Digital Commons Network^™

Inherited Local Shrinkage For Adaptive Functional Form Discovery, Jacob Colestin Schultz

Dissertations and Theses

Statistical models frequently employ nonlinear effects, interactions, and multiresolution basis expansions to represent complex relationships between predictors and responses. Determining the appropriate level of model complexity, however, remains a fundamental challenge. This dissertation introduces Inherited Local Shrinkage (ILS), a Bayesian global-local shrinkage framework for adaptive functional form discovery that enforces strong heredity among hierarchically related predictors.

ILS propagates shrinkage through directed acyclic graphs representing predictor inheritance, ensuring that increasingly complex terms are retained only when supported by simpler parent structure. The framework applies broadly to polynomial regression, interaction models, wavelets, splines, and other hierarchical basis expansions, while naturally extending to …

An Introduction To Field Excursions For The 2026 Geological Society Of America Cordilleran Section Meeting In Loreto, Baja California Sur, México, Scott E.K. Bennett, Michael H. Darin, Genaro Martínez Gutiérrez

Geology Faculty Publications and Presentations

The 122nd annual meeting of the Geological Society of America (GSA) Cordilleran Section will be held in Loreto, Baja California Sur, México, an idyllic and historic Sonoran Desert city nestled on the eastern shore of the Baja California peninsula. The 2026 Loreto meeting marks a milestone for GSA as it is the first time in the Section’s century-plus history that the meeting has been held on the Baja California peninsula and only the third time that the meeting has been held in México. Thus, the 2026 Loreto meeting and related field trips represent a meaningful expansion of the Section’s engagement …

Ambient Air Pollution And The Sex Ratio At Birth: A Systematic Review And Narrative Synthesis., Ursula Gazeley, Hallie Eilerts-Spinelli, Jasmin Abdel Ghany, Ana Bonell, Joshua Wilde

Publications, Reports and Presentations

Ambient air pollution is associated with adverse pregnancy outcomes such as stillbirth, miscarriage, and preterm birth. However, its effects on the viability, implantation, and survival of conceptuses-largely unobserved before the clinical detection of pregnancy-remain poorly understood. Shifts in the sex ratio at birth (SRB) provide a sensitive, population-level indicator of sex-biased conception and pregnancy loss. This systematic review examined whether maternal exposure to ambient air pollution before conception and during pregnancy is associated with deviations in the SRB. We searched MEDLINE, Embase, and Global Health from inception to 12 February 2025 for observational studies assessing both ambient air pollution exposure …

Systematics And Phylogeography Of Mundochthonius Chamberlin, 1929, In The Pacific Northwest (Chelicerata, Pseudoscorpiones), Amanda Rai Montoya-Cowan

Dissertations and Theses

Understanding the processes that drive genetic divergence and species formation is central to evolutionary biology. Invertebrates with low dispersal ability, such as pseudoscorpions, are especially prone to cryptic diversification due to their occupancy of niche microhabitats and sensitivity to landscape barriers. Despite their ecological roles as predators and bioindicators, pseudoscorpions remain one of the least studied arachnid groups, with limited taxonomic resolution and few integrative studies. This research focuses on the genus Mundochthonius in the Pacific Northwest, particularly M. pacificus, a morphologically conserved species whose true diversity and distribution remain poorly understood.

Field surveys guided by a GIS-based habitat …

Urban Wildlife In Your Backyard: Community Experiences With Coyotes And Outdoor Cats, Clarissa Emma Cressotti

Dissertations and Theses

Urbanization reshapes ecological processes by fragmenting habitat and altering patterns of human-wildlife interaction, often reducing biodiversity. However, at the household scale, residential yards can either enhance or inhibit ecological connectivity - functioning as informal habitat stepping stones or barriers to wildlife. This thesis examines how residents' environmental attitudes, wildlife experiences, and socio-demographic characteristics influence yard-level behaviors and shape the presence of urban-adapted wildlife species, particularly coyotes and domestic cats, across the Portland, Oregon metropolitan region. A mixed-methods, social-ecological framework guided the analysis, integrating survey data from 244 households with wildlife detections from motion-triggered cameras (Urban Wildlife Information Network, UWIN), citizen …

