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Creators: School of Life Sciences
Member of: Barrett, The Honors College Thesis/Creative Project Collection

Urban Forestry as a Carbon Offset Method at ASU West Campus

Description

As part of Arizona State University’s net-zero carbon initiative, 1000 mesquite trees were planted on a vacant plot of land at West Campus to sequester carbon from the atmosphere. Urban forestry is typically a method of carbon capture in temperate areas, but it is hypothesized that the same principle can be employed in arid regions as well. To test this hypothesis a carbon model was constructed using the pools and fluxes measured at the Carbon sink and learning forest at West Campus. As an ideal, another carbon model was constructed for the mature mesquite forest at the Hassayampa River Preserve to project how the carbon cycle at West Campus could change over time as the forest matures. The results indicate that the West Campus plot currently functions as a carbon source while the site at the Hassayampa river preserve currently functions as a carbon sink. Soil composition at both sites differ with inorganic carbon contributing to the largest percentage at West Campus, and organic carbon at Hassayampa. Predictive modeling using biomass accumulation estimates and photosynthesis rates for the Carbon Sink Forest at West Campus both predict approximately 290 metric tons of carbon sequestration after 30 years. Modeling net ecosystem exchange predicts that the West Campus plot will begin to act as a carbon sink after 33 years.

ContributorsLiddle, David Mohacsy (Author) / Ball, Becky (Thesis director) / Nishimura, Joel (Committee member) / School of Life Sciences (Contributor) / School of Mathematical and Statistical Sciences (Contributor) / Barrett, The Honors College (Contributor)

Created2021-05

A Not-So-Deserted Microbial World: The Microbiome of the Western Black Widow Spider (Latrodectus hesperus)

Description

With increasing urbanization, organisms face a myriad of novel ecological challenges. While the eco-evolutionary dynamics of urbanization are currently receiving a great deal of attention, the effect of urban disturbance on the microbiome of urban organisms is relatively unstudied. Indeed, studies of the microbiome may illuminate the mechanisms by which some species thrive after urbanization (pest implications), while other species go locally extinct (biodiversity implications). We investigated the gut microbiome of the Western black widow spider (Latrodectus hesperus). L. hesperus is an ideal model system as they are a pest species of medical importance in urban ecosystems, often forming dense urban infestations relative to the sparse populations found in their native Sonoran Desert. To gain insight into the composition of the microbiome in L. hesperus and its potential function, we sampled 4 urban, 4 desert, and 2 laboratory-reared spiders, and high-throughput sequencing of the 16S rRNA V4 region was used to investigate the diversity of gut microbiota. Dominant bacterial phyla across all samples were Firmicutes, Proteobacteria, and Actinobacteria. While desert widows showed more gut microbial diversity than urban widows, the difference was not statistically significant. The relative abundance of taxonomic classes Blastocatellia, Acidobacteriia, and Thermoleophilia detected in desert spiders was especially higher than those in urban and laboratory-reared spiders. However, urban spiders had a higher relative abundance of taxonomic class Actinomycetia. Differences in widow gut microbiome diversity improves our understanding of how features unique to a habitat, like prey diversity and soil microbes, may be shaping their microbiome. Additionally, this work further highlights the impact urbanization has on biodiversity loss, which indirectly develops a new biomarker for differentiating between urban and desert black widow spiders based on their gut microbiome.

ContributorsAsrari, Hasti (Author) / Johnson, Chad (Thesis director) / Sandrin, Todd (Committee member) / Barrett, The Honors College (Contributor) / School of Mathematical and Natural Sciences (Contributor) / School of Life Sciences (Contributor)

Created2022-12

Examining sound and urban-desert differences in the acoustic properties of Northern Mockingbird (Mimus polyglottus) calls as it relates to species survival

Description

Human activity produces ambient noise that potentially alters species’ abilities to communicate with each other—among other impacts. Given that birds are known to be sensitive to structural changes in habitat and highly communicative through sound, it is beneficial to understand how changing acoustic ecologies and ambient noise impact birds’ ability to communicate in their respective environments. In this study, mockingbird calls from an urban, desert, and intermediate study site were recorded and analyzed for differences in acoustic properties. Acoustic properties such as frequency and amplitude differed significantly across sites as it was determined that mockingbirds in urban areas increase both the peak frequency and amplitude of their calls in order to communicate. This study identifies what these changes in acoustic properties mean in relation to the survival and conservation of birds and concludes with recommendations for novel research.

ContributorsReynolds, Bailey Susana (Author) / Pearson, David (Thesis director) / Walters, Molina (Committee member) / School of Sustainability (Contributor) / School of Life Sciences (Contributor) / Dean, W.P. Carey School of Business (Contributor) / Barrett, The Honors College (Contributor)

Created2019-05