A survey of small mammals on eight islands in the Columbia and Willamette Rivers near Portland, Oregon was conducted in 1974. The islands were Govermnent , Sand, Lemon, McGuire and Sandy Islands in the Columbia River and East, Ross and Hardtack Islands in the Willamette River. The objectives of the study were to ascertain and compare the kinds, distribution and relative densitites of small mammals . A variety of traps was used to capture the animals including Museum Special Rodent Traps , back- break mouse traps, scissor and guillotine- type stab mole traps , Sherman traps , modified Young traps and pitfalls . Most traps were set in linear transects . Trapping was conducted with the objective of sampling the major habitats on each island. Observations of scats, tracks , burrows and dead animals were also noted. One species of small marmnal , Sorex vargrans , was found on all eight islands . Microtus was found on five islands and Peromyscus maniculatus on four islands . Two islands yielded Scapanus townsendii. Glaucomvs sabrinus was found on only one island. I hoped that evidence would be found to prove or disprove that current theories of island biogeography would apply to river islands. However, data in this study were inadequate to allow calculation of precise indices of population densities . Therefore, I was unable to determine if theories of island biogeography do apply to these river islands.

One important aspect related to the management of water resources under future climate variation is the occurrence of extreme precipitation events. In order to prepare for extreme events, namely floods and droughts, it is important to understand how future climate variability will influence the occurrence of such events. Recent advancements in regional climate modeling efforts provide additional resources for investigating the occurrence of extreme events at scales that are appropriate for regional hydrologic modeling. This study utilizes data from three Regional Climate Models (RCMs), each driven by the same General Circulation Model (GCM) as well as a reanalysis dataset, all of which was made available by the North American Regional Climate Change Assessment Program (NARCCAP). A comparison between observed historical precipitation events and NARCCAP modeled historical conditions over Oregon's Willamette River basin was performed. This comparison is required in order to investigate the reliability of regional climate modeling efforts. Datasets representing future climate signal scenarios, also provided by NARCCAP, were then compared to historical data to provide an estimate of the variability in extreme event occurrence and severity within the basin. Analysis determining magnitudes of two, five, ten and twenty-five year return level estimates, as well as parameters corresponding to a representative Generalized Extreme Value (GEV) distribution, were determined. The results demonstrate the importance of the applied initial/boundary driving conditions, the need for multi-model ensemble analysis due to RCM variability, and the need for further downscaling and bias correction methods to RCM datasets when investigating watershed scale phenomena.

This thesis provides an extensive look at where permitted non-farm uses and dwellings have clustered within Exclusive Farm Use (EFU) zones in the Northern Willamette Valley in Oregon. There is a looming concern that non-farm related uses and dwellings, or non-farm development, are conflicting with agricultural preservation strategies. Specifically, non-farm developments can potentially undermine the critical mass of farmland needed to keep the agricultural economy sustainable, but until now, studies have lacked spatially precise data to systematically track these phenomena. This thesis offers methodological contributions towards analyzing these operations and presents a broad account of what has been occurring in the region. Using permit approval data from the Department of Land Conservation and Development (DLCD) and 2015 county tax lot shapefiles, I geocoded the locations of these uses and dwellings. I used location quotient and spatial autocorrelation coefficients to identify non-farm hotspots in the region and summarized different typologies that have developed. The findings reveal that viticulture operations have amassed near Dundee and Newberg in Yamhill County, while commercial activities and home occupations have clustered near the Salem-Keizer UGB. Concurrently, dwellings have clustered near the Yamhill-Polk County border. Finally, I offer suggestions to improve Oregon's agricultural land use policy and data management process, as well as advocate for more intensive research in the future to generate narratives for our results.

Efforts to abate Willamette River pollution between 1926 and 1962 centered on a struggle between abatement advocates and the two primary polluters in the watershed, the City of Portland and the pulp and paper industry. Throughout the twentieth century, the Willamette was by far the most heavily populated and industrialized watershed in Oregon. Like many other of the world's rivers, the Willamette was an integral part of municipal and industrial waste removal systems. As such, the main stem of the river carried the combined wastes from sewage outfalls serving hundreds of thousands of people and millions of gallons daily of pulp and paper making effluents. Exacerbating the impacts of these pollutants on the Willamette were unavoidable geologic and hydrologic constraints impacting the river's flow and, therefore, the river's ability to dilute wastes. As the pollution load in the Willamette River increased throughout the twentieth century, accustomed activities such as recreation, sports fishing, and commercial fishing, were constrained. The polluted water also threatened potential uses of the river, such as tourism and expanded recreation after World War II. To address these concerns, beginning in 1926 clean streams advocates created ad hoc groups of public health experts, sanitary engineers, conservationists, sportsmen, and others to pressure Portland officials and industry representatives to cease polluting the river. In November 1938, continued activism and lobbying from these groups led to the passage of a citizen's initiative creating the Oregon State Sanitary Authority (OSSA). From 1939 to 1962, the OSSA took the lead in the water pollution abatement issue and realized some limited successes including pushing Portland and other cities to build sewage treatment plants and regulating pulp and paper mill discharges. However, in spite of these accomplishments, the issue of water quality grew more complex and difficult through the 1950s, as reflected in Tom McCall's November 1962 television documentary Pollution in Paradise.

