• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 5
  • 1
  • 1
  • 1
  • Tagged with
  • 9
  • 9
  • 5
  • 4
  • 3
  • 3
  • 3
  • 3
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 2
  • 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.
1

Small mammals of the Planted Forest Zone of Sarawak, East Malaysia; an assessment of dispersal ability and response to habitat fragmentation

Shadbolt, Antony January 2014 (has links)
In recent years a push to establish pulpwood plantation forestry in Sarawak, East Malaysia with Acacia mangium has been identified as a means to relieve pressure on the State’s diminishing natural forest resource whilst providing 1) economic wealth for a developing economy 2) community development, and 3) biodiversity conservation outside the protected area network. In a specially designated 504,000 hectare Planted Forest Zone (PFZ) a range of broad-scale landscape planning initiatives have been implemented in an attempt to conserve a representative sample of biodiversity across the plantation landscape. The effects of forest modification and fragmentation have been widely reported in the literature for mammals, and in this study, non-volant small mammals were fitted with tracking spools and/or radio collars and released into small forest remnants outside of their home ranges to measure response to unfamiliar habitats, forest edges and various scales of habitat fragmentation during simulated dispersal events. Medium sized patches exhibited the greatest species diversity and abundance, whereas the largest forest areas hosted the largest population of brown spiny rat (Maxomys rajah); a species that is identified as vulnerable across its natural range. Small forest patches of c.1.00 ha that had been exempt from clearing during plantation establishment are likely to be species poor and host small populations of extant species only. All species were found to make extensive use of downed woody debris for movement, and showed varied responses to a range of habitat edges including forest roads, acacia plantation compartments, old haul trails, clearings and riparian areas. Two species of treeshrew; long-footed treeshrew (Tupaia longipes) and painted treeshrew (T. picta) were shown to be able to move between the forest patch and the acacia forest while the same edges were shown to pose barriers to the brown spiny rat (M. rajah) and large treeshew (T. tana) illustrating the different ways that species may perceive and use habitat features such as corridors. Despite T. picta being common in the PFZ, comparatively little has been published on its ecology and behaviour compared with the other Bornean tupaiids. Therefore this study also reports on the movement and behaviour of this species within its own home territory as revealed from both radio telemetry and spool-and-line tracking. Home range size, dimension, average daily movement distances and nest site construction was found to be similar to other Tupaiids studied in secondary forests in Sabah, and home ranges were found to be dictated by anthropogenic landscape features such as forest roads and open areas across which no movement was recorded. Painted treeshrews were found to favour logs and fallen woody debris as movement substrates and spend the large majority of their movement at ground level. Camera trapping revealed possible interspecific nest sharing between the painted treeshrew and the three-striped ground squirrel (Lariscus insignis), fuelling the debate on whether or not treeshrews construct their own nests or use nests constructed by squirrels.
2

Zarasų rajone 2005-2009 metais įveistų želdinių būklė / Status of afforested areas in Zarasai district in 2005-2009

Kavaliauskas, Darius 01 June 2011 (has links)
Magistro darbe tiriama 2005-2009 metais Zarasų rajone ne miško žemėje įveistų želdinių kokybė. Darbo objektas – Miško želdiniai įveisti privačioje žemėje Zarasų rajone 2005–2009 metais panaudojant ES struktūrinių fondų paramą (366,37 ha). Darbo tikslas – Nustatyti 2005–2009 metais želdinių įveistų privačioje ne miško žemėje būklę Zarasų rajone. Darbo metodai – Įveistų miško želdinių ir žėlinių vertinimas natūroje atliekamas atrankiniu metodu vadovaujantis Miško atkūrimo ir įveisimo nuostatuose patvirtinta miško želdinių ir žėlinių apskaitos bei vertinimo metodiką. Surinktų duomenų analizė atliekama pasinaudojant programomis MS Excel ir STATISTICA. Darbo rezultatai. Atlikus Zarasų rajone 2005–2009 metais įveistų miškų analizę, gauta, kad su ES skirta parama privačių žemių savininkai įveisė 366,37 ha miškų. Be to, Zarasų urėdija savo lėšomis įveisė 135,52 ha miškų valstybinėse ne miško žemėse. Daugiausia miškų (137,39 ha) įveista 2007 metais, pasinaudojant ES paramos lėšomis. Vidutinis per metus įveisto miško sklypo plotas – 2,47 ha. 2010 metais buvo įvertinta 20 sklypų (33,5 ha), kuriuose 2007 metais įveistas miškas. Miško būklė vertinta pagal miško želdinių ir žėlinių apskaitos ir vertinimo metodiką, nustatyta: vidutinis aukštis, prigijimas – atkritimas, žolinės dangos agresyvumas. Įvertinus gauta, kad 80,0 % sudaro geros kokybės želdiniai, 15,0 % – patenkinami, o 5,0 % – žuvę. Daugumoje vertintų sklypų tikslinės medžių rūšys parinktos teisingai, o priežiūros darbai... [toliau žr. visą tekstą] / Quality of planted forests in non-forest land during 2005-2009 was evaluated in this master thesis. Object of work – On 2005–2009 there were planted 366,37 ha forests with EU support in private land in Zarasai district. 20 plots were selected with different habitats and quality of seedlings was evaluated. The aim of work – To evaluate the quality of planted forests on 2005–2009 in private land in Zarasai district. Research methods – Planted forest were evaluated according to a special methodic approved by Lithuania Republic Ministry of Environment. Collected data were analyzed by MS Excel, STATISTICA programmes. Findings of work – Analysis showed that 366,37 ha of forests on 2005–2009 were planted with EU support. In addition to this, Zarasai Forest Enterprise planted 135,52 ha of forests in non-forest land. The main part of forests were planted in 2007 (137,39 ha). The average plot of planted forests is 2,47 ha. In 2010 there were evaluated quality of forests planted in 2007 (20 plots - 33,5 ha). An average height, falling away of seedlings, aggressiveness of grass were defined. It was evaluated that 80,0 % of planted forests were a good quality, 15,0 % - satisfactory and 5,0 % - died. Consist of species have changed in 6 evaluated plots. In most of evaluated plots objective species were selected correctly. The main causes of satisfactory and bad quality seedlings are bad selection of species in certain habitats and bad care of planted forests.
3

