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Categorical semantics and composition of tree transducersJürgensen, Claus 30 January 2004 (has links)
In this thesis we see two new approaches to compose tree transducers and more general to fuse functional programs. The first abroach is based on initial algebras. We prove a new variant of the acid rain theorem for mutually recursive functions where the build function is substituted by a concrete functor. Moreover, we give a symmetric form (i.e. consumer and producer have the same syntactic form) of our new acid rain theorem where fusion is composition in a category and thus in particular associative. Applying this to compose top-down tree transducers yields the same result (on a syntactic level) as the classical top-down tree transducer composition. The second approach is based on free monads and monad transformers. In the same way as monoids are used in the theory of character string automata, we use monads in the theory of tree transducers. We generalize the notion of a tree transducer defining the monadic transducer, and we prove an according fusion theorem. Moreover, we prove that homomorphic monadic transducers are semantically equivalent. The latter makes it possible to compose syntactic classes of tree transducers (or particular functional programs) by simply composing endofunctors.
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Potential for synthesis between REDD+ and community forest management as understood through the lens of global political ecologyChretien, Jonathon 31 January 2013 (has links)
Global climate change is one of the defining issues of the 21st century. The phenomenon of natural climate variation being pushed beyond normal ranges has been fueled largely by industrial activities and those which support them (i.e. land-use change and the over-exploitation of natural resources). The urgency is well established with reports demonstrating an increased occurrence of rare, highly damaging weather events, and shifts in the natural range of species. The necessity of action on climate change has resulted in the development of novel global initiatives designed to address the problem across global and regional scales. Reducing Emissions from Deforestation and forest Degradation (REDD+) is emblematic of this new wave of conservation strategy. It brings together parties which are often seen as opposed on environmental issues in collaborative environmental practise.
This thesis explores the development of REDD+ as an effective and equitable solutions to this problem. REDD+ is a policy architecture designed for global deployment, the success of which will depend largely upon the engagement and involvement of local community groups. Community forest management (CFM) may inform the REDD+ design process, and enhance both land-use strategies by way of synergy. The pathway to that point is, however, uncertain and marred with potential pitfalls. This thesis uses the instructive and critical lens of political ecology to assess the potential for integrating greater CFM elements into the REDD+ policy structure. It explores how the narratives of CFM and REDD+ clash at discursive levels, while also identifying elements of each which may make them mutually beneficial. The thesis finds that much of the conflict between positions on REDD+ are the result of contrasting environmental understandings, some of which are informed by negative experiences with past environmental conservation initiatives. Greater community-centric attributes may assist in improving the local and regional acceptability of REDD+ projects by appealing to the “alternative” values of forest-dependent peoples. Some suggested policy modifications are made to improve the overall design of REDD+ to be inclusive of the concerns of forest user groups, and potential areas for future research projects are discussed. / Thesis (Master, Environmental Studies) -- Queen's University, 2013-01-28 14:57:55.951
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The effects of tropical forest management on biodiversity and ecosystem functioningSlade, Eleanor M. January 2007 (has links)
