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- All Subjects: Nature--Effect of human beings on.
- Creators: Franklin, Janet
Description
Often, when thinking of cities we envision designed landscapes, where people regulate everything from water to weeds, ultimately resulting in an ecosystem decoupled from biophysical processes. It is unclear, however, what happens when the people regulating these extensively managed landscapes come under stress, whether from unexpected economic fluctuations or from changing climate norms. The overarching question of my dissertation research was: How does urban vegetation change in response to human behavior? To answer this question, I conducted multiscale research in an arid urban ecosystem as well as in a virtual desert city. I used a combination of long-term data and agent-based modeling to examine changes in vegetation across a range of measures influenced by biophysical, climate, institutional, and socioeconomic drivers. At the regional scale, total plant species diversity increased from 2000 to 2010, while species composition became increasingly homogeneous in urban and agricultural areas. At the residential scale, I investigated the effects of biophysical and socioeconomic drivers – the Great Recession of 2007-2010 in particular – on changing residential yard vegetation in Phoenix, AZ. Socioeconomic drivers affected plant composition and increasing richness, but the housing boom from 2000 through 2005 had a stronger influence on vegetation change than the subsequent recession. Surprisingly, annual plant species remained coupled to winter precipitation despite my expectation that their dynamics might be driven by socioeconomic fluctuations. In a modeling experiment, I examined the relative strength of psychological, social, and governance influences on large-scale urban land cover in a desert city. Model results suggested that social norms may be strong enough to lead to large-scale conversion to low water use residential landscaping, and governance may be unnecessary to catalyze residential landscape conversion under the pressure of extreme drought conditions. Overall, my dissertation research showed that urban vegetation is dynamic, even under the presumably stabilizing influence of human management activities. Increasing climate pressure, unexpected socioeconomic disturbances, growing urban populations, and shifting policies all contribute to urban vegetation dynamics. Incorporating these findings into planning policies will contribute to the sustainable management of urban ecosystems.
ContributorsRipplinger, Julie (Author) / Franklin, Janet (Thesis advisor) / Collins, Scott L. (Thesis advisor) / Anderies, John M (Committee member) / Childers, Daniel L. (Committee member) / York, Abigail (Committee member) / Arizona State University (Publisher)
Created2015
Description
The recent emergence of global ‘megafires’ has made it imperative to better understand the role of humans in altering the size, distribution, and seasonality of fires. The dynamic relationship between humans and fire is not a recent phenomenon; rather, fire has deep roots in our biological and cultural evolution. Because of its long-term perspective, archaeology is uniquely positioned to investigate the social and ecological drivers behind anthropogenic fire. However, the field faces challenges in creating solution-oriented research for managing fire in the future. In this dissertation, I originate new methods and approaches to archaeological data that enable us to interpret humans’ long-term influences on fire regimes. I weave together human niche construction theory and ecological resilience, creating connections between archaeology, paleoecology, and fire ecology. Three, stand-alone studies illustrate the usefulness of these methods and theories for charting changes in land-use, fire-regimes, and vegetation communities during the Neolithic Transition (7600 - 3800 cal. BP) in eastern Spain. In the first study (Ch. II), I analyze archaeological survey data using Bayesian methods to extract land-use intensities from mixed surface assemblages from a case study in the Canal de Navarrés. The second study (Ch. III) builds on the archaeological data collected computational model of landscape fire, charcoal dispersion, and deposition to test how multiple models of natural and anthropogenic fire activity contributed to the formation a single sedimentary charcoal dataset from the Canal de Navarrés. Finally, the third study (Ch. IV) incorporates the modeling and data generated in the previous chapters into sampling and analysis of sedimentary charcoal data from alluvial contexts in three study areas throughout eastern Spain. Results indicate that anthropogenic fire played a significant role in the creation of agricultural landscapes during the Neolithic period, but sustained, low-intensity burning after the late Neolithic period maintained the human created niche for millennia beyond the arrival of agro-pastoral land-use. With global fire activity on the rise, it is vital to incorporate perspectives on the origins, development, and maintenance of human-fire relationships to effectively manage fire in today’s coupled social-ecological landscapes.
ContributorsSnitker, Grant (Author) / Barton, Michael (Thesis advisor) / Morehart, Christopher (Committee member) / Franklin, Janet (Committee member) / Arizona State University (Publisher)
Created2019