Matching Items (4)
Description
Infectious diseases have emerged as a significant threat to wildlife. Environmental change is often implicated as an underlying factor driving this emergence. With this recent rise in disease emergence and the acceleration of environmental change, it is important to identify the environmental factors that alter host-pathogen dynamics and their underlying mechanisms. The emerging pathogen Batrachochytrium dendrobatidis (Bd) is a clear example of the negative effects infectious diseases can have on wildlife. Bd is linked to global declines in amphibian diversity and abundance. However, there is considerable variation in population-level responses to Bd, with some hosts experiencing marked declines while others persist. Environmental factors may play a role in this variation. This research used populations of pond-breeding chorus frogs (Pseudacris maculata) in Arizona to test if three rapidly changing environmental factors nitrogen (N), phosphorus (P), and temperature influence the presence, prevalence, and severity of Bd infections. I evaluated the reliability of a new technique for detecting Bd in water samples and combined this technique with animal sampling to monitor Bd in wild chorus frogs. Monitoring from 20 frog populations found high Bd presence and prevalence during breeding. A laboratory experiment found 85% adult mortality as a result of Bd infection; however, estimated chorus frog densities in wild populations increased significantly over two years of sampling despite high Bd prevalence. Presence, prevalence, and severity of Bd infections were not correlated with aqueous concentrations of N or P. There was, however, support for an annual temperature-induced reduction in Bd prevalence in newly metamorphosed larvae. A simple mathematical model suggests that this annual temperature-induced reduction of Bd infections in larvae in combination with rapid host maturation may help chorus frog populations persist despite high adult mortality. These results demonstrate that Bd can persist across a wide range of environmental conditions, providing little support for the influence of N and P on Bd dynamics, and show that water temperature may play an important role in altering Bd dynamics, enabling chorus frogs to persist with this pathogen. These findings demonstrate the importance of environmental context and host life history for the outcome of host-pathogen interactions.
ContributorsHyman, Oliver J. (Author) / Collins, James P. (Thesis advisor) / Davidson, Elizabeth W. (Committee member) / Anderies, John M. (Committee member) / Elser, James J. (Committee member) / Escalante, Ananias (Committee member) / Arizona State University (Publisher)
Created2012
Description
In the face of increasing anthropogenic threats to marine systems, marine reserves
have become a popular tool to promote sustainable fisheries management and protect marine biodiversity. However, the governance structures that determine marine reserve success are not well understood. The response of resource users to reserve establishment, as well as the socioeconomic, institutional, and political contexts in which they occur, are rarely considered during reserve implementation. I use the Coupled Infrastructure Systems (CIS) framework to better understand the interdependencies between social, economic, natural, and institutional processes affecting reserve implementation and performance efficacy in the Gulf of California, Mexico. I used a combination of interviews, qualitative case study comparisons, and systematic conservation planning tools to evaluate the role of different infrastructures, institutions, and governance for marine reserve efficacy in the Gulf of California, Mexico. At a local scale, I assessed stakeholder perceptions, preferences, and knowledge on reserves in the Midriff Islands sub-region of the Gulf. My results show differences in fisher perceptions about the use of reserves for biodiversity conservation and fisheries management, misconceptions about their location, and non-compliance behavior problems. At the regional scale, I explored the trajectories of reserve implementation and performance. I show that capacity-building programs and effective collaboration between non-profit organizations, environmental, fisheries, and other government authorities are essential to coordinate efforts leading to the provisioning of infrastructure that enables effective marine reserves. Furthermore, these programs help facilitate the incorporation of fishers into diversified management and economic activities. Infrastructure provision tradeoffs should be carefully balanced for designing scientifically-sound reserves that can achieve fisheries recovery objectives and incorporating stakeholder engagement processes during the planning phase that allow fishers to include their preferences in a way that complements proposed reserve network solutions. Overall, my results highlight the importance of multiple infrastructures in understanding the dynamics of interacting action situations at various stages of marine reserve implementation and operation. I identify strengths and weaknesses within marine reserve systems that help understand what combinations of infrastructures can be influenced to increase marine reserve effectiveness and robustness to internal and external challenges, as well as delivering benefits for both nature and people.