The Effects of Tropical Forest Management on Biodiversity and Ecosystem Functioning Eleanor M. Slade 1. Between 35 % and 50 % of all closed-canopy tropical forest has been lost, and the rate of deforestation continues to increase throughout the tropics. Despite a wealth of literature on the effects of tropical forest disturbance on the diversity and composition of a variety of taxa, there is still no clear consensus on the value of disturbed forests for biodiversity. 2. If forest management practises are to be sustainable in the long-term they should maintain both biodiversity and ecosystem functioning (the interactions and processes of the ecosystem), as well as a timber harvest. However, few studies have investigated the extent to which ecosystem functioning is reduced in logged forests. The effects of different logging intensities on a variety of taxa, and the ecosystem processes with which they are associated, were assessed in the Danum Valley Conservation Area in Sabah (Malaysian Borneo). 3. Even under high logging intensities, the forests of Sabah appear to have been managed in a way that maintains timber yields in the short-term. However, other aspects of forest structure had been affected, which could have important consequences ecologically, and for the long-term sustainability of timber harvests. 4. Combining field studies with manipulative experiments allows assessment of the impacts of species changes associated with habitat modification on measures of ecosystem functioning. Dung beetle (Coleoptera: Scarabaeidae: Scarabaeinae) functional group richness and composition were manipulated in a series of field experiments. Certain functional groups and species were found to have a greater impact on ecosystem functioning than others; nevertheless a full complement of species was needed to maintain full ecosystem functioning. 5. Dung beetles appeared to be relatively robust to changes in forest structure associated with selective logging, but species richness was reduced with high-intensity logging. There was a corresponding decrease in ecosystem functioning (dung and seed removal) with a decrease in species richness, and a decrease in the biomass of large nocturnal tunnellers, suggesting that although some species are dominant, rare species are also needed to preserve full ecosystem functioning. 6. A complex interaction between birds and ants resulted in reduced herbivory of seedlings of the important timber tree, Parashorea malaanonan, in some instances. However, this interaction was not affected by either selective or high intensity logging. Seedfall of P. malaanonan, was reduced in logged forest compared to primary forest. Despite insect seed predation being higher in primary forest, there was still successful recruitment during a non-mast year. Parasitism of insect-predated seeds was found to be inversely density dependent, and was higher in logged forest where seed predation was lower. 7. The results of this thesis suggest that the forests of Sabah appear to be being logged under a management system that is compatible with sustainable timber management, but not necessarily sustainable forest management. Low intensity selective logging seems to preserve much of the original forest structure, biodiversity and ecosystem functioning compared to logging at higher intensities. However, ecosystem processes were variable in their response to logging, suggesting that management decisions should be based on the consideration of multiple taxa and processes.
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Factors Affecting Wood Fuel Consumption and Environmental Impacts in Warren County, KentuckyVann, Barry 01 August 1990 (has links)
The purpose of this research is to identify factors that contribute to wood fuel consumption as a space heating source and estimate a county-wide proportion for wood fuel consuming households. In addition, environmental problems associated with deforestation such as erosion and loss of wildlife habitat are delineated; moreover, air pollution resulting from wood fuel emissions are discussed.
An exhaustive literature review provided the basis for the study. Data on Warren County wood fuel consumption patterns were derived from a mail survey. Proportion estimates were tested by using a classical two-tail test of hypothesis. Subsequently, factors were identified and used in a multiple regression analysis.
The study found that low income households equipped with electric space heating systems located in rural areas are the most wood intensive. Unlike homes equipped with other alternate heating systems, electric space heat equipped households tend to consume wood fuel proportionally to income. The study also found that 26.3 percent of single family residences in the county use wood for space heating.
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Transição Florestal no estado de São Paulo, Brasil: fatores associados ao desmatamento e recuperação das matas nativas / The forest transition in São Paulo, Brazil: drivers related to forest loss and recoveryCalaboni, Adriane 09 June 2017 (has links)
