Matching Items (77)
Description
In 2010, a monthly sampling regimen was established to examine ecological differences in Saguaro Lake and Lake Pleasant, two Central Arizona reservoirs. Lake Pleasant is relatively deep and clear, while Saguaro Lake is relatively shallow and turbid. Preliminary results indicated that phytoplankton biomass was greater by an order of magnitude in Saguaro Lake, and that community structure differed. The purpose of this investigation was to determine why the reservoirs are different, and focused on physical characteristics of the water column, nutrient concentration, community structure of phytoplankton and zooplankton, and trophic cascades induced by fish populations. I formulated the following hypotheses: 1) Top-down control varies between the two reservoirs. The presence of piscivore fish in Lake Pleasant results in high grazer and low primary producer biomass through trophic cascades. Conversely, Saguaro Lake is controlled from the bottom-up. This hypothesis was tested through monthly analysis of zooplankton and phytoplankton communities in each reservoir. Analyses of the nutritional value of phytoplankton and DNA based molecular prey preference of zooplankton provided insight on trophic interactions between phytoplankton and zooplankton. Data from the Arizona Game and Fish Department (AZGFD) provided information on the fish communities of the two reservoirs. 2) Nutrient loads differ for each reservoir. Greater nutrient concentrations yield greater primary producer biomass; I hypothesize that Saguaro Lake is more eutrophic, while Lake Pleasant is more oligotrophic. Lake Pleasant had a larger zooplankton abundance and biomass, a larger piscivore fish community, and smaller phytoplankton abundance compared to Saguaro Lake. Thus, I conclude that Lake Pleasant was controlled top-down by the large piscivore fish population and Saguaro Lake was controlled from the bottom-up by the nutrient load in the reservoir. Hypothesis 2 stated that Saguaro Lake contains more nutrients than Lake Pleasant. However, Lake Pleasant had higher concentrations of dissolved nitrogen and phosphorus than Saguaro Lake. Additionally, an extended period of low dissolved N:P ratios in Saguaro Lake indicated N limitation, favoring dominance of N-fixing filamentous cyanobacteria in the phytoplankton community in that reservoir.
ContributorsSawyer, Tyler R (Author) / Neuer, Susanne (Thesis advisor) / Childers, Daniel L. (Committee member) / Sommerfeld, Milton (Committee member) / Arizona State University (Publisher)
Created2011
Description
Sinaloa, a coastal state in the northwest of Mexico, is known for irrigated conventional agriculture, and is considered one of the greatest successes of the Green Revolution. With the neoliberal reforms of the 1990s, Sinaloa farmers shifted out of conventional wheat, soy, cotton, and other commodities and into white maize, a major food staple in Mexico that is traditionally produced by millions of small-scale farmers. Sinaloa is now a major contributor to the national food supply, producing 26% of total domestic white maize production. Research on Sinaloa's maize has focused on economic and agronomic components. Little attention, however, has been given to the environmental sustainability of Sinaloa's expansion in maize. With uniquely biodiverse coastal and terrestrial ecosystems that support economic activities such as fishing and tourism, the environmental consequences of agriculture in Sinaloa are important to monitor. Agricultural sustainability assessments have largely focused on alternative agricultural approaches, or espouse alternative philosophies that are biased against conventional production. Conventional agriculture, however, provides a significant portion of the world's calories. In addition, incentives such as federal subsidies and other institutions complicate transitions to alternative modes of production. To meet the agricultural sustainability goals of food production and environmental stewardship, we must put conventional agriculture on a more sustainable path. One step toward achieving this is structuring agricultural sustainability assessments around achievable goals that encourage continual adaptations toward sustainability. I attempted this in my thesis by assessing conventional maize production in Sinaloa at the regional/state scale using network analysis and incorporating stakeholder values through a multicriteria decision analysis approach. The analysis showed that the overall sustainability of Sinaloa maize production is far from an ideal state. I made recommendations on how to improve the sustainability of maize production, and how to better monitor the sustainability of agriculture in Sinaloa.
ContributorsBausch, Julia Christine (Author) / Eakin, Hallie (Thesis advisor) / Bojórquez-Tapia, Luis (Committee member) / Childers, Daniel L. (Committee member) / Arizona State University (Publisher)
Created2011
Description
Ephemeral and intermittent streams are valuable sources of surface water support in the arid ecosystems of the Southwestern United States. These streams account for over 80% of the streams in the American Southwest and their importance has been indicated in many studies. Ephemeral and intermittent streams support a wide range of plant and animal species in both continuous and episodic fashions. This study aimed to gain a better understanding of the relationship between streamflow permanence and patterns of biomass and secondary production of the riparian fauna these ecosystems support. This was accomplished through a yearlong survey in the Huachuca Mountains of Southeastern, Arizona where macroinvertebrates were collected at various sites along a gradient of streamflow permanence before, during, and after the three month monsoon season that supplies most of the annual rainfall in this region. The results of my surveys indicate that 1) Sites characterized by low streamflow permanence were more responsive to changes in precipitation than sites characterized by relatively high streamflow permanence 2) In ephemeral streams, there is a significant peak in terrestrial macroinvertebrate production and biomass both during and after the monsoon season 3) streamflow permanence may convey consistent but not exceptional secondary production whereas seasonality in rainfall may convey exceptional but episodic secondary production—more so in sites where streamflow is not consistent.
