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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

Anatomia e flexibilidade do caule de quatro espécies lenhosas para o manejo biotécnico de cursos de água. / Stem anatomy and flexibility of four wood species to water courses biotechnical management

Denardi, Luciano 17 July 2007 (has links)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The use of vegetation is a common tool in Soil Bioengineering; the plants, in this case, must have flexible stems, among other characteristics. The present work aims to investigate the wood anatomy and the stem flexibility of four species: Phyllanthus sellowianus Müll. Arg. (Phyllanthaceae), Sebastiania schottiana (Müll. Arg.) Müll. Arg., Salix humboldtiana Willd. (Salicaceae) and Salix x rubens Schrank (Salicaceae). The material was collected in the municipality of Santa Maria, Rio Grande do Sul Brazil. The anatomical studies used samples from two individuals by species and the microscopic descriptions followed the IAWA Committee. The flexibility studies used fifty stem samples, with different diameters, for each species. The results showed that the modulus of elasticity is not a good parameter to evaluate stem flexibility; in substitution, it was created a new parameter: the angle of flexibility . Phyllanthus sellowianus showed to be the most indicated species to bioengineering works, followed by Sebastiania schottiana, Salix humboldtiana and Salix x rubens. The prune or even the cut of adult trunks of these species give much protection to slope stability due to the production of younger and more flexible stems. The wood anatomy of Sebastiania schottiana and Phyllanthus sellowianus, here described by the first time, also supports the recent segregation of the last species from the Euphorbiaceae. The great similarity within all studied species configures a reophyllous anatomical syndrome : abundant gelatinous fibres, small vessels, thin rays and absent or rare axial parenchyma; from these features, the presence of gelatinous fibres may be considered as the most important to stem flexibility / O uso de vegetação é uma das principais ferramentas da Bioengenharia; no caso de taludes fluviais, as plantas devem possuir caules flexíveis, entre outras características. O presente trabalho teve por objetivo investigar a anatomia e a flexibilidade do caule de Phyllanthus sellowianus Müll. Arg. (Phyllanthaceae), Sebastiania schottiana (Müll. Arg.) Müll. Arg. (Euphorbiaceae), Salix humboldtiana Willd. (Salicaceae) e Salix x rubens Schrank (Salicaceae). A coleta de material foi realizada no município de Santa Maria, Rio Grande do Sul Brasil. As amostras de madeira, para os estudos anatômicos, foram extraídas do caule de dois indivíduos, para cada espécie, e a descrição microscópica seguiu as recomendações do IAWA Committee. Para o estudo da flexibilidade utilizou-se cinqüenta amostras do caule, com diferentes diâmetros, para cada espécie. Os resultados indicaram que o módulo de elasticidade não constituí parâmetro adequado para julgar a flexibilidade de caules; para tanto, criou-se um novo parâmetro: o ângulo de flexibilidade . Phyllanthus sellowianus destacou-se como a espécie mais flexível e, portanto, a mais apta para a proteção de taludes fluviais, seguida por Sebastiania schottiana, Salix humboldtiana e Salix x rubens. A poda, ou mesmo o corte de indivíduos adultos dessas espécies, proporciona maior proteção aos taludes fluviais pela produção de caules jovens e mais flexíveis. A descrição anatômica da madeira de Sebastiania schottiana e Phyllanthus sellowianus, até então inédita, suporta o recente desmembramento dessa última espécie das Euphorbiaceae. A grande semelhança verificada no lenho destas quatro espécies configura uma síndrome anatômica de reofilia : abundante fibras gelatinosas, vasos pequenos, raios estreitos e parênquima axial escasso ou ausente; destas características, a presença de fibras gelatinosas é a mais importante para a flexibilidade do caule
22