Identificação de florestas destinadas à produção de bioenergia no Estado do Tocantins utilizando imagens de satélite e mineração de dados

Nonato, Carlos Tavares 26 August 2014 (has links)
As florestas plantadas tem atraído grande interesse pela possibilidade de utilização em aplicações bioenergéticas frente à tendência mundial de priorizar fontes de energia que proporcionem maior sustentabilidade ambiental, mais qualidade e segurança. No Brasil, os deslocamentos na geografia da cadeia produtiva agroflorestal atual em direção às regiões de fronteira agrícola (Centro-Oeste e Norte) vem criando desafios de adequação dos conhecimentos técnico-científicos já consolidados em outras regiões. Nesse contexto, o objetivo desta dissertação é avaliar a acurácia da classificação e identificação de áreas cultivadas com florestas plantadas para fins energéticos, em imagens orbitais do sensor Landsat 5 TM. Por meio de técnicas estatísticas de mineração de dados, o presente trabalho também avaliou a utilização de um amplo conjunto de atributos para identificar melhorias nos resultados da classificação. A pesquisa se concentrou em amostras de áreas plantadas no estado do Tocantins, região norte do Brasil. As técnicas de mineração de dados utilizadas se mostraram eficientes na identificação precisa de florestas plantadas em imagens do satélite Landsat 5, tanto pelo desempenho da classificação, quanto pela redução da quantidade de informação necessária para a resolução deste tipo de problema. Assim, as técnicas empregadas neste estudo possibilitam o desenvolvimento de modelos de classificação robustos no auxílio ao planejamento e à tomada de decisão sobre a plantação de florestas no território brasileiro. / Planted forests have attracted a lot of attention because of possibility of use in bioenergy applications and due to the global trend of prioritizing energy sources that provide greater environmental sustainability, more quality and security. In Brazil, the shifts in the geography of current agroforestry production chain towards the agricultural frontier areas (Midwest and North) are creating challenges to the adequacy of technical and scientific knowledge already established in other regions. So, the aim of this work is to assess the accuracy of the identification and classification of areas cultivated with plantation forests for energy, inside TM Landsat 5 images. Using statistical techniques for data mining, this study also evaluated the use of a broad set of attributes to identify improvements in the classification results. The research focused on samples of planted areas in the state of Tocantins, Northern Brazil. The data mining techniques used were effective in identifying of planted forests in Landsat 5 satellite images, both the classification performance, such as by reducing the amount of information needed to solve this kind of problem. Thus, the techniques employed in this study enable the development of robust classification models to aid in the planning and decision making on forest plantations in Brazil.
4

APLICABILIDADE DA TECNOLOGIA MÓVEL EM ATIVIDADES DE SILVICULTURA DE PRECISÃO: MAPEAMENTO, INVENTÁRIO E GEOESTATÍSTICA FLORESTAIS / MOBILE TECNOLOGY APPLICABILITY TO PRECISION SILVICULTURE ACTIVITIES: FORESTRY MAPPING, INVENTORY AND GEOSTATISTICS