Segundo a Teoria da Transição Florestal, países menos desenvolvidos teriam altas taxas de desmatamento, pois a economia destes países é baseada no desenvolvimento e expansão agrícola. Com o avanço do desenvolvimento econômico a industrialização, urbanização e a modernização do uso da terra levariam ao abandono de terras menos adequadas à agricultura que seriam ativamente reflorestadas ou regenerariam. Visto que São Paulo vem apresentando ganhos de cobertura florestal nativa, este estudo teve como objetivo principal identificar os fatores relacionados ao processo de transição florestal no estado de São Paulo entre 1960 e 2006. Para isso, o Capítulo 1 avaliou as discrepâncias entre três estimativas de cobertura florestal nativa disponíveis para o estado de São Paulo (censo agropecuário e dois mapeamentos com resolução de 10m e 30m), em escala municipal, e as possíveis fontes de viés associadas aos métodos de coleta. O Capítulo 2 identificou os fatores socioeconômicos e biofísicos associados ao desmatamento e à recuperação das florestas nativas nos municípios do estado de São Paulo em quatro períodos consecutivos (1960-1970, 1970-1980, 1980-1996, 1996-2006). Os resultados do Capítulo 1mostraram que o censo agropecuário subestima a cobertura florestal quando há áreas protegidas nos municípios. Mapas com resolução de 30m também subestimam a cobertura florestal nativa em relação aos mapas com 10m de resolução, visto que não detectam pequenos fragmentos. As três fontes de dados são congruentes, porém os vieses relacionados aos métodos podem refletir nos resultados. Logo, a escolha dos dados deve ser feita de acordo com os objetivos do estudo a ser desenvolvido e considerando os métodos de coleta e possíveis fontes de viés de cada conjunto de dados. O Capítulo 2 mostrou que as perdas de florestas ocorreram principalmente em municípios com solos mais úmidos e/ou naqueles em que houve expansão de cultivos. Enquanto ganhos de florestas ocorreram principalmente em municípios com maior cobertura florestal, maior declividade média, que empregaram maior número de trabalhadores permanentes e usaram mais fertilizantes. Estes resultados mostram que, entre 1960 e 2006, a expansão do uso da terra levou a perdas de florestas em áreas mais adequadas à agricultura de São Paulo. Com o tempo, porém, fatores que aumentam a produtividade ou reduzem a conversão de áreas naturais levaram ao aumento de florestas, principalmente em terras menos adequadas à agricultura. Tais fatores, no entanto, foram influenciados por políticas governamentais para modernização da agricultura e proteção dos ecossistemas naturais, e pela pressão do mercado externo por certificação ambiental. Estes resultados enfatizam a necessidade de se considerar, em conjunto, desenvolvimento da agricultura e conservação do meio ambiente para o desenvolvimento de políticas de uso da terra mais eficientes / According to Forest Transition Theory, less developed countries or regions present high rates of deforestation because their economy is based on agricultural development and agriculture expansion. As the economy develops industrialization, urbanization and agriculture modernization lead to the abandonment of lands less suitable for agriculture which are reforested or regenerate spontaneously. Since forest cover of São Paulo has increased, this study aimed to identify the socioeconomic and biophysical factors related to forest transition in the state of São Paulo between 1960 and 2006. For this purpose, Chapter 1 evaluate the discrepancies among three free datasets of São Paulo\'s forest cover (agricultural census, maps at 10m and 30m resolution), in municipality-scale, and the possible sources of bias. Chapter 2 identified the factors related to deforestation and forest gains in São Paulo\'s municipalities during four consecutive intervals (1960-1970, 1970-1980, 1980-1996, 1996-2006). Chapter 1 showed that census underestimate forest cover when legally protected areas are present, reflecting the limitation of survey methods in rural properties. Maps at 30m resolution also underestimate forest cover in comparison to maps at 10m resolution, since 30m resolution cannot detect small and narrow patches. The three datasets are congruent, but the results indicate that bias related to methods can affect analysis results. Therefore, users should choose a dataset according to aims of the study and considering the sources of bias in the data. Chapter 2 showed that forest losses were greater in municipalities with moist soils and large tracts of agricultural lands, while forest gains were higher in municipalities with high forest cover and steep slopes, and that employed a large number of permanent workers and relied on high fertilizer input. Between 1960 and 2006, land use expansion led to forest losses in more suitable areas for agriculture in São Paulo. Over time, factors that increase productivity or reduce pressure on land development led to forest gains mainly in less suitable lands. These proximate factors, however, were driven by underlying factors as governmental policies to modernize agriculture and protect natural ecosystems, and by external market demands for environmental certification. These results highlight the need to jointly consider agricultural development and environmental conservation policies for the development of effective land use policies
