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Theses/Dissertations

Climate change

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Full-Text Articles in Life Sciences

The Stability Of Temperate Lakes Under The Changing Climate, Aleksey Paltsev Sep 2019

The Stability Of Temperate Lakes Under The Changing Climate, Aleksey Paltsev

Electronic Thesis and Dissertation Repository

There is a collective prediction among ecologists that climate change will enhance phytoplankton biomass in temperate lakes. Yet there is noteworthy variation in the structure and regulating functions of lakes to make this statement challengeable and, perhaps, inaccurate. To generate a common understanding on the trophic transition of lakes, I examined the interactive effects of climate change and landscape properties on phytoplankton biomass in 12,644 lakes located in relatively intact forested landscapes. Chlorophyll-a (Chl-a) concentration was used as a proxy for phytoplankton biomass. Chl-a concentration was obtained via analyzing Landsat satellite imagery data over a 28-year period (1984-2011) and ...


The Association Between Dietary Niche Variation In Rodents And Climate Change Across The Paleocene-Eocene Thermal Maximum, Hannah K. Vermeer Aug 2019

The Association Between Dietary Niche Variation In Rodents And Climate Change Across The Paleocene-Eocene Thermal Maximum, Hannah K. Vermeer

Masters Theses

Mammalian teeth play a crucial role in food acquisition and breakdown and are therefore closely tied to dietary niche. This study reconstructed the diet of early Paleogene paramyid rodents across the Paleocene-Eocene Thermal Maximum (PETM) climatic event in an effort to understand the role of climate in mammalian dietary niche change. Dietary niches were quantified using three dental topographic measures: Dirichlet normal energy, relief index, and orientation patch count rotated. A Kruskal-Wallis test was conducted over eight time periods to determine if each of the dental topographic measures (i.e., diet) varied over time. Regression analysis of these measures with ...


The Vulnerability Of Littoral Structures Under Multiyear Drought Conditions, Jenna M. Keeton Aug 2019

The Vulnerability Of Littoral Structures Under Multiyear Drought Conditions, Jenna M. Keeton

All Graduate Theses and Dissertations

Climate change is associated with altered environmental conditions and shifting mosaics of suitable habitats for organisms. Climate change in the form of drought can shift important lake shoreline habitats downslope, altering the lakes chemistry and habitat availability. Additionally, negative biological consequences can occur after a loss of submerged habitat along shorelines, hereafter littoral habitat. The objective of this study is to evaluate whether littoral habitat is lost (cobble, coarse woody habitat (fallen trees; CWH), and aquatic vegetation) under drought conditions across the United States. I used the National Lakes Assessment physical habitat data collected in summer 2012, when 75% of ...


Linkage Of Climate Diagnostics In Predictions For Crop Production: Cold Impacts In Taiwan And Thailand, Parichart Promchote Aug 2019

Linkage Of Climate Diagnostics In Predictions For Crop Production: Cold Impacts In Taiwan And Thailand, Parichart Promchote

All Graduate Theses and Dissertations

This research presents three case studies of low temperature anomalies that occurred during the winter–spring seasons and their influence on extreme events and crop production. We investigate causes and effects of each climate event and developed prediction methods for crops based on the climate diagnostic information. The first study diagnosed the driven environmental-factors, including climate pattern, climate change, soils moisture, and sea level height, associated with the 2011 great flood in Thailand and resulting total crop loss. The second study investigated climate circulation and indices that contributed to wet-and-cold (WC) events leading to significant crop damage in Taiwan. We ...


Ecological And Morphological Response Of Rodents To Environmental Change Over The Late Quaternary, Catalina Tome Jul 2019

Ecological And Morphological Response Of Rodents To Environmental Change Over The Late Quaternary, Catalina Tome

Biology ETDs

The rapid progression of modern climate change is already altering ecosystems worldwide. By employing the fossil record, we can investigate how animals responded to past climatic changes and biodiversity loss. The paleontological record of the late Quaternary (past ~22000 years) encompasses a period of considerable environmental change in North America. Rising temperatures and climatic fluctuations are coupled with the extinction of the majority of large bodied mammals on the landscape. The combination of climate and extinction events led to changes in vegetation and community structure which likely affected the resources available and interactions between the remaining mammals within communities. Here ...