Indigenous Cultural Healing In The Pacific Northwest: The Columbia River Tribes And The Potential Return Of The Falls, Cj Senn

University Honors Theses

This thesis examines the historical, cultural, and ecological significance of Celilo Falls (Wyam), a once-sacred Indigenous site on the Columbia River, and the profound impacts of its submergence by The Dalles Dam in 1957. It looks into the history of the area as well as the potential for a return of the falls in the future. Drawing from a mixed-methods approach that includes a systematic literature review and qualitative interviews with Indigenous scholars, elders, and community members, the study explores how the loss of Celilo Falls disrupted Indigenous governance, economies, and spiritual practices. It further investigates how Celilo continues to …

Short Communication: Multiscale Topographic Complexity Analysis With Pytopocomplexity, L. S.-H. Lai, Adam Booth, A. R. Duvall, E. Herzig

Geology Faculty Publications and Presentations

TopoComplexity is a Python package designed for efficient and customizable quantification of topographic complexity using four advanced methods: two-dimensional continuous wavelet transform analysis, fractal dimension estimation, rugosity index, and terrain position index calculations. This package addresses the lack of open-source software for these advanced terrain analysis techniques essential for modern geomorphology and geohazard research, enhancing data comparison and reproducibility. By assessing topographic complexity across multiple spatial scales, pyTopoComplexity allows users to identify characteristic morphological scales of studied landforms. The software repository also includes a Jupyter Notebook that integrates components from the surface-process modeling platform Landlab (Hobley et al., 2017), facilitating …

Poa Annua Ecology, Biology, And Integrated Weed Management Practices In Turfgrass, David Ervin

Environmental Science and Management Faculty Publications and Presentations

Poa annua L. is one of the most widespread and troublesome weeds of turfgrass. It persists as both an annual and perennial and is adaptable to almost any static maintenance regime, including adaptation to mowing heights and evolution of herbicide resistance. This management guide is intended to provide stakeholders with a summary of new and existing knowledge on integrated Poa annua management. Here we review the basic biology and ecology, as well as practical integrated weed management (IWM) strategies developed for its control.

Urban Beavers At The Crossroads: How Ecological Knowledge, Sociodemographic, And Spatial Context Shape Public Perception And Coexistence Preferences, Matthew Guziejka

Dissertations and Theses

Urban beavers demonstrate synurbization by adapting to urban environments, offering ecological benefits such as biodiversity enhancement and flood mitigation, while also occasionally conflicting with infrastructure. This study examines how ecological knowledge, sociodemographics, and spatial context influence public perceptions and management preferences for urban beavers in the Tualatin River watershed, Oregon.

A voluntary survey of 176 participants from peri-urban areas assessed demographic characteristics, ecological knowledge, and attitudes toward management approaches. Spatial factors, such as proximity to watercourses and green spaces, were also analyzed. Logistic regression analyses were used to explore relationships between these factors and management preferences. Political orientation was significantly …

Indigenous Futures: Decolonizing Conservation And Restoring Ecological Sovereignty, Jasmine Beach

University Honors Theses

This study examines how members of Indigenous-led conservation organizations perceive the ecological and social implications of colonial conservation ideologies in the context of contemporary grassroots strategies. By analyzing the ongoing impact of conservation frameworks in Kenya, this research highlights the role of Indigenous-led initiatives in advancing sustainable, community-driven alternatives. Using a Two-Eyed Seeing approach, which integrates Traditional Ecological Knowledge (TEK) with Western scientific methods, the study employs qualitative, semi-structured interviews with leaders from Zawadisha, KENVO, Wildlife Works, and CER-Kenya. Findings indicate that these organizations, particularly those led by women, actively restore biodiversity, enhance climate resilience, and challenge exclusionary conservation policies. …

Influence Of Inselbergs On Bat Diversity In Afrotropical Ecosystems, Amanda Lee Grunwald