Brandelero, Catize 14 February 2007 (has links)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The moblie technology applicability to precision silviculture activities on planted forests involves the mapping, inventory and geostatistics. The objective of this research is to demonstrate the móbile technology potentiality in activities of precision silviculture. The precision of forested áreas surveys with GPS equipment integrated with Pocket PC computer, through bluetooth conexion, as related to measurements conducted with conventional navigation GPS, absolute format, and measurements conducted with topographic GPS with after-processing correction is evaluated in this research. Facing the difficulties to collect, manipulate and transfer the data from the analog to the digital mean a system was developed for project records, portions and forest individuals in móbile technology (Pocket PC) for planted forests inventory. To evaluate the system, real data were used in the process of simulation of the mapped áreas, where dendrometric parameters maps gathered from geostatistic processes as compared to conventional processes of forestry inventory of planted forests were evaluated. It was concluded that the navigation equipment are feasible to conduct surveys of metric precision form 3 to 10 meters. The Garmim 10 GPS showed better results than the Etrex Vista GPS, as well as in áreas with or without planted forest. The better precision of the coordinates collected with the Garmin 10 GPS were due to the function of the data collecting system for the planted forest inventory, which generates corrected means of the coordinates stored in the equipment. The data collecting system for the forestry inventories of planted forests helped to manipulate and to locate the sampling units of the forestry inventory. The mobility enabled the inventory data to be recorded and stored for further manipulation; it enabled speed and optimization of the data processing activities after the transmisssion to the computer. The inteaction between the variables used in this research, together with the georeferenced data, enabled to distinguish and to visualize distinct characteristics of the forest. Enabled to relate the productivity and to carry the zoning of better growth of the forests. The móbile technolgy use with data collecting systems for the forestry inventory of planted forests, as well as the use of mapping and geostatistics are recommended to improve the quality of forests quantification and qualification, motivating the use of precision silviculture. / A aplicação de tecnologia móvel nas atividades de silvicultura de precisão em florestas plantadas envolve o mapeamento, o inventário e a geoestatística. Essa pesquisa possui o objetivo de avaliar e demonstrar as potencialidades da tecnologia móvel em atividades de silvicultura de precisão. Neste trabalho foi avaliada a precisão de levantamentos de áreas florestais com aparelhos GPS integrados, através de conexão bluetooth com computador do tipo Pocket PC, em relação a medições processadas com GPS de navegação convencional no formato absoluto e com medições realizadas com GPS topográfico com correção de pósprocessamento. Diante das dificuldades de coletar, manipular e transferir os dados do meio analógico para o digital, foi desenvolvido um sistema de cadastro de projetos, parcelas e indivíduos florestais em tecnologia móvel (Pocket PC) para inventários de florestas plantadas. Para a avaliação do sistema, foram empregados dados reais em processo de simulação nas áreas mapeadas, onde foram avaliados os mapas de parâmetros dendrométricos obtidos a partir de processos de geoestatística em comparação com os processos convencionais de inventário florestal de florestas plantadas. Concluísse que os aparelhos de navegação são viáveis para realizar levantamentos de precisão métrica de 3 a 10m, o GPS Garmim 10 apresentou resultados melhores que o aparelho Etrex Vista, tanto em areas com ou sem floresta plantada na área. A melhor precisão das coordenadas coletadas com o aparelho GPS Garmim 10 foi proporcionada, devido à função do sistema de coleta de dados para inventário florestal de florestas plantadas, gerar a médias corrigidas das coordenadas armazenadas no aparelho. O sistema de coleta de dados para inventários florestais de florestas plantadas auxiliou na manipulação e na localização das unidades amostrais do inventário florestal. A mobilidade propiciou que os dados do inventário fossem registrados e armazenados para posterior manipulação; proporcionou rapidez e otimização das atividades no processamento dos dados após a transmissão para o computador. A interação entre as variáveis utilizadas nesta pesquisa, juntamente com os dados georreferenciados, permitiu distinguir e visualizar, características distintas da floresta. Possibilitou relacionar a produtividade e realizar o zoneamento do melhor crescimento das florestas. A aplicação da tecnologia móvel com o sistema de coletas de dados para inventário florestal de florestas plantadas, assim como o emprego de mapeamento e geoestatística são recomendados para melhorar a qualidade da quantificação e qualificação das florestas, incentivando o emprego da silvicultura de precisão.
5

Menos complementares e redundantes, porém mais jovens: organização de assembleias de aves em monoculturas florestais / Less complementary and redundant, but younger: birds assemblages organization in monoculture tree plantations

