Matching Items (70)
Description
By increasing the mean and variance of environmental temperatures, climate change has caused local extinctions and range shifts of numerous species. However, biologists disagree on which populations and species are most vulnerable to future warming. This debate arises because biologists do not know which physiological processes are most vulnerable to temperature or how to model these processes in complex environments. Using the South American locust (Schistocerca cancellata) as a model system, my dissertation addressed this debate and explained how climate limits the persistence of locust populations. Locusts of S. cancellata are serious agricultural pests with occasional outbreaks covering up to 4 million km2 over six countries. Because outbreaks are largely driven by climate, understanding how climate limits the persistence of locusts may help predict crop losses in future climates. To achieve this aim, I integrated observational, experimental, and computational approaches. First, I tested a physiological model of heat stress. By measuring the heat tolerance of locusts under different oxygen concentrations, I demonstrated that heat tolerance depends on oxygen supply during the hatchling stage only. Second, I modeled the geographic distribution of locusts using physiological traits. I started by measuring thermal effects on consumption and defecation of field-captured locusts, and I then used these data to model energy gain in current and future climates. My results indicated that incorporating physiological mechanisms can improve the accuracy of models and alter predicted impacts of climate change. Finally, I explored the causes and consequences of intraspecific variation in heat tolerance. After measuring heat tolerance of locusts in different hydration states and developmental stages, I modeled survival in historical microclimates. My models indicated that recent climate change has amplified the risk of overheating for locusts, and this risk depended strongly on shade availability, hydration state, and developmental stage. Therefore, the survival of locusts in future climates will likely depend on their access to shade and water. Overall, my dissertation argues that modeling physiological mechanisms can improve the ability of biologists to predict the impacts of climate change.
ContributorsYoungblood, Jacob (Author) / Angilletta, Michael (Thesis advisor) / Buckley, Lauren (Committee member) / Cease, Arianne (Committee member) / Smith, Brian (Committee member) / Vanden Brooks, John (Committee member) / Arizona State University (Publisher)
Created2022
Description
Adaptation to climate change is a core sustainability challenge across the Global South. Development and government organizations conceptualize and govern climate adaptation by creating national and sub-national action plans and implementing projects. This dissertation confronts the inherent tensions that arise when formal planned adaptation interventions encounter the complex, often messy realities of the implementation context. In doing so, this research examines how planned adaptation—with its incentives, provisioned resources, prescribed behaviors, and expectations of commitment from target beneficiaries —interacts with individuals and communities already balancing diverse risks while pursuing their livelihood aspirations. Two broad questions guide this dissertation: 1) how is adaptation envisioned by planners and practitioners? and, 2) how do project beneficiaries engage with, and experience planned adaptation interventions? The research employs an exploratory and inductive qualitative research design. Using Foucault’s lens of governmentality, this research utilises document analysis to examine how the first wave of Indian adaptation projects envision goals, conceptualize problems, delineate roles, and frame expectations of intended beneficiaries. Next, using a case study of an adaptation project implemented in Uttarakhand, India, the study examines the motivations and associated trade-offs behind the engagement and disengagement of the intended beneficiaries: smallholder farmers. Insights from gender-differentiated focus group discussions guide this analysis. Both inquiries are supplemented with findings from semi-structured interviews with Indian adaptation experts and project implementers. The analysis finds that: 1) project reports construct identities of the climate vulnerable beneficiary, implicitly assigning roles and transferring responsibilities for sustaining adaptation efforts beyond project timelines, 2) project participants are not default beneficiaries, but instead exercise agency in decision-making by either opting-in or opting-out of planned initiatives, and 3) the implicit and explicit costs of engaging in planned adaptation interventions are substantial, encompassing significant contributions of time, physical labor, and active participation during and post the project period. This dissertation challenges existing notions of whom planned adaptation serves, and to what end, offering new insights into its design and effectiveness. Furthermore, this research suggests that for planned adaptation to be sustainable, a concerted effort to align with evolving needs, aspirations and livelihood shifts of those on the frontlines of climate change is essential.
