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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
881

Mapping cross-channel ecosystems : A case study based on a company in the field of UX.

de la O Schöneck, Mauricio, Mathew, Roshan January 2016 (has links)
Every product or service is part of an ecosystem. The analysis of ecosystems enables organizations to understand the use and potential of a product or service. The information that flows through ecosystems is not always tangible. However, it can be categorized and accessed through different gateways. In this thesis, the authors present an overview of current service design tools and compare them to a cross-channel ecosystem’s approach. The ubiquitous nature of technology permits users to interact and perform activities uninterrupted within physical and digital space. Therefore, the inclusion of external stakeholders within an ecosystem enables a richer analysis of a product or service design. Two major factors that are taken into consideration: 1. Touchpoints within the ecosystem. 2. The information channels that can be accessed through touchpoints. This thesis involves an exploratory case study that aims at mapping cross-channel experiences and ecosystems thereafter in relation to a publishing firm located in New York. Along the conceptualization process, the authors faced difficulties understanding appropriate methods of labelling and choosing of elements that assist in the construction of an ecosystem. However, the initial drawing of the firm’s ecosystem clearly differs from the results attained from the interviews outcomes on the one hand. On the other hand, the final diagram of overlapped information channels placed over a fraction of the ecosystem, provides a tangible understanding towards the presence of touchpoints in one or more information channels. By displaying such cross-channel ecosystems, organizations can increase or re-structure their activities according to their strategy. The study gives a very concrete proposition of how the ecosystems can be mapped. Further studies and guidelines to increase an ecosystems parameters and precision of execution is still to be developed and researched.
882

Impactos potenciais da mudança climática no desenvolvimento humano : uma análise baseada na abordagem das capacitações

Correa Macana, Esmeralda January 2008 (has links)
O objetivo principal desta dissertação é analisar como a mudança climática pode afetar o processo de desenvolvimento humano. Com esse objetivo, procurou-se identificar, caracterizar e sistematizar os impactos potenciais da mudança climática em dimensões relevantes do desenvolvimento humano, tais como: saúde, educação, meios de subsistência, segurança, valores culturais e relações sociais. O trabalho propõe uma estrutura analítica na qual se identificam relações diretas e indiretas entre os componentes climáticos e do bem-estar humano e definem-se mecanismos que interligam as duas áreas, sendo estes os recursos naturais de água, solo e biodiversidade, assim como os serviços dos ecossistemas. A análise realizada não foi restrita à realidade de um país, ao invés, foram associados elementos tendo em conta as evidências em nível global. O estudo foi baseado na abordagem de desenvolvimento humano fundamentada por Amartya Sen, a qual permitiu considerar um conjunto amplo de dimensões na avaliação do bem-estar, abrangendo as diversas formas em que as pessoas são e podem ser privadas de desfrutar uma vida que eles valoram devido à mudança climática. Através da estrutura analítica proposta neste trabalho e na investigação sistemática de dois corpos de literatura (respectivamente ambiental e de desenvolvimento humano), foi possível constatar que o processo de desenvolvimento humano está determinado pela expansão de aspectos multidimensionais, como funcionamento e capacitações, bem como meios e intitulamentos que podem aumentar ou diminuir dependendo a relação com os sistemas do meio ambiente, em especial, do sistema climático. As evidências analisadas demonstraram como as alterações do clima constituem um risco latente para o retrocesso do desenvolvimento humano e ampliação das privações humanas em todo o mundo, com desproporcionais efeitos em países pobres e em desenvolvimento. Por um lado, os choques climáticos ameaçam em diferentes caminhos (direta e indiretamente) os funcionamentos e capacitações das pessoas, como a saúde, a educação, os valores culturais e as relações sociais. Por outro lado, os choques climáticos restringem o desenvolvimento humano ao afetar e limitar os "meios e intitulamentos" necessários para o sustento das pessoas, através da redução da quantidade e qualidade da água, da produção agrícola, da alteração de atividades de pesca, redução de rendimentos econômicos, entre outras formas. Os maiores impactos são em áreas rurais, as quais concentram maior proporção de pobres. O exame de impactos levou em conta a interação com aspectos de vulnerabilidade pré-existente de cada país ou região, relacionados com a exposição definida pela localização geográfica, a sensibilidade de acordo com a dependência na agricultura e nos serviços dos ecossistemas e a capacidade de adaptação determinada por aspectos sociais, econômicos, institucionais, políticos e dotação dos recursos naturais. / The main aim of this dissertation is to examine how climate change can affect the process of human development. In particular, it tries to identify, characterize and classify the potential impacts of climate change on relevant dimensions of human development, such as health, education, livelihoods, security, cultural values and social relations. The dissertation proposes an analytical structure in which it delves into direct and indirect relations between the components of the climate and well being, and set up mechanisms that link the two areas, which are the natural resources of water, soil and biodiversity as well as the ecosystem services. The analysis was not restricted to the particular realities of a given country, in contrast, it focused on evidence at a global level. This study is based on the vision of human development as characterized by the work of Amartya Sen, which enabled us to consider a wide range of dimensions in the assessment of well being, covering the various ways in which people are and can be deprived of enjoying a life that they value due to climate change. Through the analytical framework proposed in this paper and the systematic investigation of two bodies of literature (the environmental and human development), it was possible to see that the process of human development is determined by the expansion of multidimensional aspects, such as functionings and capabilities, as well as means and entitlements that may increase or decrease depending on the relation with the environment, especially the climate system. The analysis showed evidence such as that climate change is a latent risk to the setback of human development and expansion of human deprivation in the world, with disproportionate effect on poor and developing countries. The climatic shocks threaten in different ways (directly and indirectly) the functionings and capabilities of individuals, such as health, education, cultural values and social relations. Moreover, the climatic shocks restrict human development to affect and limit the "means and entitlements" necessary for the sustenance of the people, by reducing the quantity and quality of water, agricultural production, modification of fishing activities, reduction income, among other ways. The largest impacts are in rural areas, which concentrate the largest proportion of poor people. An examination of impacts took into account the interaction with aspects of pre-existing vulnerability of each country or region, associated with exposure defined by geographic location, according to the sensitivity of the dependence on agriculture and ecosystems services and the capacity of adaptation certain by social, economic, institutional, political and status of natural resources.
883