Dissertations and Theses

Humans are altering biological communities on local to global scales, driving profound changes in biodiversity and ecosystem functioning. However, significant gaps and biases in biodiversity data hinder our understanding of ecosystem interactions, making it challenging to develop effective, data-driven policies to protect remaining biodiversity. Bats, the second most species-rich groups of mammals, have a global distribution, and perform a broad array of vital ecosystem functions. Their diversity peaks in the tropics, where they often constitute more than 50% of mammal species diversity. The Afrotropics host substantial bat diversity, yet have historically been perceived as having lower species richness compared to …

Integrative Approaches To Climate Resilience Planning: Application Of A Plan Evaluation Framework, Maulsri Jha

Dissertations and Theses

In the last two decades, urban governments have streamlined and prioritized the creation and implementation of climate resilience plans to cater to the communities' vulnerabilities. Existing research illustrates that there is a gap in understanding how, or if, empirical (evidence-based) data are incorporated into the design and implementation of such plans and the extent to which their inclusion impacts outcomes in terms of vulnerability reduction. There is also a gap in the systematic study of their outcomes in terms of community resilience, and whether equity and environmental justice are promoted as priorities.

The purpose of the research is to understand …

Root Nodules Of Red Alder (Alnus Rubra) And Sitka Alder (Alnus Viridis Ssp. Sinuata) Are Inhabited By Taxonomically Diverse Cultivable Microbial Endophytes, Robyn Dove, Emily R. Wolfe, Nathan U. Stewart, Abigail Coleman, Sara Herrejon Chavez, Daniel J. Ballhorn

Biology Faculty Publications and Presentations

The root nodules of actinorhizal plants are home to nitrogen-fixing bacterial symbionts, known as Frankia, along with a small percentage of other microorganisms. These include fungal endophytes and non-Frankia bacteria. The taxonomic and functional diversity of the microbial consortia within these root nodules is not well understood. In this study, we surveyed and analyzed the cultivable, non-Frankia fungal and bacterial endophytes of root nodules from red and Sitka alder trees that grow together. We examined their taxonomic diversity, co-occurrence, differences between hosts, and potential functional roles. For the first time, we are reporting numerous fungal endophytes of alder root nodules. …

On Fire And Water: The Intersection Of Wetlands And Burning Strategies In Managing The Anthropogenic Plant Communities Of Yosemite National Park, Douglas Deur, Rochelle Bloom

Anthropology Faculty Publications and Presentations

The existing literature confirms that Native American tribes historically enhanced culturally preferred plant communities through periodic burning in what is today Yosemite National Park; in turn, beginning with nineteenth-century park development, fire suppression contributed to conifer and shrub encroachment on anthropogenic meadows and other culturally significant habitats. However, we contend that traditional burning practices cannot be understood without considering the pronounced cultural role of wetland habitats and species, and the intersection between burning practices and wetland plant communities among tribes of the Sierra Nevada Range. Our ethnographic investigations revealed that a majority of culturally important plants identified by tribal members …

Provisioning Services Decline For Both People And Critically Endangered Wildlife In A Rainforest Transformation Landscape, Katherine J. Kling, Timothy M. Eppley, A. Catherine Markham, Patricia C. Wright, Be Noel Razafindrapaoly, Rajaona Delox, Be Jean Rodolph Rasolofoniaina, Jeanne Mathilde Randriamanetsy, Pascal Elison, Natalie Vasey, Multiple Additional Authors

Anthropology Faculty Publications and Presentations

The loss and degradation of forests and other ecosystems worldwide threaten both global biodiversity and the livelihoods of people who use natural resources. Understanding how natural resource use impacts landscape provisioning services for both people and wildlife is thus critical for designing comprehensive resource management strategies. We used data from community focus groups, botanical plots and an inventory of plant species consumed by the Critically Endangered red-ruffed lemur (Varecia rubra) to assess the availability of key provisioning services for people and endemic wildlife on the Masoala Peninsula, a rainforest transformation landscape, in northeastern Madagascar (Masoala National Park and 13 surrounding …

