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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

When the environment becomes a victim of armed conflict – the rhetoric, the blame game, and the pursuit of justice.

Palmqvist, Josefin January 2023 (has links)
The difficulty garnering compensation for environmental destruction from climate change and armed conflicts has made states and organizations question whether international legal systems can protect the environment during peace or war. The case study compares how Ukraine, Azerbaijan, and the United Nations Environment Programme frame the environmental implications of Russia's invasion of Ukraine and Armenia's occupation of Azerbaijan. The aim is to explore how states invoke environmental war crimes or environmental concerns to gain advantages in conflict resolution and whether international organizations change or adapt to help states obtain environmental justice. The results are obtained by combining the theory of environmental conflicts described by Fisher (2022a) and the national/international climate and security discourse described by McDonald (2018). The case study uses framing analysis to identify environmental problems in speeches, statements to the media, letters, reports, and press releases. The main findings indicate that Ukraine has gained more support in its fight for environmental justice than Azerbaijan. Although both states used similar frames and tactics in their environmental drivers, Ukraine's ability to continuously prove its seriousness about environmental destruction sets it apart from Azerbaijan. As terms like ecocide and eco-terror become more internationally recognized, states can use them to push international organizations to make legal changes about environmental justice. However, there is also a risk that states use the need for environmental justice to improve their international reputation in the aftermath of an armed conflict.
2

Environmental Drivers of Migration in Two Israeli Raptor Species

McClain, Krystaal Moonchyld 30 December 2015 (has links)
No description available.
3

Plastic and evolutionary responses of Chlamydomonas reinhardtii to multiple environmental drivers

Brennan, Georgina Lauren January 2016 (has links)
In my thesis I present data collected from a long-term selection experiment using the freshwater model organism Chlamydomonas reinhardtii. The selection experiment was designed to disentangle the effects of the number of multiple environmental drivers (MEDs) and the identity of those environmental drivers including high CO2, high temperature, general nutrient depletion, reduced light intensity, reduced phosphate availability, the addition of a herbicide, UV radiation and reduced pH. Using up to eight environmental drivers, I show how simple organisms such as C. reinhardtii evolve in response to MEDs. The first step in this investigation is to examine the short-term response of MEDs. Data collected at the beginning of the selection experiment will provide insight into the early stages of microevolution by investigating key differences in the short-term (plastic) responses to few vs. many MEDs. Here, I focus on how the data collected from the responses to single environmental drivers can help us predict the responses to MEDs by using ecological models (additive, comparative, multiplicative). I show that the short-term plastic responses to single environmental drivers can predict the effect of MEDs using the comparative model because the response is largely driven by the single dominant driver present. I also demonstrate the importance of the number of environmental drivers (NED) for making predictions from the single environmental drivers and show that predictions become more reliable as the NED increases. The results gathered from short-term responses provide evidence that single environmental driver studies are useful for predicting the effect of MEDs. After evolution, I found that the strength of selection varies with NED in a predictable way, which connects the NED to the evolutionary response (size of the direct response) through the strength of selection. Here, I used statistical models to quantify the effect of NED on the evolutionary response to MEDs and then interpreted this by considering the possible genetic constraints on adaptation to MEDs. A subset of populations evolved in environments with five environmental drivers and all populations evolved in the single environmental driver environments are used to examine how adapting to single vs. many environmental drivers affect local adaptation. I examine how populations selected in environments with one environmental driver, five environmental drivers and the evolved control, differ in their response to new environments with the same NED, environments with different NED, and a novel environment. I found that there is a relationship between local adaptation and the strength of selection in the local environment and patterns of local adaptation are affected by the NED of new environments. Lastly, I present the phenotypic consequences of evolution under MEDs. I found that before evolution, measures of chlorophyll content and cell size decline with increasing NED. However, after evolution the relationship between chlorophyll content and cell size with NED is weaker because populations converge on the same phenotypes as they evolve. I also present a case-study of how mass spectrometry methods can be used to better understand underlying molecular mechanisms of two phenotypes (chlorophyll positive and chlorophyll negative cells). This selection experiment is a good example of how laboratory investigations and model organisms can be used to design experiments with enough replication to have high statistical power in order to make more accurate predictions on the short- long-term effects of MEDs. Whilst there have been some studies on the effects of MEDs, these studies rarely have more than three environmental drivers (sometimes 5 environmental drivers) and there are only a handful of long-term MED studies. This study can be used to develop a priori hypotheses for investigating how environmental change will shape natural microbial communities, and is especially useful for organisms where long-term studies with multiple environmental drivers are unfeasible.
4

Large-scale drivers of fish biodiversity differ across an environmentally variable Great Plains watershed