Thermal Quality Explains Shift In Habitat Association From Forest To Clearings For Terrestrial-Breeding Frogs Along An Elevation Gradient In Colombia, Zachary Lange Jul 2019

Thermal Quality Explains Shift In Habitat Association From Forest To Clearings For Terrestrial-Breeding Frogs Along An Elevation Gradient In Colombia, Zachary Lange

Masters Theses

Tropical ectotherms are considered particularly sensitive to changes in the thermal environment from climate change and habitat alteration. Understanding how such species’ thermal physiology relates to their habitat associations in thermally heterogeneous landscapes may help us predict responses and develop sound conservation strategies for the future. We conducted a mark-recapture study of three terrestrial breeding anuran species (Pristimantis medemi, P. savagei, P. frater) in adjacent forest and anthropogenic clearings at field sites spread across seven elevations (415-1350 m asl) in the Colombian Andes. We also performed thermal preference and critical thermal maximum assays in the lab to investigate the relationship ...


A Revised Land Ethic: Sustainable And Spiritual Agriculture, Environmental Studies, Brooke Maitlan Parrett May 2019

A Revised Land Ethic: Sustainable And Spiritual Agriculture, Environmental Studies, Brooke Maitlan Parrett

Student Theses 2015-Present

This paper proposes a return to the land and reconnection of spiritual practices through ethical teachings. Such a land ethic would involve answering the woes of industrial agriculture and providing a framework for farmers, consumers, and policymakers based on sustainable and spiritual considerations of the land. I analyze the loss of spiritual literacy and traditional ecological knowledge in the United States and discuss the spiritual history of agriculture in order to analyze contemporary religious perspectives on farming and agricultural ethics and thereby develop my own recommendations. The land ethic I propose combines sustainability and spirituality to develop intrinsic respect for ...


Blacklegged Tick (Ixodes Scapularis) Distribution In Maine, Usa, As Related To Climate Change, White-Tailed Deer, And The Landscape, Susan P. Elias May 2019

Blacklegged Tick (Ixodes Scapularis) Distribution In Maine, Usa, As Related To Climate Change, White-Tailed Deer, And The Landscape, Susan P. Elias

Electronic Theses and Dissertations

Lyme disease is caused by the bacterial spirochete Borrelia burgdorferi, which is transmitted through the bite of an infected blacklegged (deer) tick (Ixodes scapularis). Geographic invasion of I. scapularis in North America has been attributed to causes including 20th century reforestation and suburbanization, burgeoning populations of the white-tailed deer (Odocoileus virginianus) which is the primary reproductive host of I. scapularis, tick-associated non-native plant invasions, and climate change. Maine, USA, is a high Lyme disease incidence state, with a history of increasing I. scapularis abundance and northward range expansion. This thesis addresses the question: “To what extent has the range expansion ...


Assessing The Mechanisms And Implications Of Altered Carbon Cycling In Arctic And Boreal Lakes, Rachel Fowler May 2019

Assessing The Mechanisms And Implications Of Altered Carbon Cycling In Arctic And Boreal Lakes, Rachel Fowler

Electronic Theses and Dissertations

Dissolved organic carbon (DOC) is an important component of lake ecology, as it contributes to light attenuation and carbon cycling. In recent years, DOC declined in a suite of lakes in Greenland. I performed experiments to test potential mechanisms of DOC loss. The tested mechanisms did not reduce DOC concentration, but DOC composition was affected. I also paired water quality data with meteorological observations to evaluate effects of climate drivers on lake variables. The lake variables were temporally coherent and associated with patterns of mean annual precipitation.

In the northeastern U.S., recovery from acidification and climate change have contributed ...


Living On The Edge: Thermophysiology Of The Southern Flying Squirrel At Its Northern Range Margin, Vanessa R. Hensley May 2019

Living On The Edge: Thermophysiology Of The Southern Flying Squirrel At Its Northern Range Margin, Vanessa R. Hensley

Electronic Theses and Dissertations

Climate change has the potential to upset entire ecological systems, making predictive models of the utmost importance. The incorporation of physiological parameters into predictive models not only bolsters their accuracy but also provides a mechanistic explanation for ecological changes already observed and those yet to come. North American flying squirrels, for example, have already experienced dramatic range shifts northward over recent decades, with climate change being the suspected driver. While other studies have focused on warming winter temperatures, I explored the hypothesis that rising summer temperatures were driving the observed range shifts. Unable to find a reliable population of the ...


