Matching Items (175)
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
Habitat fragmentation, the loss of habitat in the landscape and spatial isolation of remaining habitat patches, has long been considered a serious threat to biodiversity. However, the study of habitat fragmentation is fraught with definitional and conceptual challenges. Specifically, a multi-scale perspective is needed to address apparent disagreements between landscape- and patch-based studies that have caused significant uncertainty concerning fragmentation’s effects on biological communities. Here I tested the hypothesis that habitat fragmentation alters biological communities by creating hierarchically nested selective pressures across plot-, patch-, and landscape-scales using woody plant community datasets from Thousand Island Lake, China. In this archipelago edge-effects had little impact on species-diversity. However, the amount of habitat in the surrounding landscape had a positive effect on species richness at the patch-scale and sets of small islands accumulated species faster than sets of large islands of equal total size at the landscape-scale. In contrast, at the functional-level edge-effects decreased the proportion of shade-tolerant trees, island-effects increased the proportion of shade- intolerant trees, and these two processes interacted to alter the functional composition of the regional pool when the total amount of habitat in the landscape was low. By observing interdependent fragmentation-mediated effects at each scale, I found support for the hypothesis that habitat fragmentation’s effects are hierarchically structured.
ContributorsWilson, Maxwell (Author) / Wu, Jianguo (Thesis advisor) / Smith, Andrew (Committee member) / Hall, Sharon (Committee member) / Jiang, Lin (Committee member) / Cease, Arianne (Committee member) / Arizona State University (Publisher)
Created2018
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
For my Barrett the Honors College senior thesis project, I decided to utilize my knowledge of curriculum design to create a set of learning Modules. I was influenced by my involvement in the Next Generation Service Corps to create these Modules around college student community impact. In the end I developed 6 Modules, each with 4-5 lessons and activities that focused on topics such as volunteerism, civic engagement, and meaningful careers. With interviews rolling through during the design process, I was able to iterate my design as I built it. The design was tested with 14 college students with positive feedback and engagement during the week-long period that it was available. Through this research and design, I found that such a collection of Modules could be beneficial to students to excite them about their potential and educate them about the opportunities that exist for them to take advantage of. This research could serve as a useful tool within the ASU community as an opportunity for the students to build up meaningful skills to create impact. ASU is passionate about education translating into real world applications and creating “changemakers”, and this collection has the opportunity to do just that.
ContributorsLascala, Francesca Louise (Author) / Barab, Sasha (Thesis director) / Gutierrez, Veronica (Committee member) / School for the Future of Innovation in Society (Contributor, Contributor) / Walter Cronkite School of Journalism & Mass Comm (Contributor) / Watts College of Public Service & Community Solut (Contributor) / Barrett, The Honors College (Contributor)
Created2020-05
Description
RecyclePlus is an iOS mobile application that allows users to be knowledgeable in the realms of sustainability. It gives encourages users to be environmental responsible by providing them access to recycling information. In particular, it allows users to search up certain materials and learn about its recyclability and how to properly dispose of the material. Some searches will show locations of facilities near users that collect certain materials and dispose of the materials properly. This is a full stack software project that explores open source software and APIs, UI/UX design, and iOS development.
ContributorsTran, Nikki (Author) / Ganesh, Tirupalavanam (Thesis director) / Meuth, Ryan (Committee member) / Watts College of Public Service & Community Solut (Contributor) / Department of Information Systems (Contributor) / Computer Science and Engineering Program (Contributor) / Barrett, The Honors College (Contributor)
Created2020-05
Description
Aquatic macroinvertebrates can be key contributors to nitrogen (N) and phosphorus (P) cycling in streams. Though they exhibit intense control via trophic interactions and nutrient conversion, they may be influenced by other environmental factors that can determine total excretion-derived N, P, and N:P. Garden Canyon and Ramsey Canyon, two streams in the Huachuca Mountain Range in Southern Arizona, USA, host similar insect communities, but only Garden Canyon experiences a seasonal P limitation due to the co-precipitation of phosphate with calcium carbonate (CaCO3) in its benthic substrate (Corman et al. 2015). I performed an analysis of excretion rates of aquatic insects living in these streams to test if the P limitation is reflected in rates that insects recycle nutrients. A lower mean N:P of all insect excretion rates in Garden provides evidence for an ecosystem-scale effect, though the differences in N:P of excretion rates by individual taxa between streams did not support the hypothesis. Attributing excretion rates to actual insect densities in three years reveals that natural-occurring fluctuations in excretion rates can operate on the same magnitude as fluctuations in abundances and causes steep differences in nutrient conversion between streams. Lastly, I found that since these streams support immense insect diversity, they receive excretion-derived N and P from taxa in many different functional feeding groups, which illustrates ecosystem resilience and uniqueness.