Lehrter, Richard J., II January 1900 (has links)
Master of Science / Department of Biology / Martha E. Mather / Understanding the empirical relationships between biotic diversity and components of the environment is crucial for effective research and management, particularly in highly disturbed watersheds. The Smoky Hill River is a semi-arid prairie stream with a historic native fish community that is adapted to the extreme and highly variable climatic and hydrological conditions characteristic of the Great Plains streams. Following a literature review on environmental variables, diversity responses, and analysis methods, I evaluated the importance of land use, flow, discontinuities (dams, confluences), and stream type (mainstem-tributary) variables in explaining fish richness using AICc model selection with multiple linear, Poisson and negative-binomial regressions. I then compared these results from 48 sites across three watershed regions to those from a long-term monitoring dataset (ST) using the same candidate variables. Finally, I examined phylogenetic patterns of the fish community using ordination analyses. Patterns and drivers of biodiversity differed with watershed region, land use, stream type, and flow. Fish species richness in the Smoky Hill watershed was negatively correlated with percent developed land in the Lower region of the watershed, but positively correlated with percent herbaceous grassland, the reference prairie condition, in the Upper region of the watershed. Summer mean flow was consistently and positively related to species richness in the Middle and Upper regions of the watershed where flow was limited. In the Lower region of the watershed, species richness was higher in the more flow-moderate tributaries relative to high-flow mainstem sites. In the Middle and Upper flow-limited regions, species richness was lower in the low-flow tributaries than main stem sites. Families of fish species were also related to region and stream type (mainstem vs. tributary). A comparison of two databases showed how different goals, questions, and methods result in different insights, emphasizing the need for establishing a priori goals before sampling.
5

Long-term and seasonal response of rotifer biomass and phenology to environmental variability in a eutrophic reservoir

Gao, Xiu 01 June 2021 (has links)
No description available.
6

Shallow Soft Sediment Communities in the Central Red Sea: Revealing Patterns in Community Structure across Space and Time

Alsaffar, Zahra Hassan Ali 12 1900 (has links)
Due to intensive coastal development, a combination of local (e.g. pollution, fishing) and global pressures (such as climate change) is affecting marine habitats worldwide. This is a pressing issue in Saudi Arabia, particularly considering the plans for the expansion of sea-related activities within the Saudi Arabia's Vision 2030 framework. Sustaining some of those activities, such as tourism, is dependent upon the maintenance of good ecosystem health. National monitoring programs in Saudi Arabia are scarce and a lack of sound knowledge on how marine organisms change in space and time and what the main factors driving their responses are, limits the contribution of scientists to the management and conservation of the Red Sea. Here we provide baseline knowledge, that can be critical for assessing changes associated with current and future coastal development as well as climate change by collecting data across multiple spatial (including multiple habitats) and temporal scales for the analysis of macroinvertebrate organisms and environmental drivers. One of the most striking findings is related to the low densities observed for macroinvertebrates, making populations potentially vulnerable to disturbance. We also highlight the contribution of different habitats within the seascape and the need to prioritize the features of the bottoms for management and conservation purposes. Each habitat has a unique ecological signature but they are connected to adjacent habitats through a subset of species able to utilize different biotopes within the seascape. Disrupting this ecological network may affect biodiversity patterns from local to regional levels. Within each habitat, temporal variability should be taken into account as patterns change on a seasonal and annual scale. The aim of the thesis is to contribute to the sustainable development of the Red Sea, a unique resource shared among several countries, which will result in a long-term benefit to the Kingdom of Saudi Arabia, and other countries. Information provided is critical as previous knowledge for the region was almost inexistent and allows for future studies to investigate and predict the impacts of intense coastal development and inform conservation and management decisions.
7

Methane Emissions from Wetlands with Heterogeneous Land Cover Types: Biological and Physical Drivers in a Marsh and a Peat Bog in Ohio.

Rey Sanchez, Andres Camilo 11 December 2018 (has links)
No description available.
8

