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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.
191

Fire and vegetation history of the last 2000 years in Jackson Hole, Grand Teton National Park, Wyoming

Jacobs, Karen Marie. January 2007 (has links) (PDF)
Thesis (M.S.)--Montana State University--Bozeman, 2007. / Typescript. Chairperson, Graduate Committee: Cathy Whitlock. Includes bibliographical references (leaves 47-51).
192

The vegetation ecology of Ezemvelo Nature Reserve, Bronkhorstspruit, South Africa

Swanepoel, Barbara Anna. January 2006 (has links)
Thesis (M.Sc.)(Botany)--University of Pretoria, 2006. / Includes summary. Includes bibliographical references. Available on the Internet via the World Wide Web.
193

Produção de mudas de espécies florestais de restinga, com base em estudos florísticos e fitossociológicos, visando a recuperação de áreas degradadas, em Ilha Comprida - SP /

Carrasco, Pablo Garcia. January 2003 (has links)
Orientador: Luiz Mauro Barbosa / Resumo: As florestas de restinga, expressão utilizada neste trabalho para designar as formações florestais que se desenvolvem sobre a planície arenosa litorânea, possuem heterogeneidade estrutural interna e são constituídas por mosaicos vegetacionais, sendo ameaçadas pela especulação imobiliária, retirada seletiva de recursos biológicos e atividades minerárias. A produção de mudas florestais nativas regionais, com base em estudos florísticos e fitossociológicos, visando a recuperação de áreas degradadas, em Ilha Comprida (SP), foi o objetivo deste trabalho. Foram estudadas quatro áreas de 1ha, pelo método de parcelas contíguas, evidenciando a presença de 106 espécies florestais nativas (de ampla distribuição geográfica) e 6 exóticas, sendo a família Myrtaceae a mais representativa. Houve 23 espécies comuns às quatro áreas. A suficiência amostral foi alcançada em uma área de 70 X 70m para essas formações florestais. Foram anotados os parâmetros fitossociológicos de 256 indivíduos por área, pelo método do quadrante centrado no ponto, bem como coletadas amostras de solo e submetidas às análises física e química. As quatro formações florestais perturbadas apresentaram pequena complexidade estrutural e diversidade específica baixa, com pequeno número de espécies representadas por muitos indivíduos. Os solos se mostraram pobres em nutrientes e matéria orgânica, com baixa fertilidade e teores elevados de alumínio. As formações florestais são similares às das Ilhas do Cardoso (SP) e do Mel (PR). Numa área degradada por mineração de areia, o plantio de mudas ocorreu diretamente no solo arenoso e em covas com 50% de turfa. Durante os 175 dias de avaliação, o ganho de crescimento em altura não foi significativo, sendo observada a mortalidade de 23,8% das mudas implantadas no solo com turfa e 50,4% das do solo arenoso. A adição de turfa, embora insuficiente em nutrientes, aumentou a taxa de... / Abstract: The sandbank forests, expression used in this work to designate the forest formations that grow on the coastal sandy plain, possess internal structural heterogeneity and are constituted by vegetation mosaics, being threatened by the building speculation, selective retreat of biological resources and mining activities. The production of native regional forest seedlings, with base on floristic and phytosociological studies, seeking the recovery of degraded areas, in Ilha Comprida - São Paulo State - Brasil, was the aim of this paper. They where studied four areas of 1ha each, by using the method of contiguous portions, becoming evident the presence of 106 native forest species (of wide geographical distribution) and 6 exotic species, being the family Myrtaceae the most representative. There were 23 common species to the four areas. The sampling sufficiency was reached in an area of 70m X 70m for those forest formations. Were registered the phytosociological parameters of 256 individuals for area, by applying the method of the point centered quarter, as well as collected soil samples, being submitted to the physical and chemical analyses. The four disturbed forest formations presented small structural complexity and low specific diversity, with small number of species being represented by many individuals. The soils were poor in nutrients and organic matter, with low fertility and high tenors of aluminum. The forest formations are similar to the ones of Cardoso's Island (São Paulo) and of Mel Island (Paraná - Brasil). In an area degraded by mining of sand, the planting of seedlings occurred directly in the sandy soil and in holes with addition of 50% of peat. During the 175 days of evaluation, the growth gains in height was not significant, being observed the mortality of 23.8% of the seedlings implanted in the soil with peat and 50.4% of the one of the sandy soil. The peat addition, although insufficient in nutrients, increased... / Doutor
194