Biogeographical Implications Of Climate Change For An Alpine Mammal, The American Pika, Marie Louise Westover May 2019

Biogeographical Implications Of Climate Change For An Alpine Mammal, The American Pika, Marie Louise Westover

Biology ETDs

Anthropogenic climate change has already impacted a majority of species globally. The aim of this dissertation is to understand how climate and climate change influences animal ecology and evolution across space and time, using the American pika (Ochotona. princeps) as a model system. I investigate how pika body size, diet, and occupancy are influenced by different aspects of climate over space and time. Body size in O. princeps populations best correlates to precipitation and vegetation, rather than temperature. Our findings suggest that pika body size may be more related to vegetation and food availability than the direct effects of temperature ...


Biogeography Of Endemic Dragonflies Of The Ozark-Ouachita Interior Highlands, Wade Alexander Boys May 2019

Biogeography Of Endemic Dragonflies Of The Ozark-Ouachita Interior Highlands, Wade Alexander Boys

Theses and Dissertations

A common pattern across many taxonomic groups is that relatively few species are widespread while the majority are restricted in their geographic ranges. Such species distributions are used to inform conservation status, which poses unique challenges for rare or cryptic species. Further, priority status is often designated within geopolitical boundaries, which may include only a portion of a species range. This, coupled with lack of distributional data, has resulted in species being designated as apparently rare throughout some portions of their range, which may not accurately reflect their overall conservation need. The Interior Highlands region of the central United States ...


Ecological And Economic Implications Of Increased Storm Frequency And Severity For Boreal Lakes, Kathryn Warner May 2019

Ecological And Economic Implications Of Increased Storm Frequency And Severity For Boreal Lakes, Kathryn Warner

Electronic Theses and Dissertations

In boreal regions, increased precipitation events have been linked to increased concentrations of dissolved organic carbon (DOC), however less is known about the extent and implications of these events on lakes. We assessed the effects of precipitation events on six drinking water lakes in Maine, USA to better understand how DOC concentration and quality change in response to precipitation events. Our results revealed three types of responses: (1) an initial spike in DOC concentrations and quality metrics; (2) a sustained increase in DOC concentrations and quality metrics and; (3) no change during all sampling periods. Lake residence time was a ...


Characterization Of Psychromonas Aquimarina, A New Model Organism For Climate Change, Carrie Carpenter Apr 2019

Characterization Of Psychromonas Aquimarina, A New Model Organism For Climate Change, Carrie Carpenter

Experiential Learning Projects

The current increase of average global temperature puts 25 to 35 percent of plant and animal species at an increased risk of extinction (Climate Change, 2018). Changing any environmental factor, such as increasing growth temperature, can significantly impact any organisms’ ability to survive. Because of the diversity of organisms on the planet, it is not feasible to study how each individually might adapt, but rather it is more efficient to study select organisms. This research focuses on a psychrophilic bacterium, Psychromonas aquimarina, which can survive in colder regions where most bacteria would not. This bacterium was chosen because climate change ...


Changes In Spring Arrival Times: Climate Change And The Phenology Of Spring Bird Migration, Aaron Svedlow Apr 2019

Changes In Spring Arrival Times: Climate Change And The Phenology Of Spring Bird Migration, Aaron Svedlow

Student Scholarship

Climate change and weather affect the phenology of bird migration; however, specific climatological factors associated with these observed effects have only recently been described. The relationship between local, regional, and global climate patterns and avian migration are increasingly important to understand due to the widespread, and potentially negative, implications (such as reduced fecundity) of rapid human induced climate change on bird populations. Migratory birds are under selective pressure to arrive at breeding areas at the optimal time to set up nesting territories and exploit seasonally abundant food resources, and because climate change has the potential to occur more rapidly than ...