Ekonomika rychle rostoucích dřevin / Economy of fast-growing woody species

Levý, Lukáš January 2011 (has links)
The thesis is focused on analyzing and evaluation of importance and potential of fast-growing woody species for specifics of Czech economy and local conditions. Thesis will inquire into applicability of each fast-growing species for Czech natural conditions. Further I will investigate opportunities of subvention from public authorities. Next part of thesis will be focused on all activities and processes during cultivation of fast-growing species from acquiring land to processing of wooden mass. For each activity will quantify costs of labor and physical capital during cultivation of fast-growing woody species for different subjects in Czech economy, like household owning a soil or company with unused outside areas. Thesis will be comparing possible energetic savings of profits for a number of alternatives with different energy prices development in ongoing years. Practical output of this thesis should not be only the compilation of all these information into one text, but above all also a complex formula which everyone can use for the calculation of his opportunities for cultivating of fast-growing woody species.
23

<b>BEAVER ACTIVITY AND FLORA SURVEY IN CHAIN O'LAKES STATE PARK, NOBLE COUNTY INDIANA</b>

Patrick Jaymes Mayo (17582628) 10 December 2023 (has links)
<p dir="ltr">North American beaver are ecosystem and habitat altering mammals with a wide distribution in North America. Beaver are associated with bodies of fresh water while utilizing riparian habitat by foraging on woody and herbaceous, terrestrial and aquatic vegetation, as well as creating lodges, dams, dens, and scent mounds. Chain O’Lakes State Park was chosen as a study area for surveying beaver activity and woody species communities. The aim of the study was to better understand the relationship between beaver, and specifically, the woody vegetation in their foraging and home range. There is a large swath of habitat that beaver can utilize and alter within Chain O’Lakes State Park including the lakes, streams, and forests that attract visitors. The factors that have been found to influence beaver utilization in Chain O’Lakes State Park (and North America at large) are woody species community composition, abundance of heavily preferred woody species, as well as a combination of both an absence of predators and an abundance of aquatic vegetation. Based on the distribution of heavily, occasionally, and rarely preferred woody species across the understory (new individuals) and overstory (mature individuals) stratum an inference can be made that most of the riparian habitat around the lakes will continue to and/or shift into a higher proportion of species that beaver heavily select. A minority of the habitat shall shift away from those species and towards rarely and/or occasionally selected species. I will provide USDA APHIS Wildlife Services that play a wildlife management role in Chain O’Lakes State Park with the survey information detailing how beaver and their structures interact with the ecosystem, hypothesized methods for preserving the woody species that are targeted by beaver foraging within the park, and supplementary information that may aid in maintaining the riparian habitats for the benefit of park’s biodiversity and wildlife persistence while continuing to provide an enriched experience within Northwest Indiana with the potential to inform the greater collection of parks and maintained land at large.</p>
24

Uchycování spontánní dřevité vegetace na Sokolovských výsypkách / Spontaneous establishment of woody vegetation in post mining heaps near Sokolov

Reitschmiedová, Erika January 2015 (has links)
Surface coal mining heavily disrupts vast areas of landscape. Previous studies conducted in these areas reveal that succession processes on unreclaimed sites support close to nature community. It's crucial to understand and be able to predict these processes in order to include spontaneous succession into restoration plans. The aim of my thesis is to clarify establishment and dispersion mechanisms of dominant pioneer woody species willow (Salix caprea), birch (Betula pendula) and aspen (Populus tremula). Study carried out on unreclaimed sites on a large colliery spoil heap near the town of Sokolov. I have studied establishment and growth of pioneer woody species on both graded and ungraded sites, representation of individual woody pioneer species was on sites in different distance from the edge of the spoil heap, birch's population age structure and reproduction potential of willow in accordance to age. All pioneer woody species establish and grow better on ungraded sites. The amount of willow decreases while the number of aspen individuals remains the same and the amount of birch increases with growing distance from the edge of the spoil heap. Birch's population age reveals establishment of new individuals in favourable climatic conditions. Willow is reproductively capable at the age of 10 years...
25

Influência do gado e da monocultura de eucalyptus sp. em florestas ripárias do sul do Brasil

