Ecology and Evolutionary Biology Commons^™

Understanding Local Ecological Context Through Historic And Contemporary Vegetation Maps, Ray L. Brunner

Institute for Natural Resources Publications

Oregon's historic vegetation map represents patterns of vegetation prior to widespread EuroAmerican settlement and subsequent land use changes. This map is based on General Land Office surveys from 1851 – 1910 and 1930s timber mapping and serves as a valuable resource to help understand historical context and potential vegetation. Over the past few hundred years, the vegetation composition and land cover of the Oregon and the Willamette Valley have been significantly altered, with wholesale conversion of prairies and riparian woodlands to agriculture and development and encroachment of woody vegetation in the absence of fire. Presented at the 2026 LIVE conference …

What's The Value Of A State? Accounting For The Ecosystem Services And Natural Capital Of Oregon, Kathryn Liebrecht

University Honors Theses

Ecosystem services are vital to human welfare and society, but often are overlooked when it comes to planning and setting policy. By neglecting to incorporate the benefits received from natural resources, policy makers may unknowingly be making decisions that harm the long term sustainability and use of these services. To highlight the importance of Oregon's ecosystems, the present study aims to provide a full accounting of the ecosystem services and natural capital of the state. Using data from the Institute for Natural Resources' updated Oregon statewide habitat map, Oregon's ecosystems were matched to biome categories from the Ecosystem Services Valuation …

Woofs And Warbles: The Influence Of Urban Dog Walking On Birdsong, Grace Phillips

University Honors Theses

Recreational activity in natural areas can disrupt songbird singing during critical learning or courtship periods, increasing the risk of fitness and population declines in sensitive species. Local data on birdsong disturbance caused by recreation can guide management efforts protecting wildlife, such as signage, leash laws, and dog walking bans. This study assessed bird vocalization responses to groups with and without dogs in urban greenspaces. Surveys were conducted in Fall 2024 at three parks in Portland, Oregon, with varying rates of dog and human presence. Throughout two-hour observation periods, bird vocalization activity of seven songbirds was recorded at five-minute intervals and …

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 …

Oregon Vegetation Change 1851 – 2023, Ray L. Brunner, Eleanor P. Gaines

Institute for Natural Resources Publications

This effort compares the total area and spatial overlap between vegetation classes in existing vegetation maps of different eras to provide insight into possible changes in vegetation cover between 1851 and 2023 (Table 1). There are significant differences between the classifications and methods used to make each map, so we focus here on research questions that:
a) relate to at least one specific Key Habitat, and
b) where there is existing research suggesting that the specific pattern investigated is true, and
c) where the differences between the vegetation classifications compared are expected to be smaller than the differences over time. …

Phytoplankton Community Dynamics In The Northern California Current System, Kristin E. Forgrave

Dissertations and Theses

The Northern California Current system is a productive coastal ecosystem encompassing a variety of temporal and spatial features. The photosynthetic microbial community plays a crucial role in supporting the rich ecosystem and its economically important fisheries. My research integrates data across location and two years to investigate the community composition of two major phytoplankton groups in this system: picocyanobacteria and photosynthetic picoeukaryotes (PPE). The abundances and sizes of the phytoplankton were measured using flow cytometry. I found PPE present at similar concentrations in both summer and winter seasons. Abundances of both PPE and picocyanobacteria were comparable in the winter, but …

Isolation Of Gametophytic Selection And Selective Embryo Abortion In Mimulus Guttatus, Desmond C. Willson

University Honors Theses

A lack of genomic studies examining gametophytic selection (GS) and selective embryo abortion (SEA)--which occur during the reproduction of angiosperms--leaves questions regarding the adaptive and evolutionary effects of these processes. Analyzing deviations from Mendelian segregation offers an avenue for identifying loci targeted by GS and SEA, and their contributions to purging of genetic load. However, other selective processes such as meiotic drive and cytonuclear interactions, as well as pollen and ovule abortion, can cause distortion. To distinguish the effects of GS and SEA from other causes of distortion, we will perform reciprocal crosses between highly homozygous and highly heterozygous individuals …