How To Combat Post-Natural Disaster Related Environmental Gentrification And Environmental Inequality Accelerated By Climate Change, Marielle Christie Mar 2019

How To Combat Post-Natural Disaster Related Environmental Gentrification And Environmental Inequality Accelerated By Climate Change, Marielle Christie

Honors Theses

This thesis aims to illustrate the concept of natural disaster-induced environmental gentrification. There is a heightened vulnerability to unmitigated forced displacement by socioeconomically disadvantaged residents following a natural disaster. Environmental gentrification is a variant of green gentrification. Green gentrification occurs when providing green amenities to a city increases local property values and attracts wealthier residents to a previously polluted or disenfranchised neighborhood, which displaces the low-income residents. Similarly, environmental gentrification is a process that occurs after a natural disaster and rapidly accelerates the process of traditional urban gentrification or green gentrification. As a result, environmental gentrification magnifies and facilitates further ...


Shade Trees Preserve Avian Insectivore Biodiversity On Coffee Farms In A Warming Climate, Sarah L. Schooler Jan 2019

Shade Trees Preserve Avian Insectivore Biodiversity On Coffee Farms In A Warming Climate, Sarah L. Schooler

Theses and projects

Coffee is an important export in many developing countries, with a global annual trade value of $100 billion. Climate change is projected to drastically reduce the area where coffee is able to be grown. Shade trees may mitigate the effects of climate change through temperature regulation for coffee growth, temperature regulation for pest control, and increase in pest-eating bird diversity. The impact of shade on bird diversity and microclimate on coffee farms has been studied extensively in the Neotropics, but there is a dearth of research in the Paleotropics. I examined the local effects of shade on bird presence and ...


Past, Present And Future: Geographic And Temporal Variation In A Fig–Fig Wasp Mutualism, Finn Piatscheck Jan 2019

Past, Present And Future: Geographic And Temporal Variation In A Fig–Fig Wasp Mutualism, Finn Piatscheck

Graduate Theses and Dissertations

All living organisms interact with different degrees of interdependence and in ways that are integral to their ecology and evolution. Of the many forms of species interaction, mutualism is one in which species reciprocally obtain benefits from their interactions. Because mutualism is ubiquitous in nature, mutualists are commonly associated with a broader community of species whose interactions vary across a mutualist–antagonist spectrum and in space and time, and so they play a broadly important role in ecosystem function and species evolution. Flowering plants are widely distributed, typically primary producers, and thus foundational ecosystem elements. They are also ubiquitously associated ...


Ecological Considerations And Application Of Urban Tree Selection In Massachusetts, Ashley Mcelhinney Jan 2019

Ecological Considerations And Application Of Urban Tree Selection In Massachusetts, Ashley Mcelhinney

Masters Theses

Trees provide countless environmental, economic, and societal benefits to the urban environment, and may become increasingly important to maintaining environmental quality and human well-being in the face of increasing urbanization and climate change. However, trees in these urban areas are rapidly diminishing across the United States. Much of this loss can be prevented with proper planning and management, focused on selecting tree species that are both well-suited to the area’s growing conditions and able to survive the many stress factors in an urban setting. Choosing which tree species to plant in Massachusetts is especially challenging considering the lack of ...


Population Structure And Connectivity Of A Groundwater Crustacean Across Northwestern Montana Aquifers, Megan N. Ritter Jan 2019

Population Structure And Connectivity Of A Groundwater Crustacean Across Northwestern Montana Aquifers, Megan N. Ritter

Master’s Theses

Floodplain aquifer systems are diverse and heterogenous ecosystems that serve many ecological functions, including habitat provision to a range of groundwater species. The Flathead River system of northwestern Montana is home to many floodplain aquifers of great ecological importance to the region. The basic biology, population structure, and dispersal patterns of obligate groundwater organisms that reside within the aquifers of the Flathead are still largely unknown. In this study, we investigate the population structure of one such taxon, an undescribed species of the amphipod genus Stygobromus. For our low-coverage RADseq dataset, we tested the suitability of three different analysis pipelines ...


Drought Tolerance In Soybean: Methods For Improvement, Emily Thorp Jan 2019

Drought Tolerance In Soybean: Methods For Improvement, Emily Thorp

Creative Components

As opposed to the past, plant breeders today have access to far greater technology, and far greater obstacles to overcome. One of those challenges is the need for drought tolerance in crops such as soybeans. Soybeans are a major crop, affected by drought due to a lack of tolerance traits in cultivars grown today. Drought tolerant soybeans are important globally, because soybeans are grown in many countries around the world where yield losses from drought are frequent. Therefore, it is essential for farmers to make changes to their practices to help their crops tolerate or avoid drought, and breeding programs ...


