Terrestrial and Aquatic Ecology Commons^™

Quantifying Ecological Processes Predicting Barren-Ground Caribou (Ɂetthën; Rangifer Tarandus Groenlandicus) Occurrence Across A Heterogenous Northern Indigenous Protected And Conserved Area., Eric Jolin

Theses and Dissertations (Comprehensive)

Northern ecosystems are experiencing a period of rapid and unprecedented change, with implications for species distributions, mammal community dynamics, and habitat associations. Understanding the ecological processes that shape species distributions is crucial for developing effective conservation strategies that can adapt to such change. This study examines drivers of barren-ground caribou occurrence, a species of cultural and ecological significance, across Thaıdene Nëné Indigenous Protected Area, an ecologically intact landscape of high habitat heterogeneity straddling the treeline of the Northwest Territories. I use spatial and temporal variation in caribou detections generated by camera traps to test the relative importance of apparent competition, …

Thermokarst Can Stimulate Tall Shrub Productivity And Plant-Soil Feedbacks In The Low-Arctic Tundra, Claire O'Brien

Theses and Dissertations (Comprehensive)

Warming temperatures are exacerbating permafrost thaw disturbances in the Arctic. Permafrost thaw disturbances are facilitating tall, deciduous shrub expansion. However, potential productivity differences between shrubs that colonize disturbed areas and those in undisturbed tundra remain understudied. More productive shrubs optimize for fast growth over leaf longevity, meaning they may produce more abundant and higher quality litter which could accelerate decomposition rates and lead to faster nutrient cycling. Faster nutrient cycling could create a positive feedback loop between shrubs and soil, maintaining greater ecosystem productivity. I measured in situ soil characteristics and physiological and structural shrub functional traits for green alder …

Timing Of Migration And Seasonal Movements Of Arctic Grayling (Thymallus Arcticus) In Relation To Water Temperature In The Kakisa River And Upper Mackenzie River, Nwt: Results From An Acoustic Telemetry Study., Levi Snook

Theses and Dissertations (Comprehensive)

Arctic grayling (Thymallus arcticus) are a cold-water salmonid that inhabit waterbodies throughout the circumpolar regions of the northern hemisphere. In the last decade, Ka'a'gee Tu First Nation members as well as local sport fishers, have observed lower catches of Arctic grayling during their annual spawning run in the Kakisa River, NWT. Many potential causes of this decline have been hypothesized including climate change and over harvesting. Outside of the general annual spawning activity in the headwaters of the Kakisa River, the ecology of the population, including post-spawn habitat use and migratory patterns, remained understudied. To address these knowledge gaps, acoustic …

Tailwater Trout Population Dynamics, Connor Dylan Cunningham

Graduate Theses/Dissertations

Dams have been constructed throughout the world and provide several resources for humans (e.g., flood control, hydropower). These structures heavily alter the upstream and downstream environment. One consequence of these alterations is the creation of “tailwaters”, which can create cold-water habitat via hypolimnetic releases. In the southeast United States these tailwater environments are often managed for the recreational use of nonnative salmonids. The unnatural flow regimes of tailwaters affect the biotic and abiotic conditions and ultimately the dynamic rate functions (i.e., recruitment, growth, mortality) of the fish inhabiting them. As such, the goal of this research is to provide fisheries …

Activity, Movement, And Reproductive Patterns Of The Northern Giant Musk Turtle (Staurotypus Triporcatus) In Belize, Larissa Sage Saarel

Graduate Theses/Dissertations

The Northern Giant Musk Turtle (Staurotypus triporcatus), a near-threatened species native to southern Mexico, Guatemala, Belize, and western Honduras, faces multiple environmental challenges, yet its activity patterns, movement patterns, and reproductive biology remain poorly understood. This thesis investigates both seasonal activity and reproductive cycles of female S. triporcatus in Belize. To assess diel and seasonal activity, I tracked 12 female turtles and collected data using activity loggers. I also collected movement data through radio-telemetry and acoustic tracking methods. Results indicated that the species is primarily nocturnal, with increased activity during the wet season, particularly during flooding events. Turtles …

