Life Sciences Commons^™

Associations Between Avian Spruce-Fir Species, Harvest Treatments, Vegetation, And Edges, Brian W. Rolek

Electronic Theses and Dissertations

Habitat loss is the primary cause of species loss and declines of global biodiversity. Several birds associated with the spruce-fir forest type (hereafter spruce-fir birds) have declining populations across the continent in the Atlantic Northern Forest, and the extent of coniferous forest has declined in some areas. This region is extensively and intensively managed for timber products.

To investigate the influence from harvest treatments on the spruce-fir bird assemblage during the breeding and post-breeding period in lowland conifer and mixed-wood forests, we used avian point count detection data to test for associations between avian assemblages and seven common harvest treatments. …

Legacy Habitat Suitability Of Eastern Oysters (Crassostrea Virginica) In Louisiana: A Prelude To Mississippi River Delta Freshwater Diversions, Tasia Mv Denapolis

University of New Orleans Theses and Dissertations

The Louisiana oyster industry is greatly impacted by freshwater and sediment diversions that are part of the effort to restore the state’s coastline. A habitat suitability index (HSI) proposes species-habitat relationships that can be instrumental in creating impact assessments and suitability predictions for management as new diversions are implemented. An oyster (Crassostrea virginica) HSI was developed using three variables crucial to oyster sustainability: average annual salinity, minimum monthly salinity, and average salinity during the spawning season. These Legacy HSI visualizations show annual fluctuations in the distribution of zones suitable for oyster cultivation prior to proposed diversions in Pontchartrain …

Climatic Range Filling Of North American Trees, Benjamin Seliger

Electronic Theses and Dissertations

Understanding the degree to which species distributions are controlled by climate is crucial for forecasting biodiversity responses to climate change. Climatic equilibrium, when species are found in all places which are climatically suitable, is a fundamental assumption of species distribution models, but there is evidence in support of climate disequilibria in species ranges. Long-lived, sessile organisms such as trees may be especially vulnerable to being outpaced by climate change, and thus prone to disequilibrium. In this dissertation, I tested the degree to which North American trees are in equilibrium with their potential climatic ranges using the ‘range filling’ metric, which …

Changing Land-Use From Pinus Elliottii To Eucalyptus Bentamii In Southwest Louisiana Affects Understory Vegetation Richness, Diversity, And Functional Diversity Patterns, Andrea De Stefano

LSU Doctoral Dissertations

In the Western Gulf region of the United States cold-tolerant eucalyptus have been explored as pulpwood feedstock. However, non-native plantations may alter understory species diversity, modifying environmental conditions and soil characteristics. Few studies have compared eucalyptus plantations with other ecosystems to understand the impacts of converting these land uses on understory vegetation in the United States. Three plantations were selected: (1) slash pine (Pinus elliottii) established in 2008, (2) slash pine established in 2013, and (3) and Camden white gum (Eucalyptus benthamii) established in 2013. The objectives of this study were to: (1) investigate potential changes …

Evolutionary Dynamics Of Brown Treesnake (Boiga Irregularis) Reproductive Ecology, With Implications For Invasive Species Control, Brenna Aaren Levine

Graduate Theses and Dissertations

Invasive species represent major threats to biodiversity, global economies, and human health. Consequently, extensive research has been directed towards improving methods that restrict and contain them. Yet, control measures can also act as agents of selection by significantly impacting the reproductive capacity of invasives (in the context of “eco-evo” dynamics). The end result is that control measures subsequently alter the fitness landscape of an invasive over ecologically-relevant time, and lose their efficacy by so doing. However, adaptive management can be promoted by investigating the relationships between reproductive ecology, strength of selection, and (additive) genetic variation. In short, effective control can …

Effect Of Macrograzers (Campostoma Spp. And Faxonius Spp.) On Periphyton In Ozark Streams With Considerations Given To Macrograzer Biomass, Phosphorus, And Season: Mensurative And Manipulative Studies, Kayla R. Sayre

Graduate Theses and Dissertations

Nutrient and benthic algal biomass relationships can guide numeric nutrient criteria development in lotic systems. However, herbivorous macrograzers may confound this relationship by reducing the slope of the positive relationship between nutrients and periphyton biomass in streams. I conducted a mensurative field study to determine if stoneroller and crayfish abundance related to algal biomass at varying nutrient concentrations and manipulated macrograzer presence with electrical exclosures in streams to examine macrograzer effects on algal biomass and understand whether these effects on periphyton varied with total phosphorus (TP) or season. Macrograzer density was quantified across a TP gradient (n=15 streams; range = …

