A descrição dos padrões de acumulação de espécies com o aumento da área amostrada, através da curva de acumulação de espécies, tem diversas aplicações no estudo de comunidades vegetais. Porém o uso dessa relação como uma ferramenta para determinar a suficiência amostral em estudos fitossociológicos apresenta problemas metodológicos, como a arbitrariedade da ordem de entrada das unidades amostrais na construção da curva e a pressuposição de que um patamar será obtido no ponto em que o aumento da área amostrada não acrescentar novas espécies à amostra; e também problemas relacionados ao conceito de comunidade vegetal utilizado, que é considerada como uma entidade espacialmente discreta com composição de espécies fixa e definida. Em florestas tropicais a definição desses limites é dificultada pela alta riqueza de espécies e pela falta de estabilização da curva mesmo com grandes tamanhos de amostra. Utilizando dados de três formações florestais tropicais, foram obtidas curvas médias de acumulação de espécies e seus intervalos de confiança empíricos através de procedimentos de aleatorização, que enfatizaram o caráter assintótico da curva e evidenciaram a ausência de um ponto de inflexão para a determinação objetiva de um tamanho ótimo de amostra. Entretanto, o uso dos padrões de acumulação de espécies em estudos comparativos, seja em formações diferentes ou locais dentro de uma mesma formação, mostrou ser mais informativo. A análise das variações das estimativas de riqueza e do padrão de acumulação de espécies com tamanhos crescentes de amostra indicam que é possível identificar níveis de amostragem que permitem a distinção e a comparação entre locais. Por fim, considerando as limitações das medidas tradicionais de diversidade, como a dependência do esforço amostral, foram utilizados os índices de diversidade e distinção taxonômica para caracterizar e comparar a diversidade das diferentes formações estudadas. Além da vantagem de incorporar as diferenças taxonômicas entre as espécies à estimativa de diversidade, esses índices ainda apresentaram independência do esforço amostral e menor variabilidade, permitindo sua utilização na comparação entre áreas que tenham sido amostradas com diferentes intensidades. / The description of species accumulation patterns with the increase of sampled area using the species accumulation curve has many applications to plant community studies. The use of this relation as a tool to determine the sampling sufficiency in phytosociological studies, therefore, shows methodological problems such as the arbitrariness in the order of sampling units for the curve construction and the assumption that this curve tend to a flat line with the increase of sampled area. Another constraint is the plant community concept adopted, where the plant community is saw like a spatially discrete entity with fixed species composition. In tropical forests, the identification of communities boundaries is particularly difficult and, due to their high species richness, the species accumulation curves do not become flat, even with large sample sizes. Data from a sample of 5,74ha in three tropical forests showed a mean species accumulation curves, with empiric confidence intervals obtained by randomization procedures, which emphasized the asymptotical character of the curve. The curve also stressed the absence of a inflection point and indicated that it is not possible to objectively define a optimum sample size. Therefore the use of species accumulation patterns is more informative in comparative studies, either within or between plant formations, than in the description of a given individual study area. The analysis of the variations in richness estimates and species accumulation patterns with increasing sample sizes indicated that is possible to identify optimal sampling sizes in the comparison of different forest areas that allows to distinguish them. Finally, considering the limitations of traditional diversity measures, such as sampling effort dependency, diversity and distinctness taxonomic indexes were used to characterize and compare the diversity of the three different plant formations. Besides the advantage of incorporating the taxonomic differences among species, these indexes showed independence of sampling sizes and had estimates of low variability, which allows their utilization in comparisons of areas sampled with different intensities.

