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- Creators: School of Sustainability
Description
Desert ecosystems are one of the fastest urbanizing areas on the planet. This rapid shift has the potential to alter the abundances and species richness of herbivore and plant communities. Herbivores, for example, are expected to be more abundant in urban desert remnant parks located within cities due to anthropogenic activities that concentrate food resources and reduce native predator populations. Despite this assumption, previous research conducted around Phoenix has shown that top-down herbivory led to equally reduced plant biomass. It is unclear if this insignificant difference in herbivory at rural and urban sites is due to unaltered desert herbivore populations or altered activity levels that counteract abundance differences. Vertebrate herbivore populations were surveyed at four sites inside and four sites outside of the core of Phoenix during fall 2014 and spring 2015 in order to determine whether abundances and richness differ significantly between urban and rural sites. In order to survey species composition and abundance at these sites, 100 Sherman traps and 8 larger wire traps that are designed to attract and capture small vertebrates such as mice, rats, and squirrels, were set at each site for two consecutive trap nights. Results suggest that the commonly assumed effect of urbanization on herbivore abundances does not apply to small rodent herbivore populations in a desert city, as overall small rodent abundances were statistically similar regardless of location. Though a significant difference was not found for species richness, a significant difference between small rodent genera richness at these sites was observed.
ContributorsAlvarez Guevara, Jessica Noemi (Co-author) / Ball, Becky A. (Co-author, Thesis director) / Hall, Sharon J. (Co-author) / Bateman, Heather (Committee member) / School of Sustainability (Contributor) / School of Mathematical and Natural Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2016-05
Description
In recent years, ecologists have begun to study the effects of urbanization on species diversity. While urban areas generally suffer decreased biodiversity, some species, termed “urban exploiters”, not only live in the city but depend on urban resources to thrive. It is hypothesized that urban exploiters may succeed in part due to phenotypic plasticity, in which organisms rapidly adjust their physiology or behavior to adapt to novel environmental contexts. In the city, it may be adaptive to display thermal plasticity, as the urban heat island effect caused by concrete and asphalt infrastructure prevents cooling at night. In this study, we observed the decorated cricket Gryllodes sigillatus, an invasive urban exploiter found in metropolitan Phoenix, in two separate experiments. We hypothesized that heat tolerance and activity are both plastic traits in this species. In Experiment 1, we predicted that knock-down time, a measure of heat tolerance, would be negatively affected by acclimation to a laboratory environment. Our results suggest that heat tolerance is affected by recent thermal regimes and that laboratory acclimation decreases knock-down time. In Experiment 2, we predicted that activity would increase with temperature until a point of extreme heat, at which point activity would decline. Statistical analysis for the second experiment reveals that activity decreases at 33°C, a natural urban extreme. This suggests either that 33°C is a thermal limit to physiology or that G. sigillatus is able to alter its behavior to exploit local thermal heterogeneity.
ContributorsVannan, Annika (Author) / Johnson, James Chadwick (Thesis director) / Angilletta, Michael (Committee member) / Barrett, The Honors College (Contributor) / School of Mathematical and Natural Sciences (Contributor) / School of Social and Behavioral Sciences (Contributor)
Created2015-05
Description
The objective of the research was to simulate interdependencies between municipal water-power distribution systems in a theoretical section of the Phoenix urban environment that had variable population density and highest ambient temperature. Real-time simulations were run using the Resilient Infrastructure Simulation Environment (RISE) software developed by Laboratory for Energy and Power Solutions (LEAPS) at ASU. The simulations were run at estimated population density to simulate urbanism, and temperature conditions to simulate increased urban heat island effect of Phoenix at 2020, 2040, 2060, and 2080 using the IEEE 13 bus test case were developed. The water model was simulated by extrapolated projections of increased population from the city of Phoenix census data. The goal of the simulations was that they could be used to observe the critical combination of system factors that lead to cascading failures and overloads across the interconnected system. Furthermore, a Resilient Infrastructure Simulation Environment (RISE) user manual was developed and contains an introduction to RISE and how it works, 2 chapters detailing the components of power and water systems, respectively, and a final section describing the RISE GUI as a user. The user manual allows prospective users, such as utility operators or other stakeholders, to familiarize themselves with both systems and explore consequences of altering system properties in RISE by themselves. Parts of the RISE User Manual were used in the online "help" guide on the RISE webpage.
ContributorsSchadel, Suzanne (Author) / Johnson, Nathan (Thesis director) / Hamel, Derek (Committee member) / School of International Letters and Cultures (Contributor) / School of Sustainable Engineering & Built Envirnmt (Contributor) / School of Sustainability (Contributor) / Barrett, The Honors College (Contributor)
Created2018-12