ASU Electronic Theses and Dissertations
This collection includes most of the ASU Theses and Dissertations from 2011 to present. ASU Theses and Dissertations are available in downloadable PDF format; however, a small percentage of items are under embargo. Information about the dissertations/theses includes degree information, committee members, an abstract, supporting data or media.
In addition to the electronic theses found in the ASU Digital Repository, ASU Theses and Dissertations can be found in the ASU Library Catalog.
Dissertations and Theses granted by Arizona State University are archived and made available through a joint effort of the ASU Graduate College and the ASU Libraries. For more information or questions about this collection contact or visit the Digital Repository ETD Library Guide or contact the ASU Graduate College at gradformat@asu.edu.
Displaying 1 - 3 of 3
Filtering by
- All Subjects: Biology
- Genre: Masters Thesis
- Creators: Sabo, John
Description
The southwestern willow flycatcher (Empidonax traillii extimus) is listed as an endangered species throughout its range in the southwestern United States. Little is known about its sub-population spatial structure and how this impacts its population viability. In conjunction with being listed as endangered, a recovery plan was produced by the US Fish and Wildlife Service, with recovery units (sub-populations) roughly based on major river drainages. In the interest of examining this configuration of sub-populations and their impact on the measured population viability, I applied a multivariate auto-regressive state-space model to a spatially extensive time series of abundance data for the southwestern willow flycatcher over the period spanning 1995-2010 estimating critical growth parameters, correlation in environmental stochasticity or "synchronicity" between sub-populations (recovery units) and extinction risk of the sub-populations and the whole. The model estimates two parameters, the mean and variance of annual growth rate. Of the models I tested, I found the strongest support for a population model in which three of the recovery units were grouped (the Lower Colorado, Gila Basin, and Rio Grande recovery units) while keeping all others separate. This configuration has 6.6 times more support for the observed data than a configuration assigning each recovery unit to a separate sub-population, which is how they are circumscribed in the recovery plan. Given the best model, the mean growth rate is -0.0234 (CI95 -0.0939, 0.0412) with a variance of 0.0597 (CI95 0.0115, 0.1134). This growth rate is not significantly different from zero and this is reflected in the low potential for quasi-extinction. The cumulative probability of the population experiencing at least an 80% decline from current levels within 15 years for some sub-populations were much higher (range: 0.129-0.396 for an 80% decline). These results suggest that the rangewide population has a low risk of extinction in the next 15 years and that the formal recovery units specified by the original recovery plan do not correspond to proper sub-population units as defined by population synchrony.
ContributorsDockens, Patrick E. T. (Author) / Sabo, John (Thesis advisor) / Stromberg, Juliet (Committee member) / Fenichel, Eli (Committee member) / Arizona State University (Publisher)
Created2012
Description
Introduction: Often it is presumed that in high-income countries, like the United States, water insecurity is not an issue. Yet, more than 2 million individuals in the United States are affected by water insecurity. Experiencing the effects of water insecurity are informal settlements and impoverished communities termed as “colonias”, characterized by the lack of possessing basic infrastructures and services, including water systems and wastewater disposal amongst many. Purpose: To critically analyze how water insecurity manifests in the colonias and the impacts it has on the health and well-being of the community members.
Methods: An extensive systematic literature review was conducted in the effort to bring a meaningful framework of existing challenges and potential resolutions and theorize water insecurity in colonias.
Results: The effects of water insecurity due to water scarcity and water contamination in the colonias led to health complications, unsanitary living conditions and mental distress for residents. The causes of water insecurity in the colonias were because of political exclusion, municipal underbounding and the failure to monitor water quality.
Conclusion: The dire consequences of household water insecurity to an individual, no less an entire population, are detrimental to health and well-being. Despite this acknowledgement of a critical and basic human necessity, literature reveals a robust water governance infrastructure is much needed for the people in colonias. For meaningful progress and developments to be made in addressing water insecurity for the people of colonias, this review was approached through a transdisciplinary lens - one that achieves convergence.
ContributorsPatwoary, Nargish (Author) / Wutich, Amber (Thesis advisor) / Sabo, John (Thesis advisor) / Roque, Anais (Committee member) / Arizona State University (Publisher)
Created2021
Description
In desert riparian ecosystems, rivers provide free water but access to that water diminishes with distance producing a steep gradient in the relative importance of water for growth and reproduction of riparian animals and hence, their biodiversity. Previous work suggests that water limited riparian predators eat more prey to meet their water demand where free water is not available. Here I explore the effect of water limitation on prey selection and per capita interaction strengths between a predatory spider ( Hogna antelucana) and two prey species occupying different trophic levels using a controlled field experiment conducted in the riparian forest of the San Pedro River, Cochise County, AZ. Lab measurements of water and energy content revealed that intermediate predators (smaller spiders in the genus Pardosa) had 100-fold higher energy: water ratios than an alternate prey species more basal in the food web (crickets in the genus Gryllus). Given this observation, I hypothesized that water-stressed predatory wolf spiders would select more water-laden crickets but switch to more energy rich Pardosa when water stress was experimentally eliminated. Additionally, I hypothesized that switching by quenched Hogna to Pardosa would reduce predation by Pardosa on Gryllus leading to increased abundance of the basal resource. Finally, I hypothesized that water mediated switching and release of basal prey would be stronger when male Hogna was the apex predator, because female Hogna have higher energetic costs of reproduction and hence, stronger energy limitation. Experimental water additions caused both sexes of Hogna to consume significantly higher numbers of Pardosa but this difference (between water and no-water treatments) did not vary significantly between male and female Hogna treatments. Similarly, strong negative interaction strengths between Hogna and Pardosa led to release of the basal prey species and positive interaction strengths of Hogna on Gryllus. Again strong positive, indirect effects of Hogna on Gryllus did not depend on the sex of the Hogna predator. However, water mediated indirect effects of Hogna (either sex) on Gryllus were the strongest for male Gryllus. These results suggest that water and energy co-dominate foraging decisions by predators and that in managing water-energy balance; predators can modify interaction pathways, sex-ratios of prey populations and trophic dynamics.
ContributorsLeinbach, Israel (Author) / Sabo, John (Thesis advisor) / Harrison, Jon (Committee member) / Johnson, Chadwick (Committee member) / Arizona State University (Publisher)
Created2015