Post-management vegetation change in upland heather moorland, with particular reference to the nutrient status of soils, Lake Vyrnwy Estate, Powys, Mid Wales

Johnston, Ronald January 1998 (has links)
A major component of the vegetation cover in the area chosen for this study consists of heather moorland. This provides an essential habitat for diverse populations of ground-nesting moorland birds. Common heather - Calluna vulgaris (L) Hull - is typically the dominant species of this semi-natural habitat, providing both nutrition and cover for these bird populations. Much heather-dominated vegetation is in a successional stage and management is required to prevent its progressive transformation into rough grassland and woodland scrub. Traditionally management by burning and more recently by mowing has been used to achieve this by encouraging the growth of young heather, through the removal of senescent stands of Calluna vulgaris in the degenerate phase of its life cycle. These forms of management however may also have the effect of creating conditions which favour faster growing, acidophilous grasses which may replace Calluna vulgaris over time as the dominant species. This study investigates the hypothesis that particular management treatments may have specific influences on the composition and nature of the post-management vegetation complex. Particular attention is given to the nutrient status of soils, associated with each of the management treatments chosen for investigation. The influence of this on the long-term floristic composition and vertical stratification of the Callunetum is considered. Stands of vegetation belonging to different management regimes were used as the elements of chronosequences, which were utilised to investigate vegetation change over time in relation to particular management treatments. Vegetation was described from quadrats located within this framework and quadrat-specific soil samples were taken for chemical analysis. Dendrochronology was explored as a method for determining the age of Calluna plants in each treatment category from which the efficiency of different methods of removing the Calluna canopy was assessed. Multivariate methods of classification (TWINSPAN) and indirect gradient analysis (DECORANA) were used to reveal pattern in the vegetation data, which might be attributable to the management treatments defining each of the chronosequence stages. TWINSPAN was successful in identifying homogenous groups of samples on the basis of species associations peculiar to particular treatment categories. DECORANA proved successful in suggesting environmental gradients which might be responsible for these groupings. Data obtained from the chemical analysis of soil samples was used to compare soil nutrient status in each of the treatment categories, representative of the chronosequence stages. The vegetation and soils data-sets were then combined for use in direct gradient analysis (CANOCO), to investigate the combination of management treatments and soil nutrient status as factors influencing the formation of the species associations identified at each of the chronosequence stages. Finally, management goals are discussed in the context of the results of these analyses and the role of these procedures as the basis for an extended investigation into post-management, plant/soil inter-relationships as an influence on successional trends is evaluated.
195

Produção de mudas de espécies florestais de restinga, com base em estudos florísticos e fitossociológicos, visando a recuperação de áreas degradadas, em Ilha Comprida - SP