ContributorsYogya, Yamini (Author) / Eakin, Hallie (Thesis advisor) / Aggarwal, Rimjhim (Committee member) / York, Abigail (Committee member) / Agrawal, Arun (Committee member) / Arizona State University (Publisher)
Created2024
Description
The migratory grasshopper (Melanoplus sanguinipes) is one of the most economically important grasshoppers in the western rangelands of the United States (US), capable of causing incredible amounts of damage to crops and rangelands. While M. sanguinipes has been the focus of many research studies, areas like field nutritional physiology and ecology, and interactions between nutritional physiology and biopesticide resistance have very little research. This dissertation presents a multifaceted approach through three research-driven chapters that examine the nutritional physiology of M. sanguinipes and how it interacts with an entomopathogenic fungus for grasshopper management, as well as the challenges of using biopesticides for grasshopper management. Using the Geometric Framework for Nutrition (GFN), I established baseline macronutrient intake for M. sanguinipes, both in laboratory and field populations. Through this work, I found that field and lab populations can exhibit different protein (p) to carbohydrate (c) ratios, or Intake Targets (ITs), but that the field populations had ITs that matched the nutrients available in their environment. I also used the GFN to show that infections with the fungal entomopathogen Metarhizium robertsii DWR2009 did not alter ITs in M. sanguinipes. Although, when confined to carbohydrate- or protein-biased diets, infected grasshoppers had a slightly extended lifespan relative to grasshoppers fed balanced protein:carbohydrate diets. Interestingly, in a postmortem for the grasshopper, the fungus was only able to effectively sporulate on grasshoppers fed the 1p:1c diets, suggesting that grasshopper diet can have substantial impacts on the spread of fungal biopesticides throughout a population, in the absence of any inhibitory abiotic factors. Lastly, I examined the major barriers to fungal and microsporidian biopesticide usage in the United States, including low efficacy, thermal and environmental sensitivity, non-target effects, unregistered or restricted use, and economic or accessibility barriers. I also explored potential solutions to these challenges. This dissertation's focus on Melanoplus sanguinipes and Metarhizium roberstii Strain DWR2009, generates new information about how nutritional physiology and immunology intersect to impact M. sanguinipes performance. The methodology in each of the experimental chapters provides a framework for examining other problematic grasshopper species, by determining baseline nutritional physiology, and coupling nutrition with immunology to maximize the effectiveness of biological pesticides.
ContributorsZembrzuski, Deanna (Author) / Cease, Arianne (Thesis advisor) / Harrison, Jon (Committee member) / Angilletta, Michael (Committee member) / Jaronski, Stefan (Committee member) / Arizona State University (Publisher)
Created2023
Description
Decarbonizing the energy system is one of the most challenging sustainability transitions that leaders across the globe must tackle. In governing this transition, decision-makers are increasingly pairing together decarbonization efforts with policy measures focused on issues of (in)justice. However, researchers’ understanding of the politics that have given rise to this emerging equitable energy transition agenda is under-developed. The central research question of my dissertation is: How is the energy transition made more attentive to equity through stakeholder advocacy? I examine this using qualitative methods across three analytical chapters. The study of justice in energy transitions has occurred across different lineages of scholarship. To establish a clearer understanding of the state of current research I conducted a systematic literature review. In the literature, I found a diverse advocacy community motivated by many different issues related to the energy system. Advocacy concerning inaccessible decision-making processes, environmental degradation, and energy ownership and control was common. However, there were few studies that explicitly focused on examining the relationship between advocate strategies and governance outcomes.
