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All Subjects: Urbanization

Urbanization alters herbivore rodent composition but not abundance

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

The Effects of Urban Edge Proximity on Mesopredator Populations Adjacent to Gold Canyon, Az

Description

Urbanization is a landscape-level alteration of habitat that can lead to habitat fragmentation, degradation, and the introduction of nonnative species. Due to their life history characteristics, mammalian predators are particularly vulnerable to these effects. The categorization of many species as synanthropic, benefiting from human development, has been difficult as species have a gradient of responses to urbanization. Although coyotes, gray foxes and bobcats have all been shown to benefit from light to moderate levels of urbanization, often due to the increase in food resources, they typically require access to natural areas as escape cover. Camera traps at varying distances were used to document mesopredator response to the urban edge of Gold Canyon, Arizona from November 2015 through March 2016. Coyote, gray fox and bobcat relative abundance did not vary with distance to urban edge during this time period. Although, negative trends suggest that a larger scale study may reveal a negative relationship between distance to urban edge and mesopredator abundance for all 3 of these species. The efficacy of different baits at increasing mesopredator detections was also tested, with insignificant results. However, coyotes seemed to be more likely to interact with Carman's Raccoon Lure No. 2 than coyote urine. Understanding the responses of mesopredators to urbanization will allow us to better coexist with these vulnerable species as land continues to be developed at high rates across the globe.

ContributorsEvans, Jacquelyn Diane (Author) / Cunningham, Stanley (Thesis director) / Allen, Daniel (Committee member) / College of Letters and Sciences (Contributor) / Barrett, The Honors College (Contributor)

Created2016-05

A Review on the Generation, Determination and Mitigation of Urban Heat Island

Description

Urban Heat Island (UHI) is considered as one of the major problems in the 21st century posed to human beings as a result of urbanization and industrialization of human civilization. The large amount of heat generated from urban structures, as they consume and re-radiate solar radiations, and from the anthropogenic heat sources are the main causes of UHI. The two heat sources increase the temperatures of an urban area as compared to its surroundings, which is known as Urban Heat Island Intensity (UHII). The problem is even worse in cities or metropolises with large population and extensive economic activities. The estimated three billion people living in the urban areas in the world are directly exposed to the problem, which will be increased significantly in the near future. Due to the severity of the problem, vast research effort has been dedicated and a wide range of literature is available for the subject. The literature available in this area includes the latest research approaches, concepts, methodologies, latest investigation tools and mitigation measures. This study was carried out to review and summarize this research area through an investigation of the most important feature of UHI. It was concluded that the heat re-radiated by the urban structures plays the most important role which should be investigated in details to study urban heating especially the UHI. It was also concluded that the future research should be focused on design and planning parameters for reducing the effects of urban heat island and ultimately living in a better environment.

ContributorsRizwan, Ahmed Memon (Author) / Dennis, Leung Y.C. (Author) / Liu, Chunho (Author)

Created2007-09-27