A Genus In The Bacterial Phylum Aquificota Appears To Be Endemic To Aotearoa-New Zealand, Jean F. Power, Carlo R. Carere, Holly E. Welford, Daniel T. Hudson, Kevin C. Lee, John W. Moreau, Anna-Louise Reysenbach, Thijs J.G. Ettema, Multiple Additional Authors

Biology Faculty Publications and Presentations

Allopatric speciation has been difficult to examine among microorganisms, with prior reports of endemism restricted to sub-genus level taxa. Previous microbial community analysis via 16S rRNA gene sequencing of 925 geothermal springs from the Taupō Volcanic Zone (TVZ), Aotearoa-New Zealand, revealed widespread distribution and abundance of a single bacterial genus across 686 of these ecosystems (pH 1.2-9.6 and 17.4-99.8 °C). Here, we present evidence to suggest that this genus, Venenivibrio (phylum Aquificota), is endemic to Aotearoa-New Zealand. A specific environmental niche that increases habitat isolation was identified, with maximal read abundance of Venenivibrio occurring at pH 4-6, 50-70 °C, and …

Tiny Drifters Amidst Global Change: Examining Environmental Drivers, Trophic Impacts, And Management Strategies Of Estuarine Plankton Communities In The Anthropocene, Taylor Nicole Dodrill

Dissertations and Theses

Plankton productivity supports estuarine food webs, and has been tied to the success of fisheries, macroinvertebrates, and cultured shellfish yields. Climate change and alterations to nutrient loads are thought to be influencing plankton assemblages, with toxin-producing harmful algal blooms (HABs) on the rise and nutritional quality of plankton declining globally. These shifts in plankton communities may contribute to low biomass yields and toxin-based closures of important fisheries. The objectives of this dissertation are to identify environmental drivers, trophic impacts, and management strategies to understand and respond to changing estuarine plankton communities. To address these objectives, I used a combination of …

People, Place, And Planet: Global Review Of Use-Inspired Research On Water-Related Ecosystem Services In Urban Wetlands, Jason Sauer, Heejun Chang

Geography Faculty Publications and Presentations

With climate change and urbanization, city planners and developers have increasing interest and practice in constructing, restoring, or incorporating wetlands as forms of green infrastructure to maintain water-related ecosystem services (WES). We reviewed studies that valued in functional or monetary units the water regulation and purification services of urban wetlands around the globe. We used the adaptive management cycle (AMC) as a heuristic to determine the step that a study would represent in the AMC, the connections between the cycle steps that were used or considered, and the stakeholders involved. Additionally, we identified the social, ecological, and/or technological dimension(s) of …

Drivers And Dynamics Of Phytoplankton Communities And Harmful Algal Blooms In Mountain Lakes, Lara Stephanie Jansen

Dissertations and Theses

Harmful cyanobacterial blooms (cyanoHABs) are a complex and widespread disturbance in freshwater water bodies, impacting water quality for wildlife and human populations. While cyanobacteria often bloom in warm lakes impacted by human development like agriculture, blooms are increasingly reported in cooler waters with limited development in the surrounding watershed. As much of cyanoHAB research has focused on lakes in highly developed watersheds, the understanding of factors leading to cyanobacteria dominance and blooms in the absence of major development remains limited. Mountain lakes can serve as ideal systems to study bloom-forming cyanobacteria in watersheds with minimal development. In addition, mountain lakes …

Human-Modified Landscapes Driving The Global Primate Extinction Crisis, Erik Joaquín Torres-Romero, Vincent Nijman, David Fernández, Timothy M. Eppley

Anthropology Faculty Publications and Presentations

The world's primates have been severely impacted in diverse and profound ways by anthropogenic pressures. Here, we evaluate the impact of various infrastructures and human-modified landscapes on spatial patterns of primate species richness, at both global and regional scales. We overlaid the International Union for the Conservation of Nature (IUCN) range maps of 520 primate species and applied a global 100 km2 grid. We used structural equation modeling and simultaneous autoregressive models to evaluate direct and indirect effects of six human-altered landscapes variables (i.e., human footprint [HFP], croplands [CROP], road density [ROAD], pasture lands [PAST], protected areas [PAs], and Indigenous …