Labecca, Fábio Martins 29 April 2015 (has links)
Submitted by Erika Demachki (erikademachki@gmail.com) on 2016-01-07T15:35:40Z No. of bitstreams: 2 Dissertação - Fábio Martins Labecca - 2015.pdf: 2107333 bytes, checksum: cf5e7e0ac514e7f834e6ed7aab735b5d (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Approved for entry into archive by Erika Demachki (erikademachki@gmail.com) on 2016-01-07T15:37:02Z (GMT) No. of bitstreams: 2 Dissertação - Fábio Martins Labecca - 2015.pdf: 2107333 bytes, checksum: cf5e7e0ac514e7f834e6ed7aab735b5d (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Made available in DSpace on 2016-01-07T15:37:02Z (GMT). No. of bitstreams: 2 Dissertação - Fábio Martins Labecca - 2015.pdf: 2107333 bytes, checksum: cf5e7e0ac514e7f834e6ed7aab735b5d (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Previous issue date: 2015-04-29 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / The increasing demand for timber and pulpwood has triggered an increase in areas of tree monocultures. The effects of native vegetation conversion in such monocultures have been extensively debated, but the consequences of this land use change to functionality and evolutionary history conservation have been little studied. Here, we evaluated how the avifauna responds to nature ecosystem conversion in tree monocultures by quantifying changes in local diversity (alpha diversity) and in assemblage composition (beta diversity), in their functional and phylogenetic components. We compiled forty paired bird lists in native vegetation areas and in comparable tree monoculture areas. Changes in alpha diversity were quantified by paired tests of observed values in native vegetation and in tree monocultures, and changes in assemblages composition through additive partitioning of beta diversity in nestedness and turnover components. We observed that tree monocultures are impoverished in number of species, supporting lower functional richness and less functionally similar assemblages. This demonstrates that environmental filter selecting and limiting similarity processes concurrently modify functional structure of bird assemblages, resulting in loss of functional complementarity and redundancy. Species in tree monocultures are also evolutionary younger and less related to each other. We showed that bird assemblages in tree monoculture are composed largely by functionally and phylogenetic different species from that assemblages in native vegetation. Body size, diet and foraging traits were the major functional traits in predicting the absence of the species in tree monocultures. Alson, we show that annual average temperature, annual average pluviosity and stage of understory development in tree monocultures are important predictors of diversity loss in these type of monoculture. / A crescente demanda por madeira e celulose tem desencadeado um aumento das áreas de monocultura florestal. Os efeitos da conversão de áreas de vegetação nativa nesse tipo de monocultura, por sua vez, vêm sendo extensamente debatidos. As consequências dessa mudança no uso do solo para a funcionalidade e conservação da história evolutiva foram até agora pouco estudadas. Neste estudo, nós avaliamos como a avifauna responde a conversão de ecossistemas naturais em monoculturas florestais, quantificando mudanças na diversidade local (diversidade alfa) e na composição dessas assembleias (diversidade beta) em seus componentes funcional e filogenético. Para isto, compilamos quarenta listas pareadas de aves em áreas de vegetação nativa e em áreas comparáveis de monocultura florestal. As mudanças na diversidade alfa foram testadas por testes pareados dos valores observados em vegetação nativa e em monoculturas florestais, e as mudanças na composição das assembleias através da partição aditiva da diversidade beta nos componentes de aninhamento e substituição. Observamos que as áreas de monocultura florestal são empobrecidas no número de espécies, suportam menor riqueza funcional e são menos similares funcionalmente. Isto demonstra que os processos de filtro ambiental e de similaridade limitante modificam a estrutura funcional das assembleias de aves de forma concomitante, resultando em perda de complementaridade e também de redundância funcional. As espécies presentes em áreas de monocultura são também evolutivamente mais jovens e menos aparentadas entre si. Mostramos que as assembleias de monoculturas florestais são compostas em grande parte por espécies funcionalmente e filogeneticamente diferentes daquela avifauna em vegetação nativa. Tamanho corpóreo, dieta e estratégias de forrageamento se mostraram as características funcionais importantes na predição da ausência das espécies em monoculturas florestais. Ainda, mostramos que temperatura e pluviosidade média anual, e o estádio de desenvolvimento do sub-bosque são importantes preditores da perda de diversidade nesse tipo de monocultura.
6

Diversidade de rizóbios em Florestas de Araucária no Estado de São Paulo / Rhizobia diversity in Araucaria Forests in São Paulo State, Brazil

