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- Animal population density -- Oregon -- Hayden Island (Multnomah County) (1)
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- Eastern kingbird -- Behavior -- Oregon -- Malheur National Wildlife Refuge (1)
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- Feral cats -- Feeding and feeds -- Oregon -- Hayden Island (Multnomah County) (1)
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- Fragmented landscapes -- Oregon -- Portland Metropolitan Area (1)
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Articles 1 - 19 of 19
Full-Text Articles in Population Biology
Removal As A Control Method For Trachemys Scripta Elegans And The Response Of Chrysemys Picta Bellii, Jacob Swanson
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
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 …
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
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 …
Our Peer The Pigeon: Impacts Of The Covid-19 "Anthropause" On Psu Campus Urban Foragers, Audrey Douglass
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 …
Density Of Free-Roaming Cats Related To Feeding Stations On Hayden Island, Oregon, Olivia Helback, Joe Liebezeit
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 …
Common Raven Impacts On Nesting Western Snowy Plovers: Integrating Management To Facilitate Species Recovery, Cheryl Strong, Kriss K. Neumann, Jenny L. Hutchinson, Jamie K. Miller, Amber L. Clark, Lena Chang, Joanna Iwanicha, Elizabeth Feucht, Matthew J. Lau, David J. Lauten, Sarah Markegard, Benjamin Pearl, David L. Sherer, Rachel Tertes, Susie Tharratt, Travis Wooten
Common Raven Impacts On Nesting Western Snowy Plovers: Integrating Management To Facilitate Species Recovery, Cheryl Strong, Kriss K. Neumann, Jenny L. Hutchinson, Jamie K. Miller, Amber L. Clark, Lena Chang, Joanna Iwanicha, Elizabeth Feucht, Matthew J. Lau, David J. Lauten, Sarah Markegard, Benjamin Pearl, David L. Sherer, Rachel Tertes, Susie Tharratt, Travis Wooten
Institute for Natural Resources Publications
The U.S. Pacific coast population of the western snowy plover (Charadrius nivosus nivosus; plover) has declined due to loss and degradation of coastal habitats, predation, and anthropogenic disturbance. The U.S. Fish and Wildlife Service listed the subspecies in 1993 as threatened under the Endangered Species Act due to the population declines and habitat loss. Predation of nests and chicks has been identified as an important cause of historic population declines, and thus, most predator management actions for this subspecies are focused on reducing this pressure. In recent years, common ravens (Corvus corax; ravens) have become the most common and pervasive …
Phylogeography Of Two Species Of The Genus Apochthonius Chamberlin, 1929, In The Pacific Northwest (Arachnida, Pseudoscorpiones), Brandi Lynn Welch
Phylogeography Of Two Species Of The Genus Apochthonius Chamberlin, 1929, In The Pacific Northwest (Arachnida, Pseudoscorpiones), Brandi Lynn Welch
Dissertations and Theses
I used mitochondrial COI sequence data from forty one individuals to investigate phylogenetic relationships among populations of two morphologically similar species of the pseudoscorpion genus Apochthonius, A. minimus and A. occidentalis, in western Washington, Oregon, and northern California. My goal was to assess whether genetic structure in the two species was congruent with geography. Many plant and animal species in the Pacific Northwestern United States have shown patterns of genetic differentiation that follow both north-south and east-west trends, indicating that geologic and climatic events in the past separated populations to the extent that they became genetically differentiated. A distinct geographic …
The Biology Of Eastern Kingbirds At Malheur National Wildlife Refuge: Survival, Reproduction, And Testosterone Secretion, Lucas J. Redmond
The Biology Of Eastern Kingbirds At Malheur National Wildlife Refuge: Survival, Reproduction, And Testosterone Secretion, Lucas J. Redmond
Dissertations and Theses
This dissertation presents the results of a study that I undertook to better understand the breeding biology of Eastern Kingbirds (hereafter, kingbirds) at Malheur National Wildlife Refuge in southeastern Oregon from 2003 to 2009. Kingbirds are long-distance migratory songbirds that breed across much of North America. This species is socially monogamous but, via frequent extra-pair copulations, is genetically polygamous. Kingbirds exhibit relatively high breeding site fidelity, often returning to the same tree to nest in subsequent years. Both members of a pair provide parental care, but there are often specific duties performed by both male and female kingbirds. For example, …
The Breeding Biology Of The Northern Pygmy Owl: Do The Smallest Of The Small Have An Advantage?, John F. Deshler, Michael T. Murphy
The Breeding Biology Of The Northern Pygmy Owl: Do The Smallest Of The Small Have An Advantage?, John F. Deshler, Michael T. Murphy
Biology Faculty Publications and Presentations