Orientador: Marcos Pereira Marinho Aidar / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-21T19:18:09Z (GMT). No. of bitstreams: 1 Marchiori_NidiaMara_M.pdf: 3439360 bytes, checksum: 8e5d49e665742675abd331ec9cff9ba4 (MD5) Previous issue date: 2012 / Resumo: O Nitrogênio é um nutriente essencial para o crescimento das plantas e produtividade de um ecossistema, visto sua ação como limitante para a fotossíntese ou relação com a reflectância da luz (albedo). Além disso, detém importância ecológica por ser uma ferramenta para a categorização de espécies em classes sucessionais baseado na utilização de suas formas disponíveis. Dessa forma, a compreensão da fisiologia do uso de N é essencial, especialmente em florestas tropicais, onde existem poucos estudos com essa abordagem. A Mata Atlântica (MA) é originalmente a segunda maior floresta tropical do continente americano, contudo grande parte de sua área e biodiversidade foi perdida e atualmente essa Floresta é definida como um "hotspot" para conservação da biodiversidade. O conhecimento e entendimento da estrutura e do funcionamento de ecossistemas complexos como os que compõem a MA é de suma importância para a discussão de temas atuais como o balanço de carbono global, nutrição vegetal e mudanças climáticas. Dentre os principais objetivos foram: a caracterização fitossociológica e estrutural de um trecho de Floresta Ombrófila Densa Montana (FODM), elucidar as estratégias de utilização de nitrogênio pelas plantas e avaliar através de parâmetros foliares, as respostas das plantas frente à mudança da estação do ano e a sazonalidade intrínseca. A área de coleta estava localizada na microbacia Ribeirão Casa de Pedra, Núcleo Santa Virgínia/Parque Estadual da Serra do Mar- São Luiz do Paraitinga, SP. Quanto à estrutura e composição do trecho de FODM estudado pode-se verificar uma floresta em estádio secundário inicial de regeneração avançando para uma condição mais tardia, sendo essa definição baseada tanto no histórico de utilização da área, quanto na composição de espécies e fisiologia do uso de nitrogênio. Assim, os resultados indicaram que em FODM há intensa diversidade biológica e diversidade funcional. Importante ressaltar também que esse projeto de mestrado foi parte integrante do Projeto Temático "Carbon tracker and water availability: controls of land use and climate changes" (Clima - FAPESP 08/58120-3; período de 2009-2013; coordenação Humberto Ribeiro da Rocha), cujo objetivo principal foi a quantificação à longo prazo da dinâmica dos fluxos de água, energia e CO2 em Biomas de Cerrado e Mata Atlântica no sudeste do Brasil / Abstract: Nitrogen is an essencial nutrient for plant growth and ecosystem productivity, either by limiting photosynthesis or related to the light reflectance (albedo). In addition, N has an ecological importance because it can be a tool for the categorization of species in ecological succession and functional types based on the use of its available forms. Thus, understanding the physiology of N use is essential, especially in tropical forests, where despite the impending increase of this element as a result of intensive fertilization or atmospheric deposition there are few studies using this approach. The Atlantic Forest (AF) is originally the second largest rainforest at the America continent, but much of its area and biodiversity has been lost and now the forest is defined as a "hotspot" for biodiversity conservation. The knowledge and understanding of the structure and functioning of complex ecosystems such as those that comprise the AF is of paramount importance for the discussion of current issues as the global carbon balance, plant nutrition and climate change. The main aims were: phytosociological and structural characterization of the tree component in a Montane Tropical Rainforest, understand the strategies of nitrogen use by plants and assess through leaf parameters, the response of plants to the change of season and intrinsic seasonality. The study area of the three chapters that follow are inserted in the watershed Ribeirão Casa de Pedra, Núcleo Santa Virginia Parque Estadual da Serra do Mar, located in São Luiz do Paraitinga-SP. The results indicated that Montane Tropical Rainforest was in initial secondary stage of regeneration evolving to a climax condition, based on the past human disturbance in the area, species composition and physiology of N use. Also indicated that this forest has many species and functional diversity. It is also important to note that this Master's project is part of the Thematic Project "Carbon tracker and water availability: controls of land use and climate changes" (Climate - FAPESP 08/58120-3; period 2009-2013; coordinated by Humberto Ribeiro da Rocha), whose main objective is to quantify the long-term dynamics of fluxes of water, CO2, energy at Cerrado and Atlantic Forest biomes in southeastern Brazil / Mestrado / Biologia Vegetal / Mestra em Biologia Vegetal

Doctorat en Sciences / info:eu-repo/semantics/nonPublished

La compréhension de la dynamique des forêts tropicales hyperdiverses a toujours été un défi en écologie. Historiquement les modèles se basant sur le concept de la niche ou la courbe logistique ont montré leurs limites lorsqu'il s'agissait d'expliquer la diversité d'espèces en forêt tropicale. L'arrivée des modèles neutres en écologie a permis d'exprimer dans un cadre mathématique l'échantillonnage des forêts tropicales, ouvrant de nouvelles perspectives. Ces modèles, très réduits en nombre de paramètres, ont été développés depuis la génétique des populations. Encore peu explorés, ces modèles considèrent les espèces comme étant fonctionnellement équivalentes entre elles. Pour commencer, nous réexaminerons les avancées récentes dans ce domaine extrêmement actif, pour discuter ensuite du développement futur de ces modèles. Dans un second temps, nous analyserons l'inférence des paramètres neutres, afin d'établir ce lien important entre modèles théoriques et données du terrain. De plus, nous introduirons un nouvel estimateur du paramètre décrivant la richesse d'espèces rencontrées dans ces forêts. Ces résultats seront mis en perspective par l'utilisation des données de terrain provenant des forêts sempervirentes des Ghâts Occidentaux d'Inde ainsi que des forêts humides autour du Canal du Panama. Nous testerons également ces approches sur des simulations variées. Finalement, nous essayerons d'évaluer la pertinence des estimations du paramètre de migration en les comparant avec les distances de dispersion des graines observées en forêt tropicale. / Understanding the dynamics of highly diverse communities such as tropical forests has always been a challenging task in ecology. Historically, simplified logistic models and complex niche theories have had a limited success in explaining the species diversity and composition in a tropical context. With the advent of neutral models, we have an original quantitative framework in terms of a sampling theory which opens new perspectives in the field of tropical community ecology. These parsimonious models originally developed from existing theories in population genetics, have a highly selective interpretation of niche theory defined as the functional equivalence of species which has been insufficiently explored. To begin with, we review recent advances of this extremely active field and provide insights into future developments of this theory. Further on, we provide a detailed account of parameter inference which is the crucial link between theoret ical models and field data. In addition, we improve on existing approaches by introducing a novel estimator for the parameter explaining the species richness found in these forests. These results are put into perspective by using field data from the wet evergreen forests of the Western Ghats region of India and the tropical rain forests around the Panama Canal Watershed. Our results are also rigorously tested using simulations of neutral community composition. Lastly, we provide insights into whether parameter inferences dealing with immigration correspond to the seed dispersal distances typically found in tropical forests.