De Marchi, Tiago Closs 11 January 2011 (has links)
Submitted by Silvana Teresinha Dornelles Studzinski (sstudzinski) on 2015-06-23T15:19:36Z No. of bitstreams: 1 TiagoClossDeMarchi.pdf: 3447572 bytes, checksum: 384491c29d57ca52c59ea0cda6879c8b (MD5) / Made available in DSpace on 2015-06-23T15:19:36Z (GMT). No. of bitstreams: 1 TiagoClossDeMarchi.pdf: 3447572 bytes, checksum: 384491c29d57ca52c59ea0cda6879c8b (MD5) Previous issue date: 2011 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / A mudança do uso da terra decorrente de atividades agrícolas provoca uma modificação na paisagem que leva à criação de fragmentos florestais isolados que se mantém imersos em uma matriz que pode apresentar uma maior ou menor agressividade de acordo com o seu uso. Este estudo foi realizado em duas fazendas vizinhas localizadas no município de Eldorado do Sul, RS. A Fazenda Terra Dura, pertence à empresa Celulose Riograndense S/A e a maior parte da área é utilizada para a monocultura de eucalipto (Eucalyptus spp.). Os remanescentes de floresta nativa estão exclusivamente associados aos diversos cursos d’água que cruzam a área e cercados pelo plantio de eucalipto de diversas idades e estágios de produção. A área é utilizada para o plantio de eucalipto há cerca de 30 anos e há 20 foi isolada do gado. A Fazenda Eldorado destina-se à criação extensiva de gado e sua cobertura vegetal é caracterizada por um predomínio de campo com fragmentos de florestas ripárias que o gado utiliza como local de pastejo e desedentação. Em cada uma das dez áreas selecionadas foram alocados dois transectos paralelos ao curso d’água a 20 metros de distância um do outro nos quais foram aleatorizadas cinco unidades amostrais de 10 x 10m para amostragem do componente arbóreo dos fragmentos. Em cada unidade amostral foram registradas a circunferência de todos os indivíduos com diâmetro a altura do peito maior ou igual a 5 cm (DAP ≥ 5cm). O componente juvenil foi amostrado em unidades amostrais de 5 x 5m concêntricas em cada parcela de 10 x 10m, onde foram amostrados todos os indivíduos com mais de um metro de altura e com menos de 5 cm de diâmetro e estimou-se sua altura total e seu diâmetro à altura do solo (DAS). A densidade e composição do estrato herbáceo foi amostrada em parcelas de 1 x 1 m concêntricas às unidades amostrais de 5 x 5 m. Nestas unidades amostrais foi removida toda vegetação de até 1 m de altura e identificadas taxonômicamente as espécies e separadas em formas de vida (árvore, arbusto, erva, gramíneas, pteridófita, trepadeiras, epífitos). Para avaliação do sub-bosque nos plantios de eucalipto foram selecionados quatro talhões onde foram alocados três transectos de 100 m de comprimento em diferentes distâncias da borda (5, 25 e 50 m) e dois transectos (5 e 25 m) para o interior da mata ciliar. Em cada transecto foram sorteadas cinco unidades amostrais de 5 x 5 m e amostrados todos os indivíduos juvenis utilizando os mesmos critérios anteriormente citados para este estrato. Nos fragmentos adjacentes aos plantios de eucalipto, foram encontradas 61 espécies para os adultos e 77 para os juvenis e o estoque de carbono estimado foi de 106 Mg.ha-1 para os indivíduos adultos e de 4,3 Mg.ha-1 para os herbáceos. Nas áreas com presença de gado foram amostradas 62 espécies para os adultos e 48 para juvenis, com um estoque de carbono de 85,5 Mg.ha-1 para adultos e 0,9 Mg.ha-1 para herbáceo. No sub-bosque dos plantios de eucalipto foram amostradas 32 espécies, sendo 16 exclusivas e 71 no interior da floresta ripária, com 55 exclusivas. Os resultados mostraram que florestas em pequenos fragmentos incorporados em plantações de eucalipto parecem ser melhor preservadas do que aqueles expostos à pecuária. Além disso, áreas com presença de gado apresentaram uma redução no estoque de carbono de 23,8% para o estrato arbóreo e de 79,4% no estrato herbáceo em relação às áreas sem a presença de gado. A plantação de eucalipto possui um