Thermal And Low Oxygen Tolerance Of A Southern Population Of Striped Bass (Morone Saxatilis), Daniel A. Lleras Jan 2019

Thermal And Low Oxygen Tolerance Of A Southern Population Of Striped Bass (Morone Saxatilis), Daniel A. Lleras

Electronic Theses and Dissertations

Climate change projections estimate a 2-3°C increase in water temperatures by the end of the century. The amount of habitat with suitable temperature and oxygen concentration for aquatic organisms will also be reduced. Striped bass (Morone saxatilis) inhabiting the rivers in Southeastern Georgia make an interesting study system as they do not participate in summer coastal migrations typical of their northern conspecifics. Instead, fish in this southern population remain in freshwater environments that experience warming and decreases in dissolved oxygen. The present study aims to determine the thermal and low oxygen tolerance of juvenile striped bass collected from southeast ...


Wetland Biogeochemical Responses To Predicted Climate Change Scenarios, Angela R. Shaffer Jan 2019

Wetland Biogeochemical Responses To Predicted Climate Change Scenarios, Angela R. Shaffer

Electronic Theses and Dissertations

Wetlands are one of the world's largest known carbon sinks while comprising only a small amount of the Earth's surface. However, the amount of carbon sequestered by wetlands is shrinking as droughts and human disturbance increases. Carbon in wetlands is stored through the contrast of decomposition and sedimentation of organic matter and absorption of CO2 from the atmosphere by soil microbes. Understanding how changing hydrological regimes and increased wildfires will affect wetland soil and microbial processes is important in the face of predicted climate change for future wetland conservation practices. Specifically, I seek to understand the response ...


Biogeochemical Response To Vegetation And Hydrologic Change In An Alaskan Boreal Fen Ecosystem, Danielle L. Rupp Jan 2019

Biogeochemical Response To Vegetation And Hydrologic Change In An Alaskan Boreal Fen Ecosystem, Danielle L. Rupp

Dissertations, Master's Theses and Master's Reports

Boreal peatlands store approximately one third of the earth’s terrestrial carbon, locked away in currently waterlogged and frozen conditions. Peatlands of boreal and arctic ecosystems are affected increasingly by shifting hydrology caused by climate change. The consequences of these relatively rapid ecosystem changes on carbon cycling between the landscape and the atmosphere could provide an amplifying feedback to climate warming. Alternatively, the advancement of terrestrial vegetation into once waterlogged soils could uptake carbon as a sink. Previous work suggests that fens will become an increasingly dominant landscape feature in the boreal. However, studies investigating fens, their response to hydrologic ...


Reexamining The Utility Of Existing Climate Adaptation Frameworks Through Application On A Northern Forest, Alexander Rice Jan 2019

Reexamining The Utility Of Existing Climate Adaptation Frameworks Through Application On A Northern Forest, Alexander Rice

Dissertations, Master's Theses and Master's Reports

A review of the literature reveals the strengths and limitations of various climate adaptation frameworks and illuminates a general path by which a type of adaptation can be achieved. A number of useful frameworks exist but the number of independent case studies demonstrating the adaptation process in a detailed manner is much more limited. Additionally, components of the various adaptation processes can often seem vague and concepts such as adaptability ill-defined. For land managers approaching climate adaptation independently can be difficult, particularly in the areas of goal creation and vulnerability assessment. Within frameworks where user-defined adaptation goals dictate whether or ...


Dispersal As A Buffer Against Zooplankton Community Change In Response To Fluctuating Salinity Levels On The Great Plains, Mercedes Huynh Jan 2019

Dispersal As A Buffer Against Zooplankton Community Change In Response To Fluctuating Salinity Levels On The Great Plains, Mercedes Huynh

Theses and Dissertations (Comprehensive)

The North American Great Plains is home to thousands of closed-basin lakes that are sensitive to changes in hydrology. Climate change models predict increased aridity in this region over the coming century, which is expected to lead to higher salinity levels in many freshwater lakes. Increases in salinity levels may impact zooplankton communities, as laboratory experiments show that many freshwater species have a low tolerance for elevated salinity levels, and field data demonstrate that salinity is the primary factor structuring aquatic communities on the Great Plains. Changes to zooplankton communities could lead to a trophic cascade based on their important ...


