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Articles 1 - 30 of 579

Full-Text Articles in Physical Sciences and Mathematics

Modeling Functional Redundancy In Microbial Community, Sandra Annie Tsiorintsoa May 2022

Modeling Functional Redundancy In Microbial Community, Sandra Annie Tsiorintsoa

Biology and Medicine Through Mathematics Conference

No abstract provided.


Optimal Control And The Trojan Y Chromosome Eradication Strategy, Christopher Turner May 2022

Optimal Control And The Trojan Y Chromosome Eradication Strategy, Christopher Turner

Biology and Medicine Through Mathematics Conference

No abstract provided.


Gene Drives And The Consequences Of Over-Suppression, Cole Butler May 2022

Gene Drives And The Consequences Of Over-Suppression, Cole Butler

Biology and Medicine Through Mathematics Conference

No abstract provided.


Spatial Patterning Of Predator-Prey Distributions Arising From Prey Defense, Evan C. Haskell, Jonathan Bell May 2022

Spatial Patterning Of Predator-Prey Distributions Arising From Prey Defense, Evan C. Haskell, Jonathan Bell

Biology and Medicine Through Mathematics Conference

No abstract provided.


Bioeconomic Analysis In A Predator-Prey System With Harvesting: A Case Study In The Chesapeake Bay Fisheries, Iordanka Panayotova, Maila Hallare May 2022

Bioeconomic Analysis In A Predator-Prey System With Harvesting: A Case Study In The Chesapeake Bay Fisheries, Iordanka Panayotova, Maila Hallare

Biology and Medicine Through Mathematics Conference

No abstract provided.


Effects Of Temperature Fluctuation On Interactions Between Generalist Insect Predators, Amanda N. Laubmeier, Nusrat Tabassum, Brigitte Tenhumberg May 2022

Effects Of Temperature Fluctuation On Interactions Between Generalist Insect Predators, Amanda N. Laubmeier, Nusrat Tabassum, Brigitte Tenhumberg

Biology and Medicine Through Mathematics Conference

No abstract provided.


Early Signs Of Regime Shift And Population Outbreak In A Two-Timescale Predator-Prey Model., Susmita Sadhu Dr. May 2022

Early Signs Of Regime Shift And Population Outbreak In A Two-Timescale Predator-Prey Model., Susmita Sadhu Dr.

Biology and Medicine Through Mathematics Conference

No abstract provided.


The Interplay Between Costly Reproduction And Unpredictable Environments Shapes The Stability Of Cooperative Breeding, Glenn Steven Young May 2022

The Interplay Between Costly Reproduction And Unpredictable Environments Shapes The Stability Of Cooperative Breeding, Glenn Steven Young

Biology and Medicine Through Mathematics Conference

No abstract provided.


Reconstructing The Ecological Relationships Of Late Cretaceous Antarctic Dinosaurs And How Functional Tooth Morphology Influenced These Relationships, Ian D. Broxson May 2022

Reconstructing The Ecological Relationships Of Late Cretaceous Antarctic Dinosaurs And How Functional Tooth Morphology Influenced These Relationships, Ian D. Broxson

2022 Symposium

The Sandwich Bluff Formation of the James Ross Basin of Antarctica has recently yielded a group of five late Cretaceous dinosaurs that lived contemporaneously with each other, a first for Antarctica. These five dinosaurs include fragmentary remains of two differently sized elasmarian ornithopods, a possible megaraptor, a hadrosaur, and a nodosaur. In this study we will construct a model of the ecological relationships of late Cretaceous Antarctica. Additionally, we will look at what specific factors allowed this group of four herbivores and a carnivore to coexist in a restricted locality and what niches were filled by each species. Methods to ...


The Understanding Of Mycorrhizae Networks: A Historical Approach, Jake Sun May 2022

The Understanding Of Mycorrhizae Networks: A Historical Approach, Jake Sun

The Confluence

The growth of mycorrhizal fungi into plant roots used to be viewed as a parasitic relationship between plants and fungi, where the fungal symbiont benefits and the plant host is harmed. Current research elucidates a mutualistic relationship. The mycorrhizae network assists the plants by increasing the capabilities for nutrient absorption in the soil. In exchange, the fungi receive carbon supply from the photosynthetic plants for growth. Our scientific understanding of other topics like species specificity, seed germination, and co-evolutionary influence of mycorrhizae and plants has also progressed. Additionally, we now understand that the mycorrhizal mutualism is not limited to the ...