ContributorsSanders, Ashley Marie (Author) / Sabo, John (Thesis director) / Cease, Arianne (Committee member) / School of Life Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2016-05
Description
With the millennial and Gen Z generations being comprised of avid social media users, corporations have turned to online platforms, such as Twitter and Instagram, as a way of communicating and connecting to their audiences. One method that corporations are using to attract consumers is utilizing internet memes. Brands and corporations are now marketing through internet memes to enhance and define the brand’s personality and voice. This study examines the ways corporations use internet memes to personify their brand image and the overall effectiveness of meme usage in engaging consumers. Based on an exploratory analysis of brands over several media pages, we find evidence that brands with an edgy or humorous personality have increased engagement when using this method of communication, while more luxury brands should avoid using memes. Our research was conducted by examining and analyzing the social media accounts of four companies that use memes regularly as ways to promote their brands between November 1, 2018 and February 1, 2019. Our findings suggest that there is no definite correlation between internet memes and consumer engagement, rather that they are beneficial to use in addition to traditional marketing. In order to gain a stronger understanding of the relationships between internet memes and engagement, future research can study online brand personalities more in-depth and develop theories on the effectiveness of meme usage.
ContributorsReicks, Amber Michelle (Co-author) / Ahmas, Roxanna (Co-author) / Ostrom, Amy (Thesis director) / Eaton, John (Committee member) / Department of Marketing (Contributor) / School of Community Resources and Development (Contributor) / Watts College of Public Service & Community Solut (Contributor) / Barrett, The Honors College (Contributor)
Created2019-05
Description
The United States is in a period of political turmoil and polarization. New technologies have matured over the last ten years, which have transformed an individual’s relationship with society and government. The emergence of these technologies has revolutionized access to both information and misinformation. Skills such as bias recognition and critical thinking are more imperative than in any other time to separate truth from false or misleading information. Meanwhile, education has not evolved with these changes. The average individual is more likely to come to uninformed conclusions and less likely to listen to differing perspectives. Moreover, technology is further complicating and compounding other issues in the political process. All of this is manifesting in division among the American people who elect more polarized politicians who increasingly fail to find avenues for compromise.
In an effort to address these trends, we founded a student organization, The Political Literates, to fight political apathy by delivering political news in an easy to understand and unbiased manner. Inspired by our experience with this organization, we combine our insights with research to paint a new perspective on the state of the American political system.
This thesis analyzes various issues identified through our observations and research, with a heavy emphasis on using examples from the 2016 election. Our focus is how new technologies like data analytics, the Internet, smartphones, and social media are changing politics by driving political and social transformation. We identify and analyze five core issues that have been amplified by new technology, hindering the effectiveness of elections and further increasing political polarization:
● Gerrymandering which skews partisan debate by forcing politicians to pander to ideologically skewed districts.
● Consolidation of media companies which affects the diversity of how news is shared.
● Repeal of the Fairness Doctrine which allowed media to become more partisan.
● The Citizens United Ruling which skews power away from average voters in elections.
● A Failing Education System which does not prepare Americans to be civically engaged and to avoid being swayed by biased or untrue media.
Based on our experiment with the Political Literates and our research, we call for improving how critical thinking and civics is taught in the American education system. Critical thought and civics must be developed pervasively. With this, more people would be able to form more sophisticated views by listening to others to learn rather than win, listening less to irrelevant information, and forming a culture with more engagement in politics. Through this re-enlightenment, many of America’s other problems may evaporate or become more actionable.