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Avaliação dos fluxos turbulentos de CO2, calor sensível e latente em função da profundidade óptica do aerossol sobre o arco do desflorestamento da Amazônia Legal Brasileira / Evaluation of CO2, Sensible and Latent Heat Turbulent Fluxes as Function of Aerosol Optical Depth over the Deforestation Arch in the Legal Brazilian AmazonBraghiere, Renato Kerches 28 June 2013 (has links)
Em dosséis com arquitetura foliar complexa, a radiação solar difusa pode potencializar a capacidade fotossintética, porque os penetra de modo mais eficiente. Apesar dos diversos estudos realizados nesse sentido em diferentes regiões do globo, os mecanismos e impactos do efeito da fertilização difusa sobre a América do Sul ainda continuam sendo pouco conhecidos. O Arco do Desflorestamento da Amazônia é um cenário ideal para sua maior investigação, tanto pela presença de complexos ecossistemas, quanto pela grande carga de aerossóis lançada para a atmosfera, em decorrência da queima de biomassa. Um estudo baseado em três diferentes localidades do Arco do Desflorestamento da Amazônia foi conduzido, a fim de relacionar a profundidade óptica dos aerossóis com alguns fluxos de superfície. Os resultados mostraram efeitos significativos da presença dos aerossóis tanto na troca de gás carbônico entre a vegetação e a atmosfera, quanto na troca de energia. Ainda, os fluxos mostraram ser sensíveis também às mudanças na temperatura, umidade e vento, além da influência do próprio ciclo diurno. Em cenários hipotéticos, foi possível isolar apenas o efeito do aerossol. O comportamento do fluxo de gás carbônico à presença dos aerossóis não foi o mesmo para as três localidades, o que indica uma grande dependência do fenômeno com as características da vegetação local. Na Reserva Biológica do Jaru e Ilha do Bananal, as trocas de gás carbônico entre a atmosfera e a superfície são favorecidas na presença de aerossóis, podendo atingir valores até 55% maiores em Jaru. Entretanto, Sinop apresentou uma redução de aproximadamente 12% no valor médio do fluxo de gás carbônico, para o período avaliado. Os fluxos de energia mostraram ser afetados negativamente pela presença dos aerossóis. Na Ilha do Bananal, a média do fluxo de calor sensível em cenários sem aerossóis foi em torno de 60% maior, e de até 13% maior para o fluxo de calor latente em Sinop. Devido aos processos de absorção e espalhamento da radiação solar pelos aerossóis, menos energia atinge a superfície e, portanto, há menos disponibilidade para a realização de tais trocas, como esperado. / In complex architecture canopies, the diffuse solar radiation can enhance photosynthetic capacity, as it penetrates more efficiently on them. Although several studies have been conducted on this topic over the world, the mechanisms and impacts of the \"diffuse fertilization effect\" over South America still remains poorly understood. The Amazon Deforestation Arch provides an ideal scenario for its further investigation, by the presence of complex ecosystems and by the large amounts of aerosols released into the atmosphere due to biomass burning. A study based on three different sites in the Amazon Deforestation Arch was conducted in order to relate the aerosol optical depth with some surface fluxes. The results showed significant effects of the aerosol presence in both, the exchange of carbon dioxide between the vegetation and the atmosphere, and the energy exchange. Still, the fluxes also showed to be sensitive to changes in temperature, humidity and wind velocities, as well as the influence of the diurnal cycle itself. In hypothetical scenarios, it was possible to isolate only the aerosol effect. The carbon dioxide flux behavior due to the aerosol presence was not the same for all the three locations, showing that it depends on the local vegetation characteristics. At the Jaru Biological Reserve and Bananal Island, the carbonic gas exchanges between the atmosphere and the surface increased under the aerosol presence, achieving values up to 55% higher in Jaru. However, Sinop showed a decrease by approximately 12% in the average value of the carbon dioxide flux for the evaluated period. Energy fluxes showed to be negatively affected by the presence of aerosols. In the Bananal Island the average of sensitive heat flux in scenarios without aerosols was around 60% higher, and up to 13% higher for the latent heat flux in Sinop. Due to absorption and scattering of solar radiation by the aerosols, less energy reaches the surface, and therefore there is less availability to perform such exchanges, as expected.