importante papel, embora restrito devido ao curto período de corte das árvores, para a manutenção da diversidade de espécies de florestas nativas adjacentes em seu sub-bosque e podem atuar como uma catalizadoras da regeneração da vegetação nativa e na manutenção da diversidade local. / The change in land use due to agricultural activities causes a landscape change that leads to the creation of isolated forest fragments that remain embedded in a matrix that may present a greater or lesser aggressiveness according to their use. The environmental quality of this matrix can affect species composition and forest structure through several factors that impact the surrounding environment, but on the other hand, depending on its type, the array can act as an important source of biodiversity conservation. This study was conducted in two neighboring farms located in Eldorado do Sul, RS. Terra Dura Farm, owned by Celulose Riograndense S/A and most of the area is used for the monoculture of eucalyptus (Eucalyptus spp.). The remnants of native forest are exclusively associated with the various streams that cross the area and surrounded by eucalyptus plantations of various ages and stages of production. The area is used for the planting of eucalyptus during 30 years. The cattle was isolated 20 years ago. Eldorado Farm is intended for extensive cattle ranching and its vegetation is characterized by a predominance of field with fragments of riparian forests that livestock use for grazing. We survey ten riparian fragments, five in each farm, were allocated two transects parallel to the stream to 20 m away from each other in which five were randomized plots of 10 x 10 m sampling of the tree component of the fragments. In each sampling unit circumference were recorded for all individuals with diameter at breast height greater than or equal to 5 cm (DBH ≥ 5 cm). The juvenile component was sampled in 5 x 5 m plots concentric in each plot of 10 x 10 m was sampled all individuals with more than one meter in height and less than 5 cm in diameter and estimated its total height, and its diameter at ground level (DAS). The density and composition of the herbaceous layer was sampled in plots of 1 x 1 m plots of concentric to 5 x 5 m. In these sample units of all vegetation was removed up to 1 m high, which were taxonomically identified and separated in life forms (tree, shrub, herb, grass, fern, lianes and epiphytes). To evaluate the understory in the eucalyptus plantations were selected four plots were allocated three transects of 100 m length at different distances from the edge (5, 25 and 50 m) and two transects (5 and 25 m) into the riparian vegetation. In each transect were randomly selected five samples of 5 x 5 m and sampled all juveniles using the same criteria previously cited for this stratum. In fragments adjacent to eucalyptus plantations, 61 species were found for adults and 77 for juveniles and the estimated carbon storage was 106 Mg.ha-1 for adults and 4.3 Mg.ha-1 for the herbs. In areas with presence of cattle were sampled for 62 adults and 48 for juveniles, with a carbon stock of 85.5 Mg.ha-1 for adults and 0.9 Mg.ha-1 for herbaceous. In the understory of the eucalyptus plantations were found 32 species, with 16 exclusive and 71 within the riparian forest, with 55 exclusive. Our results showed that in small forest fragments embedded in eucalypt plantations seem to be better preserved than those exposed to livestock. In addition, areas with the presence of cattle showed a reduction in carbon stock of 23.8% for the upper stratum and 79.4% in the herbaceous layer compared to areas without the presence of livestock and the planting of eucalyptus has an important role, although limited, due to shortcut the trees for the maintenance of species diversity of native forest adjacent to their understory and can act as a catalyst of the regeneration of native vegetation and maintenance of local diversity.
26