Deciduous Shrub Encroachment Effects On Tundra Soil Properties, Daniela Aguirre Jan 2019

Deciduous Shrub Encroachment Effects On Tundra Soil Properties, Daniela Aguirre

Open Access Theses & Dissertations

Deciduous shrub abundance is increasing in tundra ecosystems as an effect of rising temperatures which may change tundra physical properties and, in turn, microbial communities and biogeochemical processes. Two mechanisms through which shrub presence may affect tundra ecosystems were examined in this study; the physical presence of the shrubs and effects of increasing shrub litter inputs. In a sub-arctic alpine tundra ecosystem, dominated by the deciduous shrub Betula glandulosa, both shrub presence (shrub present and removed) and litter quantity (no litter/litter removed, ambient litter, and twice ambient litter) were manipulated; multiple ecosystem properties where measured within the treatment plots ...


Influence Of Climate Change And Prescribed Fire On Habitat Suitability And Abundance Of The High-Elevation Endemic Cow Knob Salamander (Plethodon Punctatus), Carl David Jacobsen Jan 2019

Influence Of Climate Change And Prescribed Fire On Habitat Suitability And Abundance Of The High-Elevation Endemic Cow Knob Salamander (Plethodon Punctatus), Carl David Jacobsen

Graduate Theses, Dissertations, and Problem Reports

Amphibians are facing global declines due to climate change, loss and degradation of habitat, invasive species, and disease. The Appalachian region of the eastern USA is a global biodiversity hotspot for salamanders, which are considered keystone species that influence nutrient dynamics in terrestrial and aquatic food webs. There are high rates of salamander endemism in the Appalachian region, with many species restricted to isolated, high elevation areas. The Cow Knob Salamander (Plethodon punctatus) is one such species. It is only found at elevations >675 m (most populations are above 900 m) on Shenandoah Mountain, North Mountain, and Nathaniel Mountain in ...


Changing Oceanic Conditions On The Foraging Patterns Of Cassin’S Auklets, Ptychoramphus Aleuticuschanging Oceanic Conditions On The Foraging Patterns Of Cassin’S Auklets, Ptychoramphus Aleuticus, Clare Flynn Jan 2019

Changing Oceanic Conditions On The Foraging Patterns Of Cassin’S Auklets, Ptychoramphus Aleuticuschanging Oceanic Conditions On The Foraging Patterns Of Cassin’S Auklets, Ptychoramphus Aleuticus, Clare Flynn

Pomona Senior Theses

Cassin’s auklet (Ptychoramphus aleuticus) reproductive success has been monitored on Southeast Farallon Island (SEFI) for the past 45 years. Their productivity has varied with oceanic conditions. The purpose of this study is to connect how oceanic conditions affect Cassin’s auklet foraging behaviors. The California Current System (CCS) can normally maintain high plankton productivity, and thus high seabird productivity, because of coastal upwelling. I hypothesized that lower upwelling and/or higher sea surface temperatures (SSTs) lead Cassin’s auklets to spend more time on intensive foraging behaviors such as flying and diving, and have less time to spend resting ...


Understanding The Impacts Of Current And Future Environmental Variation On Central African Amphibian Biodiversity, Courtney A. Miller Dec 2018

Understanding The Impacts Of Current And Future Environmental Variation On Central African Amphibian Biodiversity, Courtney A. Miller

University of New Orleans Theses and Dissertations

Global climate change is projected to impact multiple levels of biodiversity by imposing strong selection pressures on existing populations, triggering shifts in species distributions, and reorganizing entire communities. The Lower Guineo-Congolian region in central Africa, a reservoir for amphibian diversity, is predicted to be severely affected by future climate change through rising temperatures and greater variability in rainfall. Geospatial modelling can be used to assess how environmental variation shapes patterns of biological variation – from the genomic to the community level – and use these associations to predict patterns of biological change across space and time. The overall goal of this dissertation ...