Lammel, Daniel Renato 19 June 2007 (has links)
Araucaria angustifolia (B.) Ktz é de grande importância sócio-ambiental e econômica, sendo que ecossistemas que abrigam esta espécie foram muito degradados pela atividade antrópica, colocando-a em risco de extinção. O ciclo do nitrogênio é de vital importância para a vida, tendo especial importância no desenvolvimento e manutenção de florestas. A entrada de nitrogênio nestes sistemas é dependente de organismos diazotróficos, em especial dos rizóbios, bactérias do solo que podem formar simbiose com leguminosas e fixar nitrogênio atmosférico. O estudo da diversidade de rizóbios pode favorecer o manejo mais adequado de florestas e muitas técnicas são usadas com este fim, nas quais se destacam o uso de plantas iscas, coleta de nódulos de leguminosas a campo, isolamento das bactérias em meios de cultivo, avaliação fenotípica dos isolados e o seqüenciamento do gene 16S rRNA, todas utilizadas neste trabalho. A partir do levantamento de leguminosas no Parque Estadual de Campos do Jordão foram coletadas onze espécies de leguminosas, nove apresentaram nódulos, sendo cinco espécies descritas como nodulantes pela primeira vez. Foram isoladas 212 estirpes de bactérias, havendo variação no formato de nódulos e alta riqueza fenotípica das cepas. Houve variabilidade na diversidade fenotípica de bactérias para cada planta, Galactia crassifolia apresentou o maior valor, enquanto que Mimosa dolens apresentou o menor. Dos 212 isolados, 55 cepas foram capazes de nodular o feijoeiro e 56 de nodular a bracatinga. Foi seqüenciado parcialmente o gene 16S rRNA de 196 estirpes que foram classificadas em oito grupos genotípicos, Pantoea sp. (2%), Pseudomonas sp. (2%), Bradyrhizobium sp1 (10%), Bradyrhizobium sp2 (7%), Rhizobium sp. (1%), Burkholderia sp1 (14%), Burkholderia sp2 (26%) e Burkholderia sp3 (38%). A análise filogenética mostrou que a maioria dos grupos pertence a gêneros taxonomicamente relacionados a rizóbios. Houve variação na diversidade genotípica das bactérias em relação às plantas das quais foram isoladas, G. crassifolia apresentou o maior valor, sendo considerada a mais promíscua, enquanto que Acacia dealbata e M. dolens apresentaram os menores valores, sendo consideradas as mais especificas. Mostrou-se que o uso de avaliação fenotípica de rizóbios pode ser inadequado, já que os resultados fenotípicos foram muitas vezes divergentes dos genotípicos. Foram comparadas Florestas de Araucária com diferentes níveis de interferência antrópica (Floresta Preservada, Floresta Plantada e Floresta em Regeneração), usando as plantas-iscas caupi, amendoim, soja, bracatinga, maricá e angico. Maricá foi o mais eficiente na captura de rizóbios, enquanto que bracatinga e caupi apresentaram menor eficiência e as demais plantas falharam. Foram isoladas 78 cepas, sendo classificados como pertencentes a seis grupos genotípicos, Pseudomonas sp. (3%), Xanthomonas sp. (1%), Ralstonia sp. (6%), Herbaspirillum sp. (4%), Burkholderia sp1 (29%) e Burkholderia sp3 (57%), sendo três grupos iguais aos caracterizados anteriormente. A maioria destes grupos está relacionada a rizóbios ou bactérias endofíticas conhecidas. A Floresta em Regeneração apresentou maior diversidade de bactérias isoladas, enquanto que as Florestas Plantada e Preservada apresentaram índices semelhantes. β-rizóbios foram predominantes nas Florestas de Araucária estudadas. / Araucaria angustifolia (B.) Ktz has a great social, environmental and economic importance to south and southeastern Brazil, although ecosystems supporting this species have been degraded by human activity, making it an endangered species. The nitrogen cycle has vital importance for life and has a special role in the development and upkeep of forests. The nitrogen input in these systems is dependent on diazotrophic organisms, especially rhizobia, soil bacteria that may nodulate legumes and fix nitrogen in symbiosis with them. The study of rhizobia diversity may support better forest management practices and many techniques are used in these studies, especially the use of trap-plants, field legume nodule collection, bacteria isolation in culture media, phenotypic analysis of the strains and 16S rRNA gene sequencing, all of which were used in this work. From a survey in Campos do Jordão State Park, nine of eleven legume species collected presented nodules, of which five were reported as nodulating for the first time. A total of 212 bacterial strains were isolated from the nodules. There was great variation of nodule shape and great phenotypic richness among isolates. There was variability in the phenotypical diversity of bacteria in each plant, where Galactia crassifolia showed the highest value, while Mimosa dolens showed the lowest one. Of the 212 strains, 55 were able to nodulate common bean and 56 nodulated bracatinga (M. scabrella). The 16S rRNA gene of 196 strains were partially sequenced and classified into eight genotypic groups: Pantoea sp. (2%), Pseudomonas sp. (2%), Bradyrhizobium sp1 (10%), Bradyrhizobium sp2 (7%), Rhizobium sp. (1%), Burkholderia sp1 (14%), Burkholderia sp2 (26%) and Burkholderia sp3 (38%). Phylogenetic analysis showed that most of the groups belong to bacteria genera related to rhizobia. There was variability in the bacterial diversity related to the isolated plants, where G. crassifolia showed the highest value, being considered the most promiscuous, while Acacia dealbata and M. dolens presented the lowest values, and were considered the most specific ones. The phenotypic analysis of rhizobia was shown to be inappropriate for taxonomy, since the phenotypic results were different from the genotypic ones. Araucaria Forests with different levels of human interference (Preserved Forest, Planted Forest and Recovering Forest) were compared using cowpea, peanut, soybean, bracatinga, maricá (M. bimucronata) and angico (Parapiptadenia rigida) as trap-plants. Maricá was the most efficient in rhizobia capture, while bracatinga and cowpea showed less efficiency and the others failed. A total of 78 strains were isolated and classified into six genotypic groups: Pseudomonas sp. (3%), Xanthomonas sp. (1%), Ralstonia sp. (6%), Herbaspirillum sp. (4%), Burkholderia sp1 (29%) and Burkholderia sp3 (57%), of which three are the same as previously classified. Most of these groups are related to known rhizobia or other endophytic bacteria. The Recovering Forest showed the highest diversity of isolated bacteria, while Planted Forests and Preserved Forest showed similar indeces. β-rhizobia were predominant in the studied areas.
7