Banco de sementes autóctone e alóctone, resgate de plantas e plantio de vegetação nativa na fazenda Intermontes, município de Ribeirão Grande, SP. / Autochthonous and Allochthonous seed bank, seedling rescue and native vegetation planting at Intermontes farm, Ribeirão Grande-SP- Brazil.

Nave, André Gustavo 27 April 2005 (has links)
O acúmulo significativo de conhecimento sobre a ecologia de restauração nos últimos anos tem conduzido a mudanças na orientação dos programas de manejo e restauração florestal. A escolha ou criação de um modelo de restauração é um processo em constante aprimoramento, exigindo a necessidade de estudos que não apenas diminuam os custos envolvidos, mas também, que garantam a efetividade do objetivo proposto. Neste sentido, este trabalho testa novas metodologias de restauração visando a obtenção de informações técnicas sobre: A) a expressão do banco de sementes autóctone e alóctone na restauração florestal de diferentes situações de degradação antrópica.; B) o resgate de plântulas e indivíduos de espécies arbustivo-arbóreas regenerantes; C) a eficiência de um modelo de plantio que utiliza conceitos de Preenchimento e Diversidade e; D) a evolução da paisagem. Para análise dos bancos de sementes autóctone e alóctone foram feitos levantamentos da densidade e das espécies arbustivo-arbóreas regeneradas. No resgate de indivíduos de espécies arbustivo-arbóreas regenerantes, as plântulas e indivíduos jovens foram resgatadas em uma floresta e levadas para adapatação em viveiro, onde tiveram seus indivíduos e espécies contabilizados em termos de densidade e sobrevivência. No modelo de plantio estudado, as espécies foram reunidas em grupos de Preenchimento e Diversidade e tiveram a cobertura de copa de cada indivíduo quantificada. A evolução da paisagem foi realizada através de fotointerpretação e principalmente checagem de campo periódica. Os principais resultados dessas metodologias foram: A) As situações identificadas na Fazenda Intermontes apresentaram diferentes expressões de regeneração natural em função do número de indivíduos germinados banco de sementes autóctone. O aproveitamento dessa expressão poderá ser realizado através de metodologias diferenciadas de restauração para cada situação estudada: B) No estudo do Banco de sementes alóctone, a densidade dos indivíduos germinados se foi de 409.334 indivíduos/ha, revelando a possibilidade de uso no programa de restauração. Os indivíduos arbóreos apresentaram na área adubada um acréscimo de 137,3 % em sua altura média em relação aos indivíduos da área não adubada. C) No resgate de plântulas e indivíduos de espécies arbustivo-arbóreas regenerantes, a densidade dos indivíduos foi muito próxima para as duas épocas do ano, sendo 38.700 ind./ha e 37.900 ind./ha, mas com uma diferença significante para os indivíduos sobreviventes que apresentaram 16.500 ind./ha e 26.600 ind./ha para os meses de julho e dezembro de 2002, respectivamente. A técnica de resgate utilizada se mostrou viável uma vez que foi possível alcançar até 70,9% de sobrevivência para os indivíduos resgatados; D) No estudo sobre o modelo de plantio foram amostrados 143 espécies, demonstrando que a função do grupo da diversidade vem sendo mantida e aumentando as chances de efetivação dos processos de sucessão. Os resultados mostraram que o grupo de Preenchimento apresentou-se com uma porcentagem de cobertura significativamente maior que a do grupo de Diversidade, sendo 73,6% e 83,3% para 1,5 e 2,5 anos respectivamente. / Significant accumulation of know-how about restoration ecology has been changing forest restoration management programs’ trends during the last years. Choosing or elaborating a restoration model is a process that requires constant improvement and ecological studies that not only reduces the costs involved but also warrants the achievement of the aimed proposal. This study explores new restoration methodologies, searching for technical information about: A) autochthonous and allochthonous seed bank expression on forest restoration at different situations degraded by anthropogenic disturbances; B) seedlings and woody growing individuals rescue; C) efficiency of a planting model based on fulfillment and diversity concept; D) landscape development. The autochthonous and allochthonous seed bank were analyzed through regenerating woody species and density scouting. For the rescue of regenerating woody species, seedling and young individuals were taken from a forest and transferred to a plant nursery for adjustment, where number and species were counted regarding density and survival. In this studied planting model, species were organized and gathered into a fulfillment or diversity group, and each individual had its crown area quantified. Landscape development was analyzed by photointerpretation and specially by periodical field checking. Results from these methodologies showed that: A) Identified degraded situations at Intermontes farm displayed distinguished natural regeneration expression, influenced by the number of germinated seeds of the autochthonous seed bank. Advantage can be taken from these different outcomes by using distinct restoration methodologies for each studied situation. B) For the autochthonous seed bank study, germinated seed density was 409,334 ind./ha, indicating its potential role on restoration programs. Woody individuals at fertilized sites had a medium height enhancement of 137,7% when compared to those at non fertilized sites. C) For seedlings and woody growing individuals rescue, individual density was similar for both seasons (38700ind./ha and 37900ind./ha) but significantly distinct for individual survivor, with values of 16500ind./ha for July and 2600ind./ha for December. Rescue technique turned out to be a viable possibility since it achieved survival of 70,9% for rescued individuals. D) This planting model study registered 143 species, indicating that the diversity group’s role has been maintained and enhances the chance of successional process success. The fulfilling group had a significant higher percentage of crown area than the diversity group, with 73,6% and 83,3% for 1,5 and 2,5 years, respectively.
27

