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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.
1

Agrupamento ecológico e funcional de espécies florestais na Amazônia Sul Ocidental

Vasconcelos Neto, Elias Lourenço 01 June 2012 (has links)
Made available in DSpace on 2015-04-13T12:17:47Z (GMT). No. of bitstreams: 1 Elias Vasconcelos Neto.pdf: 488878 bytes, checksum: 3ba462c0237a8d31abd240eff4c8da1e (MD5) Previous issue date: 2012-06-01 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The Amazon forest is a mixture of hundreds of species, with different ages and growth rates, knowing them, both for researchers as to Amazonian populations, is a major challenge. The aim of this study was to perform species ecological and functional grouping of Acre state forests. This work was developed from data of 95 permanent plots, with one hectare each (100 x 100m), sub-divided into plots of 10 x 10 and installed on Projeto de Colonização (PC) Pedro Peixoto, State Forest of Antimary (FEA) and ST Management. In these sub-plots all individuals with diameter at breast height (DBH) greater than or equal to 10 cm were measured. The collect period was from 1996 to 2007, with measurements at non-regular intervals. The clustering process occurred in three stages: (1) cluster analysis to group the most populous species. For this process, the variables employed were Periodic Annual Increment in diameter - IPADAP Medium in High, Medium and Low competition and 95% percentile of cumulative frequency distribution of diameters using Ward hierarchical method; (2) discriminant analysis, to allocate the least populated species to the groups formed, using variables of the 95% percentile of the cumulative frequency distribution of diameters and the average annual periodic increments in diameter (IPADAP) and the Fisher method, (3) subjective stage, used to allocate species with few individuals to formed groups. Ward method used in cluster analysis and the Fisher method used for discriminant proved to be effective in creating and training groups. The use of these methods resulted in formation of ten groups of species with high growth rates of similarity between individuals of the same group and low similarity between groups. Variables: IPADAP for stand and IPADAP in low, medium and high competition and P95 of cumulative frequency distribution of diameters shown are variables useful for the purposes of grouping of species. Variations in the growth rates for the overall mean data were reduced when calculated for each group of species. / A floresta amazônica é uma mistura de centenas de espécies, com diferentes idades e taxas de crescimento, o seu conhecimento, tanto para pesquisadores quanto para as populações amazônicas, é um grande desafio. O objetivo deste estudo foi efetuar o agrupamento ecológico e funcional de espécies presentes na floresta do Estado do Acre. Este trabalho foi desenvolvido a partir de dados de 95 parcelas permanentes, com área de um hectare cada (100 x 100m), subdividida em subparcelas de 10 x 10 e instaladas no Projeto de Colonização (PC) Pedro Peixoto, Floresta Estadual do Antimary (FEA) e ST Manejo. Nestas sub-parcelas todos os indivíduos com diâmetro a altura do peito (DAP) maior ou igual a 10 cm foram medidos. O período de coleta foi de 1996 até 2007, com medições em intervalos de tempo não regulares. O processo de agrupamento ocorreu em três estágios: (1) análise de Cluster para fazer o agrupamento das espécies mais populosas. Para esse processo foram empregadas as variáveis Incremento Periódico Anual em diâmetro - IPADAP médio em Alta, Media e Baixa competição e percentil 95% da distribuição de frequência cumulativa dos diâmetros pelo método hierárquico Ward; (2) análise Discriminante, para alocar as espécies menos populosas aos grupos formados, utilizando-se as variáveis percentil 95% da distribuição de frequência cumulativa dos diâmetros e os incrementos periódicos médios anuais em diâmetro (IPADAP) e o método de Fisher; (3) estágio subjetivo, utilizado para alocar as espécies com poucos indivíduos aos grupos formados. O método Ward utilizado na análise de Cluster e o método de Fisher usado no discriminante demonstraram-se eficazes na criação e formação dos grupos. A utilização destes métodos resultou na formação de dez grupos de espécies com crescimentos de alta similaridade entre indivíduos do mesmo grupo e baixa similaridade entre grupos. As variáveis: IPADAP para o povoamento e IPADAP em baixa, média e alta competição e P95 da distribuição de frequência cumulativa dos diâmetros demonstraram-se variáveis úteis para a realização do agrupamento de espécies. As variações nas taxas de crescimento relativas à média total dos dados foram reduzidas quando calculada para cada grupo de espécies.
2

Lesní vegetace východního Polabí v polovině 20. století a dnes / Forest vegetation in Eastern Elbe Basin in the mid-20th century and today

