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Full-Text Articles in Physical Sciences and Mathematics

A Study Of Red Snapper (Lutjanus Campechanus) Ecology In The Northern Gulf Of Mexico And The Effect Of Variable River Outflow Using Stable Isotope Analysis Of The Food Web And Eye Lenses, Caitlin C. Slife Aug 2022

A Study Of Red Snapper (Lutjanus Campechanus) Ecology In The Northern Gulf Of Mexico And The Effect Of Variable River Outflow Using Stable Isotope Analysis Of The Food Web And Eye Lenses, Caitlin C. Slife

Dissertations

In the Mississippi Bight and surrounding waters, river outflow impacts the basal resources of the Red Snapper food web, altering carbon sources and impacting prey and predator isotopes. In this study, the impact of riverine outflow on nutrients, particulate organic matter (POM), and physical water parameters on Red Snapper and their food web was analyzed using stable isotope and stomach content analysis over 5 years. The Mississippi, Pearl, Pascagoula, and Mobile rivers were included in the analysis of river impact. The Mississippi and Mobile rivers were found to significantly impact nutrients and POM in the region. River outflow was also …


Quantifying Aboveground Biomass In A Tropical Forest Using A Lidar Waveform Weighted Allometric Model, Alejandro Rojas Aug 2022

Quantifying Aboveground Biomass In A Tropical Forest Using A Lidar Waveform Weighted Allometric Model, Alejandro Rojas

Theses and Dissertations

Our knowledge of the distribution and amount of terrestrial above ground biomass (AGB) has increased using lidar technology. Recent advancements in satellite lidar has enabled global mapping of forest biomass and structure. However, there are large biases in satellite lidar estimates which impacts our understanding of carbon dynamics, particularly in tropical forests.

Ni-Meister et al. (2022) developed a lidar full waveform weighted height-based allometric model which produced very good results in temperate deciduous/conifer forest in the continental US. The purpose of this study was to evaluate this biomass model in an African tropical forest using the Land Vegetation and Ice …


Classifying The 2022 Status Of Tsuga Canadensis (Eastern Hemlock) Along The Kentucky Portion Of The Pine Mountain Wildlands Corridor., Grace M. Embree Aug 2022

Classifying The 2022 Status Of Tsuga Canadensis (Eastern Hemlock) Along The Kentucky Portion Of The Pine Mountain Wildlands Corridor., Grace M. Embree

Electronic Theses and Dissertations

The invasion of the Hemlock Woolly Adelgid (HWA) (Adelges tsugae) has posed a continual threat in the United States to the Eastern Hemlock (Tsuga canadensis) trees since the 1950s. HWA feed on eastern hemlock needles, reducing the amount of healthy photosynthesizing vegetative area. The use of satellite imagery has been instrumental in identifying areas of eastern hemlock presence. Satellite platforms like Landsat and AVIRIS are commonly used for identification, classification, and mapping of eastern hemlock. Sentinel-2 imagery was released in 2015 for free access. It has a finer spatial grain of with the majority of the …


Competing Behaviors Of Thermoregulation And Ambush Foraging In The Timber Rattlesnake (Crotalus Horridus Horridus): A Mechanistic Assessment Of Thermal Conduction, Larry K. Kamees Aug 2022

Competing Behaviors Of Thermoregulation And Ambush Foraging In The Timber Rattlesnake (Crotalus Horridus Horridus): A Mechanistic Assessment Of Thermal Conduction, Larry K. Kamees

Graduate Theses and Dissertations

The interaction between the biophysical environment and ectotherm morphology elicits behaviors designed to maintain internal body temperature (Tb) within a range that promotes physiological functions. The short-term requirements of mass (energy requirements) and heat balance are subject to tradeoffs imposed by the organisms current physiological (heat and mass budgets) and environmental (biophysical, demographic, social, and predation) constraints and available resources. In temperate forests, extreme temperatures are common in summer even with intermittent sun exposure due to dense canopy cover. In Spring and Fall, temperatures can range from below freezing to 35 ℃ in 24 hrs. An ambush predator like the …


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 …


Context Dependence Of Warming Induced Shifts In Alpine Soil Microbial Functions, Sydne Rose Spinella May 2022

Context Dependence Of Warming Induced Shifts In Alpine Soil Microbial Functions, Sydne Rose Spinella

Open Access Theses & Dissertations

Atmospheric warming is occurring due to anthropogenic release of carbon dioxide. Climate change has the potential to increase microbial activity in soil, where a significant amount of terrestrial carbon is stored, which may lead to release of this soil carbon into the atmosphere, positively feeding back to global temperature rise. Understanding how the indirect impacts of climate warming, like shifts in plant community composition, affect soil microbes can improve predictions of ecosystem functions and services under climate change. This project examined direct and indirect consequences of warming on microbial processes using independent and combined treatments of experimental warming and dominant …


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. …


Mp765: Creating The Orono Bog Boardwalk: A Facility For Education, Research, And Recreation, Ronald B. Davis Apr 2022

Mp765: Creating The Orono Bog Boardwalk: A Facility For Education, Research, And Recreation, Ronald B. Davis

Miscellaneous Publications

A memoir by Dr. Ronald Davis detailing the creation of the Orono Bog Boardwalk. The Orono Bog Boardwalk is a premier destination in the Bangor/Orono area for persons wishing to experience the beauty and fascinating plants and animals of a Maine bog. The 1-mile boardwalk loop trail begins at the forested wetland edge in the Bangor City Forest, and after 800 feet crosses the Orono town line into the portion of the Orono Bog owned by the University of Maine. Along the way the boardwalk passes through a wide range of changing vegetation and environments on its way to the …