Riccarton Bush and the natural and social realities of native trees in Christchurch, New Zealand

Doody, Brendan J. January 2008 (has links)
Urbanization has destroyed and fragmented previously large areas of natural habitat. Small remnants that still exist in numerous cities will be unable to sustain many viable wild plant populations if they do not expand into the surrounding urban matrix. Residential gardens surrounding such remnants, and which form a significant component of urban green space in many cities, could play a role in redressing this problem. Riccarton Bush, a 7.8 hectare forest remnant, and its surrounding suburban residential area, in Christchurch, New Zealand, is a good example. Over 125 years the reported number of native vascular plants in the bush has declined by a third. My study was an attempt to understand: 1) the ecological, social and cultural factors influencing the dispersal and regeneration of 12 native bird-dispersed woody species from Riccarton Bush, into surrounding residential properties; and 2) the potential role residential properties could play in the future of the bush. To examine these diverse factors I adopted an interdisciplinary research approach combining methodologies, concepts and theories from ecology and the social sciences. In a broader context my work was an attempt to demonstrate how urban ecology can further develop and strengthen by adopting and integrating new methodologies, theories and concepts. The ecological component involved recording individuals of the study species found on 90 randomly selected properties within a 1.4 km radius of the bush. Soil samples were also collected from 31 of those properties and placed in a glasshouse and the study species that germinated were recorded. Results showed some species, particularly kahikatea (Dacrycarpus dacrydioides), the most abundant species in the bush, are being dispersed and establishing on properties predominantly within 250 m of the forest margin. These juveniles are not reaching maturity as most gardeners tend to remove all non-planted woody species. Qualitative interviews with 16 residents and a quantitative survey of the residents of 85 of the properties provided insights into the social context which these natural processes were operating. Using notions of place and performance I argue that gardens are continuously created and recreated by humans and non-humans. Residents attempt to create and maintain a garden that fulfils their individual and familial needs and desires (e.g., aesthetics, leisure and privacy), and public responsibilities such as ensuring they have a ‘neat’ and ‘tidy’ garden. This involves selecting plants for colour, shape and the care they require, and encouraging certain performances (e.g., flowering) while controlling other undesirable plants and performances (e.g. growth, spread and shading). While people make connections between native plants, belonging and identity; the ‘scientific’ demarcation between native and exotic species often becomes obscured as the garden is co-created by people and plants. Some plants become more significant than others but usually this is attributable to their performances rather than whether they are native or exotic. Residential gardens have the potential to play a major role in the conservation of species restricted to urban remnants. My research suggests that although the potential exists for woody species restricted to Riccarton Bush to naturally regenerate in nearby gardens, this will not happen without human intervention. Plants will need to be eco-sourced and propagated to avoid detrimental impacts on the genetic health of remnant populations, and then actively planted in gardens. The success of such planting initiatives will be increased by providing residents with information about the plants that are suitable for their performative needs and desires (e.g., the size, colour, and maintenance requirements of plants) and, most importantly, control over the location of plantings. In concluding, I argue that by adopting new concepts, theories and methodologies, the productivity, creativity and relevance of urban ecology can be significantly enhanced.
28

Banco de sementes autóctone e alóctone, resgate de plantas e plantio de vegetação nativa na fazenda Intermontes, município de Ribeirão Grande, SP. / Autochthonous and Allochthonous seed bank, seedling rescue and native vegetation planting at Intermontes farm, Ribeirão Grande-SP- Brazil.

