Matching Items (6)
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- All Subjects: Urbanization
- All Subjects: plateau pika
- Creators: Wu, Jianguo
Description
The plateau pika (Ochotona curzoniae), a small burrowing lagomorph that occupies the high alpine grassland ecosystems of the Qinghai-Tibetan Plateau in western China, remains a controversial subject among policymakers and researchers. One line of evidence points to pikas being a pest, which has led to massive attempts to eradicate pika populations. Another point of view is that pikas are a keystone species and an ecosystem engineer in the grassland ecosystem of the QTP. The pika eradication program raises a difficult ethical and religious dilemma for local pastoralists, and is criticized for not being supported by scientific evidence. Complex interactions between pikas, livestock, and habitat condition are poorly understood. My dissertation research examines underpinning justifications of the pika poisoning program leading to these controversies. I investigated responses of pikas to habitat conditions with field experimental manipulations, and mechanisms of pika population recovery following pika removal. I present policy recommendations based on an environmental ethics framework and findings from the field experiments. After five years of a livestock grazing exclusion experiment and four years of pika monitoring, I found that grazing exclusion resulted in a decline of pika habitat use, which suggests that habitat conditions determine pika population density. I also found that pikas recolonized vacant burrow systems following removal of residents, but that distances travelled by dispersing pikas were extremely short (~50 m). Thus, current pika eradication programs, if allowed to continue, could potentially compromise local populations as well as biodiversity conservation on the QTP. Lethal management of pikas is a narrowly anthropocentric-based form of ecosystem management that has excluded value-pluralism, such as consideration of the intrinsic value of species and the important ecological role played by pikas. These conflicting approaches have led to controversies and policy gridlock. In response, I suggest that the on-going large-scale pika eradication program needs reconsideration. Moderation of stocking rates is required in degraded pika habitats, and Integrated Pest Management may be required when high stocking rate and high pika density coexist. A moderate level of livestock and pika density can be consistent with maintaining the integrity and sustainability of the QTP alpine steppe ecosystem.
ContributorsBadingqiuying (Author) / Smith, Andrew T. (Thesis advisor) / Wu, Jianguo (Committee member) / Minteer, Ben (Committee member) / Anderies, John (Committee member) / Harris, Richard B. (Committee member) / Arizona State University (Publisher)
Created2016
Description
Context – Urbanization can have negative effects on bat habitat use through the loss and isolation of habitat even for volant bats. Yet, how bats respond to the changing landscape composition and configuration of urban environments remains poorly understood.
Objective – This study examines the relationship between bat habitat use and landscape pattern across multiple scales in the Phoenix metropolitan region. My research explores how landscape composition and configuration affects bat activity, foraging activity, and species richness (response variables), and the distinct habitats that they use.
Methods – I used a multi-scale landscape approach and acoustic monitoring data to create predictive models that identified the key predictor variables across multiple scales within the study area. I selected three scales with the intent of capturing the landscape, home range, and site scales, which may all be relevant for understanding bat habitat use.
Results – Overall, class-level metrics and configuration metrics best explained bat habitat use for bat species associated with this urban setting. The extent and extensiveness of water (corresponding to small water bodies and watercourses) were the most important predictor variables across all response variables. Bat activity was predicted to be high in native vegetation remnants, and low in native vegetation at the city periphery. Foraging activity was predicted to be high in fine-scale land cover heterogeneity. Species richness was predicted to be high in golf courses, and low in commercial areas. Bat habitat use was affected by urban landscape pattern mainly at the landscape and site scale.
Conclusions – My results suggested in hot arid urban landscapes water is a limiting factor for bats, even in urban landscapes where the availability of water may be greater than in outlying native desert habitat. Golf courses had the highest species richness, and included the detection of the uncommon pocketed free-tailed bat (Nyctinomops femorosaccus). Water cover types had the second highest species richness. Golf courses may serve as important stop-overs or refuges for rare or elusive bats. Urban waterways and golf courses are novel urban cover types that can serve as compliments to urban preserves, and other green spaces for bat conservation.
