• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 272
  • 150
  • 15
  • 13
  • 5
  • 3
  • 3
  • 3
  • 3
  • 3
  • 3
  • 3
  • 3
  • 3
  • 2
  • Tagged with
  • 539
  • 149
  • 128
  • 116
  • 90
  • 83
  • 71
  • 69
  • 52
  • 47
  • 46
  • 45
  • 40
  • 39
  • 37
  • 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.
71

Drivers and biodiversity consequences of landscape-scale deforestation in the western Brazilian Amazon

Ochoa Quintero, Jose Manuel January 2014 (has links)
No description available.
72

Land-use change in the Neotropics : regional-scale predictors of deforestation and local effects on carbon storage and tree-species diversity

Kirby, Kathryn January 2004 (has links)
Land-use change, and in particular tropical deforestation, is the leading cause of species extinctions globally, and is the second most important source of CO2 emissions after fossil fuel combustion. I examine two policy-relevant questions that relate to tropical deforestation and land use change: (1) At regional scales, what biophysical and infrastructure-related factors are associated with deforestation? and (2) At a local scale, what are some of the impacts of land use change on above- and below-ground carbon stocks and on tree-species richness? The first question was examined for the Brazilian Amazon through spatially-explicit correlation analyses of deforestation and a series of predictor variables that included highways and roads, annual rainfall, dry season length, soil characteristics, site accessibility, and population density. The proximity of a site to roads and highways was the strongest predictor of deforestation, with more accessible sites more likely to be deforested. Dry season length was also a strong, positive predictor of deforestation. The results suggest that current plans to expand road infrastructure in Amazonia will have a significant impact on the forests of the areas transected. / The second question was examined in the context of a 3,198 ha area in Eastern Panama that is managed collectively by an Indigenous Embera community.
73

Essays in environment and development

Zwane, Alix Peterson. January 2002 (has links)
Thesis (Ph. D.)--Harvard University, 2002. / Includes bibliographical references (leaves 149-159).
74

Effects of international trade and corruption on tropical deforestation

Alimov, Bobur S. January 2002 (has links)
Thesis (Ph. D.)--University of Connecticut, 2002. / Includes bibliographical references.
75

Land-use change in the Neotropics : regional-scale predictors of deforestation and local effects on carbon storage and tree-species diversity

Kirby, Kathryn January 2004 (has links)
No description available.
76

Environmental ethics challenges in the case of Congo basin deforestation : a theological ethical perspective

Buwani, Didier Ngangani 06 1900 (has links)
Environmental issues such as climate change, deforestation, loss of biodiversity are of concern worldwide. Several conflicts on environmental resources management are raised between governments, multinational companies and the local population. Particularly in developing countries, natural resources management is one of the crises where most experiment takes place. Lack of natural resources management can cause war and contribute to poverty. As is observed in the indigenous population of the Congo Basin. This research project aims to investigate the causes of deforestation in the Congo Basin and the environmental ethics challenges, when the researcher focuses on the policies related to the forest management in the region. A consideration of the ethical aspects is motivated by the fact that indigenous communities depend directly on the forests’ services and resources, and therefore are the most affected by the impact of deforestation. To establish an ethics on the participative approach on forest management could strengthen collaboration between local communities, multinational companies and government. / Philosophy, Practical and Systematic Theology / M. Th. (Theological ethics)
77

Reaching the 2014 UN New York Declaration on Forests Goals, using satellites to monitor global value chains

Näsström, Rickard January 2015 (has links)
This master thesis in geography investigates how remote sens- ing can be used in Transnational Corporations (TNC) global Corporate Social Responsibility (CSR) initiatives. The study aims to delineate an accurate method in remote sensing to be used to monitor deforestation in global value chains. Research questions asked are 1) What are the current monitoring practises used by TNCs to monitor global value chains? 2) Which is the most user-friendly and accurate remote sensing technique to map deforestation? 3) How can remote sensing successfully be implemented in TNCs CSR-initiatives? The study is approached from two perspectives, building on theories of value chains, and qualitative methods to answer the first research question. While the second question is a method study, investigating how well a spectral approach versus a contextual approach can map deforest- ation in Landsat scenes. The results are compared with Global Forest Watch (GFW), and the highest accuracy were acquired from the WICS (Window Indipendent Context Segmentation) technique. Conclusions includes that remote sensing can be used in CSR initiatives, to establish a baseline level or as a fifth dimen- sion in a score sheet approach. However, inconclusive mapping of value chains are a big hinder today.
78

The effects of deforestation and forest fragmentation on a central Amazonian frog community