André Gustavo Nave 27 April 2005 (has links)
O acúmulo significativo de conhecimento sobre a ecologia de restauração nos últimos anos tem conduzido a mudanças na orientação dos programas de manejo e restauração florestal. A escolha ou criação de um modelo de restauração é um processo em constante aprimoramento, exigindo a necessidade de estudos que não apenas diminuam os custos envolvidos, mas também, que garantam a efetividade do objetivo proposto. Neste sentido, este trabalho testa novas metodologias de restauração visando a obtenção de informações técnicas sobre: A) a expressão do banco de sementes autóctone e alóctone na restauração florestal de diferentes situações de degradação antrópica.; B) o resgate de plântulas e indivíduos de espécies arbustivo-arbóreas regenerantes; C) a eficiência de um modelo de plantio que utiliza conceitos de Preenchimento e Diversidade e; D) a evolução da paisagem. Para análise dos bancos de sementes autóctone e alóctone foram feitos levantamentos da densidade e das espécies arbustivo-arbóreas regeneradas. No resgate de indivíduos de espécies arbustivo-arbóreas regenerantes, as plântulas e indivíduos jovens foram resgatadas em uma floresta e levadas para adapatação em viveiro, onde tiveram seus indivíduos e espécies contabilizados em termos de densidade e sobrevivência. No modelo de plantio estudado, as espécies foram reunidas em grupos de Preenchimento e Diversidade e tiveram a cobertura de copa de cada indivíduo quantificada. A evolução da paisagem foi realizada através de fotointerpretação e principalmente checagem de campo periódica. Os principais resultados dessas metodologias foram: A) As situações identificadas na Fazenda Intermontes apresentaram diferentes expressões de regeneração natural em função do número de indivíduos germinados banco de sementes autóctone. O aproveitamento dessa expressão poderá ser realizado através de metodologias diferenciadas de restauração para cada situação estudada: B) No estudo do Banco de sementes alóctone, a densidade dos indivíduos germinados se foi de 409.334 indivíduos/ha, revelando a possibilidade de uso no programa de restauração. Os indivíduos arbóreos apresentaram na área adubada um acréscimo de 137,3 % em sua altura média em relação aos indivíduos da área não adubada. C) No resgate de plântulas e indivíduos de espécies arbustivo-arbóreas regenerantes, a densidade dos indivíduos foi muito próxima para as duas épocas do ano, sendo 38.700 ind./ha e 37.900 ind./ha, mas com uma diferença significante para os indivíduos sobreviventes que apresentaram 16.500 ind./ha e 26.600 ind./ha para os meses de julho e dezembro de 2002, respectivamente. A técnica de resgate utilizada se mostrou viável uma vez que foi possível alcançar até 70,9% de sobrevivência para os indivíduos resgatados; D) No estudo sobre o modelo de plantio foram amostrados 143 espécies, demonstrando que a função do grupo da diversidade vem sendo mantida e aumentando as chances de efetivação dos processos de sucessão. Os resultados mostraram que o grupo de Preenchimento apresentou-se com uma porcentagem de cobertura significativamente maior que a do grupo de Diversidade, sendo 73,6% e 83,3% para 1,5 e 2,5 anos respectivamente. / Significant accumulation of know-how about restoration ecology has been changing forest restoration management programs’ trends during the last years. Choosing or elaborating a restoration model is a process that requires constant improvement and ecological studies that not only reduces the costs involved but also warrants the achievement of the aimed proposal. This study explores new restoration methodologies, searching for technical information about: A) autochthonous and allochthonous seed bank expression on forest restoration at different situations degraded by anthropogenic disturbances; B) seedlings and woody growing individuals rescue; C) efficiency of a planting model based on fulfillment and diversity concept; D) landscape development. The autochthonous and allochthonous seed bank were analyzed through regenerating woody species and density scouting. For the rescue of regenerating woody species, seedling and young individuals were taken from a forest and transferred to a plant nursery for adjustment, where number and species were counted regarding density and survival. In this studied planting model, species were organized and gathered into a fulfillment or diversity group, and each individual had its crown area quantified. Landscape development was analyzed by photointerpretation and specially by periodical field checking. Results from these methodologies showed that: A) Identified degraded situations at Intermontes farm displayed distinguished natural regeneration expression, influenced by the number of germinated seeds of the autochthonous seed bank. Advantage can be taken from these different outcomes by using distinct restoration methodologies for each studied situation. B) For the autochthonous seed bank study, germinated seed density was 409,334 ind./ha, indicating its potential role on restoration programs. Woody individuals at fertilized sites had a medium height enhancement of 137,7% when compared to those at non fertilized sites. C) For seedlings and woody growing individuals rescue, individual density was similar for both seasons (38700ind./ha and 37900ind./ha) but significantly distinct for individual survivor, with values of 16500ind./ha for July and 2600ind./ha for December. Rescue technique turned out to be a viable possibility since it achieved survival of 70,9% for rescued individuals. D) This planting model study registered 143 species, indicating that the diversity group’s role has been maintained and enhances the chance of successional process success. The fulfilling group had a significant higher percentage of crown area than the diversity group, with 73,6% and 83,3% for 1,5 and 2,5 years, respectively.
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Pression d'herbivorie et dynamique des communautés végétales : influence à court et moyen termes des populations de cervidés sur la diversité des communautés végétales en forêt / Herbivory pressure and vegetation community dynamics : short- and mid-term impacts of deer populations on the diversity of forest vegetation communities