Japan is one of the world’s 34 biodiversity hotspots, according to Conservation International (CI). The methods used by various organisations to define priorities differ, however, and all have weaknesses when trying to identify hotspots at finer resolutions. The goal of this thesis is to investigate how biodiversity hotspots in Japan could be revealed and mapped in order to encapsulate conservation elements of biodiversity in practical ways and at various scales. Bioquality is a term that emphasises the concentration within a community of elements of biodiversity with high conservation value. It evaluates the global rarity and taxonomic distinctiveness of plant species or infra-specific taxa using four Star categories. At a plant community level, the Genetic Heat Index (GHI), which is a standardised global range size rarity score, is calculated using weighted Star statuses of species in the community. Bioquality hotspots are assessed here for the first time for the flora and vegetation in Japan – and for temperate Asia – by categorising the Japanese flora into Stars and by applying GHI to survey data and literature-based sources. Keys to Stars are developed for the Japanese flora, with adjustments for variability in species geographic range size information and for taxonomic relatedness. A Flora of Japan (FOJ) database was compiled as a BRAHMS database, containing 8,262 accepted names (30,656 taxon names in total, including synonyms) in 258 families – the first full database of Japanese vascular plants. A total of 7,145 taxa are assigned Stars; from the rarest to the widespread class, there are 884 Black, 756 Gold, 833 Blue, and 4,672 Green Star taxa, confirming that Japan as a whole contains a high proportion of globally rare taxa (23% taxa in Black or Gold). A protocol for calibrating the weight of Stars based on species geographic range is developed based on fine-resolution distribution maps within Japan and coarse–resolution Taxonomic Database Working Group (TDWG) code information. The protocol optimises calculation for temperate regions. The first ever bioquality hotspot maps of Japan are produced using two independent data sources on species distribution at national level: 1) 50 botanical prefectures using 4,830 species from the FOJ database; 2) 1,418 Horikawa ‘geoquadrats’ (0.1° latitude by 0.15° longitude grid) maps covering 829 species. The Ryukyu Islands and Ogasawara Islands are identified as bioquality hotspots, and high mountain ranges in mainland Japan are predicted to contain areas potentially high in GHI; the spatial patterns of GHI are generally concordant between maps of different resolutions. These findings highlight that bioquality assessment can be applied meaningfully at various spatial resolutions. Using field sampling data and existing literature, three study sites are further investigated on a local level: 1) the satochi-satoyama landscape, the current national priority area for biodiversity conservation; 2) various vegetation types of Okinawa-jima Island, the Ryukyu Islands; and 3) the Utaki sacred groves within the predicted hotspot of the Ryukyu Islands. The Ryukyu Islands are confirmed to contain bioquality hotspots within many individual sites, while there was generally low GHI across the satochi-satoyama landscape. The field study outcomes, together with a gap analysis of the existing coverage of protected areas, highlight three important points that are directly relevant to national biodiversity conservation planning: 1) the Ryukyu Islands urgently need newly designated protected areas; 2) the satochi-satoyama landscape conservation should redirect its focus on cultural benefits to the public; 3) the existing protected areas, particularly on mountain areas, need re-evaluation in terms of upgrading their status in light of the bioquality assessment.

No description available.