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Análise de alguns aspectos de dinâmica florestal em uma área degradada no interior do parque estadual do Jurupará, Ibiúna, São Paulo. / Analysis of some aspects of forest dynamics in a degradated area inside the jurupará state park, Ibiúna, São Paulo state.Souza, Silvana Cristina Pereira Muniz de 18 June 2002 (has links)
O presente trabalho teve como objetivo investigar a resiliência de uma área desflorestada há aproximadamente 20 anos, ocupada atualmente com pastagem e cultivo de Citrus sp. Essa resiliência foi avaliada através dos seguintes aspectos da dinâmica florestal: análise do banco de sementes, da chuva de sementes e de indivíduos jovens regenerantes. Este trabalho foi conduzido no Parque Estadual do Jurupará (23°51' S e 47°11' W), abrangendo os municípios paulistas de Ibiúna e Piedade, em uma região de transição entre a Floresta Ombrófila Densa e a Floresta Estacional Semidecidual. Foram alocadas três faixas de amostragem, cada uma com cinco parcelas aleatorizadas de 10 X 20 m, uma num trecho ocupado com um plantio abandonado de Citrus sp, adjacente ao remanescente florestal, e as restantes num trecho ocupado com pastagem, uma a 0-20 m e outra a 80-100 m de distância do remanescente florestal. Para a avaliação da chuva de sementes, foram lançados aleatoriamente em cada parcela três coletores de sementes circulares de 0,52 m de diâmetro, com coletas mensais das sementes depositadas. Para a avaliação do banco de sementes foram instalados em cada parcela, três subparcelas de 0,25 X 0,25 m, para coleta de solo até 0,05 m de profundidade em duas épocas distintas: estação chuvosa (janeiro/2001) e na estação seca (agosto/2001). Para a avaliação dos indivíduos jovens regenerantes, foram implantadas aleatoriamente 4 subparcelas de 0,5 X 0,5 m, nas quais foram realizadas três avaliações de todos os indivíduos arbustivos-arbóreos com altura entre 0,30 e 1,30 m. Na avaliação da chuva de sementes na área ocupada com o cultivo de Citrus sp, foi observada alta densidade de sementes autóctones de espécies arbustivo-arbóreas (Leandra sp. com 20.638,73 sem.m -2 e Tibouchina sp. com 12.681,85 sem.m -2 ) que ocupavam a área junto com aos indivíduos de Citrus sp. Na pastagem verificou-se a predominância de espécies ruderais, a densidade média das espécies arbustivo-arbóreas foi de 335,75 sem.m -2 , na pastagem próxima do remanescente florestal e de 577,58 sem.m -2 na pastagem distante do remanescente florestal. Na avaliação do banco de sementes no cultivo de Citrus sp, as espécies ruderais consistiram em 99,88% das espécies germinadas na estação chuvosa, e 99,73% na estação seca. Na pastagem, na estação chuvosa, para as duas distâncias, 100% das espécies germinadas eram espécies herbáceas tipicamente ruderais; na estação seca esta forma de vida predominou em 99,66% na área próxima ao remanescente florestal e 99,92% na área mais distante. No levantamento dos indivíduos jovens regenerantes, encontrou-se densidade 5,8 ind.m -2 na área de Citrus sp e de 1,2 ind.m -2 e 2,2 ind.m -2 na pastagem a 0-20 m e 80-100 m de distância do remanescente florestal, respectivamente. Apenas na chuva de sementes foram encontradas diferenças significativas entre a área de Citrus sp e a pastagem, para os demais aspectos analisados não foram encontradas diferenças significativas entre a área de Citrus sp e pastagem. Na pastagem, para todos os apectos analisados, não foram encontradas diferenças significativas entre as diferentes distâncias, rejeitando a hipótese de que a resiliência da pastagem estudada está inversamente relacionada com as distâncias do remanescente florestal nesse trabalho. / This work had as a goal identifying the resilience of an area, which was deforested in the past, currently used as pasture and Citrus sp crop. This resilience was evaluated through the following aspects of forest dynamics: soil seed bank analysis, seed rain and saplings. It was conducted in the Jurupará State Park in Ibiúna and Piedade (São Paulo State), in a transition area between the Ombrophil Forest and the Semideciduous Seasonal Forest. In this area, three sampling strips were allocated, each one with five 10 X 20 m plots, being one inside the Citrus sp crop and the others inside the pasture, distant 0-20 m and 80-100 m from the forest remant. For evaluating the seed rain, three circular seeds collectors of 0.52 cm in diameter were randomly set in each plot, with monthly samplings of the deposited seeds. For evaluating the seed bank, soil of three 0.25 X 0.25 m sub-plots and 0.05 m deep was collected in two different seasons: rainy season (January/2001) and dry season (August/2001). To the saplings evaluation, four 0.5 X 0.5 m sub-plots were implanted randomly, in which three evaluations of all the shrubs and trees individuals (0.30-1.30m height) were performed. At the seed rain inside the Citrus sp crop, a high density of autoctone seed of shrubs and trees species (Leandra sp. with 20,638.73 seed.m -2 and Tibouchina sp. with 12,681.85 seeds.m -2 ) was observed; inside the pasture, there were a predominance of ruderal species, while the average density of shrubs and trees species were, 335.75 seeds.m -2 in the pasture distant 0-20m from the remaining forest and 577.58 seeds.m -2 in the pasture distant 80-100m from the remaining forest. At the soil seed bank evaluation in the experimental area inside the Citrus sp crop, the ruderal species were 99.88% of the germinated species in the rainy season and 99.73% in the dry season. In the experimental area inside the pasture, for the rainy season, 100% of the germinated species were herbal species typically ruderal in both distances; in the soil collected in the dry season, this life form was predominant in 99.66% and 99.92% in both distances, respectively. In the saplings counting, a 5.8 ind.m -2 density inside was found the Citrus sp crop and 1.2 and 2.2 ind.m -2 inside the pasture in both distances. Only for the seeds rain significant differences were found between the Citrus sp crop and the pasture. No significant differences were found between the two distances within the pasture area strips, denying the hypothesis that the resilience of the study area is inversely related to the remaining forest distance.