Objective – This study examines the relationship between bat habitat use and landscape pattern across multiple scales in the Phoenix metropolitan region. My research explores how landscape composition and configuration affects bat activity, foraging activity, and species richness (response variables), and the distinct habitats that they use.
Methods – I used a multi-scale landscape approach and acoustic monitoring data to create predictive models that identified the key predictor variables across multiple scales within the study area. I selected three scales with the intent of capturing the landscape, home range, and site scales, which may all be relevant for understanding bat habitat use.
Results – Overall, class-level metrics and configuration metrics best explained bat habitat use for bat species associated with this urban setting. The extent and extensiveness of water (corresponding to small water bodies and watercourses) were the most important predictor variables across all response variables. Bat activity was predicted to be high in native vegetation remnants, and low in native vegetation at the city periphery. Foraging activity was predicted to be high in fine-scale land cover heterogeneity. Species richness was predicted to be high in golf courses, and low in commercial areas. Bat habitat use was affected by urban landscape pattern mainly at the landscape and site scale.
Conclusions – My results suggested in hot arid urban landscapes water is a limiting factor for bats, even in urban landscapes where the availability of water may be greater than in outlying native desert habitat. Golf courses had the highest species richness, and included the detection of the uncommon pocketed free-tailed bat (Nyctinomops femorosaccus). Water cover types had the second highest species richness. Golf courses may serve as important stop-overs or refuges for rare or elusive bats. Urban waterways and golf courses are novel urban cover types that can serve as compliments to urban preserves, and other green spaces for bat conservation.
ContributorsBazelman, Tracy C (Author) / Wu, Jianguo (Thesis advisor) / Chambers, Carol L. (Thesis advisor) / Smith, Andrew T. (Committee member) / Arizona State University (Publisher)
Created2016
Description
The highly-social plateau pika (Lagomorpha: Ochotona curzoniae) excavates vast burrow complexes in alpine meadows on the Tibetan Plateau. Colonies of over 300 individuals/ha have been reported. As an ecosystem engineer, their burrowing may positively impact ecosystem health by increasing plant species diversity, enhancing soil mixing, and boosting water infiltration. However, pikas are commonly regarded as pests, and are heavily poisoned throughout their range. The underlying assumption of eradication programs is that eliminating pikas will improve rangeland quality and decrease soil erosion. This dissertation explores the link between plateau pikas and the alpine meadow ecosystem in Qinghai Province, PRC. This research uses both comparative field studies and theoretical modeling to clarify the role of pika disturbance. Specifically, these studies quantify the impact of pikas on nutrient cycling (via nutrient concentrations of vegetation and soil), hydrology (via water infiltration), local landscape properties (via spatial pattern description), and vascular plant communities (via species richness and composition). The competitive relationship between livestock and pikas is examined with a mathematical model. Results of this research indicate that pika colonies have both local and community level effects on water infiltration and plant species richness. A major contribution of pika disturbance is increased spatial heterogeneity, which likely underlies differences in the plant community. These findings suggest that the positive impact of plateau pikas on rangeland resources has been undervalued. In concurrence with other studies, this work concludes that plateau pikas provide valuable ecosystem services on the Tibetan Plateau.