Narrativas das percepções e conectividades de caminhantes nas paisagens dos areais pampeanos: perspectivas ambientais para geração de ambiências

Silva, Luis Alberto Pires da January 2008 (has links)
Neste texto que evoca as percepções de muit@s, narradas e tramadas a partir da ambiência entre os diferentes caminhantes que se propuseram o desafio de caminhar em direção à Campanha gaúcha, busco traçar os caminhos desde os primeiros humanos que se estabeleceram no que hoje se constitui o sudoeste sul-riograndense e seu encontro com as paisagens do Pampa, até @s errantes que ainda buscam caminhos nos tempos atuais nesses pagos. Os caminhos e olhares que hoje traçamos estão retratados pelas percepções da ambiência estabelecida nas atividades de campo pelos atores que elegeram estudar os areais e o processo de sua gênese, a arenização, em suas pesquisas de pós-graduação e pela atenção dispensada aos jovens e professoras de uma unidade federal de ensino, CEFET, que traduziram sua visão e conceito de paisagem por imagens fotográficas, desenhos e comentários destas. Parte do caminho é narrada pelo autor, mesmo procurando respostas as questões da dinâmica ecológica estabelecida sobre os areais e por vezes encontrando material para reflexão sobre as mesmas, continua buscando respostas para perguntas ainda não formuladas, no intuito de encontrar novos motivos de reflexão onde não se tinha buscado. / This text that evokes the perceptions of many, narrated and made from the environment between the different walkers which proposed the challenge of moving towards the Campanha Gaúcha, I track the paths since the first humans who have settled in the Southwest South-Rio-Grandense and their ways towards Pampa's landscapes, until those who still seek ways in current times those pagos. The roads and looks that we traced today are portrayed by the perceptions of the environment established in field activities by stakeholders who elected to study the sand and the process of its genesis, the sandiness in their search for Graduate degree and the attention given by young people and teachers of a federal unit of instruction, CEFET, who translated its vision and concept of landscape by photographic images, drawings and comments. Part of the path is narrated by the author, even looking for answer the questions of ecological dynamics established on the sand and sometimes finding material for reflection on them, still seeking answers to questions not made yet, in order to find new reasons for reflection where no one had sought.
884