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A redução compensada do desmatamento no Mato Grosso: uma análise econômica-ecológica / Compensated reduction in Mato Grosso state: an Ecological economic analysisKaechele, Karin Teixeira 09 August 2007 (has links)
Esta dissertação analisa o Instrumento de Comando e Controle da Política Ambiental do Estado do Mato Grosso - o SLAPR, através dos pilares da Economia Ecológica (escala, alocação e distribuição). O SLAPR: Sistema de Licenciamento Ambiental em Propriedades Rurais tem como um dos seus objetivos reduzir o desmatamento ilegal em propriedades particulares. Por meio de imagens de satélite e do uso de ferramenta do Sistema de Informação Geográfica (SIG), pôde-se concluir que este Instrumento não é eficaz. Este trabalho discute um instrumento Econômico - o Pagamento pelo Serviço Ecossistêmico (PSE) carbono, pelo desmatamento evitado dos biomas amazônicos no âmbito do Protocolo de Kyoto para os proprietários detentores de 80% ou mais de cobertura florestal em suas reservas legais. Ressalta-se que esta é uma política second best, visto que se propõe a tratar da problemática ambiental aliando Instrumentos de Comando e Controle (estimando-se a escala) com um Instrumento Econômico. O mecanismo de PSE para as reservas legais nos biomas amazônicos no estado do Mato Grosso tem como princípios: 1 -definição clara do serviço comercializado, 2-verificação da oferta e da demanda, 3-o desenvolvimento da valoração e pagamento deste serviço e 4- desenvolvimento de uma rede institucional onde haja uma instituição gestora, um seguro, uma agência reguladora e uma instituição certificadora e acreditadora. / The focus of this dissertation is the system adopted by the State of Mato Grosso [Brazil] for managing and taking command and control of its environmental policies through the pillars of Ecological Economics, i.e. scale, allocation and distribution. One of the goals of SLAPR [\"System for Environmental Licensing of Rural Properties\", for short] is to reduce illegal deforesting in private properties. However, the use of satellite images and the application of SIG - \"Geographic Information System\" have led to the conclusion that SLAPR is not an efficient tool. This essay therefore discusses a new economic tool: PSE -\"Payment for Eco-Systemic Service - Carbon\", in exchange for prevented deforesting of Amazonian Biomes, within the scope of the Kyoto Protocol. It should be emphasized that this is a \"second best\" policy, since its proposal is to deal with environmental issues by combining an \'Economic Instrument\' with \'Command-and-Control Instrument, in order to estimate the scale in question. The following are the principles of PSE mechanisms for legal forest reserves within the Amazonian Biomes of the State of Mato Grosso: 1) a clear definition of the ecosystem services rendered; 2) offer-and-demand verification; 3) development of improved value-and-payment procedures for rendered services; and 4) development of an institutional net that includes a managing agency, a regulating agency, a certifying agency and an accrediting agency.