ContributorsMcCartin, Michael Patrick (Author) / Sabo, John (Thesis director) / Stromberg, Juliet (Committee member) / Barrett, The Honors College (Contributor) / School of Life Sciences (Contributor)
Created2014-05
Description
Sustainability visioning (i.e. the construction of sustainable future states) is considered an important component of sustainability research, for instance, in transformational sustainability science or in planning for urban sustainability. Visioning frees sustainability research from the dominant focus on analyzing problem constellations and opens it towards positive contributions to social innovation and transformation. Calls are repeatedly made for visions that can guide us towards sustainable futures. Scattered across a broad range of fields (i.e. business, non-government organization, land-use management, natural resource management, sustainability science, urban and regional planning) are an abundance of visioning studies. However, among the few evaluative studies in the literature there are apparent deficits in both the research and practice of visioning that curtails our expectations and prospects of realizing process-based and product-derived outcomes. These deficits suggests that calls instead should focus on the development of applied and theoretical understanding of crafting sustainability visions, enhancing the rigor and robustness of visioning methodology, and on integrating practice, research, and education for collaborative sustainability visioning. From an analysis of prominent visioning and sustainability visioning studies in the literature, this dissertation articulates what is sustainability visioning and synthesizes a conceptual framework for criteria-based design and evaluation of sustainability visioning studies. While current visioning methodologies comply with some of these guidelines, none adhere to all of them. From this research, a novel sustainability visioning methodology is designed to address this gap to craft visions that are shared, systemic, principles-based, action-oriented, relevant, and creative (i.e. SPARC visioning methodology) and evaluated across all quality criteria. Empirical studies were conducted to test and apply the conceptual and methodological frameworks -- with an emphasis on enhancing the rigor and robustness in real world visioning processes for urban planning and teaching sustainability competencies. In-depth descriptions of the collaborative visioning studies demonstrate tangible outcomes for: (a) implementing the above sustainability visioning methodology, including evaluative procedures; (b) adopting meaningful interactive engagement procedures; (c) integrating advanced analytical modeling, sustainability appraisal, and creativity enhancing procedures; and (d) developing perspective and methodological capacity for long-range sustainability planning.
ContributorsIwaniec, David (Author) / Wiek, Arnim (Thesis advisor) / Childers, Daniel L. (Committee member) / Lant, Timothy (Committee member) / Arizona State University (Publisher)
Created2013
Description
Land management practices such as domestic animal grazing can alter plant communities via changes in soil structure and chemistry, species composition, and plant nutrient content. These changes can affect the abundance and quality of plants consumed by insect herbivores with consequent changes in population dynamics. These population changes can translate to massive crop damage and pest control costs. My dissertation focused on Oedaleus asiaticus, a dominant Asian locust, and had three main objectives. First, I identified morphological, physiological, and behavioral characteristics of the migratory ("brown") and non-migratory ("green") phenotypes. I found that brown morphs had longer wings, larger thoraxes and higher metabolic rates compared to green morphs, suggesting that developmental plasticity allows greater migratory capacity in the brown morph of this locust. Second, I tested the hypothesis of a causal link between livestock overgrazing and an increase in migratory swarms of O. asiaticus. Current paradigms generally assume that increased plant nitrogen (N) should enhance herbivore performance by relieving protein-limitation, increasing herbivorous insect populations. I showed, in contrast to this scenario, that host plant N-enrichment and high protein artificial diets decreased the size and viability of O. asiaticus. Plant N content was lowest and locust abundance highest in heavily livestock-grazed fields where soils were N-depleted, likely due to enhanced erosion and leaching. These results suggest that heavy livestock grazing promotes outbreaks of this locust by reducing plant protein content. Third, I tested for the influence of dietary imbalance, in conjunction with high population density, on migratory plasticity. While high population density has clearly been shown to induce the migratory morph in several locusts, the effect of diet has been unclear. I found that locusts reared at high population density and fed unfertilized plants (i.e. high quality plants for O. asiaticus) had the greatest migratory capacity, and maintained a high percent of brown locusts. These results did not support the hypothesis that poor-quality resources increased expression of migratory phenotypes. This highlights a need to develop new theoretical frameworks for predicting how environmental factors will regulate migratory plasticity in locusts and perhaps other insects.