Redundância funcional em comunidades campestres / Functional redundancy in grassland plant communities

Joner, Fernando January 2008 (has links)
Os campos do Rio Grande do Sul apresentam grande biodiversidade, beleza cênica e um importante recurso para a economia do estado, cuja principal atividade é a pecuária. O manejo inadequado do campo traz conseqüências graves para a diversidade e sustentabilidade desse ecossistema através da perda de espécies promovida pelo pastejo excessivo. Entretanto, algumas espécies desempenham as mesmas funções nos ecossistemas, logo a perda de algumas espécies pode não afetar o seu funcionamento, pela compensação de outras espécies do mesmo grupo funcional. Esta redundância funcional aumentaria a confiabilidade do funcionamento do ecossistema quando perturbado, funcionando como um tipo de "seguro" contra a perda de espécies. A hipótese da redundância funcional foi avaliada em ecossistemas campestres através de um experimento de remoção no qual os tratamentos avaliados consistiram em: 1) remoção de duas espécies graminóides, 2) remoção de duas espécies herbáceas não-graminóides, 3) remoção de uma espécie de graminóide e uma herbácea não-graminóide e 4) sem remoção. As evidências indicam que existe redundância funcional para as espécies de plantas em ecossistemas campestres, pois a remoção de uma espécie de cada grupo funcional causou menos modificações na composição de espécies das comunidades que a remoção de duas espécies do mesmo grupo funcional. Observou-se também que a porcentagem da cobertura das espécies remanescentes tende a compensar a remoção de espécies do mesmo grupo funcional. Entretanto, os tratamentos não tiveram efeito para a biomassa aérea. A avaliação de um banco de dados de um experimento de pastejo realizado anteriormente revelou que a redundância funcional está positivamente relacionada com a resistência da comunidade ao pastejo, enquanto a riqueza de espécies não apresentou relação. Áreas de campo com maiores níveis de redundância funcional são mais resistentes ao pastejo, sofrendo menos modificações na composição de espécies de suas comunidades. Além disso, um manejo adequado não reduz os níveis de redundância funcional dos campos. Áreas de campo dentro de unidades de conservação deveriam ser manejas adequadamente mantendo os níveis de redundância funcional e a estabilidade deste ecossistema. Entretanto, novos estudos são necessários para avaliar a importância da redundância funcional em experimentos de longa duração. / Grasslands from Rio Grande do Sul present great biodiversity, scenic beauty and an important resource to the province economy, which main activity is cattle grazing. Inadequate pasture management brings serious consequences to ecosystem diversity and sustainability by the loss of species promoted by excessive grazing. Although, some species may role the same functions in ecosystems, therefore loss of some species may not affect functioning, due to species compensation within functional groups. This functional redundancy would increase ecosystem reliability when perturbations occur, working as an "insurance" to species loss. Functional redundancy hypothesis was evidenced in grassland plant communities through a removal experiment in which evaluated treatments were: 1) removal of two graminoid species, 2) removal of two forb species, 3) removal of one species of each functional group and 4) no removal (control). Evidences point to functional redundancy for grassland plant species; removal of one species of each functional group caused less harm to community species composition than removal of two species of the same functional group. Furthermore, remaining species percent covers tend to compensate removed species of the same functional group. However, treatments did not effected aboveground biomass. Data set evaluation of a previously conducted cattle-grazing experiment reveled that functional redundancy is positively related to community resistance to cattle grazing, otherwise species richness presented no relation. Grassland areas with higher levels of functional redundancy are more resistant to cattle grazing, suffering less modification in community species composition. Also, adequate management do not reduce functional redundancy on pastures. Grassland areas inside conservation units should be managed adequately maintaining redundancy levels and ecosystem reliability. Although, new studies are required to better evaluate functional redundancy implications in long term experiments.
885