Comparison Of Heavy Metals In Spinach Grown On The Roof Ground Location At Portland State University, Tyler A. Robin May 2022

Comparison Of Heavy Metals In Spinach Grown On The Roof Ground Location At Portland State University, Tyler A. Robin

Student Research Symposium

As a result of urbanization, fresh, healthy food can be expensive and easily contaminated but space for local farming is limited. Roofs can be underutilized in densely populated cities and can offer a space for local fresh farming. The purpose of this study is to continue a previous study done in 2021, to find if growing leafy vegetables on the roof can limit heavy metal exposure from air pollutants. This study compares spinach grown on the roof in 2021, 2019 and spinach bought from stores around the Portland State University campus and the heavy metals found in these greens. The ...


Development And Validation Of An Edna Protocol For Monitoring Endemic Asian Spiny Frogs In The Himalayan Region Of Pakistan, Muhammad Saeed, Muhammad Rais, Ayesha Akram, Maggie R. Williams, Kenneth F. Kellner, Syed A. Hashsham, Drew R. Davis Apr 2022

Development And Validation Of An Edna Protocol For Monitoring Endemic Asian Spiny Frogs In The Himalayan Region Of Pakistan, Muhammad Saeed, Muhammad Rais, Ayesha Akram, Maggie R. Williams, Kenneth F. Kellner, Syed A. Hashsham, Drew R. Davis

Earth, Environmental, and Marine Sciences Faculty Publications and Presentations

Wildlife monitoring programs are instrumental for the assessment of species, habitat status, and for the management of factors affecting them. This is particularly important for species found in freshwater ecosystems, such as amphibians, as they have higher estimated extinction rates than terrestrial species. We developed and validated two species-specific environmental DNA (eDNA) protocols and applied them in the field to detect the Hazara Torrent Frog (Allopaa hazarensis) and Murree Hills Frog (Nanorana vicina). Additionally, we compared eDNA surveys with visual encounter surveys and estimated site occupancy. eDNA surveys resulted in higher occurrence probabilities for both A. hazarensis and N. vicina ...


It Won’T Be Easy, Allison Arkush Apr 2022

It Won’T Be Easy, Allison Arkush

Theses, Dissertations, and Student Creative Activity, School of Art, Art History and Design

Interdisciplinary artist Allison Arkush engages a wide range of materials, modalities, and research in her practice. In It Won’t Be Easy, Arkush places and piles her multimedia sculptures throughout the gallery to create installations that overlap ­with her writing and poetry, sometimes layering in (or extending out to) audio and video components. This approach facilitates the probing exploration of prevailing value systems through a flattening of hierarchies among and between humans, the other-than-human, and the inanimate—though no less lively. Her work meditates on and ‘vendiagrams’ things forsaken and sacred, the traumatic and nostalgic. The exhibition title acknowledges that ...


Spatial And Temporal Patterns Of Fire On Saipan, Cnmi, Ilan E. Bubb, Zachary B. Williams Mar 2022

Spatial And Temporal Patterns Of Fire On Saipan, Cnmi, Ilan E. Bubb, Zachary B. Williams

Marine & Environmental Sciences Faculty Articles

Sediment core studies from Saipan suggest that fires did not play a prominent role in the disturbance regime of the Mariana Islands and have increased in frequency since human settlement around 4,000 years ago. On Saipan fires are understood to interrupt the pattern of succession leading to the degradation of native limestone forests, the proliferation of grasslands and the eventual creation of badlands. Little baseline data regarding the spatial and temporal patterns of fire on Saipan exist to create effective Fire Management Plans. This project uses Landsat 8 images from April 2013 to July 2020 and the Normalized Burn ...