Responses Of Native And Invasive Aquatic Vegetation To Changes In Water Depth In An Ozark Spring-Fed Pond, Daphne Miles

Graduate Theses/Dissertations

Spring-fed aquatic ecosystems in the Ozark Highlands are characterized by stable water depths, clear water, and diverse aquatic vegetation (filamentous algae, submerged, floating, and emergent plants). Sudden changes in water depth can impact aquatic vegetation dynamics but the impacts of prolonged changes are poorly understood. I investigated seasonal and annual changes to aquatic vegetation abundance in a spring impoundment during and after a two-year period of low water depth that was caused by a broken outlet below an artificial dam. Water depth was significantly lower in 2020 and 2021 (low water years), compared to 2022 and 2023 (high water years). …

Seagrass Buried In The Dark: Reduced Light And Moderate Levels Of Burial Have Additive And Lethal Impacts On Posidonia Sinuosa, Nicole Said, Chanelle Webster, Kathryn Mcmahon, Natasha Dunham, Charlie Phelps, Ankje Frouws, Jack Robinson, Kieryn L. Kilminster, Simone Strydom

Reports accepted as research outputs

Executive Summary: Quantifying interactive effects among multiple stressors is important for understanding cumulative impacts on seagrasses, which is imperative for informing the appropriate management of marine ecosystems. To date, many thresholds used to understand seagrass response to dredging are based on singular stressors, such as light reduction or burial, but these pressures often occur simultaneously. Understanding the impacts of multiple stressors, which may act additively, synergistically or antagonistically, could require adjustment of existing single pressure derived thresholds. Furthermore, the recovery time of seagrasses to individual and multiple pressures has been identified as a major gap in literature. Improving our understanding …

Investigating The Mechanisms Of Freeze Tolerance In Lemna Minor, Tamara Bouchard

Honors Theses and Capstones

Freezing presents a significant abiotic stress to aquatic plants, yet little is known about the mechanisms by which species like Lemna minor (duckweed) survive subzero temperatures in nature. This study investigates whether L. minor employs freeze-avoidance or freeze-tolerance strategies and explores the potential role of its microbiome in enhancing cold resilience. Using both field-collected fronds from naturally frozen ponds and controlled freezing experiments in the lab, I assessed survival through viability staining and post-thaw survival. Results showed that L. minor can survive natural ice encasement and that prior cold acclimation significantly improves tissue survival under induced freezing. Trypan blue staining …

The Δ¹³C Signature Of Dissolved Organic And Inorganic Carbon Reveals Complex Carbon Transformations Within A Salt Marsh, Meagan J. Eagle, Kevin D. Kroeger, John W. Pohlman, Joseph J. Tamborski, Zhaohui Aleck Wang, T. W. Brooks, Jennifer O. Keefe Suttles, Adrian Mann

OES Faculty Publications

Coastal wetlands have high rates of atmospheric CO₂ uptake, which is subsequently respired back to the atmosphere, stored as organic matter within flooded, anoxic soils, or exported to the coastal ocean. Transformation of fixed carbon occurs through a variety of subsurface aerobic and anaerobic microbial processes, and results in a large inventory of dissolved carbon. Carbon source and the roles of aerobic respiration, sulfate reduction, and methane cycling were evaluated within salt marsh peat and the underlying sandy subterranean estuary. There is a large increase in dissolved inorganic carbon (DIC, 7,350 ± 3,900 μmol L^-¹), dissolved organic carbon …

Seasonal Occupancy Of The Thermal Plume Of A Spring Tributary To The South Fork Roanoke River, Virginia., Steven L. Powers, Michael M. Calvert, Charlotte M. Spaulding