Índice de uso do solo por habitante (IUSH): proposta e aplicação / Land use human index (LUHI): proposal and application

Parras, Rafael 30 July 2018 (has links)
Submitted by Rafael Parras (rafael.parras@unesp.br) on 2018-09-21T12:27:40Z No. of bitstreams: 1 Dissertação_PARRAS_Impressão.pdf: 1866752 bytes, checksum: 9dbe2131a5a40499159c2de8517a007b (MD5) / Approved for entry into archive by Neli Silvia Pereira null (nelisps@fcav.unesp.br) on 2018-09-21T17:54:28Z (GMT) No. of bitstreams: 1 parras_r_me_jabo.pdf: 1866752 bytes, checksum: 9dbe2131a5a40499159c2de8517a007b (MD5) / Made available in DSpace on 2018-09-21T17:54:28Z (GMT). No. of bitstreams: 1 parras_r_me_jabo.pdf: 1866752 bytes, checksum: 9dbe2131a5a40499159c2de8517a007b (MD5) Previous issue date: 2018-07-30 / Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) / RESUMO – O sistema de produção vegetal compreende a informação sobre os sistemas representativos das explorações agrícolas. A observação do comportamento do uso e da ocupação do solo indica a dinamização agropecuária associada à “pressão” que os habitantes e a agricultura exercem sobre os recursos ambientais de uma unidade político administrativa, e é um importante fator para os tomadores de decisão. As mudanças antropogênicas do uso do solo causam um desequilíbrio ecológico no ambiente e são capazes de interferir no sistema de produção agrícola, pois os fatores necessários para a manutenção dos sistemas de produção podem ser consumidos limitando sua capacidade. Partindo do exposto, propõe-se o cálculo e a aplicação de um índice que permite comparar o comportamento do desenvolvimento de uma sociedade no que tange ao uso e ocupação do solo em uma unidade política administrativa. O Índice de uso do solo por habitante (IUSH) consiste da relação entre o uso e a ocupação do solo (área) de uma unidade política administrativa e o número de habitantes desta mesma unidade em um determinado momento. Ao observar os resultados obtidos na análise multivariada de componentes principais, nota-se que os recursos naturais demandados diretamente pela população da unidade político administrativa, como por exemplo, a água consumida, o esgoto coletado e o esgoto tratado, se agruparam separadamente dos relacionados ao comportamento de uso e ocupação do solo, como fragmentos florestais e áreas urbanizadas com acesso pavimentado. Esta separação indica a insustentabilidade. Estes dados comprovam que o IUSH mensura a pressão exercida por um determinado número de habitantes sobre os recursos naturais de uma unidade política-administrativa. Ao analisar, ao longo do tempo, este índice indica o aumento ou a diminuição da demanda sobre os recursos naturais disponíveis. Estes valores poderão auxiliar os tomadores de decisão para uma gestão mais sustentável em sistemas de produção vegetal. Posteriormente o IUSH poderá ser usado para comparar unidades político administrativas quanto a gestão sustentável de suas áreas. / ABSTRACT – The observation of the behavior of the use and occupation of the soil associated to the "pressure" that the inhabitants exert on the environmental resources of an administrative political unit is an important point for the decision makers. Anthropogenic changes in land usage cause an ecological imbalance in the environment and are able to interfering with the agricultural production system. The factors necessary for the maintenance of production systems can be consumed by limiting their capacity. Based on this, it is proposed the calculation and the application of an index that allows comparing the behavior of the society development regarding the occupation of land use in a political administrative unit. The Land Use Human Index (LUHI) consists of the relationship between the use and occupation of the soil (area) of a unit administrative political and the number of inhabitants, of this same unit, at a given moment. When analyzing, over time, this index is able to indicate the increase or decrease of the demand on the available natural resources. These values can help to take decisions towards more sustainable management. When observing the results obtained in the multivariate analysis of the main components, it can be observed that the natural resources demanded directly by the population of the administrative political unit, such as the water consumed, collected sewage and treated sewage, they can grouped separately from those related to the behavior of use and occupation of the soil, such as forest fragments and urbanized areas with paved access. These data show that the LUHI measures the pressure exerted by a certain number of inhabitants on the natural resources of a political-administrative unit. Subsequently the LUHI can be used to compare political administrative units regarding the sustainable management of their areas. / 142749/2016-8
886