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Múltiplas ameaças e um mosaico de manchas de habitat de diferentes qualidades: a persistência de mamíferos de maior porte em uma região de pós-fronteira na Amazônia / Multiple threats and a mosaic of habitat patches of varying quality: the persistence of large mammals across a post-frontier Amazonian regionMoraes, Paula Elias 21 September 2016 (has links)
A expansão das atividades humanas está associada a várias ameaças antrópicas que afetam a biodiversidade tropical, especialmente a perda e fragmentação de habitat, o continuado crescimento populacional humano e a expansão de infraestrutura, como estradas e rodovias. Embora seja esperado que as ameaças antrópicas interajam e criem mosaicos de manchas de habitat de diferentes qualidades, há ainda poucos estudos sobre os efeitos aditivos e interativos de diferentes ameaças sobre a biodiversidade ou sobre a capacidade de espécies nativas de usar remanescentes de diferentes qualidades. De fato, a maioria dos estudos focaram em apenas uma ou poucas ameaças isoladas, na escala do fragmento em vez da escala da paisagem e não consideraram as variações na qualidade dos remanescentes. Mamíferos de maior porte são um bom modelo de estudo porque possuem um conjunto de características que os tornam particularmente vulneráveis a várias ameaças antrópicas. Dada a dificuldade de obter dados sobre estas espécies elusivas em escalas espaciais adequadas, entrevistas com moradores locais vêm sendo cada vez mais usadas para acessar a distribuição de mamíferos de maior porte, e podem fornecer informações confiáveis. Através da estimativa da ocorrência de 15 espécies de mamíferos de maior porte por meio de entrevistas com o chefe de 12 unidades domésticas em cada uma de 20 paisagens em uma região de pós-fronteira de 1 milhão ha na Amazônia, investigamos: (i) que tipo de habitat e em qual escala espacial está associado com a ocorrência das espécies, e (ii) os efeitos, a importância relativa e as interações de quatro ameaças antrópicas - cobertura de habitat, fragmentação de habitat, densidade populacional humana e densidade de estrada - sobre a persistência das espécies. Dados de presença/ausência nos arredores de 227 unidades domésticas foram analisados usando modelos lineares generalizados mistos e seleção de modelos baseada no Critério de Informação de Akaike em duas etapas. A persistência das espécies maiores e ameaçadas não foi necessariamente afetada pela qualidade do habitat, mas elas responderam majoritariamente a cobertura de habitat em escalas maiores. A chance de persistência de todas as espécies - mesmo das duas menores, que não responderam à perda de habitat isoladamente - foi afetada por alguma combinação das quatro ameaças antrópicas. Efeitos aditivos entre as ameaças antrópicas foram mais importantes do que as interações entre elas na determinação da ocorrência de mamíferos de maior porte. Enquanto os efeitos da perda de habitat foram mais fortes do que os efeitos da fragmentação de habitat per se, a densidade de estradas foi tão importante quanto à perda de habitat para a ocorrência das espécies. Por último, não houve um padrão claro em termos do grau de ameaça e do tamanho corpóreo por trás da reposta dos mamíferos de maior porte a ameaças antrópicas combinadas. Nosso estudo sugere que áreas protegidas em terras públicas ou privadas na Amazônia devem ser grandes para assegurar a persistência de mamíferos de maior porte, mas podem incluir mosaicos de florestas primárias e secundárias. Os resultados também ressaltam a necessidade de considerar os impactos acumulados de múltiplas ameaças simultaneamente - em especial, as consequências da expansão da malha viária - em planejamentos e manejos, de maneira a evitar subestimar a chance de extinções. Evitar que paisagens na Amazônia se tornem muito desmatadas e alteradas é fundamental, dado que a persistência até mesmo das espécies mais comuns pode ser prejudicada, afetando um dos serviços ecossistêmicos mais importantes para moradores locais - a carne de caça - e potencialmente erodindo o valor que estes atribuem às florestas / The expansion of human activities is associated to a myriad of anthropogenic threats that affect tropical biodiversity, especially habitat loss and fragmentation, the continued human population growth and the expansion of infrastructure, as roads and highways. Although anthropogenic threats are expected to interact and to create mosaics of patches of varying quality, their additive and interaction effects on biodiversity, as well as the extent native species are able to use remnants of distinct quality, have yet been poorly studied. Indeed most studies focused on only one or few threats in isolation, on the patch rather than the landscape scale and did not considered the varying quality of remnants. Large mammals are a good study model as they have a set of traits that make them particularly vulnerable to several anthropogenic threats. Due to the difficulties in gathering data on these elusive species at adequate spatial scales, interviews with local residents have increasingly being used to access their distribution and can provide reliable information. By estimating