Removal As A Control Method For Trachemys Scripta Elegans And The Response Of Chrysemys Picta Bellii, Jacob Swanson

University Honors Theses

The red-eared slider is considered one of the most ubiquitous freshwater turtles globally. Several key ecological advantages and life history traits of this species jointly impact growth rates and survivorship of native freshwater turtles where sympatry occurs. Evaluation of current management actions for red-eared slider turtles is limited, resulting in a paucity of information to guide management for the species and conservation of declining native freshwater turtles. We used previously collected mark-recapture and removal sampling data from sites with sympatric populations of red-eared slider and western painted turtles. We examined the effects of control (trapping and removal) of red-eared sliders …

A Multispecies Hierarchical Model To Integrate Count And Distance-Sampling Data, Neil A. Gilbert, Caroline M. Blommel, Matthew T. Farr, David S. Green, Kay E. Holekamp, Elise F. Zipkin

Institute for Natural Resources Publications

Integrated community models—an emerging framework in which multiple data sources for multiple species are analyzed simultaneously—offer opportunities to expand inferences beyond the single-species and single-data-source approaches common in ecology. We developed a novel integrated community model that combines distance sampling and single-visit count data; within the model, information is shared among data sources (via a joint likelihood) and species (via a random-effects structure) to estimate abundance patterns across a community. Parameters relating to abundance are shared between data sources, and the model can specify either shared or separate observation processes for each data source. Simulations demonstrated that the model provided …

Selection During Reproduction In Mimulus Guttatus, Desmond C. Willson, Karla De Lima Berg, Mitch Cruzan

Student Research Symposium

A lack of genomic studies examining gametophytic selection and selective embryo abortion—which occur during the reproduction of angiosperms—leaves questions regarding the adaptive and evolutionary effects of these processes. Analyzing deviations from Mendelian segregation offers an avenue for identifying loci targeted by GS and SEA, and their contributions to purging of genetic load. However, other selective processes such as meiotic drive and cytonuclear interactions, as well as pollen and ovule abortion, can cause distortion. To distinguish the effects of GS and SEA from other causes of distortion, we will perform reciprocal crosses between highly homozygous and highly heterozygous individuals of Mimulus …

Relationship Between Trunk Cross-Sectional Area Growth And Water Stress In Garry Oaks (Q. Garryana): A Species Of Conservation Concern, John Cochrane

Student Research Symposium

In the Pacific Northwest, Quercus garryana (Garry oak trees) support over 627 native species. Garry oak natural habitat was originally maintained by indigenous practices but has been reduced to 5-10% of its range due to change in land management strategies. To support oak conservation, we need to understand heat and water affect the growth and physiology of this species. In this study, we created a fixed linear model of trunk cross-sectional growth with water stress (Ψ), photosynthetic water-use efficiency (δ¹³C), and leaf Carbon-Nitrogen ratio. We collected branch samples from the canopies of 47-64 mature Garry oaks in the …

Phytoplankton Community Dynamics In The Northern California Current System, Kristin Forgrave

Student Research Symposium

The Northern California Current system is a productive coastal ecosystem that encompasses a variety of temporal and spatial features. The photosynthetic microbial community plays a crucial role in supporting the rich ecosystem and economically important fisheries. My research integrates data across distance and two years to investigate the community composition of two major phytoplankton groups in this system: picocyanobacteria and picoeukaryotes. The abundances and sizes of the phytoplankton were measured using flow cytometry. Picoeukaryotes were found to be present at similar concentrations in both summer and winter. Abundances of both cell types were comparable in the winter, but picocyanobacteria were …

How Beavers (Castor Canadensis) Affect Habitat Availability For Two Native Oregon Turtles: Actinemys Marmorata And Chrysemys Picta Bellii, Rodé Krige