Does Restoration Of Urban Riparian Zones Impact Stream Water Quality In Portland, Oregon, Ash Ivanov Mar 2022

Does Restoration Of Urban Riparian Zones Impact Stream Water Quality In Portland, Oregon, Ash Ivanov

University Honors Theses

Riparian zones influence urban stream quality through factors such as shading the stream, adding nutrients through leaf litter, stabilizing the stream banks to reduce turbidity, and filtering toxins out of the water. Riparian restoration often involves changing plant assemblage to be more diverse and include primarily native species instead of non-native, improving connection to the stream through changing stream morphology, improving species habitat, and reducing pollution. The goal of this study was to determine if urban riparian restoration projects in the region were successful, and if not, why that may be the case. The study was performed in the Portland ...


Interacting Effects Of Disease And Weather Variability On Rangeland Biodiversity Associated With Black-Tailed Prairie Dog (Cynomys Ludovicianus) Colonies, Courtney J. Duchardt, J. D. Hennig, D. Pellatz Jan 2022

Interacting Effects Of Disease And Weather Variability On Rangeland Biodiversity Associated With Black-Tailed Prairie Dog (Cynomys Ludovicianus) Colonies, Courtney J. Duchardt, J. D. Hennig, D. Pellatz

International Grassland Congress Proceedings

Rangeland ecosystems worldwide are experiencing novel pressures during the Anthropocene, including land conversion, disease dynamics, non-native species, and climate change. These issues can be compounded in rangelands occupied by burrowing rodents. Often considered keystone species important for maintaining rangeland biodiversity, these species often experience widespread control efforts because of their potential to reduce forage for livestock. We examined the effects of climatic variation and disease on bird communities associated with a North American burrowing rodent, the black-tailed prairie dog (Cynomys ludovicianus). Following an outbreak of sylvatic plague (Yersinia pestis) in the prairie dog population, we observed rapid shifts in taxa ...


Ecological Changes Of The Lower Niobrara River Valley And Lewis And Clark Lake Delta From Past To Present, Madalyn Christine Bollig Jan 2022

Ecological Changes Of The Lower Niobrara River Valley And Lewis And Clark Lake Delta From Past To Present, Madalyn Christine Bollig

Dissertations and Theses

Over half of the world’s large river systems are impacted by dams. These may prevent sediment flow downstream, resulting in accumulation in the upstream reservoir. On the Missouri River, deltas and associated backwater-affected areas occur in nine locations across six reservoirs. One of these, the Lewis and Clark Lake delta-backwater, is influenced by sediment inputs from both the Missouri River and the Niobrara River. While the extension of the prograding delta into the reservoir has been well documented, there has been little research on upstream (backwater) effects of the delta on the lower Niobrara River. This study examined ecological ...


A Global Agenda For Advancing Freshwater Biodiversity Research, Alain Maasri, Sonja C. Jähnig, Hendrik Freitag, 93 Co-Authors Dec 2021

A Global Agenda For Advancing Freshwater Biodiversity Research, Alain Maasri, Sonja C. Jähnig, Hendrik Freitag, 93 Co-Authors

Biology Faculty Publications

Global freshwater biodiversity is declining dramatically, and meeting the challenges of this crisis requires bold goals and the mobilisation of substantial resources. While the reasons are varied, investments in both research and conservation of freshwater biodiversity lag far behind those in the terrestrial and marine realms. Inspired by a global consultation, we identify 15 pressing priority needs, grouped into five research areas, in an effort to support informed stewardship of freshwater biodiversity. The proposed agenda aims to advance freshwater biodiversity research globally as a critical step in improving coordinated actions towards its sustainable management and conservation.


Body Mass And Body Condition Variation Of Mallards (Anas Platyrhynchos) Within And Among Winters Within The Lower Mississippi Alluvial Valley, John Thompson Veon Dec 2021

Body Mass And Body Condition Variation Of Mallards (Anas Platyrhynchos) Within And Among Winters Within The Lower Mississippi Alluvial Valley, John Thompson Veon

Graduate Theses and Dissertations

Most North American waterfowl overwinter in southern North America before migrating back to breeding grounds in the northern US and Canada. These species face the challenge of needing to maintain or increase their body mass during an environmentally difficult winter period. Successful body mass maintenance during the winter period has major ramifications not only for their winter survival but for their fitness across the entire year. Recent research in Europe and the western United States suggests that the body mass of mallards (Anas platyrhynchos) has increased from the late 1960s to early 2000s. However, the factors responsible for increases in ...