Urban Green Roofs Can Support A Diversity Of Parasitoid Wasps, Aramee C. Diethelm, Susan Masta

Biology Faculty Publications and Presentations

Green roofs are often installed atop buildings to provide ecological services such as mitigating storm water runoff and cooling air within urban heat islands. We found that green roofs in Portland, Oregon, also can support biodiversity, including a diverse assemblage of parasitoid wasps, with 20 morphospecies from 10 families present on the four roofs we surveyed. The roofs with greater plant diversity and structural complexity harbored comparatively more parasitoid morphospecies than the structurally simpler Sedum-dominated roofs. The oldest green roof supported much greater diversity than the younger roofs, including a comparably planted roof three times its size. Parasitoid wasps from …

Spatial Analysis Of Burn Severity And Streamflow Response In The Western Conus, Will Brendan Long

Dissertations and Theses

Wildfire increases the magnitude of runoff in catchments, which can lead to the degradation of ecosystems, risk to infrastructure, and loss of life. The Labor Day Fires of 2020 provided an opportunity to compare multiple large and severe wildfires with the objective of determining potential changes to hydrologic processes in Oregon Cascades watersheds. Geographic information systems (GIS) were implemented to determine the total percentage burned and percentage of high burn severity class of six watersheds on the west-slope of the Oregon Cascade Range. In addition, two control watersheds were included to contrast the influence of climatic effects. Spatial arrangement of …

Using An Affinity Analysis To Identify Phytoplankton Associations, Weiju Zhu, Zhaojian Ding, Yangdong Pan, Quanxi Wang

Environmental Science and Management Faculty Publications and Presentations

Phytoplankton functional traits can represent particular environmental conditions in complex aquatic ecosystems. Categorizing phytoplankton species into functional groups is challenging and time-consuming, and requires high-level expertise in species autecology. In this study, we introduced an affinity analysis to aid the identification of candidate associations of phytoplankton from two data sets comprised of phytoplankton and environmental information. In the Huaihe River Basin with a drainage area of 270,000 km2 in China, samples were collected from 217 selected sites during the low-water period in May 2013; monthly samples were collected during 2006–2011 in a man-made pond, Dishui Lake. Our results indicated that …

Efficiency In The Upper Deschutes Basin: Understanding The Hydrosocial Implications Of Irrigation Canal Piping, Rebecca Anderson

Dissertations and Theses

In response to water scarcity, irrigation efficiency projects aim to conserve water for in-stream flow and agricultural use. Piping irrigation canals is a common irrigation efficiency method which reduces the loss of incidental recharge, resulting in trade-offs within a hydrosocial system. Few studies have focused on the consequences of canal piping and none have integrated a critical analysis of the social factors involved in deciding what constitutes 'efficient' water use. This study seeks to fill this gap by combining natural and social science to give attention to the scales and perspectives involved in irrigation efficiency canal piping and the material …

Citizens' Preferences On Green Infrastructure Practices And Their Enhancement In Portland, Oregon, Katsuya Tanaka, Hal T. Nelson, Nicholas Mccullar, Nishant Parulekar

Public Administration Faculty Publications and Presentations

Green infrastructure (GI) has been gaining increasing attention due to its efficiency in controlling and purifying urban stormwater runoff, creating environmental amenities, and biodiversity conservation. Nevertheless, the existing knowledge of people's preferences for GI is not yet sufficient for evidence-based policymaking for enhancing GI. This study analyzes citizens' perceptions of the relative importance of six GI practices and estimates their willingness to pay (WTP) to enhance them. To this end, the study applies two types of stated preference methods (best-worst scaling and contingent valuation) to citizen survey data collected in Portland, Oregon. We found that GI practices that are more …