Diversidade de rizóbios em Florestas de Araucária no Estado de São Paulo / Rhizobia diversity in Araucaria Forests in São Paulo State, Brazil

Daniel Renato Lammel 19 June 2007 (has links)
Araucaria angustifolia (B.) Ktz é de grande importância sócio-ambiental e econômica, sendo que ecossistemas que abrigam esta espécie foram muito degradados pela atividade antrópica, colocando-a em risco de extinção. O ciclo do nitrogênio é de vital importância para a vida, tendo especial importância no desenvolvimento e manutenção de florestas. A entrada de nitrogênio nestes sistemas é dependente de organismos diazotróficos, em especial dos rizóbios, bactérias do solo que podem formar simbiose com leguminosas e fixar nitrogênio atmosférico. O estudo da diversidade de rizóbios pode favorecer o manejo mais adequado de florestas e muitas técnicas são usadas com este fim, nas quais se destacam o uso de plantas iscas, coleta de nódulos de leguminosas a campo, isolamento das bactérias em meios de cultivo, avaliação fenotípica dos isolados e o seqüenciamento do gene 16S rRNA, todas utilizadas neste trabalho. A partir do levantamento de leguminosas no Parque Estadual de Campos do Jordão foram coletadas onze espécies de leguminosas, nove apresentaram nódulos, sendo cinco espécies descritas como nodulantes pela primeira vez. Foram isoladas 212 estirpes de bactérias, havendo variação no formato de nódulos e alta riqueza fenotípica das cepas. Houve variabilidade na diversidade fenotípica de bactérias para cada planta, Galactia crassifolia apresentou o maior valor, enquanto que Mimosa dolens apresentou o menor. Dos 212 isolados, 55 cepas foram capazes de nodular o feijoeiro e 56 de nodular a bracatinga. Foi seqüenciado parcialmente o gene 16S rRNA de 196 estirpes que foram classificadas em oito grupos genotípicos, Pantoea sp. (2%), Pseudomonas sp. (2%), Bradyrhizobium sp1 (10%), Bradyrhizobium sp2 (7%), Rhizobium sp. (1%), Burkholderia sp1 (14%), Burkholderia sp2 (26%) e Burkholderia sp3 (38%). A análise filogenética mostrou que a maioria dos grupos pertence a gêneros taxonomicamente relacionados a rizóbios. Houve variação na diversidade genotípica das bactérias em relação às plantas das quais foram isoladas, G. crassifolia apresentou o maior valor, sendo considerada a mais promíscua, enquanto que Acacia dealbata e M. dolens apresentaram os menores valores, sendo consideradas as mais especificas. Mostrou-se que o uso de avaliação fenotípica de rizóbios pode ser inadequado, já que os resultados fenotípicos foram muitas vezes divergentes dos genotípicos. Foram comparadas Florestas de Araucária com diferentes níveis de interferência antrópica (Floresta Preservada, Floresta Plantada e Floresta em Regeneração), usando as plantas-iscas caupi, amendoim, soja, bracatinga, maricá e angico. Maricá foi o mais eficiente na captura de rizóbios, enquanto que bracatinga e caupi apresentaram menor eficiência e as demais plantas falharam. Foram isoladas 78 cepas, sendo classificados como pertencentes a seis grupos genotípicos, Pseudomonas sp. (3%), Xanthomonas sp. (1%), Ralstonia sp. (6%), Herbaspirillum sp. (4%), Burkholderia sp1 (29%) e Burkholderia sp3 (57%), sendo três grupos iguais aos caracterizados anteriormente. A maioria destes grupos está relacionada a rizóbios ou bactérias endofíticas conhecidas. A Floresta em Regeneração apresentou maior diversidade de bactérias isoladas, enquanto que as Florestas Plantada e Preservada apresentaram índices