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 the …


Socio-Economic Factors Of Environmental Problems, Manzura Kamalova, D. Shakenov Mar 2022

Socio-Economic Factors Of Environmental Problems, Manzura Kamalova, D. Shakenov

Karakalpak Scientific Journal

People consciously and intensively rebuild their nature according to their own needs, creating rural and urban areas in which they live. People care about the quality of life in the context of the unity of nature and culture. Social is a relatively new discipline that deals with urban space and environmental issues. One way to imagine what is beneficial to people is to find out what is economically best for the person. The article examines the economic factors that form the attitude towards social ecology in Kazakhstan. The article concludes that society should cooperate to achieve common things, both for …


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 Ratio …


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 …


Investigating The Effects Of Climate Change On The Phenology Of Achillea Millefolium, Aquilegia Coerulea, And Penstemon Cyanocaulis, Hannah O’Toole, Kailey Hicks, Lisa Long, Jackson Garske, Anna Sher Jan 2022

Investigating The Effects Of Climate Change On The Phenology Of Achillea Millefolium, Aquilegia Coerulea, And Penstemon Cyanocaulis, Hannah O’Toole, Kailey Hicks, Lisa Long, Jackson Garske, Anna Sher

DU Undergraduate Research Journal Archive

As the effects of climate change are starting to unearth themselves, the impacts can be observed by tracking the patterns of cyclical natural phenomena also known as phenology, and monitoring how they have changed over time. These cycles are at the crux of making ecosystems viable for their local biodiversity, and understanding the ongoing change allows for further understanding of the ecosystem’s change over time. In this study, we look at the ordinal flowering dates of the Achillea millefolium, Aquilegia coerulea, and Penstemon cyanocaulis over the past century. Our data give insight into how warmer temperatures occurring earlier in …


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 changes …


Unified Methods In Collecting, Preserving, And Archiving Coral Bleaching And Restoration Specimens To Increase Sample Utility And Interdisciplinary Collaboration, Rebecca Vega Thurber, Emily R. Schmeltzer, Andréa G. Grottoli, Robert Van Woesik, Robert J. Toonen, Mark Warner, Kerri L. Dobson, Rowan H. Mclachlan, Katie Barott, Daniel J. Barshis, Justin Baumann, Leila Chapron, David J. Combosch, Adrienne M.S. Correa, Thomas M. Decarlo, Mary Hagedorn, Laetitia Hédouin, Kenneth Hoadley, Thomas Felis, Christine Ferrier-Pagès, Carly Kenkel, Ilsa B. Kuffner, Jennifer Matthews, Mónica Medina, Christopher Meyer, Corinna Oster, James Price, Hollie M. Putnam, Yvonne Sawall Jan 2022

Unified Methods In Collecting, Preserving, And Archiving Coral Bleaching And Restoration Specimens To Increase Sample Utility And Interdisciplinary Collaboration, Rebecca Vega Thurber, Emily R. Schmeltzer, Andréa G. Grottoli, Robert Van Woesik, Robert J. Toonen, Mark Warner, Kerri L. Dobson, Rowan H. Mclachlan, Katie Barott, Daniel J. Barshis, Justin Baumann, Leila Chapron, David J. Combosch, Adrienne M.S. Correa, Thomas M. Decarlo, Mary Hagedorn, Laetitia Hédouin, Kenneth Hoadley, Thomas Felis, Christine Ferrier-Pagès, Carly Kenkel, Ilsa B. Kuffner, Jennifer Matthews, Mónica Medina, Christopher Meyer, Corinna Oster, James Price, Hollie M. Putnam, Yvonne Sawall

Biological Sciences Faculty Publications

Coral reefs are declining worldwide primarily because of bleaching and subsequent mortality resulting from thermal stress. Currently, extensive efforts to engage in more holistic research and restoration endeavors have considerably expanded the techniques applied to examine coral samples. Despite such advances, coral bleaching and restoration studies are often conducted within a specific disciplinary focus, where specimens are collected, preserved, and archived in ways that are not always conducive to further downstream analyses by specialists in other disciplines. This approach may prevent the full utilization of unexpended specimens, leading to siloed research, duplicative efforts, unnecessary loss of additional corals to research …


Causes And Consquences Of Fire In Forest Ecosystems Of The Selway-Bitterroot Wilderness, Melissa Jaffe Jan 2022

Causes And Consquences Of Fire In Forest Ecosystems Of The Selway-Bitterroot Wilderness, Melissa Jaffe

Graduate Student Theses, Dissertations, & Professional Papers

No abstract provided.


Methods And Means For Registration, Measurement, Processing And Evaluation Of Thermographic Information With Application In Systems For Medical Diagnostics And Ecology, Stanyo Kolev Jan 2022

Methods And Means For Registration, Measurement, Processing And Evaluation Of Thermographic Information With Application In Systems For Medical Diagnostics And Ecology, Stanyo Kolev

Books

Chapter 1. General principles in methods and means for recording, measuring and processing thermographic information. Applications of thermography, mainly in the fields of medicine and ecology, are presented. Problems related to the accuracy of measurement with an infrared camera are discussed. External (Atmosphere, Physical characteristics of body coverings, Geometric factors, Environment, Infrared characteristics of the object under study and Behavioral factors) and internal (Stressor, Blood circulation, Physical activity, Sweating, etc.) factors that affect the accuracy of measurement are described. The causes leading to errors in thermographic measurements are analyzed, the main ones being: water vapor, ozone and carbon dioxide in …


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 …


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.