Preservation of rare plant species often requires establishment of new populations. Survivorship surveys are the most common method of post-introduction monitoring. However, they provide an incomplete picture of establishment success. This study is an attempt to develop a model for determining establishment success by determining the factors affecting recruitment in introduced populations of a rare species. Erigeron decumbens is an endangered forb endemic to the Willamette Valley of western Oregon. Several populations of E. decumbens have been introduced by governmental and non-profit agencies. While there has been some monitoring of the survival of introduced plants, no systematic surveys have measured recruitment in the new populations. We monitored recruitment in five introduced populations, and compared abiotic and biotic characteristics in these and five stable natural populations. Seventy percent of introduced populations produced fewer than one recruit for every three survivors. Thirty percent produced at least one and one half recruits for every one survivor. The factors that affected recruitment were site specific. Low recruitment (less than one recruit per three survivors) was associated with dominance by exotic species (Dactylis glomerata, Rosa eglanteria, Vicia tetrasperma, and Leucanthemum vulgare), high litter cover, high soil electrical conductivity, and low silt levels. Recruitment was highest at sites with higher native plant species richness and soil characteristics falling within the variation of large natural populations. Viable seed number per individual had the strongest linear relationship with recruitment, demonstrating that seed viability could be a strong limitation for this species (r² = 0.83). The results of this study suggest numerous guidelines for future reintroductions of E. decumbens. This research also demonstrates the utility of recruitment surveys to determine factors important in the success of introduced populations of rare plant species. / Graduation date: 2013

This study investigated the local and sustainable food movements in the Willamette Valley of Oregon. The aim of the research was to better understand the current condition of the phenomenon, what it means to the communities studied and the future role it will play in the state. Other research objectives that were studied included the impact of demographics on food movements, successes and barriers to success and determining the motivations of people involved. Key players in the city of Corvallis and Portland were interviewed to gather qualitative data about the movement. Interviewees were chosen based on criteria established through literature review that pointed towards groups that would be the most valuable on which to focus. The study revealed a dynamic and progressive social movement that has profound and beneficial implications on the civic wellbeing of the communities studied both currently and for their future. In addition, through this work key goals were identified that can be transferred to other communities looking to work towards a more sustainable food system in order to better facilitate their growth and prosperity. / Graduation date: 2013

Thesis (Ph. D.)--Oregon State University, 2003. / Typescript (photocopy). Includes bibliographical references. Also available online.

55 pages / This work has been done as a preliminary ecological survey of an aquatic habitat in a Douglas fir forest association. Since this is a preliminary study it is not expected to be complete in all details affecting the associations within a community. Little work of this type has been conducted previously, and much more work should be done along these lines in order to have a more complete understanding of the ecology of this, or a similar area. Perhaps this work will be of less value in itself than the assistance it may afford others who are beginning similar undertakings. In this work an attempt has been made to point out many of the physical factors which have an influence on, or directly affect the community, e.g., the size of the pond, the location, depth, etc. A descriptive account will be given of the flora and fauna, and an attempt has been made to present the interrelations between the organisms and their environment.

My research examines the prehistoric subsistence of native peoples of the Willamette Valley, Oregon through an analysis of the regional zooarchaeological records, and then modeling regional diet breadth. Through this analysis, I challenge commonly held stereotypes that the indigenous people of the Willamette Valley were strictly root eaters, and the basis for this claim, that salmon were not part of Native subsistence. The results of my research indicate that given the incomplete nature of the ethnohistoric record, very little can be said about expected cultural behaviors, such as salmon consumption, that appear to be absent in the Willamette Valley. In addition, since the faunal assemblage is so small in the Willamette Valley, zooarchaeological data are simply inadequate for studying the relationship between prehistoric peoples and their animal resources. Finally, optimal foraging modeling suggests that salmon is one of the higher ranked resources available to the Native People of the Willamette Valley.

This study conducts a dam-scale cost versus benefit analysis in order to explore the feasibility of each the 13 U.S. Army Corps of Engineers (USACE) commissioned dams in Oregon’s Willamette River network. Constructed between 1941 and 1969, these structures function in collaboration to comprise the Willamette River Basin Reservoir System (WRBRS). The motivation for this project derives from a growing awareness of the biophysical impacts that dam structures can have on riparian habitats. This project compares each of the 13 dams being assessed, to prioritize their level of utility within the system. The study takes the metrics from the top three services (flood regulation, hydropower generation and recreation) and disservices (fish mortality, structural risk and water temperature hazards) and creates a rubric that scores the feasibility of each dam within the system. Within a range between 0 to 3 for three dam services and 0 to -4.5 for two disservices, the overall calculated score elucidates for each structure whether its contribution to the WRBRS is positive or negative. Further analysis searches for spatiotemporal trends such as anomalous tributaries or magnified structural risk for structures exceeding a certain age. GIS data from the National Inventory of Dams (NID), U.S. Geologic Survey (USGS) water measurements, raw data from USACE, and peer-reviewed studies comprise the statistics that generate results for this analysis. The computed scores for each dam yield an average overall score of -1.31, and nine of the 13 structures have negative results, indicating that the WRBRS faces challenges going forward. The study seeks to contribute to the increasingly relevant examination of dam networks at the watershed scale.