University Honors Theses

Oregon is home to two native freshwater turtle species: the northwestern pond turtle and the western painted turtle. Both turtles are Oregon conservation strategy species with a status rating of sensitive, indicating declining populations. Oregon's decline in these turtle's populations is thought to be predominantly due to loss and degradation of habitat that results from development and urbanization. Beavers' ability to dam streams and create ponds may be creating habitat usable by turtles, but the relationship is under-studied. This study assessed water temperature, basking habitat, and overall turtle habitat suitability at beaver-dammed and control ponds in Portland, Oregon. Average basking …

Willow Abundance And Condition Mapping In Rocky Mountain National Park, Eric M. Nielsen

Institute for Natural Resources Publications

Riparian and wetland willow species have undergone serious declines in Rocky Mountain National Park as a consequence of a variety of environmental changes and, most recently, damage resulting from moose overpopulation. To address concerns about the long-term status of willows in the park, we developed remote sensing-based raster maps of riparian and wetland willow species presence, canopy cover percentage, canopy height, and leaf area index. All outputs were produced at 3-meter resolution, and represent willows as they existed in 2021. The mapping was performed via random forests classification and regression models trained on several hundred vegetation plots from a variety …

Impacts Of Floodplain Restoration On Water Temperature And Macroinvertebrates In Whychus Creek, Oregon, Wesley Nathan Noone

Dissertations and Theses

Stream restoration is a proposed climate adaptation tool, however, outcomes of floodplain restoration on stream temperature have been debated. Despite a growing number of studies that investigated water temperature in restored streams, few have quantified thermal heterogeneity in new habitat types created by restored hydrogeomorphic processes and the impact of thermal diversity on the aquatic macroinvertebrate community. In this study, I evaluated three hypotheses: 1) restoration increases habitat diversity, 2) habitat diversity increases water temperature heterogeneity, and 3) restored reaches have more diverse macroinvertebrate communities. I collected a total of 40 macroinvertebrate samples and characterized environmental conditions in three reaches …

Examining Mesopredator Detections In The Portland Metropolitan Area, Hunter Storm

University Honors Theses

Mesopredators--medium-sized predators such as coyote (Canis latrans), common raccoon (Procyon lotor), and Virginia opossum (Didelphis virginiana)--are well established in cities and live closely with humans. However, we still know relatively little about these animals' habitat selection and behavior as they navigate urban space.

In collaboration with the nationwide Urban Wildlife Information Network (UWIN), we established 27 monitoring sites spanning 50 km of the Portland metropolitan area. Using motion-triggered camera traps active during spring 2022 we collected presence and absence data for three non-domestic mesopredator species: coyote, raccoon, and opossum. Using 40 landscape and sociodemographic …

The Distribution And Reproductive Success Of The Western Snowy Plover Along The Oregon Coast - 2022, David J. Lauten, Kathleen A. Castelein, Daniel Farrar, Mary Lee, Eleanor P. Gaines

Institute for Natural Resources Publications

We monitored the distribution, abundance and productivity of the federally threatened Western Snowy Plover (Charadrius nivosus nivosus) along the central and south coast of Oregon from 1 April – 15 September 2022. We surveyed and monitored plover activity in a project area that included, from north to south, Sutton Beach, Siltcoos River estuary, the Dunes Overlook, North Tahkenitch Creek, Tenmile Creek, Coos Bay North Spit, Bandon Snowy Plover Management Area, New River Habitat Restoration Area (HRA) and adjacent lands, and Floras Lake. Our objectives for the project area in 2022 were to: 1) estimate the size of the adult Snowy …

Urban Nesting Biology, Population Viability And Ecology Of The Willow Flycatcher, Empidonax Traillii, Stephanie Alexandra Byrne Doorly

Dissertations and Theses

Reproductive success, in any species, relies both on the habitat utilized to reproduce and on the successful reproductive output of individual animals within a population. Populations in turn rely on the reproductive fitness of the individual. Whether populations remain stable, grow, or decline ultimately relies on the combined reproductive output of the individuals within that population.