Tocher, Mandy Darlene January 1996 (has links)
An investigation into the effects of deforestation and habitat fragmentation on a central Amazonian frog community was carried out on the Biological Dynamics of Forest Fragments Project, (BDFFP) based in Manaus, Amazonas, Brazil. Three aspects of deforestation were investigated: the effects of fragmentation and reserve size, the influence of matrix habitat and the effects offorest edge on frogs in 10- hectare isolates. Very few frogs species were lost from fragments (regardless of size) following fragmentation and isolation for 7-10 years. Instead, frog species richness increased, with an average increase in 10 species per fragment. The increase in species was brought about by an increase in matrix associated species, some of which were present in the absence of their preferred breeding habitat. Different frog species had varied responses to fragmentation. The abundance of Eleutherodactylus fenestratus, a terrestrial breeder, increased significantly as fragment size decreased, and its abundance was significantly higher in both large and small fragments than in continuous forest. Colostethus stepheni, a semi-terrestrial breeder, was less abundant in fragments than continuous forest. Finally, Eleutherodactylus zimmermanae and Osteocephalus sp.A did not differ significantly in abundance among fragments, or between fragments and continuous forest. Multiple regression analysis indicated that variation in litter depth and canopy cover may explain the observed increase in E. fenestratus abundance in small fragments. Breeding success of pool breeders attracted to artificial pools was variable, but there was no evidence of reduced breeding success in fragments relative to primary forest. Overall, fragmentation appeared to affect the frog community less severely than other taxonomic groups. Species richness in tropical forest remnants showed a tendency to increase as a result of fragmentation, and only one of four species exhibited lowered abundance in fragments. The effects of fragmentation and subsequent small isolated populations of frog species in fragments was alleviated somewhat by the ability of central Amazonian frogs to utilise matrix habitat. Litter frogs, wallow breeders and upland forest pool breeders all displayed an ability to permeate, and in most cases become residents of matrix habitat. Both matrix with a history of cut and burn and matrix which was only cut supported a similar frog community. Thus, for central Amazonian frogs isolates were not truly isolated due to the ability of frogs to utilise matrix habitat. Litter frogs in 10- hectare isolates displayed an independence from edge related abiotic and biotic gradients. This independence was true for frog species richness, abundance and composition. Consequently, forest fragments are in effect larger for frogs than for other taxa who are constrained by edge effects to exist only within the core of large fragments. Colostethus stepheni was one species found to be negatively affected by habitat fragmentation. Abundance of Colostethus stepheni was significantly lower in fragments and matrix habitat compared to primary continuous forest. This species was also found to be sensitive to edge, with higher abundances recorded as distance from the edge increased. The community level approach adopted in this study, as opposed to intensive investigation of single species, may well have overlooked other' sensitive' species which show more subtle responses to habitat fragmentation than that of Colostethus stepheni. The ability to use matrix and the relative independence from edge related phenomena accounts for the resilience of central Amazonian frogs in a disturbed and fragmented landscape. However, with respect to matrix habitat, forest surveyed in this study has not been repeatedly cut or cut and burnt (with the exception of pasture-land where the frog community is depauperate). In other areas of the Amazon, away from the experimental plots of the BDFFP, matrix habitat is destroyed more frequently. More work is needed to determine the ability of central Amazonian frogs to utilise matrix habitat which is disturbed more frequently.
79

Economic Development and Forest Cover: Evidence from Satellite Data

Crespo Cuaresma, Jesus, Danylo, Olha, Fritz, Steffen, McCallum, Ian, Obersteiner, Michael, See, Linda 01 1900 (has links) (PDF)
We use satellite data on forest cover along national borders in order to study the determinants of deforestation differences across countries. We combine the forest cover information with data on homogeneous response units, which allow us to control for cross-country geoclimatic differences when assessing the drivers of deforestation. Income per capita appears to be the most robust determinant of differences in cross-border forest cover and our results present evidence of the existence of decreasing effects of income on forest cover as economic development progresses.(authors' abstract) / Series: Department of Economics Working Paper Series
80

Análise da expansão da fronteira agrícola e do desflorestamento no bioma Amazônia dos estados de Mato Grosso, Pará e Rondônia / Analysis of the expansion of the agricultural frontier and deforestation in the Amazon Biome in the states of Mato Grosso, Pará and Rondônia