The Abiotic And Biotic Controls Of Arctic Lake Food Webs: A Multifaceted Approach To Quantifying Trophic Structure And Function, Stephen L. Klobucar

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The Arctic is warming faster than any other region of the globe. To conserve and manage many thousands of lakes across arctic landscapes, scientists need to understand historic and present conditions within these lakes to predict how the lakes, and the organisms that inhabit them, may respond to a changing climate. The goal of my research was to improve our understanding of what physical, chemical, and biological factors contribute to: 1) how lake food webs are assembled; and, 2) how these food webs may change in the future. First, I used long-term observations and lab experiments to determine how fish …

An Evaluation Of Bull Trout Movement Dynamics In The Walla Walla River, Courtney Newlon

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Bull trout are a fish species listed as threatened under the Endangered Species Act. Historically, they ranged from Northern California at the southernmost extent, into Canada at the northern most extent, and east into Nevada and Montana. Bull trout are highly migratory and require large, unfragmented habitats to persist and are thus highly susceptible to human induced land-use practices. The goal of my thesis was to obtain a better understanding of bull trout movement patterns in the Walla Walla River, Washington using complimentary techniques; Passive Integrated Transponder (PIT) technology and otolith microchemistry. PIT tags can be injected into a fish …

Assessing The Ecological Implications Of The Altered Flow And Sediment Regimes Of The Rio Grande Along The West Texas-Mexico Border, Demitra E. Blythe

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Large, exotic (those whose headwaters are in distant places) rivers are some of the most unique and diverse ecosystems on earth. Because they often flow through a multitude of biomes and climates, their waters are a vital resource not only for the organisms that inhabit these rivers, but for human societies as well. Thus, large rivers, like the Rio Grande, that flow through arid and agricultural regions are highly regulated and diverted. Regulation and dewatering upset a river’s natural flow regime (e.g., magnitude, duration, timing of large flood events), subsequently impacting the river’s ability to transport its sediment supply, and …

Fall Migration And Winter Habitat Use Of Northern Saw-Whet Owls (Aegolius Acadicus) In The Ozark Highlands, Mitchell L. Pruitt

Graduate Theses and Dissertations

Studying movement ecology is important not only in understanding the distribution of a species, but in understanding the magnitude of migration through certain regions, as well as explaining regional differences in demographics. The Northern Saw-whet Owl (Aegolius acadicus) is a small, migratory forest owl found throughout much of North America. Despite being captured widely during fall migration, the species’ movement ecology is poorly understood. Exploratory studies outside the saw-whet owl’s normal range have successfully captured the species during fall migration. In the Ozark Highlands ecoregion of the central United States, their status has been considered vagrant during fall and winter. …

Importance Of Forests Outside Protected Area Networks For Large-Seeded Tree Species And Their Large-Bodied Avian Frugivores--A Study In Vazhachal Reserve Forest, India, Aditi Achyut Lele

Graduate Theses and Dissertations

Western Ghats, the mountain chain running along the west coast of India, is one of eight global hotspots of biodiversity and is particularly notable for its endemic flora and fauna. Yet only 10% of this land enjoys the protected status. Vast forested lands exist outside the protected network of national parks and wildlife sanctuaries in the form of reserve forests, community forests, and private lands. The present study sought to understand the role of such forests in the context of ecological system involving large-seeded tree species that depend on large-bodied avian frugivores for seed dispersal. I conducted a study over …

Revision Of The Genus Monatractides (Parasitengona, Torrenticolidae) Of The United States And Canada: New Species, Re-Descriptions, Phylogenetics, And A Key To Species, Whitney Anne Nelson

Graduate Theses and Dissertations

The full suite of known Monatractides (Parasitengona, Torrenticolidae) taxa of North America (north of Mexico) are investigated herein using integrative methods. Species hypotheses are supported with morphology, geography, and phylogenetic analysis of the barcoding region of COI for 154 individuals from over 100 localities. Relationships between species are examined with a combined analysis of COI and 28S rDNA for 55 specimens. Previously described species are examined and re-described with color images and updated information, where possible. Our results indicate the need to synonymize two species: M. californica (Marshall, 1943) is a junior synonym of M. geographica (Marshall, 1943). We describe …