We studied the Willow Flycatcher (Empidonax traillii; henceforth WIFL), a well-studied Neartic-Neotropical migrant passerine whose breeding range extends from the east to west coast of North America. Across much of their range, and in particular in the western regions, breeding population are …

Climate And Intraspecific Geographic Variation Of Nests And Eggs In The Eastern Kingbird Tyrannus Tyrannus, Samantha Marie Gillette

Dissertations and Theses

The reproductive success of birds is ultimately driven by the traits of nests, eggs, and incubation behavior and the interactions among them. Avian reproduction varies on large geographic scales, most prominently between tropic- vs. temperate-breeding species, but also on finer scales, such as along latitudinal and elevational geographic gradients. However, despite the importance of eggs and nests, how their traits vary geographically in response to differences in regional climate remains understudied.

We studied Eastern Kingbirds (Tyrannus tyrannus), which have been previously demonstrated to alter incubation length in response to local climate conditions. Our study sites, Kansas (KS), New …

Effects Of Green Crab (Carcinus Maenas) Across Variable Densities Of Eelgrass (Zostera Marina), Kimberly Alexis Brown

Dissertations and Theses

Eelgrass (Zostera marina) plays a critical role in estuarine ecosystem function by sustaining a variety of marine and freshwater species, but it's increasingly threatened by the aggressive non-native green crab (Carcinus maenas). The abundance of C. maenas is on the rise within the coastal environment of Oregon and it is imperative to know how these populations will affect the long-term health of Z. marina. C. maenas have been linked to declines in Z. marina coverage and shellfish abundance, but there has been no research on to what extent the density of Z. marina affects its …

Post-Fire Tree Mortality And Regeneration Patterns As Proxies Of Conifer Forest Resilience, Sebastian Upton Busby

Dissertations and Theses

Shifting wildfire patterns and climate conditions, magnified by anthropogenic climate change, are threatening the resilience of conifer forests in North America and more specifically, the western US. If native conifer species are functionally maladapted to novel fire patterns and post-fire climate conditions, large-scale shifts in conifer forest structure, composition, and extent may occur as warming intensifies. Forest resilience in the context of fire and climate can be understood and quantified by the survival of trees through fire events and success of trees to regenerate post-fire and maintain population levels. In this dissertation, I use field observations and remote sensing to …

Mitonuclear Mismatch Is Associated With Increased Male Frequency, Outcrossing, And Male Sperm Size In Experimentally-Evolved C. Elegans, Brent William Bever

Dissertations and Theses

We provide the first controlled study of how male frequencies and rates of outcrossing evolve in response to mitonuclear mismatch by allowing replicate lineages of C. elegans nematodes containing either mitochondrial or nuclear mutations of electron transport chain (ETC) genes to evolve under three sexual systems: facultatively outcrossing (wildtype), obligately selfing, and obligately outcrossing. In partial support of a tenet of the mitonuclear sex hypothesis, which predicts that outcrossing will be favored in cases of mitonuclear mismatch, we found evolution of increased male frequency in at least one replicate line of all four ETC mutant backgrounds tested--nuclear isp-1, mitochondrial …

Representation Justice As A Research Agenda For Socio-Hydrology And Water Governance, Melissa Haeffner, Dana E. Hellman, Alida Cantor, Idowu Ajibade, Vinka Oyanedel-Craver, Maura Kelly, Laura Schifman, Lisa Weasel

Environmental Science and Management Faculty Publications and Presentations

We propose representation justice as a theoretical lens for socio-hydrology and water governance studies. An exploratory survey of 496 water sector employees in the United States revealed that self-identifying females felt more strongly discriminated against due to their gender and other social factors, compared to self-identifying males. Responses unveiled how macro- and microaggressions impede career pathways to leadership positions and, therefore, representation. We identify ways in which socio-hydrology can benefit from a representation justice lens by considering the following: (1) how power and politics shape the composition of the water sector and decision-making processes; (2) how available quantitative data do …