the occurrence of 15 large mammal species through interviews with the head of 12 households within each of 20 landscapes across a 1-million ha post-frontier region in Amazonia, we investigated: (i) which habitat type at which spatial scale is associated with species occurrence, and (ii) the effects, relative importance and interactions of four anthropogenic threats - habitat cover, habitat fragmentation, human population density and road density - on species persistence. Presence/absence data across the surroundings of 227 households was analyzed using generalized linear mixed-effects models, and a two-step model selection based on Akaike’s Information Criteria. The persistence of larger and endangered species was not necessarily affected by habitat quality, but they responded to habitat cover mostly at larger spatial scales. The chance of persistence of all species - even the two smallest that were not affected by habitat loss alone - was disrupted by some combination of the four anthropogenic threats. Additive effects between anthropogenic threats were more important than their interaction in determining the occurrence of large mammals. While the effects of habitat loss were stronger than the effects of habitat fragmentation per se, road density was as important as habitat loss to species occurrence. Finally, there was no clear pattern in threat status or body size underlying the response of large mammals to combined anthropogenic threats. Our study suggest that protected areas in public or private lands in Amazonia should be large to secure the persistence of large mammals, but may include mosaics of primary and secondary forest. The findings also highlight the need to take into account the accumulated impacts of multiple threats simultaneously - particularly, the consequences of the expansion of the road network - in planning and management, as a way to avoid underestimating the chance of extinctions. Preventing Amazonian landscapes to become heavily deforested and altered is critical, as the persistence of even common species can be impaired, affecting one of the most important ecosystem services provided to local residents - bushmeat - and potentially eroding the value people attribute to forests
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Regeneração florestal após desmatamento: estudo da região de Santarém, Pará, Brasil / Regrowth forest after deforestation: study on Santarém region, Para, BrazilMenezes, Diego Pinheiro de 15 March 2017 (has links)
A superfície da terra foi modificada nos últimos 50 anos mais do que em qualquer outro período da História, mais intensa e rápida nos trópicos pela expansão das frentes de ocupação humana sobre floresta madura. A Amazônia brasileira, caracterizada pela alternância de ciclos econômicos extrativistas, exemplifica esse processo. Entre o abandono de áreas degradadas e a abertura de novas frentes de ocupação, ocorre a regeneração florestal. A floresta secundária tem uma reconhecida importância para o restabelecimento das funções dos ecossistemas e dos estoques de nutrientes perdidos da floresta madura, mas ignorados por muitos anos de taxas oficiais de desmatamento na Amazônia brasileira. Este estudo apresenta uma abordagem utilizando Análise de Imagens Baseada em Objetos Geográficos (GEOBIA) para classificar os estágios de sucessão secundária numa área com cerca de 11.124 km² na região de Santarém (Pará, Brasil). Dentre os resultados, foram produzidas 19 diferentes classificações cobrindo o período 1984 a 2016, que permitiu identificar a redução da floresta madura e da floresta secundária devido à expansão da fronteira agrícola. Outro resultado relevante foi a modelagem de uma árvore de decisão aplicável às imagens de refletância de superfície coletadas pelos satélites LANDSAT, processando esses atributos de classificação em um aplicativo de mineração de dados / The earth surface was modified in the last 50 years more than in any other period of the History, more intense and fast in the tropics by the expansion of human occupation frontiers on the mature forest. The Brazilian Amazon, characterized by alternating extractive economic cycles, exemplifies this process. Between the degraded areas abandonment and the new occupation fronts, forest regeneration takes place. The secondary forest has a recognized importance for the restoration of ecosystem functions and the nutrient stocks lost from the mature forest but ignored for many years of official deforestation rates in the Brazilian Amazon. In this study, an approach using Geographic Object-Based Imaging Analysis (GEOBIA) is presented to classify the stages of secondary succession in an area with near 11,124 km² on Santarém region (Pará State, Brazil). Among the results, 19 different classifications were produced covering the period 1984 to 2016, which allowed identify the reduction of mature forest and secondary forest due to agricultural frontier expansion. Another relevant result was the modeling of a decision tree applicable to surface reflectance images collected by the LANDSAT satellites, processing these classifications attributes in a data mining software
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