ContributorsHogan, Brigitte Wieshofer (Author) / Smith, Andrew T. (Thesis advisor) / Anderies, J. Marty (Committee member) / Briggs, John M. (Committee member) / Stromberg, Juliet C. (Committee member) / Wu, Jianguo (Committee member) / Arizona State University (Publisher)
Created2010
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
Description
With a growing majority of humans living within cities and towns, urbanization is one of the most persistent drivers of change in global land use and challenges to sustainability and biodiversity conservation. The development of cities and towns can substantially shape local and regional environments in which wildlife communities persist. Although urbanization can negatively affect wildlife communities – through processes such as habitat fragmentation and non-native species introduction – cities can also provide resources to wildlife, such as through food, water, and space, creating potential opportunities for conservation. However, managing wildlife communities persisting in urbanizing landscapes requires better understanding of how urbanized landscapes influence the ability of wildlife to coexist with one another and with people at local and regional scales. In this dissertation, I addressed these research needs by evaluating the environmental and human factors driving dynamic wildlife community distributions and people’s attitudes towards wildlife. In my first two chapters,I used wildlife camera data collected from across the Phoenix Metropolitan Area, AZ to examine seasonal patterns of wildlife space use, species richness, and interspecific interactions across levels of urbanization with varying landscape characteristics, including plant productivity and spatial land use heterogeneity. Here I found that urbanization was a primary driver of wildlife community characteristics within the region, but that seasonal resource availability and landscape heterogeneity could have mediating influences that require further exploration. In my third chapter, I partnered
with wildlife researchers across North America to examine how relationships between urbanization and community composition vary among cities with distinct social-ecological characteristics, finding that effects of local urbanization were more negative in warmer, less vegetated, and more urbanized cities. In my fourth and final chapter, I explored the potential for human-wildlife coexistence by examining how various ideological, environmental, and sociodemographic factors influenced Phoenix area residents’ level of comfort living near different wildlife groups. Although I found that residents’ attitudes were primarily shaped by their relatively static wildlife values, comfort living near wildlife also depended on the characteristics of the neighboring environment, of the residents, and of the wildlife involved, indicating the potential for facilitating conditions for human-wildlife coexistence. Altogether, the findings of this dissertation suggest that the management of wildlife and their interactions with people within cities would benefit from more proactive and holistic consideration of the interacting environmental, wildlife, and human characteristics that influence the persistence of biodiversity within an increasingly urbanized world.
ContributorsHaight, Jeffrey Douglas (Author) / Hall, Sharon J (Thesis advisor) / Lewis, Jesse S (Thesis advisor) / Larson, Kelli L (Committee member) / Wu, Jianguo (Committee member) / Arizona State University (Publisher)
Created2023
Description
The science community has made efforts for over a half century to address sustainable development, which gave birth to sustainability science at the turn of the twenty-first century. Along with the development of sustainability science during the past two decades, a landscape sustainability science (LSS) perspective has been emerging. As interests in LSS continue to grow rapidly, scholars are wondering what LSS is about and how LSS fits into sustainability science, while practitioners are asking how LSS actually contributes to sustainability in the real world. To help address these questions, this dissertation research aims to explore the currently underused problem-driven, diagnostic approach to enhancing landscape sustainability through an empirical example of urbanization-associated farmland loss (UAFL). Based mainly on multimethod analysis of bibliographic information, the dissertation explores conceptual issues such as how sustainability science differs from conventional sustainable development research, and how the past, present, and future research needs of LSS evolve. It also includes two empirical studies diagnosing the issue of urban expansion and the related food security concern in the context of China, and proposes a different problem framing for farmland preservation such that stakeholders can be more effectively mobilized. The most important findings are: (1) Sustainability science is not “old wine in a new bottle,” and in particular, is featured by its complex human-environment systems perspective and value-laden transdisciplinary perspective. (2) LSS has become a vibrant emerging field since 2004-2006 with over three-decade’s intellectual accumulation deeply rooted in landscape ecology, yet LSS has to further embrace the two featured perspectives of sustainability science and to conduct more problem-driven, diagnostic studies of concrete landscape-relevant sustainability concerns. (3) Farmland preservationists’ existing problem framing of UAFL is inappropriate for its invalid causal attribution (i.e., urban expansion is responsible for farmland loss; farmland loss is responsible for decreasing grain production; and decreasing grain production instead of increasing grain demand is responsible for grain self-insufficiency); the real problem with UAFL is social injustice due to collective action dilemma in preserving farmland for regional and global food sufficiency. The present research provides broad implications for landscape scientists, the sustainability research community, and UAFL stakeholders.
ContributorsZhou, Bingbing (Author) / Wu, Jianguo (Thesis advisor) / Aggarwal, Rimjhim (Committee member) / Anderies, John Marty (Committee member) / Janssen, Marcus Alexander (Committee member) / Turner II, Billie Lee (Committee member) / Arizona State University (Publisher)
Created2020