Microbes On The Mountain: Plant-Microbe Associations And Interactions On Mount St. Helens, Emily Rose Wolfe

Dissertations and Theses

Plant-microbe associations and interactions provide critical context to studies in both community and ecosystem ecology, especially in systems that are relatively new and still undergoing early successional processes. Microbes can colonize the surfaces and interiors of all plant tissues, and these assemblages vary in composition both spatially and temporally, even within the same plant. Endophytes are bacteria or fungi that spend most of their lifecycles living within plant tissues asymptomatically--typically, "endophyte" refers specifically to aboveground tissues such as leaves and stems, and therefore may have direct influences on defenses against herbivory, pathogen or pest tolerance, and even afterlife effects on …

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, …

Beaver Reintroduction And Its Potential As An Ecological Conservation Measure For At-Risk Amphibian Species In The Pacific Northwest, Danielle Schwantes

University Honors Theses

Amphibian decline is a major concern in the Pacific Northwest (PNW), with many amphibian species listed as sensitive, threatened or endangered throughout the region. Some of the predicted main causes of amphibian decline are climate change and loss of habitat. The reintroduction of beavers into ecoregions of the PNW could be an important step in the conservation of this region’s amphibians, due to the beaver’s ability to engineer and structurally manipulate forest ecosystems. Beavers are able to restore wetland quality, productivity and biodiversity, creating vital amphibian habitat. This work explored the linkage between beaver presence and wetland hydrology, geomorphology, landscape …

Spiders You May Encounter While Social Distancing: A Field Guide To Oregon, Daniel K. Hufnagel

Anthós

This document is simply a short field guide on the many endearing spiders you have encountered or will potentially encounter while social distancing in Oregon. Included are journal entries for six different species of spider, with each log containing an illustration and a description of the physical appearance, behavior, and habitat of the arachnid listed. Also included is a basic diagram depicting the anatomy of the common spider.

Our Peer The Pigeon: Impacts Of The Covid-19 "Anthropause" On Psu Campus Urban Foragers, Audrey Douglass

University Honors Theses

The 2020 COVID Pandemic presented a paradigm shift dubbed, by some scholars, the 'Anthropause', an ecological epoch in which humans faded from the public sphere. As was the case for many urban species that depend on the foraging of food waste, this meant a fundamental disruption to their food systems and to the entire urban eco-web. The PSU Campus Park Blocks presents a unique opportunity to observe animal behavior, while also a succinct microcosm to study food waste flow changes, and compare species layout to other urban parks in the METRO area. Decreased food waste output from proximal …

Human Impact On Pacific Harbor Seals In Urban Southern Puget Sound, Washington, Vicky Gomez

University Honors Theses

This research proposal aims to highlight the quantitative and qualitative impact of human disturbances Pacific Harbor Seals (Phocca vitulina) are experiencing in urban southern Puget Sound, Washington and how the data collected can educate the community to protect and conserve a healthy population of Harbor Seals. Urbanization and areas utilized by harbor seals within urban settings prompted data collection from four nearby sites: site A, Carylon Beach, includes pedestrian and boat disturbances, site B, Tacoma Tidal Flats, only experience boat disturbances, site C, West Bay Marina, experiences motorized and non-motorized boat disturbances and site D, Gertrude Island, is …

Density Of Free-Roaming Cats Related To Feeding Stations On Hayden Island, Oregon, Olivia Helback, Joe Liebezeit

University Honors Theses

Free-roaming cats have a devastating impact on wildlife populations with stray/feral cats being the most problematic. In some areas, community members provide these cats with food, water, and shelter often in conjunction with a trap, neuter, return (TNR) program. Hayden Island located north of Portland, Oregon is home to a managed colony of feral and stray cats. Some island residents provide feeding stations for the cats and actively participate in population management. To determine how feeding stations might affect cat spatial distribution, camera traps were placed at 19 different stations in urban and natural areas on Hayden island. Additional annual …