Theoretical and Empirical Investigations of Ecosystem Development in Boreal Wetlands

January 2015 (has links)
abstract: Despite the breadth of studies investigating ecosystem development, an underlying theory guiding this process remains elusive. Several principles have been proposed to explain ecosystem development, though few have garnered broad support in the literature. I used boreal wetland soils as a study system to test a notable goal oriented principle: The Maximum Power Principle (MPP). The MPP posits that ecosystems, and in fact all energy systems, develop to maximize power production or the rate of energy production. I conducted theoretical and empirical investigations to test the MPP in northern wetlands. Permafrost degradation is leading to rapid wetland formation in northern peatland ecosystems, altering the role of these ecosystems in the global carbon cycle. I reviewed the literature on the history of the MPP theory, including tracing its origins to The Second Law of Thermodynamics. To empirically test the MPP, I collected soils along a gradient of ecosystem development and: 1) quantified the rate of adenosine triphosphate (ATP) production--literally cellular energy--to test the MPP; 2) quantified greenhouse gas production (CO2, CH4, and N2O) and microbial genes that produce enzymes catalyzing greenhouse gas production, and; 3) sequenced the 16s rRNA gene from soil microbes to investigate microbial community composition across the chronosequence of wetland development. My results suggested that the MPP and other related theoretical constructs have strong potential to further inform our understanding of ecosystem development. Soil system power (ATP) decreased temporarily as the ecosystem reorganized after disturbance to rates of power production that approached pre-disturbance levels. Rates of CH4 and N2O production were higher at the newly formed bog and microbial genes involved with greenhouse gas production were strongly related to the amount of greenhouse gas produced. DNA sequencing results showed that across the chronosequence of development, the two relatively mature ecosystems--the peatland forest ecosystem prior to permafrost degradation and the oldest bog--were more similar to one another than to the intermediate, less mature bog. Collectively, my results suggest that ecosystem age, rather than ecosystem state, was a more important driver for ecosystem structure and function. / Dissertation/Thesis / Doctoral Dissertation Biology 2015
887

The Effects of Non-native and Native Anuran Tadpoles on Aquatic Ecosystem Processes

January 2015 (has links)
abstract: Non-native consumers can significantly alter processes at the population, community, and ecosystem level, and they are a major concern in many aquatic systems. Although the community-level effects of non-native anuran tadpoles are well understood, their ecosystem-level effects have been less studied. Here, I tested the hypothesis that natural densities of non-native bullfrog tadpoles (Lithobates catesbeianus) and native Woodhouse's toad tadpoles (Anaxyrus woodhousii) have dissimilar effects on aquatic ecosystem processes because of differences in grazing and nutrient recycling (excretion and egestion). I measured bullfrog and Woodhouse's carbon, nitrogen, and phosphorus nutrient recycling rates. Then, I determined the impact of tadpole grazing on periphyton biomass (chlorophyll a) during a 39-day mesocosm experiment. Using the same experiment, I also quantified the effect of tadpole grazing and nutrient excretion on periphyton net primary production (NPP). Lastly I measured how dissolved and particulate nutrient concentrations and respiration rates changed in the presence of the two tadpole species. Per unit biomass, I found that bullfrog and Woodhouse's tadpoles excreted nitrogen and phosphorus at similar rates, though Woodhouse's tadpoles egested more carbon, nitrogen, and phosphorus. However, bullfrogs recycled nutrients at higher N:C and N:P ratios. Tadpole excretion did not cause a detectable change in dissolved nutrient concentrations. However, the percent phosphorus in mesocosm detritus was significantly higher in both tadpole treatments, compared to a tadpole-free control. Neither tadpole species decreased periphyton biomass through grazing, although bullfrog nutrient excretion increased areal NPP. This result was due to higher biomass, not higher biomass-specific productivity. Woodhouse's tadpoles significantly decreased respiration in the mesocosm detritus, while bullfrog tadpoles had no effect. This research highlights functional differences between species by showing non-native bullfrog tadpoles and native Woodhouse's tadpoles may have different effects on arid, aquatic ecosystems. Specifically, it indicates bullfrog introductions may alter primary productivity and particulate nutrient dynamics. / Dissertation/Thesis / Masters Thesis Biology 2015
888