Carrasco, Pablo Garcia [UNESP] January 2003 (has links) (PDF)
Made available in DSpace on 2015-08-20T17:09:18Z (GMT). No. of bitstreams: 0 Previous issue date: 2003. Added 1 bitstream(s) on 2015-08-20T17:27:22Z : No. of bitstreams: 1 000198921.pdf: 2918884 bytes, checksum: 858554e57fcf4b30242b7463d4895c3f (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / As florestas de restinga, expressão utilizada neste trabalho para designar as formações florestais que se desenvolvem sobre a planície arenosa litorânea, possuem heterogeneidade estrutural interna e são constituídas por mosaicos vegetacionais, sendo ameaçadas pela especulação imobiliária, retirada seletiva de recursos biológicos e atividades minerárias. A produção de mudas florestais nativas regionais, com base em estudos florísticos e fitossociológicos, visando a recuperação de áreas degradadas, em Ilha Comprida (SP), foi o objetivo deste trabalho. Foram estudadas quatro áreas de 1ha, pelo método de parcelas contíguas, evidenciando a presença de 106 espécies florestais nativas (de ampla distribuição geográfica) e 6 exóticas, sendo a família Myrtaceae a mais representativa. Houve 23 espécies comuns às quatro áreas. A suficiência amostral foi alcançada em uma área de 70 X 70m para essas formações florestais. Foram anotados os parâmetros fitossociológicos de 256 indivíduos por área, pelo método do quadrante centrado no ponto, bem como coletadas amostras de solo e submetidas às análises física e química. As quatro formações florestais perturbadas apresentaram pequena complexidade estrutural e diversidade específica baixa, com pequeno número de espécies representadas por muitos indivíduos. Os solos se mostraram pobres em nutrientes e matéria orgânica, com baixa fertilidade e teores elevados de alumínio. As formações florestais são similares às das Ilhas do Cardoso (SP) e do Mel (PR). Numa área degradada por mineração de areia, o plantio de mudas ocorreu diretamente no solo arenoso e em covas com 50% de turfa. Durante os 175 dias de avaliação, o ganho de crescimento em altura não foi significativo, sendo observada a mortalidade de 23,8% das mudas implantadas no solo com turfa e 50,4% das do solo arenoso. A adição de turfa, embora insuficiente em nutrientes, aumentou a taxa de... / The sandbank forests, expression used in this work to designate the forest formations that grow on the coastal sandy plain, possess internal structural heterogeneity and are constituted by vegetation mosaics, being threatened by the building speculation, selective retreat of biological resources and mining activities. The production of native regional forest seedlings, with base on floristic and phytosociological studies, seeking the recovery of degraded areas, in Ilha Comprida - São Paulo State - Brasil, was the aim of this paper. They where studied four areas of 1ha each, by using the method of contiguous portions, becoming evident the presence of 106 native forest species (of wide geographical distribution) and 6 exotic species, being the family Myrtaceae the most representative. There were 23 common species to the four areas. The sampling sufficiency was reached in an area of 70m X 70m for those forest formations. Were registered the phytosociological parameters of 256 individuals for area, by applying the method of the point centered quarter, as well as collected soil samples, being submitted to the physical and chemical analyses. The four disturbed forest formations presented small structural complexity and low specific diversity, with small number of species being represented by many individuals. The soils were poor in nutrients and organic matter, with low fertility and high tenors of aluminum. The forest formations are similar to the ones of Cardoso's Island (São Paulo) and of Mel Island (Paraná - Brasil). In an area degraded by mining of sand, the planting of seedlings occurred directly in the sandy soil and in holes with addition of 50% of peat. During the 175 days of evaluation, the growth gains in height was not significant, being observed the mortality of 23.8% of the seedlings implanted in the soil with peat and 50.4% of the one of the sandy soil. The peat addition, although insufficient in nutrients, increased... / FAPESP: 00-02020/9
196

A família Pinnulariaceae (Bacillariophyceae) no estado de São Paulo : levantamento florístico /

Rocha, Angélica Cristina Righetti da. January 2008 (has links)
Orientador: Carlos Eduardo de Mattos Bicudo / Banca: Maria do Carmo Bittencourt Oliveira / Banca: Albano Geraldo Emílio Magrin / Resumo: Os estudos das diatomáceas do estado de São Paulo são bastante recentes, especialmente os taxonômicos. A grande maioria das referências para esse grupo de algas, incluindo a família Pinnulariaceae, aparece em listas constantes de trabalhos ecológicos e/ou de saneamento ambiental, cujas identificações não são, na maioria das vezes, passíveis de identificação e tampouco as unidades amostrais utilizadas ou as preparações feitas foram preservadas para permitir re-estudo. Em todos esses trabalhos, pouca atenção foi dada ao estudo taxonômico da comunidade perifítica em relação à planctônica. O presente trabalho visou a conhecer os gêneros, espécies, variedades e formas taxonômicas da família Pinnulariaceae que ocorrem nas águas continentais do estado de São Paulo, bem como a variabilidade, em nível de população, das características diacríticas dos táxons, a avaliação de características diacríticas como diagnósticas na separação de táxons, subsidiar a hierarquização das características diagnósticas infragenéricas com vistas a futura revisão taxonômica de gêneros e/ou de espécies e fornecer subsídios a projetos de outras áreas da investigação que demandem o conhecimento prévio da composição florística da diatomoflórula local. O inventário florístico foi realizado a partir de material de ambientes de águas continentais do estado de São Paulo, de modo que as amostras foram selecionadas com o fim de abranger, o mais homogeneamente possível, a área do estado, bem como amostras de material tanto plânctônico quanto perifítico. Foram examinadas 103 lâminas semipermanentes confeccionadas de 101 amostras provenientes de 60 municípios. / Abstract: Studies on the São Paulo state diatoms are very recent yet, especially those regarding their taxonomy. Most references, including the ones referring to the family Pinnulariaceae, are included in simple lists of ecological and/or sanitary engeneering publications. Many times, taxonomic identifications in these publications do not allow reidentification, because the sampling units or the slide mountings used for the publication were not preserved, making reidentification not anymore possible. In all those papers, little attention was paid to the taxonomic study of the periphytic community comparing to the planktonic one. Present paper aimed (1) at knowing the genera, species, varieties and taxonomic formae of family Pinnulariaceae present in the state of São Paulo continental waters; (2) as well as the variability, at population level, of the diacritic characteristics of different taxa; (3) at evaluating the diacritic features used as diagnostic during separation of different taxa; (4) at subsidizing the hierarchization of the infrageneric diagnostic characteristics aiming at a future taxonomic revision of genera and/or species; and (5) subsidizing projects in others fields of knowledge that will demand previous knowledge of the floristic composition of the diatom flora. Present floristic inventory was carried out using material gathered from freshwater environments all over the state of São Paulo, so that samples were selected would cover, the most homogeneous possible, the São Paulo State area, as well as material from both plankton and periphyton. One hundred and three semipermanent slides were prepared from 101 sample units gathered from 60 municipalities. / Mestre
197