The remainder of the research presented in this dissertation analyzes two state-level policy processes in New Mexico and Illinois. In both cases, justice-oriented policy instruments were bundled with climate policy. First, using public documents and
interviews, I used process tracing to examine policy development and enactment. I find that different types of learning processes were critical in shaping justice policy provisions and that justice advocacy was instrumental in passing climate policy. Second, I used content analysis to examine the mechanisms within these processes driving and resolving justice conflicts. My findings show that disagreements about justice are rooted in divergent historic experiences of energy production and regulation. I also find that issues of (dis)trust and uncertainty contributed to disagreements and reinforced conflicts that diminished support for energy transition policy.
This dissertation provides empirical evidence of the importance of learning for shaping justice policy provisions and building energy transition coalition power, the nature of uncertainty and (dis)trust in destabilizing justice efforts and reducing
support for climate policy, and the ways in which incremental change may lead to transformative outcomes.
ContributorsShelton, Rebecca (Author) / Eakin, Hallie (Thesis advisor) / Breetz, Hanna (Committee member) / Stevis, Dimitris (Committee member) / Arizona State University (Publisher)
Created2024
Description
How can we understand and pursue sustainability transitions that disrupt everyday practices and social norms? This dissertation finds potential answers to this fundamental sustainability governance question in Arizona utilities’ efforts to legitimate wastewater as a drinking water source. Due to widespread public concern regarding the direct potable reuse of wastewater (DPR), utilities and other stakeholders have developed innovative governance approaches. By offering tastings of DPR water (often in the form of beer), utilities create spaces for deliberation within a traditionally top-down policy planning paradigm, and furthermore, invite feelings—emotions and bodily sensations—into policymaking. This dissertation explores and advances Arizona's emerging transition to deliberative water governance through three distinct investigations. The first of these, an institutional analysis based on interviews with 34 regional stakeholders and observations at 56 water industry meetings, identifies direct experiences with DPR (e.g., tastings) as a pivotal strategy to institutionalize new wastewater practices. The second investigation examines utility-sponsored initiatives to promote DPR and finds that, instead of assuming that consumers behave as rational choice or bounded rationality would predict, water utilities’ use of drinking water tastings reflects a new normative assumption, termed embodied rationality. The third investigation applies embodied rationality in action research with skeptical consumers and reuse industry stakeholders to co-design an exhibit about DPR that engaged more than 1,100 people. Drawing insights from the literatures of embodied and enacted cognition, practice theory, organizational institutionalism, sustainability transitions management, and design research, this dissertation proposes an analytical approach, normative framework, and practical tools for collaboratively addressing real-world sustainability challenges.
ContributorsManheim, Marisa (Author) / White, Dave (Thesis advisor) / Spackman, Christy (Committee member) / Eakin, Hallie (Committee member) / Arizona State University (Publisher)
Created2024
Description
Vector control plays an important role in the prevention and control of mosquito-borne diseases (MBDs). As there are no (prophylactic) drugs and/or vaccines available for many arboviral diseases (such as zika, chikungunya, Saint Louis encephalitis, Ross River virus), the frontline approach to prevent or reduce disease morbidity and mortality is through the reduction of the mosquito vector population size and/or reducing vector-human contact using insecticides. Frontline tools in malaria (an MBD caused by a parasite) control and elimination have been drugs (targeting the malaria parasite) and insecticides (targeting the vectors) through indoor residual spraying (IRS) (spraying the internal walls and sometimes the roofs of dwellings with residual insecticides to kill adult mosquito vectors), and long-lasting insecticidal nets (LLINs), while arboviral vectors are frequently targeted using outdoor fogging and space spraying (indoor or outdoor spraying of insecticides to kill adult mosquito vectors). Integrative and novel vector control efforts are urgently needed since the aforementioned tools may not be as effective against those mosquito species that are resistant to insecticides and/or have a different (or changed) behavior allowing them to avoid existing tools. In Chapters 2 and 3, I investigate mosquito vector surveillance in Arizona by (i) discussing the species composition and public health implications of the State’s mosquito fauna, and (ii) comparing the effectiveness of 4 different carbon dioxide (CO2) sources in attracting different mosquito species on the Arizona State University Tempe Campus. In Chapters 4 and 5, I investigate a novel vector control tool by (i) completing a literature review on using electric fields (EFs) to control insects, and (ii) presenting novel data on using Insulated Conductor Wires (ICWs) to generate EFs that prevent host-seeking female Aedes aegypti from entering spaces. In Chapter 6, I discuss the non-target effects of chemical malaria control on other arthropods, including other biological and mechanical infectious disease vectors. Overall, this dissertation highlights the important role that the development of novel surveillance and vector control tools could play in improved mosquito control, which ultimately will reduce disease morbidity and mortality.