Southeastern Fishes Council Proceedings

Detection of temperate stream fishes varies widely across seasons as streams teeming with life in summer often appear empty during winter sampling efforts. While much literature documents the disproportionate use of the thermal plumes of spring tributaries by cold water fishes during summer, few studies have investigated occupancy of those habitats by warm water fishes in winter. We conducted quantitative snorkeling observations within the near uniform temperatures (10-14^oC) of the thermal plume of a spring tributary to the South Fork Roanoke River across seasons and compared number of fishes observed and species richness to control observations made just …

Co2 In Flowing Freshwaters: Macro Scale Database Compilation, Addressing Ph Bias In Co2 Estimates, And Quantifying Cross-Scale Interactions, Timothy R. Toavs

LSU Doctoral Dissertations

This dissertation focuses on carbon dioxide (CO₂) dynamics in flowing freshwaters, contributing to the growing body of knowledge about inland water carbon cycles. The research is structured into three main chapters, each progressing towards the objective of utilizing variability in flowing freshwaters to further understand carbon dynamics, anthropogenic land cover impacts, and potential impacts from a changing climate. Chapter one compiles a 30-year dataset of pCO₂ measurements from flowing freshwater systems across the contiguous United States. This dataset, referred to as CDFLOW, includes over 750,000 pCO₂ estimates from more than 35,000 locations. It serves …

Native Freshwater Mussel Communities In The Lower Grand River, Michigan: Assessing Tributary Confluence Effects And Updating Survey Information, Grayson L. Kosak

Masters Theses

Freshwater mussels (Unionidae) are ecosystem engineers and keystone species vital to stream ecosystems yet represent the most imperiled group of freshwater fauna. Conservation of unionids necessitates further understanding how assemblages interact with watershed features. This study investigates mussel occupancy, distribution, and assemblage structure upstream and downstream of tributary confluences in the lower Grand River, Michigan, alongside updated surveys of the unionid community with comparisons to previous assessments conducted by Michigan Natural Features Inventory (MNFI) in 2002–2003. Unionid density, richness, and diversity were greater upstream of confluences. No significant distance-gradient effects were observed. Assemblage structure differed between upstream and downstream reaches …

Social Learning And Cultural Enrichment For Fish Welfare, Chiawen Chiang, Becca Franks

Animal Sentience

This commentary examines how understanding animal culture—shared behaviors and knowledge transmitted through social learning—plays a role in advancing welfare practices for captive fishes. Despite extensive evidence of fishes' complex sociocultural capacities, their psycho-social needs remain underestimated and unmet in zoos and aquaria. We explore what considering fish culture might mean for welfare practices: diverse social learning opportunities, cultural development, and thoughtful group management. More knowledge about wild fishes' lives will help bridge the gap between their full, complex lives and current captive welfare practices.

Invasion Stress Mitigates Climate Stress In A Brackish Marsh Amphipod, Lorna E. Haworth, Sarah Nancollas, Susie N. Landa, Anne E. Todgham, Richelle L. Tanner

Biology, Chemistry, and Environmental Sciences Faculty Articles and Research

1. Organisms in coastal brackish ecosystems face not only highly variable environmental conditions, but the intensity and stochasticity of these environmental conditions are anticipated to increase due to climate change. While environmental changes are often presented unilaterally as stressors, there are some anthropogenic environmental transformations, such as the introduction of habitat forming plant species, that may mitigate physiological stress imposed by warming. In Suisun Marsh in the California Delta, native plant canopies allow light and heat to penetrate to the understory yet the canopies of the introduced Phragmites australis reed block out sunlight and heat for organisms living below.
2. We set …

Bat Activity Across Urban Forest Plantings In Lexington, Kentucky, Grayson Marie Collier

Online Theses and Dissertations

Urbanization has led to major forest loss and negatively impacts ecosystem services. Urban reforestation efforts, such as Reforest the Bluegrass (RTB) in the Lexington-Fayette metropolitan area of Kentucky, have been implemented to address these negative effects, and to create habitat for forest-dependent wildlife such as bats. My research focused on assessing differences in bat activity across a 20-year chronosequence of RTB sites. Acoustic detectors were deployed across 10 different-aged plantings at 60 randomly-defined detector locations. Each planting was surveyed across 8 sampling periods from May – August 2023. Each recording session spanned ca. 7 consecutive nights, yielding a total of …