semelhantes. β-rizóbios foram predominantes nas Florestas de Araucária estudadas. / Araucaria angustifolia (B.) Ktz has a great social, environmental and economic importance to south and southeastern Brazil, although ecosystems supporting this species have been degraded by human activity, making it an endangered species. The nitrogen cycle has vital importance for life and has a special role in the development and upkeep of forests. The nitrogen input in these systems is dependent on diazotrophic organisms, especially rhizobia, soil bacteria that may nodulate legumes and fix nitrogen in symbiosis with them. The study of rhizobia diversity may support better forest management practices and many techniques are used in these studies, especially the use of trap-plants, field legume nodule collection, bacteria isolation in culture media, phenotypic analysis of the strains and 16S rRNA gene sequencing, all of which were used in this work. From a survey in Campos do Jordão State Park, nine of eleven legume species collected presented nodules, of which five were reported as nodulating for the first time. A total of 212 bacterial strains were isolated from the nodules. There was great variation of nodule shape and great phenotypic richness among isolates. There was variability in the phenotypical diversity of bacteria in each plant, where Galactia crassifolia showed the highest value, while Mimosa dolens showed the lowest one. Of the 212 strains, 55 were able to nodulate common bean and 56 nodulated bracatinga (M. scabrella). The 16S rRNA gene of 196 strains were partially sequenced and classified into eight genotypic groups: Pantoea sp. (2%), Pseudomonas sp. (2%), Bradyrhizobium sp1 (10%), Bradyrhizobium sp2 (7%), Rhizobium sp. (1%), Burkholderia sp1 (14%), Burkholderia sp2 (26%) and Burkholderia sp3 (38%). Phylogenetic analysis showed that most of the groups belong to bacteria genera related to rhizobia. There was variability in the bacterial diversity related to the isolated plants, where G. crassifolia showed the highest value, being considered the most promiscuous, while Acacia dealbata and M. dolens presented the lowest values, and were considered the most specific ones. The phenotypic analysis of rhizobia was shown to be inappropriate for taxonomy, since the phenotypic results were different from the genotypic ones. Araucaria Forests with different levels of human interference (Preserved Forest, Planted Forest and Recovering Forest) were compared using cowpea, peanut, soybean, bracatinga, maricá (M. bimucronata) and angico (Parapiptadenia rigida) as trap-plants. Maricá was the most efficient in rhizobia capture, while bracatinga and cowpea showed less efficiency and the others failed. A total of 78 strains were isolated and classified into six genotypic groups: Pseudomonas sp. (3%), Xanthomonas sp. (1%), Ralstonia sp. (6%), Herbaspirillum sp. (4%), Burkholderia sp1 (29%) and Burkholderia sp3 (57%), of which three are the same as previously classified. Most of these groups are related to known rhizobia or other endophytic bacteria. The Recovering Forest showed the highest diversity of isolated bacteria, while Planted Forests and Preserved Forest showed similar indeces. β-rhizobia were predominant in the studied areas.
8

Étude de l’émergence et de la dynamique évolutive d’Armillaria ostoyae, agent pathogène du pin maritime / Study of the emergence and evolutionary dynamics of Armillaria ostoyae a pathogen of maritime pine

