Matching Items (3)
Filtering by

Clear all filters

152591-Thumbnail Image.png
Description
The explicit role of soil organisms in shaping soil health, rates of pedogenesis, and resistance to erosion has only just recently begun to be explored in the last century. However, much of the research regarding soil biota and soil processes is centered on maintaining soil fertility (e.g., plant nutrient availability)

The explicit role of soil organisms in shaping soil health, rates of pedogenesis, and resistance to erosion has only just recently begun to be explored in the last century. However, much of the research regarding soil biota and soil processes is centered on maintaining soil fertility (e.g., plant nutrient availability) and soil structure in mesic- and agro- ecosystems. Despite the empirical and theoretical strides made in soil ecology over the last few decades, questions regarding ecosystem function and soil processes remain, especially for arid areas. Arid areas have unique ecosystem biogeochemistry, decomposition processes, and soil microbial responses to moisture inputs that deviate from predictions derived using data generated in more mesic systems. For example, current paradigm predicts that soil microbes will respond positively to increasing moisture inputs in a water-limited environment, yet data collected in arid regions are not congruent with this hypothesis. The influence of abiotic factors on litter decomposition rates (e.g., photodegradation), litter quality and availability, soil moisture pulse size, and resulting feedbacks on detrital food web structure must be explicitly considered for advancing our understanding of arid land ecology. However, empirical data coupling arid belowground food webs and ecosystem processes are lacking. My dissertation explores the resource controls (soil organic matter and soil moisture) on food web network structure, size, and presence/absence of expected belowground trophic groups across a variety of sites in Arizona.
ContributorsWyant, Karl Arthur (Author) / Sabo, John L (Thesis advisor) / Elser, James J (Committee member) / Childers, Daniel L. (Committee member) / Hall, Sharon J (Committee member) / Stromberg, Juliet C. (Committee member) / Arizona State University (Publisher)
Created2014
149374-Thumbnail Image.png
Description

River and riparian areas are important foraging habitat for insectivorous bats. Numerous studies have shown that aquatic insects provide an important trophic resource to terrestrial consumers, including bats, and are key in regulating population size and species interactions in terrestrial food webs. Yet these studies have generally ignored how structural

River and riparian areas are important foraging habitat for insectivorous bats. Numerous studies have shown that aquatic insects provide an important trophic resource to terrestrial consumers, including bats, and are key in regulating population size and species interactions in terrestrial food webs. Yet these studies have generally ignored how structural characteristics of the riverine landscape influence trophic resource availability or how terrestrial consumers respond to ensuing spatial and temporal patterns of trophic resources. Moreover, few studies have examined linkages between a stream's hydrologic regime and the timing and magnitude of aquatic insect availability. The main objective of my dissertation is to understand the causes of bat distributions in space and time. Specifically, I examine how trophic resource availability, structural components of riverine landscapes (channel confinement and riparian vegetation structure), and hydrologic regimes (flow permanence and timing of floods) mediate spatial and temporal patterns in bat activity. First, I show that river channel confinement determines bat activity along a river's longitudinal axis (directly above the river), while trophic resources appear to have stronger effects across a river's lateral (with distance from the river) axis. Second, I show that flow intermittency affects bat foraging activity indirectly via its effects on trophic resource availability. Seasonal river drying appears to have complex effects on bat foraging activity, initially causing imperfect tracking by consumers of localized concentrations of resources but later resulting in disappearance of both insects and bats after complete river drying. Third, I show that resource tracking by bats varies among streams with contrasting patterns of trophic resource availability and this variation appears to be in response to differences in the timing of aquatic insect emergence, duration and magnitude of emergence, and adult body size of emergent aquatic insects. Finally, I show that aquatic insects directly influence bat activity along a desert stream and that riparian vegetation composition affects bat activity, but only indirectly, via effects on aquatic insect availability. Overall, my results show river channel confinement, riparian vegetation structure, flow permanence, and the timing of floods influence spatial and temporal patterns in bat distributions; but these effects are indirect by influencing the ability of bats to track trophic resources in space and time.

ContributorsHagen, Elizabeth M (Author) / Sabo, John L (Thesis advisor) / Fisher, Stuart G. (Committee member) / Grimm, Nancy (Committee member) / Schmeeckle, Mark W (Committee member) / Stromberg, Juliet C. (Committee member) / Arizona State University (Publisher)
Created2010
131609-Thumbnail Image.png
Description
In the event of a climate disaster, everything changes, but the places we’ve romanticized as a frontier will become new to us once again. New Sonoran is, in essence, an American story on a global problem. It draws on American pioneer/Old West/cowboy culture, the lasting effects of climate change denial,

In the event of a climate disaster, everything changes, but the places we’ve romanticized as a frontier will become new to us once again. New Sonoran is, in essence, an American story on a global problem. It draws on American pioneer/Old West/cowboy culture, the lasting effects of climate change denial, and the individualism that pervades American culture. I want to use this project to underscore the actual isolation of individualism, as well as create a new story that speaks to a problematic but evocative cultural history while accessing an uncertain future. For this project, I drew from a varied palette of media: comics, video games, and the pervasive cultural malaise that surrounds my current generation.
The work is based in anxieties, but its media influences are a strong indicator of tone and concept. At the very least, they helped me articulate why I wanted to work on a graphic novel on a post-climate change Sonoran. This desert that I’ve grown used to will change irrevocably, but it will be a new frontier to explore while the old will become a loss to mourn. This cycle of change is something I want to highlight in my work: we can worry, mourn, and fear, but there’s going to be something new.
New Sonoran is a graphic novel based upon the journey of Sage, a cartographer and anthropologist who travels the desert, annotating maps and studying a desert irrevocably affected by global climate change. As she catalogues the changes and losses in this new landscape, she learns how residents have adapted, and how people may still relate to the land.
ContributorsBarbee, Amelia Bernadette (Author) / Soares, Rebecca (Thesis director) / Schmidt, Peter (Committee member) / Department of English (Contributor, Contributor) / Barrett, The Honors College (Contributor)
Created2020-05