Cyperus Blepharoleptos Maxent Ecological Niche Models, Samuel A. Schmid, Maxwell G. Gebhart, Gray Turnage

GRI Publications

Invasive species are one of the foremost threats to global biodiversity and predicting where they can inhabit is of primary concern for researchers and resource managers. Ecological niche models (ENMs) are a useful tool for addressing this problem. This study focuses on Cyperus blepharoleptos (Cuban bulrush), an aquatic sedge that is invasive in the southeastern United States. To model the ecological niche of C. blepharoleptos, 1,137 records were compiled from North and South America and partitioned into training and testing data. Five BioClim variables (BIO1, BIO7, BIO12, BIO14, and BIO15) were selected as environmental variables for modeling. Using Maxent, 12 …

Spatial Ecology Of Large Bodied Ichthyofauna In The Red River Of The North Basin, William Marshall Stuart

School of Natural Resources: Dissertations, Theses, and Student Research

Understanding spatial patterns and processes is essential for designing research studies, implementing management actions, and planning restoration efforts. The Red River of the North basin spans a broad geographic area where jurisdictional oversight is divided among several entities (Manitoba, CAN; North Dakota, USA; Minnesota, USA; South Dakota, USA), creating a mosaic of regulatory and functional process zones. Understanding the spatial ecology of freshwater fishes in this disjointed landscape is essential to address diverse life history requirements and the movement constraints imposed by anthropogenic structures. Long-term acoustic telemetry revealed that large bodied ichthyofauna employ a diverse range of movement strategies (i.e., …

Spatiotemporal Patterns In Orbicella Faveolata Wound Regeneration As An Indicator Of Colony Health, Alexander G. Wheeler

All HCAS Student Capstones, Theses, and Dissertations

Anthropogenic (e.g. damage from anchors, scuba divers, tissue sampling) and natural disturbances (e.g. predation, storm damage) can result in wounding of live tissue on coral colonies. Wounding has been shown to detract from a common resource pool, increasing disease susceptibility and impairing coral growth and reproductive activity. Regeneration not only varies between species, but also between conspecifics in the same location. A colony’s capacity to regenerate tissue can be an indicator of a colony’s condition and resilience. Understanding the physiological and environmental factors that affect tissue regeneration alongside the ultimate impact of sampling (disease and predation correlations) are needed for …

The Influence Of Wind Energy Development On Occupancy Of Medium And Large-Sized Mammals In South Texas, Elwynn Sherman

Theses and Dissertations

Conservation paradigms have shifted from single to multi-species approaches for assessing and conserving mammalian populations and the habitats that they occupy. The effect of wind turbine development is an important anthropogenic change to study due to the increasing demand for wind energy in Texas. In this study, I gathered remote camera trap data on medium and large-sized mammal populations in south Texas Tamaulipan thornscrub habitat. The objectives were to determine species presence, the effect of habitat characteristics and anthropogenic disturbances on species occupancy, and the effect of temperature on species detection. The results showed that distance from wind turbines did …

Comparing Metabolism And Hypoxia Tolerance Of Native And Non-Native Florida Freshwater Fishes In Climate Change Scenarios, Benjamin A. Share

All HCAS Student Capstones, Theses, and Dissertations

As climate change brings rising water temperatures and lower dissolved oxygen (DO) concentrations to freshwater bodies, it has become increasingly important to understand how this will affect ecosystems with established non-native or invasive species. Fishes of the family Cichlidae are the most pervasive non-native fishes in the Everglades and may increase their range further north under a changing climate. To better understand potential invasibility and competition with native fishes, the metabolism and hypoxia tolerance of non-native Blue Tilapia Oreochromis aureus was compared to native Bluegill Lepomis macrochirus when acclimated across a range of seasonal and projected temperatures. Intermittent-flow respirometry was …