Relative influence of temperature and disturbance on vegetation dynamics in the Low Arctic : an investigation at multiple scales.

Lantz, Trevor Charles 11 1900 (has links)
Climate change will affect Arctic plant communities directly, by altering growth and recruitment, and indirectly, by increasing the frequency of natural disturbance. Since the structure of northern vegetation influences global climate, understanding both temperature and disturbance effects on vegetation is critical. Here, I investigate the influence of temperature and disturbance on Low Arctic vegetation at several spatio-temporal scales in the Mackenzie Delta Region, N.W.T. To disentangle the relative impact of temperature and disturbance on forest-tundra and tundra ecosystems, I sampled microenvironmental variability, plant community composition, and green alder abundance, growth, and reproduction on disturbed (burns and thaw slumps) and undisturbed sites across a regional temperature gradient. Disturbed areas showed increases in alder productivity, catkin production, and seed viability, as well as differences in plant community composition and microenvironment. The magnitude of plot-level responses to disturbance compared to variation across the temperature gradient suggests that in the short-term, increasing the frequency of disturbance may exert a stronger influence on tundra ecosystems than changes in temperature. At the plot level, increases in alder seed viability and recruitment at warmer sites point to the fine-scale mechanisms by which shrub abundance will change. To examine the relative influence of temperature and biophysical variables on landscape-level patterns of shrub dominance, I mapped Low Arctic vegetation using aerial photos. At this broader scale, correlations between temperature and the areal extent of shrub tundra suggest that warming will increase the dominance of shrub tundra. To assess the magnitude of changes in temperature and thaw slump activity, I analyzed climate records and mapped retrogressive thaw slumps using aerial photographs. An increase in thaw slump activity in recent decades, coincident with higher temperatures, suggests that continued warming will change the area affected by thermokarst disturbances like slumps. Taken together, my research indicates that the effects climate change will be magnified by shifts in the frequency of disturbance, initiating changes to Arctic vegetation with significant implications for global climate. My work also shows that to fully understand the influence of patch-landscape feedbacks on Arctic vegetation dynamics, the effects of disturbance must be examined across longer temporal and broader spatial scales. / Forestry, Faculty of / Graduate
198

The ecology of terricolous lichens of the northern conifer-hardwood forests of central Canada.

Lambert, John D. H. January 1964 (has links)
Missing pg.75
199

Ecological studies of the arctic-alpine flora of the Gaspé Penninsular and of Bic.

Scoggan, Homer J. January 1942 (has links)
No description available.
200

Beiträge zur Ökologie der Felsflora Untersuchungen aus dem Curfirsten- und Sentisgebiet /

Oettli, Max. January 1904 (has links)
Thesis--Zürich. / "Arbeit aus dem botanischen Museum des eidgenössischen Polytechnikums in Zürich." "Separatabdruck aus dem Jahrbuch der St. Gallischen Naturwissenschaftlichen Gesellschaft, 1903." "Auch erschienen als: drittes. Heft der Botanischen Exkursionen und pflanzengeographischen Studien aus der Schweiz." Includes bibliographical references (p. 169-171).

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