We explored the breeding biology of the Northern Pygmy-Owl (Glaucidium gnoma) from 2007 to 2009 in a forested reserve in Portland, Oregon. Large body size is often assumed to give animals reproductive advantages, and we tested whether body size affected timing of breeding and examined variation in diet, breeding date, clutch size, and reproductive success to explore whether the presumed benefits of large body size are evident in this species. The average size of 13 clutches was 5.8, and nest success was high (92%); 22 successful nests fledged an average of 5.2 young. Dates of first laying varied …
Lifetime Reproductive Success Of Female Eastern Kingbirds (Tyrannus Tyrannus): Influence Of Lifespan, Nest Predation And Body Size, Michael T. Murphy
Lifetime Reproductive Success Of Female Eastern Kingbirds (Tyrannus Tyrannus): Influence Of Lifespan, Nest Predation And Body Size, Michael T. Murphy
Biology Faculty Publications and Presentations
I report on the lifetime reproductive success (LRS) of female Eastern Kingbirds (Tyrannus tyrannus) in central New York. I investigated the major correlates of LRS and specifi cally tested the hypothesis that small body size yields reproductive benefi ts. Lifetime reproductive success varied widely: 15–20% of females failed to fledge young over their life, whereas 50% of young were fledged by 20% of females. Female lifespan varied between one and eight years, and females that died after one breeding season tended to be smaller-bodied than long-lived females (≥2 seasons). I therefore conducted analyses of LRS for the entire sample and …
Woodland Amphibian Distribution In Parks And Greenspaces Of The Portland, Oregon Metropolitan Area: A Multiple Scale Investigation, Laura A. Roberts
Woodland Amphibian Distribution In Parks And Greenspaces Of The Portland, Oregon Metropolitan Area: A Multiple Scale Investigation, Laura A. Roberts
Dissertations and Theses
Loss of biodiversity due to habitat fragmentation is worldwide problem. With growing human populations and increasing urbanization, it is a necessity to conduct studies on wildlife occurring in urban areas. Currently there is a deficit of research investigating woodland amphibians in urban environments. My objectives were to describe amphibian species richness and abundance in the Portland, Oregon, Metropolitan region, and relate patterns of variation to variables at three increasingly large spatial scales: 1) local microenvironmental (i.e. amphibian/substrate interaction), (2) macrohabitat/patch (i.e. park or greenspace), and 3) landscape (surrounding parks and greenspaces). Environmental variables occurring within the three spatial scales were …
Human Trampling In The Upper Rocky Intertidal: Trampling And Recovery In Barnacle Mediated Succession, Timothy Lawrence Grubba
Human Trampling In The Upper Rocky Intertidal: Trampling And Recovery In Barnacle Mediated Succession, Timothy Lawrence Grubba
Dissertations and Theses
Marine intertidal ecosystems are vulnerable to human interference, because trampling can be a significant problem. I studied the impacts of trampling on community patterns and succession in a rocky intertidal habitats. This study was divided into two phases: (1) a trampling phase and (2) a recovery phase. Both phases are focused on two barnacles, Balanus glandula and Chthamalus dalli, and on fucoid and red algae. The trampling phase tested the effects of trampling on these organisms. The effects of herbivores, primarily limpets (Collisella digitalis) were also tested to determine whether anthropogenic (trampling) and natural (herbivory and limpet …
The Distribution Of Zooplankton In Selected Oregon Lakes, Mary Elizabeth Claska
The Distribution Of Zooplankton In Selected Oregon Lakes, Mary Elizabeth Claska
Dissertations and Theses
Zooplankton samples were collected from 166 Oregon lakes. The lakes included a wide range in size, trophic status, and water quality. Lakes were located throughout the state. Zooplankton were identified using standard taxonomic keys and counted. Seventy-four species were identified from the 200 total samples, including 32 species of cladocera, 22 copepods, and 11 rotifers. Two species of copepod were recorded for the first time in Oregon: Diaptomus mississippiensis and Diaptomus pallidus. Seven species had widespread distributions throughout most of the watersheds in the state. Seventeen other species had distributions restricted to eastern, central, or western Oregon. The remaining …
A Population Study Of Three Iris (Iridaceae) Species Native To The Siskiyou Mountains In Southwestern Oregon And Adjacent California, Carol Anne Wilson
A Population Study Of Three Iris (Iridaceae) Species Native To The Siskiyou Mountains In Southwestern Oregon And Adjacent California, Carol Anne Wilson
Dissertations and Theses
The series Californicae is a natural grouping of Iris species native to Oregon, Washington and California. Natural and experimental hybridization is characteristic of the series which has led to confusing taxonomies for some species. Populations of species belonging to this series and found on the northwestern slopes of the Siskiyou Mountains cf southwestern Oregon and adjacent California were investigated. Methods used were numerical classification techniques for morphological characters including both discriminant and K-means cluster analyses and a chemotaxonomi c analysis of flavonoid pigments using thin layer chromatography.
