Matching Items (2)
Description
Remote sensing, with its capacity to capture continuous, high spatial and spectral resolution data, has emerged as an invaluable tool for ecological research and addressing conservation challenges. To fully harness the potential of remote sensing, spectral ecology has emerged as a field that investigates the interactions between the electromagnetic spectrum and biological processes. This dissertation capitalizes on a model system to explore the spectral ecology of a dominant, highly polymorphic, keystone, and endemic tree species (Metrosideros polymorpha). M. polymorpha not only serves as a model organism for studying adaptive radiation and intraspecific variation but also presents a critical conservation challenge. The recent introduction of the fungal disease Ceratocystis lukuohia has resulted in millions of M. polymorpha mortalities. This dissertation employs leaf-level spectroscopy data and canopy-level imaging spectroscopy data. Imaging spectroscopy captures reflectance across the visible to short-wave infrared (VSWIR) spectrum to provide high-spectral resolution data that enable canopy trait retrievals, species classifications, disease resistance detection, and genotype differentiation. Chapter 1 serves as an introduction, framing the subsequent chapters by presenting an overview of spectral ecology, imaging spectroscopy, and M. polymorpha. Chapter 2 explores M. polymorpha trait and spectra variation across environmental gradients. This chapter concludes that intraspecific variation follows the leaf economic spectrum and that elevation is a dominant driver of M. polymorpha trait and spectral variation. In Chapter 3, leaf-level spectroscopy was able to discriminate between sympatric, conspecific varieties of M. polymorpha and their hybrids as well as individuals resistant and susceptible to Ceratocystis wilt. Together, Chapters 2 and 3 support the concept of “genetic turnover,” akin to species turnover, wherein environmental conditions filter M. polymorpha genotypes present in a given region. Chapter 4 classifies M. polymorpha across the over 10,000 km2 of Hawai'i Island to aid in conservation efforts, demonstrating the potential of imaging spectroscopy to classify vegetation on large geographic scales. The final chapter builds on the prior chapters to present a M. polymorpha genetic diversity map for Hawai'i Island. In conclusion, this dissertation examines the spectral ecology of a model system to advance the understanding of ecological dynamics and address a pressing conservation challenge.
ContributorsSeeley, Megan (Author) / Asner, Gregory P (Thesis advisor) / Turner II, Billie L (Thesis advisor) / Martin, Roberta E (Committee member) / Frazier, Amy (Committee member) / Arizona State University (Publisher)
Created2023
Description
Anthropogenic land use has irrevocably transformed the natural systems on which humankind relies. Understanding where, why, and how social and economic processes drive globally-important land-use changes, from deforestation to urbanization, has advanced substantially. Illicit and clandestine activities--behavior that is intentionally secret because it breaks formal laws or violates informal norms--are poorly understood, however, despite the recognition of their significant role in land change. This dissertation fills this lacuna by studying illicit and clandestine activity and quantifying its influence on land-use patterns through examining informal urbanization in Mexico City and deforestation Central America. The first chapter introduces the topic, presenting a framework to examine illicit transactions in land systems. The second chapter uses data from interviews with actors involved with land development in Mexico City, demonstrating how economic and political payoffs explain the persistence of four types of informal urban expansion. The third chapter examines how electoral politics influence informal urban expansion and land titling in Mexico City using panel regression. Results show land title distribution increases just before elections, and more titles are extended to loyal voters of the dominant party in power. Urban expansion increases with electoral competition in local elections for borough chiefs and legislators. The fourth chapter tests and confirms the hypothesis that narcotrafficking has a causal effect on forest loss in Central America from 2001-2016 using two proxies of narcoactivity: drug seizures and events from media reports. The fifth chapter explores the spatial signature and pattern of informal urban development. It uses a typology of urban informality identified in chapter two to hypothesize and demonstrate distinct urban expansion patterns from satellite imagery. The sixth and final chapter summarizes the role of illicit and clandestine activity in shaping deforestation and urban expansion through illegal economies, electoral politics, and other informal transactions. Measures of illicit and clandestine activity should--and could--be incorporated into land change models to account for a wider range of relevant causes. This dissertation shines a new light on the previously hidden processes behind ever-easier to detect land-use patterns as earth observing satellites increase spatial and temporal resolution.
ContributorsTellman, Elizabeth (Author) / Turner II, Billie L (Thesis advisor) / Eakin, Hallie (Thesis advisor) / Janssen, Marco (Committee member) / Alba, Felipe de (Committee member) / Jain, Meha (Committee member) / Arizona State University (Publisher)
Created2019