ContributorsCease, Arianne (Author) / Harrison, Jon (Thesis advisor) / Elser, James (Thesis advisor) / DeNardo, Dale (Committee member) / Quinlan, Michael (Committee member) / Sabo, John (Committee member) / Arizona State University (Publisher)
Created2012
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
Urban sustainability is a critical component of sustainable human societies. Urban riparian parks are used here as a case study seeking to understand the social-ecological relationships between the subjective evaluation of ecosystem services and the vision and management of one kind of green infrastructure. This study explored attitudes towards ecosystem services, asking whether 1) the tripartite model is an effective framing to measure attitudes towards ecosystem services; 2) what the attitudes towards ecosystem services are and whether they differ between two types of park space; and 3) what the relationship is between management and the attitudinal assessment of ecosystem services by park users. A questionnaire was administered to 104 urban riparian park users in Phoenix, AZ evaluating their attitudes towards refugia, aesthetics, microclimate and stormwater regulation, and recreational and educational opportunities. The operationalization of the tripartite model was validated and found reliable, but may not be the whole story in determining attitudes towards ecosystem services. All components of attitude were positive, but attitudes were stronger in a habitat rehabilitation area with densely planted native species and low flows, than in a more classic park with mowed lawns and scattered vegetation, a mix of native and non-native species, and open water. Park users were more positive towards refugia, stormwater regulation, recreation, and educational opportunities in the habitat rehabilitation area. On the other hand, microclimate regulation and aesthetic qualities were valued similarly between the two parks. Most attitudes supported management goals, however park users valued stormwater regulation less than managers. Qualitative answers suggest that the quality of human interactions differ between the parks and park users consider both elements of society and the physical environment in their subjective evaluations. These findings reveal that park users highly value ecosystem services and that park design and management mediates social-ecological relationships, which should at least underlie the context of economic discussions of service value. This study supports the provision of ecosystem services through green infrastructure and suggests that an integration of park designs throughout urban areas could provide both necessary services as well as expand the platform for social-ecological interactions.
ContributorsWilson, Lea Ione (Author) / Childers, Daniel L. (Thesis advisor) / Larson, Kelli L. (Committee member) / Stromberg, Juliet (Committee member) / Arizona State University (Publisher)
Created2012
Description
Many studies have shown that as the calcium carbonate precipitates, it sequesters phosphate. Although the geochemical interactions between phosphate and calcium carbonate are known, only a few studies have considered calcium carbonate deposition's effect on stream ecology. Further, those studies considering decomposition have produced conflicting results. In this study, nutrient-diffusing cups with organic substrata were used to determine the nutrient limitation of decomposers in the travertine streams in the Huachuca Mountains. After processing a subset of the experiments, only one site (in Huachuca Canyon) from the four study streams was significantly nutrient-limited (NP co-limitation).
ContributorsNevarez, Nicole Michelle (Author) / Elser, James (Thesis director) / Sabo, John (Committee member) / Corman, Jessica (Committee member) / Barrett, The Honors College (Contributor) / School of Life Sciences (Contributor)
Created2013-05
Description
Nutrient recycling by fish can be an important part of nutrient cycles in both freshwater and marine ecosystems. As a result, understanding the mechanisms that influence excretion elemental ratios of fish is of great importance to a complete understanding of aquatic nutrient cycles. As fish consume a wide range of diets that differ in elemental composition, stoichiometric theory can inform predictions about dietary effects on excretion ratios.
We conducted a meta-analysis to test the effects of diet elemental composition on consumption and nutrient excretion by fish. We examined the relationship between consumption rate and diet N : P across all laboratory studies and calculated effect sizes for each excretion metric to test for significant effects.
Consumption rate of N, but not P, was significantly negatively affected by diet N : P. Effect sizes of diet elemental composition on consumption-specific excretion N, P and N : P in laboratory studies were all significantly different from 0, but effect size for raw excretion N : P was not significantly different from zero in laboratory or field surveys.
Our results highlight the importance of having a mechanistic understanding of the drivers of consumer excretion rates and ratios. We suggest that more research is needed on how consumption and assimilation efficiency vary with N : P and in natural ecosystems in order to further understand mechanistic processes in consumer-driven nutrient recycling.
ContributorsMoody, Eric (Author) / Corman, Jessica (Author) / Elser, James (Author) / Sabo, John (Author) / College of Liberal Arts and Sciences (Contributor) / School of Life Sciences (Contributor) / Julie Ann Wrigley Global Institute of Sustainability (Contributor)
Created2015-03-01
Description
Fashion is an inherently political and reflective medium for the daily ramblings and revolutions of a society. Much of the time the influence is subtle. Silhouettes and fabrics reflect different stances on conservatism, on sex, on the degrees to which we fetishize luxury, and on infinite other attitudes of an era. Other times the influence is extremely direct, with text printed on the clothing that explicitly articulates a current societal dynamic. I began exploring fashion in 2016, as the country had reached an unprecedented and linguistically weaponized divide.