An Examination of Net Primary Production in Southern Appalachian Wetlands

Maguigan, Mike 14 August 2015 (has links)
Southern Appalachian wetlands have yet to be studied in terms of net primary production (NPP), thus few studies have been conducted to examine what environmental factors have relationships with NPP. To that end, this research investigates several facets of southern Appalachian wetland production. The research was divided into three studies. The first study was conducted to answer the question of what environmental factors have relationships with NPP. It appears that stream discharge and annual precipitation had the strongest relationships with NPP (r = 0.91, p <0.05 and r = 0.81, p <0.05, respectively), yet both factors showed multicolinearity (r = 0.97, p <0.05). The strong relationships between hydrologic factors and NPP is similar to montane wetlands in the western United States. The second study was conducted to examine the relationship between water chemistry and NPP. Calcium (Ca), Magnesium (Mg), and pH were examined in order to determine if any of the aforementioned factors had a relationship with NPP. Neither Ca (r = -0.34, p = 0.0835) nor Mg (r =-0.38, p = 0.0535) had strong relationships with NPP, though pH (r = -0.66, p <0.05) had a strong negative relationship with NPP. The acidity of the stream water, driven by the acid rain in the southern Appalachians, creates enhanced conditions for wetland plants to grow. The third study was conducted to establish which vegetation index was best for estimating NPP from proximally and remotely sensed data. The findings suggest that VARIRed Edge was best for examining NPP at the in situ level, NDVI was best for examining NPP at the airborne level, and the DVI was the best for examining NPP at the satellite level. NPP in southern Appalachian wetlands is driven by the chemistry, specifically the pH, of stream discharge and annual precipitation and can be monitored by NDVI using NAIP data or DVI using Landsat data. The examination of NPP in southern Appalachians in response to environmental factors and water chemistry along with the examination of vegetation indices at three levels of platforms will help to monitor and manage these rare and unique ecosystems in the future.
9

Reflective equilibrium applied in practice: Identifying climate migration environmental drivers in Guatemala for the further prioritization of Loss and Damage strategies

Montes, Rebeca January 2023 (has links)
The climate crisis has forced vulnerable countries in the Global South, such as Guatemala, to migrate. This study has two main focuses. The first one is identifying the region's most critical environmental mobility drivers. This is accomplished through a method called Reflective Equilibrium, which integrates justice, ethics, and community perspectives, allowing the connection of a community's judgments to its inherent principles so that the final judgments are consistent with each principle. Thus, this method enables reaching the first result of this work, which is identifying the two most critical environmental drivers in Guatemala while emphasizing the need to incorporate local voices and experiences to ensure fair and humane prioritization. The drivers identified are droughts and rainstorms. The second focus of this work proposes a framework that aims to guide decision-makers in which types of impacts arising from these drivers should be financially prioritized. The methods used for this investigation are a combination of literature review and risk assessment called the "standard model," providing a systemic approach to minimize, avert or address the identified environmental drivers. However, the need to include aspects of justice and rights in this prioritization is noted, as it is constantly neglected in public decisions. In addition, financing strategies are explored through the proposed framework in this study and can be applied beyond Guatemala, serving as a guide for prioritizing funding in other contexts where climate mobility drivers are a constant concern. The study suggests that Guatemalan decision- makers benefit from similar studies to provide evidence of the negative impacts of irresponsible activities by developed countries in their climate finance requests. The main aim of such an action would be to reach multilateral agreements that can be sought to safeguard fundamental human rights and protect Guatemala's natural resources by providing loss and damage funds. Recommendations for future research include estimating budgets for mitigation/adaptation strategies, assessing costs associated with the risks found here, and identifying thresholds for catastrophic events, specifically in Guatemala, thereby improving preparedness and response mechanisms.
10

Patterns and mechanisms of intraspecific trait variation across thermal gradients in a marine gastropod

Villeneuve, Andrew R 02 April 2021 (has links)
As the earth’s climate changes due to anthropogenic emissions, it has increasingly become an imperative within the ecological community to understand existing species adaptations to climate change. Much focus has been paid to how a species might react to climate change, but the role of locally adapted traits and responsible environmental mechanisms have received less attention. Quantifying how sublethal (e.g. growth rates) and lethal (e.g. thermal tolerance) trait performance vary between populations can thus improve our understanding of how populations, and the entire species, will react to climate change. Here, I quantified the spatial patterns of performance of several traits in populations of the predatory marine snail Urosalpinx cinerea from across two thermal gradients on the Pacific and Atlantic coasts of North America. In chapter 2, I quantified local adaptation and plasticity of thermal tolerance, warming tolerance, and developmental traits of Urosalpinx. I found that while low latitude populations have evolved higher thermal tolerance than their low latitude counterparts, they also demonstrate negative plasticity in response to higher acclimation temperatures. This is likely a result of low latitude population adaptation to cooler developmental conditions. Further, low latitude populations live in environments much closer to their thermal maxima than high latitude counterparts, resulting in higher climate sensitivity in low latitudes. In chapter 3, I quantified growth and consumption rates of Urosalpinx via a common garden experiment. I found evidence for a novel pattern of trait adaptation, wherein high latitude populations tended to have higher trait performance at higher thermal optima than low latitude counterparts. This can be attributed to the maximizing of growth rate during short growing seasons at high latitudes. Together, these results demonstrate that local adaptation in endemic across two traits in Urosalpinx. I demonstrate that these traits tend to be adapted to aspects of the environment directly related to aspects of Urosalpinx phenology, and not to environmental means as is commonly assumed. These insights suggest that models of organismal performance under climate change must consider not only the potential for local adaptation in populations, but also the aspects of the environment to which these populations are evolved.

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