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Description
Land-use change has arguably been the largest contributor to the emergence of novel zoonotic diseases within the past century. However, the relationship between patterns of land-use change and the resulting landscape configuration on disease spread is poorly understood as current cross-species disease transmission models have not adequately incorporated spatial features

Land-use change has arguably been the largest contributor to the emergence of novel zoonotic diseases within the past century. However, the relationship between patterns of land-use change and the resulting landscape configuration on disease spread is poorly understood as current cross-species disease transmission models have not adequately incorporated spatial features of habitats. Furthermore, mathematical-epidemiological studies have not considered the role that land-use change plays in disease transmission throughout an ecosystem.

This dissertation models how a landscape's configuration, examining the amount and shape of habitat overlap, contributes to cross-species disease transmission to determine the role that land-use change has on the spread of infectious diseases. To approach this, an epidemiological model of transmission between a domesticated and a wild species is constructed. Each species is homogeneously mixed in its respective habitat and heterogeneously mixed in the habitat overlap, where cross-species transmission occurs. Habitat overlap is modeled using landscape ecology metrics.

This general framework is then applied to brucellosis transmission between elk and cattle in the Greater Yellowstone Ecosystem. The application of the general framework allows for the exploration of how land-use change has contributed to brucellosis prevalence in these two species, and how land management can be utilized to control disease transmission. This model is then extended to include a third species, bison, in order to provide insight to the indirect consequences of disease transmission for a species that is situated on land that has not been converted. The results of this study can ultimately help stakeholders develop policy for controlling brucellosis transmission between livestock, elk, and bison, and in turn, could lead to less disease prevalence, reduce associated costs, and assist in population management.

This research contributes novelty by combining landscape ecology metrics with theoretical epidemiological models to understand how the shape, size, and distribution of habitat fragments on a landscape affect cross-species disease transmission. The general framework demonstrates how habitat edge in single patch impacts cross-species disease transmission. The application to brucellosis transmission in the Greater Yellowstone Ecosystem between elk, cattle, and bison is original research that enhances understanding of how land conversion is associated with enzootic disease spread.
ContributorsPadilla, Dustin (Author) / Perrings, Charles (Thesis advisor) / Brauer, Fred (Committee member) / Jayasuriya, Suren (Committee member) / Arizona State University (Publisher)
Created2020
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Description
The proliferation of plastic has created a wicked global sustainability challenge. From the extraction of fossil fuels to end-of-life management and pollution, plastic imposes significant negative impacts to human health, economic well-being, and the environment. One proposed solution is to replace conventional plastic with biomass-based plastics and plastic alternatives (BBPAs),

The proliferation of plastic has created a wicked global sustainability challenge. From the extraction of fossil fuels to end-of-life management and pollution, plastic imposes significant negative impacts to human health, economic well-being, and the environment. One proposed solution is to replace conventional plastic with biomass-based plastics and plastic alternatives (BBPAs), such as paper or bio-based plastics. While these products may have advantageous properties, they require biomass as a feedstock. Given the scale of the plastics problem, this biomass demand may be significant. In my dissertation, I evaluate the magnitude of biomass required, and assess the potential impact of this biomass demand on global land use. After examining the scope and the scale of the problem in chapter one, I evaluate the assumptions that have been made regarding the land-use impacts of BBPAs in chapter two. In chapter three, I use a global land-system model (CLUMondo) to evaluate the potential land-use change of large-scale production of BBPAs. In chapter four, I evaluate how certification schemes could be used as a policy tool to mitigate the land-use impacts of bio-based alternatives. I find that the current studies evaluating the land-use impacts of these products make optimistic and unrealistic assumptions regarding land-use. Using a global model, I show how high production scenarios of BBPAs could induce significant land-use change at the global level. Finally, I demonstrate that reliance on certification schemes would likely be insufficient to prevent negative impacts from this scale of land change. Overall, this dissertation suggests that large-scale replacement of plastic with BBPAs could incur significant land-use impacts. Policies designed to mitigate the impacts of plastic need to account for this impact to land-use, lest they risk substituting one global problem for another.
ContributorsHelm, Levi (Author) / Kinzig, Ann (Thesis advisor) / Dooley, Kevin (Committee member) / Turner II, Billie (Committee member) / Verburg, Peter (Committee member) / Arizona State University (Publisher)
Created2023