Pospíšková, Marie January 2014 (has links)
This thesis describes the shift in vegetation of broadleaf forests in eastern part of the Elbe River Basin between 1958-1968 and 2011-2013. It emphasizes the understorey vegetation. From lowland woodlands in other temperate regions in Europe and North America changes towards eutrophic and mesophytic vegetation are documented, specifically driven by changes in forest management and by atmospheric depositions; in some localities the game impact can be also important. The data were obtained by sampling 190 typological semi-permanent plots, which were precisely located - in 43% the original soil pit was found. The vegetation on study sites shifted towards nutrient-demanding, shade- adapted species, it was partly ruderalized. These changes can be seen on the level of species and communities as well as on phytosociological level. Increase of soil pH and moisture was discovered using Ellenberg indicator values. The number of seedlings and cover of shrubs also increased significantly. Homogenization of sites was significant as well although total number of species and alpha- diversity remained unchanged. These changes are probably caused by changes in forest management and by atmospheric depositions of nitrogen. On subset of plots in game-preserves the vegetation also demonstrated eutrophication but no increase in...
3

Změny lesní vegetace Šumavy a jejího podhůří během druhé poloviny 20. století / Forest vegetation changes in the Bohemian Forest during the second half of 20th century

Prach, Jindřich January 2012 (has links)
Long-term forest vegetation changes were studied in the Bohemian Forest and its foothills. New vegetation relevés were taken at sites of typological plots established by forest engineers between 1955 and 1980. Data from 158 semi-permanent plots were analysed using modern statistical methods. The data show significant changes and homogenization of the vegetation. Ellenberg indicator values indicate eutrofication. Repeated measurements of soil pH suggest acidification, but the interpretation of these data is complicated by methodological problems. The forests under study exhibit high spatial variability. No main prevailing trend in vegetation changes was found. The changes are considered to be related to sulphur and nitrogen deposition and forest management. The influence of increasing age of forest stands seems to be unimportant. Discussed are not only vegetation changes and their possible causes but also the possibilities and limitations of using such old forestry data in botanical and ecological studies.
4

Dlouhodobé změny vegetace ve vápencových lomech Českého krasu / Vegetation succession on abandoned limestone quarries of Czech Karst

BARTOŠOVÁ, Alena January 2014 (has links)
Vegetation sampling was carried out to determine changes on the limestone quarries after 30 years. These semi-permanent plots are located in the Czech Karst Protected Landscape Area in the Czech Republic.
5

Změny vegetace vlhkých luk ve Slavkovském lese / Vegetation changes of wet meadows in Slavkovský les

Šimák, Martin January 2018 (has links)
This thesis focuses on the changes of vegetation of the wet meadows in Slavkovský Les during past decade. It uses data on vegetation gained from 100 permanent plots. By the analysis of the species composition and diversity it aims to elucidate the changes of the wet meadows over the last ten years. It aims to define, which are declining and which are becoming more common. Applied management should have a great impact on the observed vegetation changes so its effect is studied in the thesis as well. The knowledge of the suitable management should lead to conservation of the local biodiversity. The abiotic environmental factors are important as well as they can influence the species composition. These factors were studied by the application of Ellenberg indicator values on the species present in the study. These changes were compared in time and in a combination of time with a management type. Thus, we should be able to say how the environment has changed in the past decade and whether the type of management has any effect on the changes. Furthermore, the thesis explores whether changes in species composition over time may be explained by species traits. The results indicate that the species diversity and composition have indeed changed during the past decade. Apparently, the higher amount of...
6

Estrutura e diversidade da comunidade arbórea do Parque Natural Municipal da Lajinha (Juiz de Fora, MG, Brasil)