Machine Learning For Species Habitat Analysis, Abigail Lavallin Nov 2021

Machine Learning For Species Habitat Analysis, Abigail Lavallin

Graduate Theses and Dissertations

Management and conservation initiatives will always be controlled by finite resources, whether financialor temporal. Understanding a species’ spatial ecology, and how its requirements vary across habitats and locations is key to a successful species management plan. During recent decades, it has been noted how many species populations have declined, despite conservation practices working to increase their numbers. The most prevalent impacts affecting fauna populations have come from anthropogenic change in the form of habitat loss and destruction, along with fragmentation, and global climate change. There is a clear need for management practices to now operate on an entire landscape instead ...


The Sandhill Crane State: A Naturalist’S Guide To Nebraska, Paul Johnsgard Oct 2021

The Sandhill Crane State: A Naturalist’S Guide To Nebraska, Paul Johnsgard

Zea E-Books Collection

This book includes the locations, descriptions, and points of biological, historical, geological, or paleontological interest of nearly 350 sites in Nebraska, most of which are free to access. Its 53,000 words include accounts of 9 state historical parks, 8 state parks, 2 national forests, 2 national monuments, and 7 national wildlife refuges as well as 181 wildlife management areas, 56 waterfowl production areas, and 54 state recreation areas. It also includes 48 state and county maps, 18 drawings, 33 photographs, and nearly 200 literature citations.

doi: 10.32873/unl.dc.zea.1305


Temperature Stress And Disease Drives The Extirpation Of The Threatened Pillar Coral, Dendrogyra Cylindrus, In Southeast Florida, Nicholas P. Jones, Lystina Kabay, Kathleen Semon Lunz, David S. Gilliam Jul 2021

Temperature Stress And Disease Drives The Extirpation Of The Threatened Pillar Coral, Dendrogyra Cylindrus, In Southeast Florida, Nicholas P. Jones, Lystina Kabay, Kathleen Semon Lunz, David S. Gilliam

Marine & Environmental Sciences Faculty Articles

Rare species population dynamics can elucidate the resilience of an ecosystem. On coral reefs, climate change and local anthropogenic stressors are threatening stony coral persistence, increasing the need to assess vulnerable species locally. Here, we monitored the threatened pillar coral, Dendrogyra cylindrus, population in southeast Florida, USA, in relation to consecutive heat stress events in 2014 and 2015. In the fall of each year, D. cylindrus colonies bleached following intense thermal stress and by June 2020 all monitored colonies died from a white-syndrome type disease. This resulted in the ecological extinction of D. cylindrus in the Southeast Florida Coral Reef ...


Himalayan Rangelands Ecology And Animal Production Influenced By Changing Social And Economic Culture In Northern Areas Of Pakistan, Syed Hassan Raza Jul 2021

Himalayan Rangelands Ecology And Animal Production Influenced By Changing Social And Economic Culture In Northern Areas Of Pakistan, Syed Hassan Raza

International Grassland Congress Proceedings

No abstract provided.


21st Century Ecopoetics And Ecotheory, Robert Balun Jul 2021

21st Century Ecopoetics And Ecotheory, Robert Balun

Open Educational Resources

Ecopoetics is the study of literature that is concerned with ecology and nature. However, beyond just literature about nature, this course will examine how ecology and nature have become complicated in the 21st century, the age of the Anthropocene, the age of the climate crisis and the 6th mass extinction (don’t worry, we will define these and other key terms).

In the 21st century, humans are now confronted with a growing awareness of their destructive impact on the earth, its environments, and its human and non-human inhabitants. In this class we will examine how ecology and nature have become ...


A Year In Syntropy: Exploring Syntropic Agriculture, Ajah Eills May 2021

A Year In Syntropy: Exploring Syntropic Agriculture, Ajah Eills

College Honors Program

Syntropic agriculture is a form of sustainable agriculture that originated in Brazil around 25 years ago. Although it has since spread throughout Brazil and Australia, there has yet to be a comprehensive study of the driving scientific principles behind syntropy. For my thesis, I conducted literature research and interviews with farmers, with the goal of describing the ecological principles on which syntropy is based, including its primary goal to improve soil health. Much of my thesis contrasted syntropic agriculture with conventional agriculture as practiced in the United States today, but I also explored the differences between syntropic agriculture and other ...


