference seeks to estimate regression models with measurement error in explanatory variables by replacing the mismeasured variable by its conditional expectation, given a surrogate variable, in an estimation procedure that would have been used if the true variable were available. This study examines the effect of the uncertainty...
Surface transient storage (STS) in stream ecosystems serve an important function in retaining nutrients and refugia for aquatic communities. Unfortunately, they can retain contaminants as well. Therefore, it is of importance to determine the residence time distribution (RTD). A RTD of a particular STS zone encompasses the time it takes...
Advances in technology such as 3D digital scanning and spatial analysis software have provided archaeologists with novel data. Specifically, these methods increase the researcher's ability to measure artifact morphology and past networks of cultural transmission, to potentially track the movement of past peoples and ideas through space and time. This...
Effects of gastrointestinal transit on plasma concentrations of drugs from enteric-coated pellet formulations were demonstrated using pharmacokinetic models describing plasma concentrations of drugs from various enteric-coated pellet formulations. Gastric emptying time, lag time of emptying, and drug release rate from pellets in the small intestine, along with other pharmacokinetic parameters...
Persistent organochlorines (OCs) bioaccumulate in aquatic biota and potentially impair reproduction via endocrine disruption. The present research evaluated estrogenic effects of the OCs, chlordecone (CD) and o,p'-DDT/DDE, and the antiestrogenicity of 3,4,5,3',4',5'-hexachlorobiphenyl (345-HCB) in juvenile rainbow trout, utilizing vitellogenesis as a biomarker. Vitellogenesis, estrogen regulated hepatic production of the yolk...
In this thesis we develop a theoretical framework for the identification of situations where the equal frequency (EF) or equal variance (EV) subclassification may produce lower bias and/or variance of the estimator. We conduct simulation studies to examine the EF and EV approaches under different types of model misspecification. We...
Posting advisory speed signs at sharp horizontal curve locations is a common practice in the U.S. These signs recommend drivers safe speeds to negotiate such curves. Literature indicates that adherence to advisory speeds is, in general, poor. Moreover, limited research is available that quantifies safety implications of these signs. This...
The Forest Inventory and Analysis (FIA) program conducts an annual inventory throughout the United States. In the western United States, 10% of all plots (one panel) are measured annually, and a moving average is used for estimating current condition and change of forest attributes while alternative methods are sought in...
The use of remote sensing techniques in coastal science and engineering has rapidly increased in the past few decades. This dissertation outlines new remote sensing tools using two remote sensing technologies (lidar and X-band marine radar) along with two nearshore hydrodynamic and morphodynamic analyses supported or motivated by these remote...
Disease acts as a powerful selective force in natural systems, driving the rapid evolution of resistance in the host. In the face of a myriad of pathogenic challenges in natural systems, hosts must balance the energetic needs of maintenance and reproduction with costly resistance mechanisms. In this dissertation I will...
Reintroduction programs are increasingly being used to save animals from extinction and aid in their recovery. The California Condor (Gymnogyps californianus), one of the most endangered birds in the world, is a remarkable example of how reintroduction programs can help rapidly increase a species' population numbers and range following a...
This study examined the utilization of selected student services by domestic and
foreign students in their sophomore, junior, or senior year at Oregon State University during
Winter 1994 to find out if differences in awareness, usage, and satisfaction existed between
them. It also examined if differences in awareness, usage, and...
Understanding the mechanism of resistance, relative fitness and competitiveness of herbicide resistant biotypes is important to predict population dynamics and to establish resistance management strategies. This study was conducted to determine the level of resistance to acetolactate synthase (ALS) inhibitors and the mechanism of resistance of ALS-inhibitor resistant downy brome...
This dissertation presents a research series demonstrating the use of pharmacokinetic modeling and simulations as tools to assess drug concentration and disposition in patient populations. For drugs requiring therapeutic drug monitoring, these tools are necessary to ensure patients are receiving a safe and effective dose of medication to address their...
Shorebirds display great variation in mating systems and breed in dynamic environments that are increasingly subject to human threats worldwide. In order to adequately assess productivity and demography of shorebird populations, it is important to understand factors that influence patterns of parental care and reproductive success. The Black Oystercatcher (Haematopus...
This dissertation is about the likelihood analysis of ordered categorical responses in a longitudinal/spatial study, meaning regression-like analysis when the response variable is categorical with ordered categories, and is measured repeatedly over time or space on the experimental or sampling units. Particular attention is given to the multivariate ordinal probit...
In order to produce infectious virus progeny, vaccinia virus (VV)
undergoes morphogenic proteolysis to regulate the structural rearrangements of
virus particles. Several of the major structural precursor proteins of VV are
cleaved at a conserved Ala-Gly-X (where X is any amino acid) motif by the VV
I7L core protein proteinase...