Labbé, Frédéric 11 December 2015 (has links)
Dans la forêt de pin maritime (Pinus pinaster) des Landes de Gascogne (sud-ouest de France), la mortalité des pins causée par le champignon pourridié Armillaria ostoyae (Basidiomycète) a augmenté au cours des 30 dernières années. Les premiers cas de cette maladie ont été signalés quelques années après un changement majeur dans l'utilisation des terres, qui a eu lieu dans cette région suite au remplacement des landes et marais d'origine par une forêt plantée et gérée da façon intensive. Notre objectif était de comprendre les facteurs à l'origine de cette maladie émergente. Pour cela, nous avons étudié la distribution spatiale des dommages causés par le pathogène en relation avec des facteurs historiques, estimé la variabilité des traits fongiques liés au parasitisme et saprophytisme, et étudié l'histoire démographique d'A. ostoyae. La répartition actuelle de la mortalité induite par A. ostoyae est apparue dépendre de la présence des forêts préexistantes, ce qui suggère qu'A. ostoyae était fréquent dans ces zones forestières anciennes, qui ont agi comme un réservoir pour la colonisation des forêts plantées récentes. La production de rhizomorphes était significativement corrélée avec la virulence, suggérant que ce trait joue un rôle important dans le stade parasitaire d'A. ostoyae. Aucune relation significative entre le parasitisme et saprophytisme n'a été détectée, suggérant une absence de compromis évolutif entre ces traits. Enfin, le meilleur scénario démographique pour expliquer la structure de la population d'A. ostoyae dans la forêt des Landes est un scénario en deux étapes : il y aurait eu d'abord une diminution puis une expansion de la population fongique, qui semblait suivre la dynamique de la population d'hôtes. Le temps de génération d’A. ostoyae a été estimé entre 10 et 20 ans. / In the maritime pine (Pinus pinaster) forest of the Landes de Gascogne (south-western France), pine mortality due to the root rot fungus Armillaria ostoyae (Basidiomycete) has been increasing over the last 30 years. The first cases of this disease were reported a few years after a major change in land use which occurred in this region following the replacement of original moors by an intensively managed planted forest. Our aim was to understand the factors driving this disease emergence. For this, we investigated the spatial distribution of pathogen damage related to historical factors, estimated the variation in fungal traits related to parasitism and saprophytism and investigated the demographic history of A. ostoyae. The current distribution of A. ostoyae mortality appeared depending on the pre-existing forests, suggesting that A. ostoyae was commonly distributed in pre-existing forest areas which acted as a reservoir for the colonization of recent planted forests. The rhizomorphs production was significantly correlated with virulence, suggesting that this trait plays an important role in the parasitic stage of A. ostoyae, but no significant relationship between parasitism and saprophytism components was detected, which may suggest that there is no trade-off between these traits. Finally, the best demographic scenario to explain A. ostoyae population structure in the Landes forest is a two step scenario: there was first a decrease and then an expansion in the fungal population, which appeared to follow the dynamics of the host population. The generation time of A. ostoyae was estimated between 10 and 20 years.
9

Dynamics of Forest Ecosystems Under Global Change: Applications of Artificial Intelligence in Mapping, Classification, and Projection

Akane Ota Abbasi (17123185) 10 October 2023 (has links)
<p dir="ltr">Global forest ecosystems provide essential ecosystem services that contribute to water and climate regulation, food production, recreation, and raw materials. They also serve as crucial habitats for numerous terrestrial species of amphibians, birds, and mammals worldwide. However, recent decades have witnessed unprecedented changes in forest ecosystems due to climate change, shifts in species distribution patterns, increased planted forest areas, and various disturbances such as forest fires, insect infestations, and urbanization. These changes can have far-reaching impacts on ecological networks, human well-being, and the well-being of global forest ecosystems. To address these challenges, I present four studies to quantify forest dynamics through mapping, classification, and projection, using artificial intelligence tools in combination with a vast amount of training data. (I) I present a spatially continuous map of planted forest distribution across East Asia, produced by integrating multiple sources of planted and natural forest data. I found that China contributed 87% of the total planted forest areas in East Asia, most of which are located in the lowland tropical/subtropical regions and Sichuan Basin. I also estimated the dominant genus in each planted forest location. (II) I used continent-wide forest inventory data to compare the range shifts of forest types and their constituent tree species in North America in the past 50 years. I found that forest types shifted more than three times as fast as the average of their constituent tree species. This marked difference was attributable to a predominant positive covariance between tree species ranges and the change of species relative abundance. (III) Based on individual-level field surveys of trees and breeding birds across North America, I characterized New World wood-warbler (<i>Parulidae</i>) species richness and its potential drivers. I identified forest type as the most powerful predictor of New World wood-warbler species richness, which adds valuable evidence to the ongoing physiognomy versus composition debate among ornithologists. (IV) In the appendix, I utilized continent-wide forest inventory data from North America and South America and the combination of supervised and unsupervised machine learning algorithms to produce the first data-driven map of forest types in the Americas. I revealed the distribution of forest types, which are useful for cost-effective forest and biodiversity management and planning. Taken together, these studies provide insight into the dynamics of forest ecosystems at a large geographic scale and have implications for effective decision-making in conservation, management, and global restoration programs in the midst of ongoing global change.</p>

Page generated in 0.097 seconds