ContributorsJobe, Ndey Bassin (Author) / Paaijmans, Krijn (Thesis advisor) / Cease, Arianne (Committee member) / Hall, Sharon (Committee member) / Huijben, Silvie (Committee member) / Arizona State University (Publisher)
Created2024
Description
Adaptation and transformation have emerged as a key themes for human-environment research, especially in the context of rapid social-ecological changes. The 2008 global financial crisis constitutes a major driver of change with social-ecological ramifications that have yet to be fully explored. Using Greece, the poster child of the euro-crisis as a case-study, this dissertation examines how adaptive capacity is mobilized and even enhanced in times of crisis, paying particular attention to the role played by natural capital. To do so, I focus on the back-to-land trend whereby urbanites seek to engage in food production post-crisis (2008-onwards). In-depth qualitative analysis of back-to-landers’ motivations, experiences, and challenges is integrated with quantitative data about household demographics, incomes and assets, and land management characteristics. The dissertation is organized in three main result papers (chapters). The first seeks to understand why people turn to the land in times of crisis, and the role played by agency. The second analyzes the various assets that people mobilize in order to go back to the land, paying particular attention to the different mobilities necessary for their livelihood transformation. The third examines environmental safety nets in terms of material and non-material benefits that ecosystems provide to people. This research contributes to a wider social-ecological scholarship that seeks to understand how people adapt and transform when confronted with crises, focusing on how land and associated ecosystem services contribute to the resilience of these households, and the role played by agency in this process.
ContributorsBenessaiah, Karina (Author) / Turner II, Billie L. (Thesis advisor) / Eakin, Hallie (Committee member) / Chan, Kai M.A. (Committee member) / Arizona State University (Publisher)
Created2018
Description
Climate change impacts are evident throughout the world, particularly in the low lying coastal areas. The multidimensional nature and cross-scale impacts of climate change require a concerted effort from different organizations operating at multiple levels of governance. The efficiency and effectiveness of the adaptation actions of these organizations rely on the problem framings, network structure, and power dynamics of the organizations and the challenges they encounter. Nevertheless, knowledge on how organizations within multi-level governance arrangements frame vulnerability, how the adaptation governance structure shapes their roles, how power dynamics affect the governance process, and how barriers emerge in adaptation governance as a result of multi-level interactions is limited. In this dissertation research, a multilevel governance perspective has been adopted to address these knowledge gaps through a case study of flood risk management in coastal Bangladesh. Key-informant interviews, systematic literature review, spatial multi-criteria decision analysis, social network analysis (SNA), and content analysis techniques have been used to collect and analyze data. This research finds that the organizations involved in adaptation governance generally have aligned framings of vulnerability, irrespective of the level at which they are operated, thus facilitating adaptation decision-making. However, this alignment raises concerns of a neglect of socio-economic aspects of vulnerability, potentially undermining adaptation initiatives. This study further finds that the adaptation governance process is elite-pluralistic in nature, but has a coexistence of top-down and bottom-up processes in different phases of adaptation actions. The analysis of power dynamics discloses the dominance of a few national level organizations in the adaptation governance process in Bangladesh. Lastly, four mechanisms have been found that can explain how organizational culture, practices, and preferences dictate the emergence of barriers in the adaptation governance process. This dissertation research overall advances our understanding on the significance of multilevel governance approach in climate change adaptation governance.