In an effort to address these trends, we founded a student organization, The Political Literates, to fight political apathy by delivering political news in an easy to understand and unbiased manner. Inspired by our experience with this organization, we combine our insights with research to paint a new perspective on the state of the American political system.
This thesis analyzes various issues identified through our observations and research, with a heavy emphasis on using examples from the 2016 election. Our focus is how new technologies like data analytics, the Internet, smartphones, and social media are changing politics by driving political and social transformation. We identify and analyze five core issues that have been amplified by new technology, hindering the effectiveness of elections and further increasing political polarization:
● Gerrymandering which skews partisan debate by forcing politicians to pander to ideologically skewed districts.
● Consolidation of media companies which affects the diversity of how news is shared.
● Repeal of the Fairness Doctrine which allowed media to become more partisan.
● The Citizens United Ruling which skews power away from average voters in elections.
● A Failing Education System which does not prepare Americans to be civically engaged and to avoid being swayed by biased or untrue media.
Based on our experiment with the Political Literates and our research, we call for improving how critical thinking and civics is taught in the American education system. Critical thought and civics must be developed pervasively. With this, more people would be able to form more sophisticated views by listening to others to learn rather than win, listening less to irrelevant information, and forming a culture with more engagement in politics. Through this re-enlightenment, many of America’s other problems may evaporate or become more actionable.
ContributorsStenseth, Kyle (Co-author) / Tumas, Trevor (Co-author) / Mokwa, Michael (Thesis director) / Eaton, John (Committee member) / Department of Information Systems (Contributor) / Department of Supply Chain Management (Contributor) / Sandra Day O'Connor College of Law (Contributor) / Watts College of Public Service & Community Solut (Contributor) / Barrett, The Honors College (Contributor)
Created2019-05
Description
Locusts are a major crop pest in many parts of the world and different species are endemic to different countries. In Latin America, the South American Locust (Schistocerca cancellata) is the predominant species found mostly in Argentina, Chile, Bolivia, Paraguay, and southern Brazil with Argentina being the most affected. Several control and management practices, including biological control, have been implemented in these countries in the past to control the locusts and reduce their impact on crop and vegetation, however, effective long-term control and management practices will require a detail understanding of how the predominant locust species in this region responds to resource variation. Research has shown that there is strong evidence that locusts, and many other organisms, will actively balance dietary macronutrients (protein, carbohydrates, and lipids) to optimize growth, survival, and/or reproduction. A study by Cease et. al, 2017, on the dietary preferences of the Mongolian locust (Oedaleus asiaticus) showed that it prefers diets that are high in carbohydrates over diets that are high in protein, in this case locusts self-selected a 1:2 ratio of protein:carbohydrate. This and many other studies provide vital insight into the nutritional and feeding preferences of these locust species but the effects that this difference in protein: carbohydrate preferences has on growth, egg production, flight potential, and survival has yet to be fully explored, hence, this study investigates the effects that nitrogen fertilization of wheatgrass will have on the growth, egg production, survival, and flight muscle mass of the South American locust in a controlled, laboratory environment.
ContributorsManneh, Balanding (Author) / Cease, Arianne (Thesis director) / Overson, Rick (Committee member) / School of Sustainability (Contributor) / School of Life Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2018-05
Description
In the face of the world's most pressing sustainability challenges, such as climate change, ecosystem degradation, and loss of biodiversity, the following questions must be explored: Why are these situation occurring? How can we understand their complexity? How can we research these challenges to mitigate negative outcomes? This thesis investigates the relationships between people and nature through coupled human and natural systems, or CHANS, and argues for a transdisciplinary research approach for sustainability science. The following questions and topics are discussed: 1. The Complexity of Sustainability and Implications for Traditional Research Approaches 2. Coupled Human and Natural Systems Research 3. What is Transdisciplinary Research, and How Does it Relate to the Living With Locusts Team's Coupled Human and Natural Systems Research? This thesis uses the case of a team researching international locust plagues to argue for this approach. The team's project is titled "Living With Locusts" and is directed by Arianne Cease of Arizona State University's School of Sustainability.
ContributorsLantz, Kayna Mishelle (Author) / Cease, Arianne (Thesis director) / Campbell, Jacob (Committee member) / School of Sustainability (Contributor) / School of Life Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2016-12