Vegetation Characteristics And Bird Communities Associated With Singing Painted Buntings In Northwest Arkansas, Lauren Kristina Thead

Graduate Theses and Dissertations

It has been shown that bird communities are affected by the species composition and physical structure of plant communities. Within avian communities, the bird species that are the most localized in distribution tend to be the most affected by habitat changes. My research analyzed plant and bird communities found with the Painted Bunting (Passerina ciris Linnaeus), a locally common but declining species throughout much of its range. First, I describe vegetation characteristics associated with singing male Painted Buntings in northwest Arkansas. I categorized field sites with singing male Painted Buntings as either managed for wildlife or unmanaged, based on land-use …

Temperature And Polyunsaturated Fatty Acid’S Effect On Daphnia Magna Reproduction, Mark Albright

Electronic Theses and Dissertations

Organisms adapt to their environments by adjusting their biochemistry and physiology; such adaptation is limited by resource availability and physiological constraints. The freshwater crustacean Daphnia magna inhabits a wide range of environments and must survive and reproduce within a range of temperatures. One limit to low-temperature adaptation is thought to be the availability of unsaturated fatty acids necessary to maintain proper fluidity of cellular membranes. D. magna maintained at 10 ºC on a diet poor in unsaturated fatty acids have been observed to produce clutches that fail to develop. However, this has not been observed on a diet rich in …

Impacts Of Ammonia And Temperature On Freshwater Snail Behavior And Physiology., Megan Christine Dewhatley

Electronic Theses and Dissertations

Gastropods are one of the most imperiled groups of animals in North America, yet there are major gaps in the literature pertaining to pollutants and climate change, and especially sublethal impacts. This dissertation assesses the effects of climate warming and unionized ammonia (NH₃), one of the most abundant water pollutants, on the behavior and physiology of two caenogastropod snails: fine-ridged elimia (Elimia semicarinata) and Shawnee rocksnails (Lithasia obovata) (Gastropoda: Neotaenioglossa: Pleuroceridae). Righting behavior, or the movement used by snails to turn themselves right-side-up, was used as the main endpoint; delays in this behavior compromise …

Not Gone With The Wind: Addressing Effects Of Offshore Wind Development On Bat Species In The Northeastern United States, Zara Rae Dowling

Doctoral Dissertations

Development of coastal and offshore wind energy resources has the potential to add considerable renewable electricity capacity to the United States electrical grid, but could have detrimental impacts on wildlife. Land-based wind energy facilities are estimated to kill hundreds of thousands of bats every year in the United States, and could threaten population viability of some species. Little is known about the potential impacts of offshore wind development on bat populations along the North Atlantic coast, but a number of species are known to frequent marine islands or fly over the ocean during migration. This dissertation helps to characterize risks …

Patterns And Drivers Of Stream Benthic Macroinvertebrate Community Taxonomy And Function In Agroecosystems, Edward M. Krynak

Electronic Thesis and Dissertation Repository

Anthropogenic activities continue to expand and intensify resulting in vast areas of the globe being dominated by human land uses. Effective land management and conservation decisions depend on our ability to understand and predict biological response to further disturbance in already stressed ecosystems. Moreover, insight into biological response to ecological stressors may be advanced by using trait and functional community measures in combination with taxonomy. My dissertation goal was to describe patterns and drivers of variation in benthic macroinvertebrate communities (BMIC) taxonomic composition and function in streams in an agriculturally dominated landscape. I achieved my goal by conducting three related …

Hierarchical Variation In Cellulose Decomposition Across Southern Ontario Reference Streams, Jenna R. Webb

Electronic Thesis and Dissertation Repository

The cotton strip assay (CSA) has been promoted as a method of incorporating functional indicators into standardized river assessments by study of organic-matter decomposition. However, operationalization of the CSA as an indicator requires testing the spatial and temporal controls of variance associated with decomposition of cotton strips at regional reference sites. I conducted a hierarchically structured study of decomposition rates in Ontario, Canada. Cotton strips were deployed during the spring, summer and fall in pool and riffle habitats of 22 streams located in three distinct physiographic regions. Partitioning of variation among hierarchical scales associated with rates of decomposition were examined …