have become a popular tool to promote sustainable fisheries management and protect marine biodiversity. However, the governance structures that determine marine reserve success are not well understood. The response of resource users to reserve establishment, as well as the socioeconomic, institutional, and political contexts in which they occur, are rarely considered during reserve implementation. I use the Coupled Infrastructure Systems (CIS) framework to better understand the interdependencies between social, economic, natural, and institutional processes affecting reserve implementation and performance efficacy in the Gulf of California, Mexico. I used a combination of interviews, qualitative case study comparisons, and systematic conservation planning tools to evaluate the role of different infrastructures, institutions, and governance for marine reserve efficacy in the Gulf of California, Mexico. At a local scale, I assessed stakeholder perceptions, preferences, and knowledge on reserves in the Midriff Islands sub-region of the Gulf. My results show differences in fisher perceptions about the use of reserves for biodiversity conservation and fisheries management, misconceptions about their location, and non-compliance behavior problems. At the regional scale, I explored the trajectories of reserve implementation and performance. I show that capacity-building programs and effective collaboration between non-profit organizations, environmental, fisheries, and other government authorities are essential to coordinate efforts leading to the provisioning of infrastructure that enables effective marine reserves. Furthermore, these programs help facilitate the incorporation of fishers into diversified management and economic activities. Infrastructure provision tradeoffs should be carefully balanced for designing scientifically-sound reserves that can achieve fisheries recovery objectives and incorporating stakeholder engagement processes during the planning phase that allow fishers to include their preferences in a way that complements proposed reserve network solutions. Overall, my results highlight the importance of multiple infrastructures in understanding the dynamics of interacting action situations at various stages of marine reserve implementation and operation. I identify strengths and weaknesses within marine reserve systems that help understand what combinations of infrastructures can be influenced to increase marine reserve effectiveness and robustness to internal and external challenges, as well as delivering benefits for both nature and people.
ContributorsMancha Cisneros, Maria del Mar (Author) / Gerber, Leah R. (Thesis advisor) / Abbott, Joshua K. (Committee member) / Anderies, John M. (Committee member) / Torre, Jorge (Committee member) / Arizona State University (Publisher)
Created2017
Description
Institutions (rules, norms, and shared strategies) are social feedback systems that structure actors’ decision-making context. It is important to investigate institutional design to understand how rules interact and generate feedbacks that affect robustness, i.e., the ability to respond to change. This is particularly important when assessing sustainable use/conservation trade-offs that affect species’ long-term survival. My research utilized the institutional grammar (IG) and robust institutional design to investigate these linkages in the context of four international conservation treaties.
First, the IG was used to code the regulatory formal treaty rules. The coded statements were then assessed to determine the rule linkages and dynamic interactions with a focus on monitoring and related reporting and enforcement mechanisms. Treaties with a regulatory structure included a greater number and more tightly linked rules related to these mechanisms than less regulatory instruments. A higher number of actors involved in these activities at multiple levels also seemed critical to a well-functioning monitoring system.
Then, drawing on existing research, I built a set of constitutive rule typologies to supplement the IG and code the treaties’ constitutive rules. I determined the level of fit between the constitutive and regulatory rules by examining the monitoring mechanisms, as well as treaty opt-out processes. Treaties that relied on constitutive rules to guide actor decision-making generally exhibited gaps and poorer rule fit. Regimes which used constitutive rules to provide actors with information related to the aims, values, and context under which regulatory rules were being advanced tended to exhibit better fit, rule consistency, and completeness.
The information generated in the prior studies, as well as expert interviews, and the analytical frameworks of Ostrom’s design principles, fit, and polycentricity, then aided the analysis of treaty robustness. While all four treaties were polycentric, regulatory regimes exhibited strong information processing feedbacks as evidenced by the presence of all design principles (in form and as perceived by experts) making them theoretically more robust to change than non-regulatory ones. Interestingly, treaties with contested decision-making seemed more robust to change indicating contestation facilitates robust decision-making or its effects are ameliorated by rule design.