Pessoa, José Felipe Salomão 26 July 2016 (has links)
Submitted by Renata Lopes (renatasil82@gmail.com) on 2017-01-16T13:19:07Z No. of bitstreams: 1 josefelipesalomaopessoa.pdf: 2240048 bytes, checksum: 698aecc874e0df59ca702e747e6bf1be (MD5) / Approved for entry into archive by Diamantino Mayra (mayra.diamantino@ufjf.edu.br) on 2017-01-31T10:34:55Z (GMT) No. of bitstreams: 1 josefelipesalomaopessoa.pdf: 2240048 bytes, checksum: 698aecc874e0df59ca702e747e6bf1be (MD5) / Made available in DSpace on 2017-01-31T10:34:55Z (GMT). No. of bitstreams: 1 josefelipesalomaopessoa.pdf: 2240048 bytes, checksum: 698aecc874e0df59ca702e747e6bf1be (MD5) Previous issue date: 2016-07-26 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / O objetivo do estudo foi fornecer informações sobre a estrutura, composição florística e o estado de conservação do Parque Natural Municipal da Lajinha, Juiz de Fora, MG. Foram alocadas, aleatoriamente e georreferenciadas 25 parcelas permanentes, de 20 x 20 m, totalizando 1393 indivíduos arbóreos vivos e 145 mortos em pé (CAP ≥ 15,7 cm), pertencentes a 155 espécies, 100 gêneros e 51 famílias. Nectandra nitidula, Eugenia hiemalis, Bathysa australis, Virola bicuhyba, Alchornea triplinervea são as cinco espécies com maior VI, enquanto Fabaceae (23), Myrtaceae (14), Lauraceae (11), Euphorbiaceae (8), Sapindaceae (7), Meliaceae (5), Monimiaceae (5) e Rubiaceae (5) são as famílias com maior riqueza de espécies. O índice de diversidade de Shannon (H’) foi um dos mais altos registrados para florestas da região (H’ = 4,36 nats.ind-1), contendo inclusive espécies ameaçadas (Ocotea odorifera, Virola bicuhyba, Dicksonia sellowiana), segundo critérios do Livro vermelho da flora do Brasil. Metade da comunidade e a maioria das mortas se enquadram na primeira classe diamétrica proposta (7,5 cm), o que reflete elevado grau de competição. A distribuição diamétrica da comunidade seguiu o modelo “J-reverso”, padrão para comunidades florestais tropicais. O elevado índice de equabilidade de Pielou (J’ = 0,866) mostra baixa dominância ecológica e alta heterogeneidade florística da comunidade, confirmadas pelas análises de agrupamento florístico (coeficiente de Morisita-Horn), inferior a 0,5, e DCA (Análise de Correspondência Distendida), que apresentou altos valores, superiores a 0,3 (Eixo 1 = 0,49 e Eixo 2 = 0,33). O resultado da análise de similaridade florística nas unidades amostrais, utilizando o coeficiente qualitativo de Jaccard, evidencia a importância das espécies de baixa densidade na amostra. Esses resultados expõem a complexidade da dinâmica de funcionamento dos processos bióticos presentes em uma comunidade florestal secundária. Estudos com medições posteriores poderão analisar aspectos e atributos funcionais dessas espécies e seu papel efetivo na comunidade. A presença de espécies raras para o Estado de Minas Gerais e o alto índice de diversidade encontrado evidencia o potencial biológico do Parque Natural da Lajinha e reforça a necessidade da adequação do mesmo para se tornar Unidade de Conservação. / The aim of this study is to provide information about the conservation status, structure and composition of the Parque Natural Municipal da Lajinha, Juiz de Fora, Minas Gerais State, Brazil. Randomly placed and georeferenced 25 permanent plots of 20 x 20 m, totaling 1393 individuals living arboreal and 145 dead in sampled (CAP ≥ 15,7 cm), belonging to 155 species, 100 genera and 51 families. Nectandra nitidula, Eugenia hiemalis, Bathysa australis, Virola bicuhyba, Alchornea triplinervea are the five species with higher IV as Fabaceae (23), Myrtaceae (14), Lauraceae (11), Euphorbiaceae (8), Sapindaceae (7), Meliaceae (5), Monimiaceae (5) and Rubiaceae (5) are families with the highest species richness. The Shannon diversity index (H’) was one of the highest recorded for the region's forests (H’ = 4,36 nats.ind-1), containing including endangered species (Ocotea odorifera, Virola bicuhyba, Dicksonia sellowiana), according to Red Book of Brazilian flora. Half community and most dead fall within the first class proposal diameter (7,5 cm), which reflects the high degree of competition. The community diametric distribution followed the model "J-reverse" standard for tropical forest communities. The high evenness index of evenness (J’ = 0.866) shows low ecological dominance and high floristic heterogeneity of the community, floristic confirmed by cluster analysis (Morisita-Horn coefficient) is less than 0,5, and DCA, which showed values greater than 0,3 (Axis 1 = 0,49 and Axis 2 = 0,33). The result of floristic similarity analysis using qualitative coefficient of Jaccard highlights the importance of species of low density in the sample. These results expose the complexity of the operating dynamics of biotic processes present in a secondary forest community. Further resampling studies may analyze functional aspects and attributes of these species and their effective role in community. The presence of rare species for the state of Minas Gerais, the availability of resources for the regional fauna and high diversity index shows the biological potential of the Natural Park of Lajinha and reinforces the need to adapt the same to become a Unit Conservation.
7

From arable field to forest: Long-term studies on permanent plots / Vom Acker zum Wald: Dauerflächenuntersuchungen zur Sukzession auf Ackerbrachen

Dölle, Michaela 23 September 2008 (has links)
No description available.
8

Vegetační změny českých nížinných lesů během posledních desetiletí / Vegetation changes in Czech lowland forests over the past decades

Kopecký, Martin January 2015 (has links)
Vegetation changes in Czech lowland forests over the past decades Martin Kopecký ABSTRACT To explore decadal changes in plant species diversity and composition of typical lowland forests in the Czech Republic, I compared vegetation on plots sampled decades ago with vegetation on the same plots sampled recently. First I evaluated the robustness of the approach used in my thesis. In Chapter 1, we provided the first direct test of the effect of uncertainty in original plot location on results from vegetation resurvey. We found that temporal trends in vegetation diversity and composition were comparable between exactly relocated permanent and only approximately relocated semi-permanent plots. Therefore, we conclude that the resurvey of semi-permanent plots is robust to the uncertainty in original plot location. Then, we showed that vegetation in lowland oak forest shifted from species-rich communities of thermophilous forest toward species poorer communities of mesic forest (Chapter 2). The species typical for thermophilous oak forests and nationally endangered species suffered the most significant decline. We identified as the main driver behind these changes shift from traditional coppicing toward high forest management after WWII. Further, we explored the processes behind temporal shifts in species diversity...

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