"We've Created Cheap Energy Off The Backs Of Salmon": Dam Removal Politics And Alliances In The Lower Snake River Basin, Krista Harrington

Dissertations and Theses

Dams, once considered by many to be good for water development in the Western U.S., might not be a part of a climate resilient future. Dams have come under increasing scrutiny due to undesirable ecological implications. Although dam removal proposals are growingly popular in recent decades, they are controversial since they impact different stakeholders in different ways. In the Pacific Northwest, the Lower four Snake River dams have long been criticized for their negative impacts on salmon. In February 2021, US Congressman Mike Simpson (R-Idaho) proposed a comprehensive framework to deconstruct the Lower four Snake River dams as an attempt …

Extreme Winds Alter Influence Of Fuels And Topography On Megafire Burn Severity In Seasonal Temperate Rainforests Under Record Fuel Aridity, Cody Evers, Andres Holz, Sebastian Upton Busby, Max Nielsen-Pincus

Environmental Science and Management Faculty Publications and Presentations

Nearly 0.8 million hectares of land were burned in the North American Pacific Northwest (PNW) over two weeks under record-breaking fuel aridity and winds during the extraordinary 2020 fire season, representing a rare example of megafires in forests west of the Cascade Mountains. We quantified the relative influence of weather, vegetation, and topography on patterns of high burn severity (>75% tree mortality) among five synchronous megafires in the western Cascade Mountains. Despite the conventional wisdom in climate-limited fire regimes that regional drivers (e.g., extreme aridity, and synoptic winds) overwhelm local controls on vegetation mortality patterns (e.g., vegetation structure and …

Modeling Environmental Factors Related To Drought-Induced Tree Mortality Based On Lidar And Hyperspectral Imagery, Lauren Nicole Sharwood

Dissertations and Theses

Climate change is projected to bring more frequent and prolonged droughts, causing widespread forest die-off. Identifying tree mortality over large spatial extents in response to the most recent California drought will help forest managers and conservationists understand where there may be a greater likelihood of future die-offs. In order to find more at-risk areas, this study evaluated how interacting site-specific topographic, climate, substrate, and stand characteristics mediated tree mortality in the Central Sierra Nevada during the 2012-2016 drought. The author used lidar and hyperspectral imagery provided by the National Ecological Observatory Network to identify individual dead trees using the Random …

The 2019 Conference On Health And Active Transportation: Research Needs And Opportunities, David Berrigan, Astrid Dannenberg, Michelle Lee, Kelly Rodgers, Janet R. Wojcik, Behram Wali, Calvin P. Tribby, Ralph Buehler, James F. Sallis, Multiple Additional Authors

Urban Studies and Planning Faculty Publications and Presentations

Active transportation (AT) is widely viewed as an important target for increasing participation in aerobic physical activity and improving health, while simultaneously addressing pollution and climate change through reductions in motor vehicular emissions. In recent years, progress in increasing AT has stalled in some countries and, furthermore, the coronavirus (COVID-19) pandemic has created new AT opportunities while also exposing the barriers and health inequities related to AT for some populations. This paper describes the results of the December 2019 Conference on Health and Active Transportation (CHAT) which brought together leaders from the transportation and health disciplines. Attendees charted a course …

Exploring Linkages Between Landscape Patterns And Freshwater And Estuarine Bivalves In The Coast Range Of Oregon, Kaegan Michael Scully-Engelmeyer

Dissertations and Theses

Spatial configurations of landscape variables (biotic, abiotic, and socio-ecological) affect and are affected by ecological processes and species in watersheds. This dissertation explores relationships among landscape patterns, ecosystem processes and bivalve species dynamics in coastal watersheds in Oregon, USA. I approached this broad topic through two primary avenues of research: investigating cross-ecosystem threats from pesticide use in forestland management to downstream aquatic environments, and the landscape ecology of an at-risk freshwater mussel species.

Terrestrial land use activities present cross-ecosystem threats to riverine and marine species and processes. Specifically, pesticide runoff can disrupt hormonal, reproductive, and developmental processes in aquatic organisms, …