The Red-Tailed Hawk On Sauvie Island, Oregon, Kevin J. Lien
The Red-Tailed Hawk On Sauvie Island, Oregon, Kevin J. Lien
Dissertations and Theses
A study was undertaken to determine the abundance, distribution, perching heights, diets and territory sizes of Red-Tailed Hawks on Sauvie Island, Oregon. Sauvie Island supported a large wintering population of non-territorial Red-Tailed Hawks. The establishment of territories began around 10 January. Average perch height was found to be 14.2 m. Average perch height increased from fall to spring, corresponding-to the onset of the breeding season and to the onset of egg-laying and incubation. Voles (Microtus spp.) were the principal prey year-round, though waterfowl were more important in terms of biomass in the winter and early spring. Territory sizes on the …
A Study Of Leslie Model Under Stochastic Environments, Kamran Shaukat
A Study Of Leslie Model Under Stochastic Environments, Kamran Shaukat
Dissertations and Theses
The prediction and analysis of changes in the numbers of biological populations rest on mathematical formulations of demographic events (births and deaths) classified by the age of individuals. The development of demographic theory when birth and death rates vary statistically over time is the central theme of this work. A study of the standard Leslie model for the demographic dynamics of populations in variable environments is made. At each time interval a Leslie matrix of survival rates and fertilities of a population is chosen according to a Markov process and the population numbers in different age classes are computed. Analytical …
Some Physical And Biological Factors Affecting Red-Tailed Hawk Productivity, Stewart Wayne Janes
Some Physical And Biological Factors Affecting Red-Tailed Hawk Productivity, Stewart Wayne Janes
Dissertations and Theses
Various physical and biological factors affecting annual productivity in a Red-tailed Hawk population in north-central Oregon were investigated. The percentage of the population successfully fledging one or more young was the most important factor in determining the number of young fledged per pair in a given year. Neither clutch size nor the number of young fledged per successful nest varied significantly. Percent pair success was correlated with several January weather variables. A cold and dry January is positively correlated with Red-tailed Hawk productivity. This is apparently related to the onset of rapid vegetative growth and this in turn is positively …
Mammals Of The Bull Run, Edward M. Thatcher
Mammals Of The Bull Run, Edward M. Thatcher
Dissertations and Theses
This study of mammals of the Bull Run Planning Unit has a dual character. First, mammals of special scientific or natural history interest such as threatened or endangered species were sought. This was in conjunction with a Mt. Hood Bull Run Planning Unit. Second, a zoogeographical study of mammals of the Bull Run was performed. Abundance and distributional data was recorded for each species observed. This data was related to availability to moisture as indicated by plant associations trapped. Difference in habitat utilization along a moisture gradient was investigated as a possible coexistence mechanism for sympatric small mammals in the …
"The Population Explosion And Ecology", Paul R. Ehrlich
"The Population Explosion And Ecology", Paul R. Ehrlich
Special Collections: Oregon Public Speakers
No abstract provided.