First, the IG was used to code the regulatory formal treaty rules. The coded statements were then assessed to determine the rule linkages and dynamic interactions with a focus on monitoring and related reporting and enforcement mechanisms. Treaties with a regulatory structure included a greater number and more tightly linked rules related to these mechanisms than less regulatory instruments. A higher number of actors involved in these activities at multiple levels also seemed critical to a well-functioning monitoring system.
Then, drawing on existing research, I built a set of constitutive rule typologies to supplement the IG and code the treaties’ constitutive rules. I determined the level of fit between the constitutive and regulatory rules by examining the monitoring mechanisms, as well as treaty opt-out processes. Treaties that relied on constitutive rules to guide actor decision-making generally exhibited gaps and poorer rule fit. Regimes which used constitutive rules to provide actors with information related to the aims, values, and context under which regulatory rules were being advanced tended to exhibit better fit, rule consistency, and completeness.
The information generated in the prior studies, as well as expert interviews, and the analytical frameworks of Ostrom’s design principles, fit, and polycentricity, then aided the analysis of treaty robustness. While all four treaties were polycentric, regulatory regimes exhibited strong information processing feedbacks as evidenced by the presence of all design principles (in form and as perceived by experts) making them theoretically more robust to change than non-regulatory ones. Interestingly, treaties with contested decision-making seemed more robust to change indicating contestation facilitates robust decision-making or its effects are ameliorated by rule design.
ContributorsBrady, Ute (Author) / Anderies, John M. (Thesis advisor) / Schoon, Michael (Committee member) / Minteer, Ben A. (Committee member) / Gerber, Leah (Committee member) / Siddiki, Saba (Committee member) / Arizona State University (Publisher)
Created2020
Description
Social-ecological systems (SES) are replete with hard and soft human-made components (or infrastructures) that are consciously-designed to perform specific functions valued by humans. How these infrastructures mediate human-environment interactions is thus a key determinant of many sustainability problems in present-day SES. This dissertation examines the question of how some of the designed aspects of physical and social infrastructures influence the robustness of SES under global change. Due to the fragility of rural livelihood systems, locally-managed common-pool resource systems that depend on infrastructure, such as irrigated agriculture and community forestry, are of particular importance to address this sustainability question. This dissertation presents three studies that explored the robustness of communal irrigation and forestry systems to economic or environmental shocks. The first study examined how the design of irrigation infrastructure affects the robustness of system performance to an economic shock. Using a stylized dynamic model of an irrigation system as a testing ground, this study shows that changes in infrastructure design can induce fundamental changes in qualitative system behavior (i.e., regime shifts) as well as altered robustness characteristics. The second study explored how connectedness among social units (a kind of social infrastructure) influenced the post-failure transformations of large-N forest commons under economic globalization. Using inferential statistics, the second study argues that some attributes of the social connectedness that helped system robustness in the past made the system more vulnerable to undesirable transformations in the current era. The third study explored the question of how to guide adaptive management of SES for more robustness under uncertainty. This study used an existing laboratory behavioral experiment in which human-subjects tackle a decision problem on collective management of an irrigation system under environmental uncertainty. The contents of group communication and the decisions of individuals were analyzed to understand how configurations of learning-by-doing and other adaptability-related conditions may be causally linked to robustness under environmental uncertainty. The results show that robust systems are characterized by two conditions: active learning-by-doing through outer-loop processes, i.e., frequent updating of shared assumptions or goals that underlie specific group strategies, and frequent monitoring and reflection of past outcomes.
ContributorsYu, Jae Hoon David (Author) / Anderies, John M. (Thesis advisor) / Janssen, Marco A. (Committee member) / Muneepeerakul, Rachata (Committee member) / Arizona State University (Publisher)
Created2015