Habitat Preferences Of Blue Marlin (Makaira Nigricans) And Black Marlin (Istiompax Indica) In The Eastern Pacific Ocean, Nima Farchadi, Michael G. Hinton, Andrew R. Thompson, Zhi-Yong Yin

Theses

Overexploitation and climate change can reduce the abundance and shift the spatial distribution of marine species. Determining the habitat suitability of a mobile pelagic species, such as Makaira nigricans (BUM) and Istiompax indica (BLM), can help describe their spatiotemporal distribution patterns over a broad spatial scale, which is a crucial need for fisheries management. Using 14 years (1997-2010) of Inter-American Tropical Tuna Commission (IATTC) catch data from purse-seine vessels in the eastern Pacific Ocean (EPO), we modeled the dynamic habitat suitability of BUM and BLM in response to environmental variables within the EPO using a species distribution model (MaxEnt) with …

Investigation Of Biogeochemical Mechanisms Of Greenhouse Gas Production In The Urban Hudson River Estuary, Brian Alan Brigham

Dissertations, Theses, and Capstone Projects

Coastal megacities deposit significant amounts of carbon (C), nitrogen (N) and other pollutants into surrounding waters. These inputs, including wastewater and surface water runoff, may affect estuarine and adjacent wetland biogeochemical cycles, microbial production and ultimately greenhouse gas (GHG) efflux. In many megacities pollutant loading is typically greatest after periods of precipitation when the volume of wastewater and storm water runoff exceeds local sanitation capacity, resulting in the discharge of raw sewage into adjacent waters. These combined sewage overflow (CSO) events have received considerable attention primarily due to their potential impact on human health and eutrophication. However, whether these events …

Plant Stimuli-Responsive Biodegradable Polymers For The Use In Timed Release Fertilizer Coatings, Spencer Heuchan

Electronic Thesis and Dissertation Repository

The use of nitrogen-based fertilizers continues to accelerate with human population growth and increases in global food requirements. Enhanced efficiency fertilizers (EEFs) have been developed to improve the synchronization between nutrient supply and crop nutrient demand. However, many of the current controlled release fertilizers are coated with non-degradable polymers that contribute to accumulation of microplastics within ecosystems. This thesis describes research towards the development of a new class of fertilizer coatings using a self-immolative polymer known as poly (ethyl glyoxylate) (PEtG). PEtG itself does not have suitable properties to produce a viable coating but once blended with another degradable polyester …

Nitrogen Cycling During A Period Of Environmental Change, Kaizad Patel

Electronic Theses and Dissertations

Natural and anthropogenic disturbances have altered the N cycle on the regional to global scale. Although numerous studies have examined the effects of chronic atmospheric N deposition on ecosystem processes, less is known about intra-annual variability of these processes, or how these responses might be altered under conditions of changing climate. The work described in this dissertation focuses on the effects of a changing chemical and physical climate, particularly terrestrial N processes (a) during Maine’s changing winters, and (b) in response to chronic elevated N additions.

Subnivean winter soil processes were examined at the Dwight B. DeMerritt Forest (DBDF) and …

Atmospheric Change Promotes Increasing Cyanobacteria Dominance In Swedish Lakes, Erika Christiane Freeman

Electronic Thesis and Dissertation Repository

The frequency and intensity of cyanobacteria blooms are increasing globally. The interacting effects of environmental drivers, including increased temperature, altered precipitation, reduced acidification-with associated shifts in nutrient limitation- and increased dissolved organic matter loads to lakes are predicted to create favourable environmental conditions for cyanobacteria in northern lakes. This prediction was tested in 28 nutrient-poor Swedish lakes over 16 years (1998-2013). Increases in cyanobacteria abundance were identified in 21% of the study sites, composed mostly of increases in three specific genera: Merismopedia, Chroococcus, and Dolichospermum. Increases in temperature favoured Merismopedia dominance in lakes with low pH and high nitrogen to …

Physiological Responses Of The State – Listed Texas Pigtoe To Environmental Stress, Sara M. Rumbelow