Boulanger, Vincent 27 April 2010 (has links)
Les cervidés, animaux mobiles et herbivores, peuvent influencer les distributions, assemblages et dynamiques d'espèces végétales. L'objectif de cette thèse est d'évaluer le rôle joué par les cervidés sur la composition, stratification et dynamique de la végétation forestière. Le ré-échantillonnage de relevés couplant composition et abroutissement de la flore, implantés en 1976 en Forêt d'Arc-en-Barrois (52) a permis d'identifier (i) des espèces ligneuses préférées (Cornus sp., Rosa arvensis) ou au contraire évitées par les cervidés qui sélectionnent les espèces arbustives et à bois dense et (ii) le niveau trophique et la pression d'abroutissement comme gradients structurant la végétation et déterminant les dynamiques des espèces et des communautés. Nous analysons plus précisément le rôle des cervidés dans la progression spectaculaire de Cynoglossum germanicum, espèce rare, épizoochore et toxique.A partir d'un réseau national d'enclos/exclos suivis sur 10 ans, nous montrons que les cervidés limitent la croissance des arbustes et des espèces compétitrices, ce qui profite à la richesse spécifique de la strate herbacée. La valeur écologique et patrimoniale des espèces en progression est discutée. A l'aide de données de chasse, nous tentons d'isoler les rôles des différentes espèces d'ongulés dans ces dynamiques.Ces résultats exposent la complexité et la diversité des effets des cervidés sur la végétation forestière. Enfin, ce travail met l'accent sur la nécessité des suivis temporels intégrant toutes les composantes de l'écosystème forestier pour mieux appréhender les changements en cours. / This thesis aims at assessing the impacts of deer on forest vegetation composition, stratification and dynamics.We resampled a network of relevés coupling vegetation and browsing surveys, settled in 1976 in the national forest of Arc-en-Barrois. We identified (i) ligneous species that are either preferred (Cornus sp., Rosa arvensis) or avoided by deer, which tend to select shrubs species with dense wood and (ii) trophic level and browsing pressure as gradients that determine plant communities structures and dynamics. Then, we highlight the roles of deer in the spectacular expansion of Cynoglossum germanicum, a rare, epizoochorous and toxic species. According to a national network of exclosures, monitored for over 10 years, we show that deer limit shrubs and competing species growth, which in turn benefits to the herbaceous species richness probably through an increased light availability. Ecological and patrimonial value of the benefitting species is discussed. Using hunting statistics, we try to isolate the role of the various ungulate species in these dynamics.These results provide evidence for the diversity and complexity of deer impacts on forest vegetation. Finally, we demonstrate the need for long term monitoring programs, including all the forest ecosystem components so that we could better appreciate the forces driving the current changes

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