Incorporating Demographic Structure And Variable Interaction Types Into Community Assembly Models, Akhil Reddy Alasandagutti, Nayan Chawla May 2021

Incorporating Demographic Structure And Variable Interaction Types Into Community Assembly Models, Akhil Reddy Alasandagutti, Nayan Chawla

Honors Theses

Theoretical studies of ecological food webs have allowed ecologists to remove the constraints of specific location and timescales from their study of ecological communities; food webs are generally complex and thus empirical study is difficult. Further, this theoretical approach allows ecologists to compare ecological processes and outcomes across any possible food web structures. However, these simulated communities are only as useful as the model from which they were constructed. Modifying existing considerations in these models, and generating new ones, are the jobs of theoretical ecologists that seek to achieve the shared goal of a majority of simulations: representation of real ...


Terra Dispositions: A Lithospheric Investigation Of Wet-Matter, Alec Rovensky May 2021

Terra Dispositions: A Lithospheric Investigation Of Wet-Matter, Alec Rovensky

Architecture Senior Theses

Human intervention of the landscape by damming, filling wetlands and over-extracting is resulting in the rapid perversion of water bodies through the desertification or flooding of terrain and the ensuing contamination of reservoirs. In turn, these changes are disrupting ecosystems, reshaping geological borders, and causing irreversible damage that poses a threat to clean water supplies. As humans exert agency over local hydrology, there is scarce consideration of the ensuing ecological consequences. This thesis aims to expose the ecological transformations of territories laced with human agency by examining the residues left by water in order to deviate from the misplaced nostalgia ...


Distributions And Habitat Associations Of Blue Point Pyrgulopsis And Blue Point Tryonia, Chenoa Janine Wilcox May 2021

Distributions And Habitat Associations Of Blue Point Pyrgulopsis And Blue Point Tryonia, Chenoa Janine Wilcox

UNLV Theses, Dissertations, Professional Papers, and Capstones

Springsnails and other crenophilic species are often of conservation concern due to endemism, narrow habitat requirements, and susceptibility to habitat degradation. Because there is a distinct lack of natural history information for many of these organisms, management of species that are of concern is often based on data from non-target species related to the species of interest. In this thesis, I provide background information regarding springsnails in western North America (Chapter 1), describe a study investigating the distribution and habitat associations of two springsnails endemic to a single spring (Chapter 2), and provide supplemental information on habitat characteristics associated with ...


The Effect Of Changing Substrate On Arctic Aquatic Invertebrates Abundance, Tom Dolman Apr 2021

The Effect Of Changing Substrate On Arctic Aquatic Invertebrates Abundance, Tom Dolman

Michael D. Wilson Symposium

Climate change is directly affecting tundra ecosystems in northern regions, and warming temperatures have caused discontinuous permafrost and thawing sediments across the region. This project investigates how increasing erosion and the foraging patterns of migratory snow geese may degrade habitat for aquatic invertebrates in the upper Mast River, located in Wapusk National Park, Manitoba, Canada. In the past two decades, many of the important species of aquatic invertebrates have shown declines. Declining invertebrate populations are predicted to affect aquatic ecosystems and decrease the resources available to shorebirds and waterfowl, which breed and migrate through this area.


Contamination In The Upper Columbia: Smelting And Its Impact To The Environment And Human Health, Brenden Murphy Apr 2021

Contamination In The Upper Columbia: Smelting And Its Impact To The Environment And Human Health, Brenden Murphy

WWU Honors College Senior Projects

The objectives of this project include discussing the historical context of the smelting that occurred in Washington and Canada over the past century and how political events shaped the geographies of the region(s). Another objective will be to assess the level of environmental impact to the Upper Columbia region and the potential health effects to organisms and humans from the pollution released from the smelters. We will also explore the interaction of different agencies and stakeholders and the political processes of environmental cleanup to which parties are held responsible. Explaining the different advocacy and conservation groups already involved in ...