Amaral, Daniel Furlan 29 October 2018 (has links)
A geração de excedentes agrícolas sustentou o crescimento populacional dos últimos 10.000 anos. Historicamente, a relação entre produção de alimentos e número de habitantes foi vista como positiva, mesmo quando em detrimento do meio ambiente. Desde o século XIX, o questionamento sobre a disponibilidade de oferta suficiente para atender o aumento da população foi afastado com a abertura de novas terras, o desenvolvimento de técnicas e tecnologias inovadoras e a intensificação do comércio internacional. Porém, novas preocupações surgiram, notadamente a capacidade de suporte do planeta frente ao aumento da produção, seus impactos sobre a biodiversidade e as emissões de Gases de Efeito Estufa. Esses elementos modificaram a percepção sobre as consequências do crescimento econômico sem a observância de condicionantes socioambientais e ensejaram negociações internacionais com o objetivo de propor soluções para esse problema. O Brasil, detentor de vastas extensões de florestas, tornou-se central nas discussões, nas quais obteve avanços com a efetiva consolidação do conceito de desenvolvimento equilibrado. Contudo, pouco se evoluiu na compensação aos países em desenvolvimento pelas externalidades geradas ao planeta pelos ativos ambientais. A despeito desse fato, houve significativas melhorias na proteção ao meio ambiente no Brasil com a aprovação de legislação restritiva à abertura de novas áreas, programas governamentais e estrutura burocrática voltada à sua implementação, além de ferramentas para o dimensionamento do uso e ocupação do solo no bioma Amazônia. A partir dessas informações, foram analisados econometricamente por painéis espaciais dois temas pertinentes à relação entre a fronteira agrícola e o desflorestamento nos municípios do bioma Amazônia dos estados de Mato Grosso, Pará e Rondônia. No primeiro, foram estimados os condicionantes dos usos da terra, no qual se concluiu que as políticas e os instrumentos públicos, eficazes na redução das taxas de desflorestamento, não atuaram de forma eficiente na intensificação e melhor aproveitamento do uso da terra, em particular das pastagens, e da melhoria das condições econômicas e sociais da região. Também se observou que a valorização dos produtos florestais tem efeitos positivos sobre as áreas de vegetação. No segundo, foi estimada a relação entre a expansão da área de soja e as ações de políticas públicas e setoriais. As conclusões são de que a redução da participação de plantios nos desflorestamentos após 2006 se deu, em primeiro lugar, pela queda das taxas de desflorestamento, a qual diminuiu a abertura de novas áreas disponíveis para a soja, e foi, em seguida, complementada pela restrição de compra pelas empresas signatárias da Moratória da Soja. Os setores público e privado, portanto, agiram em conjunto para que os cultivos de soja passassem a representar percentual pequeno das novas áreas desflorestadas. A partir desses dois estudos, conclui-se que o desenvolvimento da agricultura da região depende de políticas públicas coordenadas que promovam o uso mais intensivo das lavouras e pastagens e o fortalecimento de pagamentos por serviços ambientais para conservação e preservação dos recursos naturais. Dada a forte dependência espacial, recomenda-se que as ações sejam direcionadas de forma mais homogênea entre os municípios a fim de potencializar seus efeitos. / The generation of agricultural surpluses has sustained population growth for the last 10,000 years. Historically, the relationship between food production and the number of inhabitants was seen as positive, even when it was at the expense of the environment. Since the nineteenth century, the question of having a sufficient food supply to meet population growth has been averted by opening new lands, developing innovative techniques and technologies, and intensifying international trade. However, new concerns have emerged: notably the planet\'s capacity to support increased food production, its impacts on biodiversity and greenhouse gas emissions. These elements have modified perceptions about the consequences of economic growth without observing socio-environmental constraints, and have led to international negotiations that aim to propose solutions to this problem. Brazil, which has vast tracts of forests, has become central to these discussions, in which it has made progress with the effective consolidation of the concept of balanced development. However, little progress has been made in compensating developing countries for the externalities their environmental assets generate for the planet. In spite of this fact, there were significant improvements in the protection of Brazil\'s environment, with the approval of legislation restricting the opening of new areas, government programs and bureaucratic structures for their implementation, and tools for ascertaining land use and occupation of the Amazon Biome. Based on this information, two topics pertaining to the relationship between the agricultural frontier and deforestation in the municipalities of the Amazon Biome in the states of Mato Grosso, Pará and Rondônia were econometrically analyzed by spatial panels. In the first topic, land use determinants were estimated, with the conclusion that the policies and public instruments that effectively reduced deforestation rates have not been as efficient in intensifying and improving land use, especially pastures, and in improving the region\'s social and economic conditions. Appreciation of forest products has also had a positive effect on areas of vegetation. In the second, the relationship between soybean acreage expansion and the actions of public and sector policies was estimated, concluding that the reduction in the share of plantings in deforestation rates after 2006 was primarily due to the fall in deforestation rates, which reduced the opening of new areas for soybeans, and this was complemented by the restrictions imposed on purchases by the companies signing the Soy Moratorium. The public and private sectors, therefore, acted together so that soybean crops would represent a small percentage of newly deforested areas. Based on these two studies, the conclusion is that development of agriculture in the region depends on coordinated public policies that promote a more intensive use of crops and pastures, and the strengthening of payments for environmental services related to the conservation and preservation of natural resources. Given the strong spatial dependence, actions should be directed more homogeneously among the municipalities in order to maximize their effects.

Page generated in 0.1317 seconds