Biology Theses

Systematic habitat destruction over the last 100 years combined with major anthropogenic stressors such as aquatic contaminants, exotic species, and economic endeavors are driving the decline in freshwater unionid species diversity. Two hundred fifty-seven individual adult Texas pigtoe (Fusconaia askewi) mussels (mean length, mm ± 1 SD; 58.7 ± 13.8) were collected from the upper Sabine river near Hawkins, Texas and taken to the University of Texas at Tyler to evaluate three factors likely impacting mussels in East Texas: siltation (a surrogate for bank erosion), elevated temperature and nitrogen. The impact of siltation was evaluated by burying mussels …

Genetic Diversity In An Invasive Clonal Plant? A Historical And Contemporary Perspective, Elliot D. Weidow

University of New Orleans Theses and Dissertations

Introduced populations of Eichhornia crassipes (Pontederiaceae) possess extremely low levels of genetic diversity due to severe bottleneck events and clonal reproduction. While populations elsewhere have been well studied, North American populations of E. crassipes remain understudied. We used Amplified Fragment Length Polymorphism markers to assess genetic diversity and population structure in North American E. crassipes populations. Patterns of diversity over the past fifty years were analyzed using herbarium specimens. Furthermore, we sampled populations across the Gulf Coast of the United States throughout a year to determine contemporary genetic diversity and assess potential seasonal effects. Genetic diversity was found to be …

Bubble Stream Production By Belugas (Delphinapterus Leucas), Megan Slack

Theses

Bubble stream production in belugas has been poorly characterized and its function is not well understood. I examined behavioral states when producing bubble streams (“bubbling”), and when bubbling calls, to determine whether bubbling was significantly associated with a particular call category or behavioral state. Using 19 hours of video and audio recordings collected over a two-day period, I quantified bubble streams of a 4-month old calf and an unrelated adult female housed together. Based on the overall activity budgets and pool of vocalizations for both animals, I calculated the expected counts of bubble streams with and without vocalizations, assuming that …

Remote Sensing For Management Of Invasive Plants In Great Lakes Coastal Wetlands, Matthew James Unitis

Boise State University Theses and Dissertations

Great Lakes coastal wetlands are some of the most crucial ecosystems to biodiversity in the Great Lakes Basin, yet suffer increasing degradation due to invasive plants. Wetland plant invasions can be controlled in their initial stages, but early detection of invasive plants using field surveys are often untenable due to budget constraints. Remote sensing techniques offer solutions to management objectives during the early stages of invasion on a landscape scale due to their ability to cheaply create spatially explicit information about plant distributions. Some invasive plants, such as Typha x. glauca, are conspicuous on a large scale, and can be …

Using Anthropogenic Risks To Inform Salmonid Conservation At The Landscape Scale, Andrew W. Witt

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The expansion and industrialization of humanity has caused many unforeseen consequences to the natural world. Due to the importance of freshwater for people, rivers have been particularly altered to meet human needs, often at the expense of the natural world. Supplying water for farms, industries, and cities has reshaped the natural state of rivers by altering river paths, chemistry, and species compositions. These changes have harmed many species that prospered before widespread human alterations, including the native trout and salmon of western North America. As human populations continue to grow, new threats will surface for rivers, and the trout and …

Patterns Of Threatened Vertebrates Based On Trophic Level, Diet, And Biogeography, Shaley A. Valentine

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Humans have indirectly and directly contributed to the extinction of over 500 species within the past 500 years, a rate far higher than we have seen in the past. The high extinction rate and the fact that 18% of vertebrates may become extinct within the next century have pushed Earth into a biodiversity crisis. Understanding what makes species more at risk of extinction is needed to protect Earth’s biodiversity.

Generally, it is expected that predators have greater extinction risk than omnivores and herbivores because predators are larger in body size, depend on other animal species for food, need large home …

Coastal Wetland Dynamics Under Sea-Level Rise And Wetland Restoration In The Northern Gulf Of Mexico Using Bayesian Multilevel Models And A Web Tool, Tyler Hardy

Master's Theses

There is currently a lack of modeling framework to predict how relative sea-level rise (SLR), combined with restoration activities, affects landscapes of coastal wetlands with uncertainties accounted for at the entire northern Gulf of Mexico (NGOM). I developed such a modeling framework – Bayesian multi-level models to study the spatial pattern of wetland loss in the NGOM, driven by relative RSLR, vegetation productivity, tidal range, coastal slope, and wave height – all interacting with river-borne sediment availability, indicated by hydrological regimes. These interactions have not been comprehensively investigated before. I further modified this model to assess the efficacy of restoration …