ContributorsIshtiaque, Asif (Author) / Chhetri, Netra (Thesis advisor) / Eakin, Hallie (Thesis advisor) / Myint, Soe W (Committee member) / Arizona State University (Publisher)
Created2019
Description
Aboveground net primary production (ANPP) is an important ecosystem process that, in drylands, is most frequently limited by water availability. Water availability for plants is in part controlled by the water holding capacity of soils. Available water holding capacity (AWHC) of soils is strongly influenced by soil texture and depth. This study drew upon localized rain gauge data and four data-sets of cover-line and biomass data to estimate ANPP and to determine annual precipitation (PPT). I measured soil depth to caliche and texture by layer of 112 plots across the four landscape units for which estimation of ANPP were available. A pedotransfer function was used to estimate AWHC from soil depth increments to depth of caliche measurements and texture analysis. These data were analyzed using simple and multivariate regression to test the effect of annual precipitation and available water holding capacity on aboveground net primary production. Soil texture remained constant among all plots (sandy loam) and depth to caliche varied from 15.16 cm to 189 cm. AWHC and the interaction term (PPT*AWHC) were insignificant (p=0.142, p=0.838) and annual PPT accounted for 18.4% of the variation in ANPP. The y-intercept was significantly different for ANPP ~ annual PPT when considering AWHC values either above or below 3 cm. Shrub ANPP was insensitive to precipitation regardless of AWHC (R2=-0.012, R2=0.014). Results from this study indicate that a model incorporating annual PPT and AWHC may not serve as a good predictor for ANPP at a site level where there is little variation in soil texture.
ContributorsWagner, Svenja K (Author) / Sala, Osvaldo E. (Thesis advisor) / Cease, Arianne (Committee member) / Hall, Sharon (Committee member) / Peters, Debra (Committee member) / Arizona State University (Publisher)
Created2019
Description
Motivated by the need for cities to prepare and be resilient to unpredictable future weather conditions, this dissertation advances a novel infrastructure development theory of “safe-to-fail” to increase the adaptive capacity of cities to climate change. Current infrastructure development is primarily reliant on identifying probable risks to engineered systems and making infrastructure reliable to maintain its function up to a designed system capacity. However, alterations happening in the earth system (e.g., atmosphere, oceans, land, and ice) and in human systems (e.g., greenhouse gas emission, population, land-use, technology, and natural resource use) are increasing the uncertainties in weather predictions and risk calculations and making it difficult for engineered infrastructure to maintain intended design thresholds in non-stationary future. This dissertation presents a new way to develop safe-to-fail infrastructure that departs from the current practice of risk calculation and is able to manage failure consequences when unpredicted risks overwhelm engineered systems.
This dissertation 1) defines infrastructure failure, refines existing safe-to-fail theory, and compares decision considerations for safe-to-fail vs. fail-safe infrastructure development under non-stationary climate; 2) suggests an approach to integrate the estimation of infrastructure failure impacts with extreme weather risks; 3) provides a decision tool to implement resilience strategies into safe-to-fail infrastructure development; and, 4) recognizes diverse perspectives for adopting safe-to-fail theory into practice in various decision contexts.
Overall, this dissertation advances safe-to-fail theory to help guide climate adaptation decisions that consider infrastructure failure and their consequences. The results of this dissertation demonstrate an emerging need for stakeholders, including policy makers, planners, engineers, and community members, to understand an impending “infrastructure trolley problem”, where the adaptive capacity of some regions is improved at the expense of others. Safe-to-fail further engages stakeholders to bring their knowledge into the prioritization of various failure costs based on their institutional, regional, financial, and social capacity to withstand failures. This approach connects to sustainability, where city practitioners deliberately think of and include the future cost of social, environmental and economic attributes in planning and decision-making.
ContributorsKim, Yeowon (Author) / Chester, Mikhail (Thesis advisor) / Eakin, Hallie (Committee member) / Redman, Charles (Committee member) / Miller, Thaddeus R. (Committee member) / Arizona State University (Publisher)
Created2018