Ecosystem Spatial Heterogeneity: Formation, Consequences, and Feedbacks

January 2015 (has links)
abstract: An understanding of the formation of spatial heterogeneity is important because spatial heterogeneity leads to functional consequences at the ecosystem scale; however, such an understanding is still limited. Particularly, research simultaneously considering both external variables and internal feedbacks (self-organization) is rare, partly because these two drivers are addressed under different methodological frameworks. In this dissertation, I show the prevalence of internal feedbacks and their interaction with heterogeneity in the preexisting template to form spatial pattern. I use a variety of techniques to account for both the top-down template effect and bottom-up self-organization. Spatial patterns of nutrients in stream surface water are influenced by the self-organized patch configuration originating from the internal feedbacks between nutrient concentration, biological patchiness, and the geomorphic template. Clumps of in-stream macrophyte are shaped by the spatial gradient of water permanence and local self-organization. Additionally, significant biological interactions among plant species also influence macrophyte distribution. The relative contributions of these drivers change in time, responding to the larger external environments or internal processes of ecosystem development. Hydrologic regime alters the effect of geomorphic template and self-organization on in-stream macrophyte distribution. The relative importance of niche vs. neutral processes in shaping biodiversity pattern is a function of hydrology: neutral processes are more important in either very high or very low discharge periods. For the spatial pattern of nutrients, as the ecosystem moves toward late succession and nitrogen becomes more limiting, the effect of self-organization intensifies. Changes in relative importance of different drivers directly affect ecosystem macroscopic properties, such as ecosystem resilience. Stronger internal feedbacks in average to wetter years are shown to increase ecosystem resistance to elevated external stress, and make the backward shifts (vegetation loss) much more gradual. But it causes increases in ecosystem hysteresis effect. Finally, I address the question whether functional consequences of spatial heterogeneity feed back to influence the processes from which spatial heterogeneity emerged through a conceptual review. Such feedbacks are not likely. Self-organized spatial patterning is a result of regular biological processes of organisms. Individual organisms do not benefit from such order. It is order for free, and for nothing. / Dissertation/Thesis / Doctoral Dissertation Biology 2015
889

Ecology and the City: A Long-Term Social-Ecological Examination of the Drivers and Diversity of Urban Vegetation

January 2015 (has links)
abstract: 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. / Dissertation/Thesis / Doctoral Dissertation Biology 2015
890

Understanding Introduced Megafauna in the Anthropocene: Wild Burros as Ecosystem Engineers in the Sonoran Desert

January 2017 (has links)
abstract: Megafauna species worldwide have undergone dramatic declines since the end of the Pleistocene, twelve thousand years ago. In response, there have been numerous calls to increase conservation attention to these ecologically important species. However, introduced megafauna continue to be treated as pests. This thesis evaluates the extent of this conservation paradox in relation to changing megafauna diversity from the Pleistocene to the Anthropocene and finds that introductions have provided refuge for a substantial number threatened and endangered megafaunal species and has restored generic diversity levels per continent to levels closer to the Pleistocene than the Holocene. Furthermore, this thesis describes a previously unstudied behavior of wild burros (Equus asinus), an introduced megafauna whose pre-domestic ancestors are Critically Endangered. Wild burros dig wells to access groundwater and in doing so substantially increase water availability on several scales, create sites that are visited by numerous species and are comparable to natural water sources in terms of species richness, and provide germination nurseries for important riparian pioneer plant species. My results suggest that relaxing concepts of nativity in an age of extinction will provide new understandings of ecological function and can help focus attention on broader conservation goals. / Dissertation/Thesis / Appendix C / Appendix F / Masters Thesis Biology 2017

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