While taking a fashion technology course under the instruction of Galina Mihaleva, I developed a tracksuit incorporating concealed LED displays that are capable of scrolling customizable text on the sides of the garment. I expanded on this futuristic execution of politically charged clothes by utilizing a more realistic application of the LED technology in the Bouis Vuitton project. This project is a collection of six white vinyl bags with semi-flexible LED displays projecting revolutionary slogans through the vinyl textile.
The bags act as an appropriate housing for technology that is intended for significantly longer use, as bags have a longer lifespan in wardrobes than clothes and return to trend more frequently. The production investment in the technology is more equitable to the investment in the production of a bag and facilitates the wearer’s broadcasting of concise messages. The result is a collection of functional, utilitarian pieces with a clean, futuristic look and a mixed modern and vintage silhouette scrolling pro-revolutionary messages.
Broadcasting the knock-off name ‘BOUIS VUITTON’, I’ve inserted only my first initial into the reputable luxury company and paired it with slogans: ‘EAT THE RICH’ and ‘HEADS WILL ROLL’. The collection articulates a sense of nihilism felt by the youngest generations growing up on the outside of a very exclusive economic and political sphere. Three upcycled vintage luggage pieces evoke associations with the white American upper-class society of the 1960s. The luggage pieces were retrofitted in white vinyl and white-enameled metal fixtures. Three additional soft bags made of the same material reflect a utilitarian style of functional bags on trend with Spring/Summer 2019 streetwear. For the runway presentation of the bags, the models are dressed in navy-colored Dickies boiler suits, white retro-style Fila sneakers, and white ascots reminiscent of the historical male ruffled cravat. The contradictions of iconic silhouettes from both upper and lower-class American fashion history further the juxtaposition of anti-capitalist slogans posted on luxury goods.
Bouis Vuitton: Bags for the Revolution is intended to embody an unapologetic disregard for established wealth and political power in the most public of venues: the sidewalk, the mall, the high and the low-income neighborhoods – wherever people are wearing clothes. Fashion is the modern protest that requires no permit, and the new poster is a luxury bag.
While taking a fashion technology course under the instruction of Galina Mihaleva, I developed a tracksuit incorporating concealed LED displays that are capable of scrolling customizable text on the sides of the garment. I expanded on this futuristic execution of politically charged clothes by utilizing a more realistic application of the LED technology in the Bouis Vuitton project. This project is a collection of six white vinyl bags with semi-flexible LED displays projecting revolutionary slogans through the vinyl textile.
The bags act as an appropriate housing for technology that is intended for significantly longer use, as bags have a longer lifespan in wardrobes than clothes and return to trend more frequently. The production investment in the technology is more equitable to the investment in the production of a bag and facilitates the wearer’s broadcasting of concise messages. The result is a collection of functional, utilitarian pieces with a clean, futuristic look and a mixed modern and vintage silhouette scrolling pro-revolutionary messages.
Broadcasting the knock-off name ‘BOUIS VUITTON’, I’ve inserted only my first initial into the reputable luxury company and paired it with slogans: ‘EAT THE RICH’ and ‘HEADS WILL ROLL’. The collection articulates a sense of nihilism felt by the youngest generations growing up on the outside of a very exclusive economic and political sphere. Three upcycled vintage luggage pieces evoke associations with the white American upper-class society of the 1960s. The luggage pieces were retrofitted in white vinyl and white-enameled metal fixtures. Three additional soft bags made of the same material reflect a utilitarian style of functional bags on trend with Spring/Summer 2019 streetwear. For the runway presentation of the bags, the models are dressed in navy-colored Dickies boiler suits, white retro-style Fila sneakers, and white ascots reminiscent of the historical male ruffled cravat. The contradictions of iconic silhouettes from both upper and lower-class American fashion history further the juxtaposition of anti-capitalist slogans posted on luxury goods.
Bouis Vuitton: Bags for the Revolution is intended to embody an unapologetic disregard for established wealth and political power in the most public of venues: the sidewalk, the mall, the high and the low-income neighborhoods – wherever people are wearing clothes. Fashion is the modern protest that requires no permit, and the new poster is a luxury bag.
ContributorsViton, Benjamin Douglas (Author) / Sewell, Dennita (Thesis director) / Mihaleva, Galina (Committee member) / School of Art (Contributor) / College of Integrative Sciences and Arts (Contributor) / Barrett, The Honors College (Contributor)
Created2019-05