Thesis (M. Tech. (Agriculture)) -- Central University of Technology, Free State, 2013 / ntroduction: Good quality Eucalyptus is of importance to South Africa’s pulp and paper industry. Limited land is available for forestry, therefore Eucalyptus with genotypes for good pulp and paper qualities, particularly hybrids, are bred and cloned via cuttings. Although these Eucalyptus clones keep the favourable genotypes in the population, many have difficulty with rooting. Research has shown that rhizobacteria can improve rooting. Thus, one strategy to enhance the rooting of cuttings is to use rhizobacterial preparations. The aim of this study was to characterise rhizobacterial communities of Eucalyptus hybrid and species and identify possible plant-growth promoting rhizobacteria (PGPR). Materials and methods: Rhizospheric samples were collected from Eucalyptus hybrids and species. The rhizobacterial communities were characterised using fatty acid methyl esters (FAME) analysis and denaturing gradient gel electrophoresis (DGGE). DGGE fragments were further sequenced to identify rhizobacteria. Results and discussion: FAME analysis successfully achieved a broad characterisation of the Eucalyptus hybrid and species rhizobacterial communities based on their fatty acid composition. Myristic acid (C14:0) was the most abundant fatty acid. DGGE profiles gave a molecular profile of the Eucalyptus hybrid and species rhizobacterial communities based on their DNA composition. Nitrosomona eutropha was present in all samples which illustrates a nitrogen-rich environment. Adhaenbacter aquaticus was unique to the better rooting Eucalyptus hybrid GU111. Conclusion: This study provided some insight into the diversity of rhizobacterial communities of Eucalyptus hybrids and species. Possible PGPR were identified and the observation made that the nature of the soil environment changes with the aging of the associated host. These findings allow further investigation into the formulation of potential rhizobacterial preparations for rooting enhancement of Eucalyptus cuttings.

The natural vegetation of the Cradle of Humankind World Heritage Site (COH WHS) was classified using Braun-blanquet methodology. This identified 22 distinct plant communities and 2 variants. Sampling took place over two growing seasons with a total of 91 releves being compiled. A stratified random approach to sampling used Land Types as a means of primary area stratification, with terrain position providing the means for further refinement. The grassland comprised of 12 plant communities and 2 variants and the woodland comprised of 10 plant communities. The classification of the woodland areas included some bush clumps associated with the entrances of caves which were also described independently in which seven distinct plant communities were identified A positive linear correlation exists between the size of the cave entrances and the extent to which the surrounding woody vegetation extends. This suggests the likelihood of cave entrance size influencing the surrounding vegetation. / Environmental Sciences / M. Tech. (Nature Conservation)

Les lisières forestières constituent un enjeu pour la gestion des territoires, par la biodiversité qu’elles abritent, les processus écologiques qu’elles régulent et les services environnementaux qu’elles rendent à l’agriculture et à la foresterie. C’est pourquoi il est nécessaire de connaitre et quantifier précisément leurs influences sur la végétation pour proposer des mesures de gestion adaptées à la variabilité des situations de lisière. En référence aux hypothèses de la littérature, ce travail vise à comprendre comment varie la répartition des communautés végétales forestières en réponse à la diversité des types de lisières, dans un paysage agriforestier. Les espèces vasculaires de la strate basse de la végétation forestière ont été recensées le long de 28 transects, représentatifs de sept types de lisières des coteaux de Gascogne. Ces transects, perpendiculaires à la bordure et dirigés vers l’intérieur du bois, comportent 20 quadrats contigus de 2 m × 2 m. J’ai cherché à mesurer la profondeur d’influence des effets de lisières sur la végétation par la méthode de régression à deux phases. Face à l’hétérogénéité observée, j’ai caractérisé les patrons de distribution des communautés végétales par cinq modèles continus pour les comparer. Les lisières structurent la répartition des communautés végétales suivant un gradient, de la bordure vers l’intérieur du bois, mais les patrons sont plus variables qu’attendus et remettent en cause la généricité du modèle théorique à deux phases largement admis dans la littérature. Néanmoins, un patron de distribution de la végétation commun à l’ensemble des lisières a été identifié au moyen de la méthode STATIS d’analyse à k-tableaux. L’analyse des effets de lisière sur un sous-échantillon d’espèces a été affinée par la prise en compte des caractéristiques biologiques et écologiques des espèces d’une part, et des variables environnementales, à différentes échelles spatio-temporelles d’autre part. Les traits biologiques et écologiques des espèces répondent davantage à l’âge et l’histoire des lisières qu’à la distance à la bordure. La hiérarchie des facteurs environnementaux, paysagers et historiques confirment le rôle prépondérant de la qualité locale de l’habitat dans la structure des communautés. La variabilité temporelle des effets de lisière a été abordée par un suivi horaire des variations microclimatiques au cours d’une année. Les faibles écarts microclimatiques entre la lisière et l’intérieur du bois au cours des saisons suggèrent un rôle faible du microclimat sur la structure des assemblages d’espèces. Enfin, la variabilité spatiale des lisières dans un paysage de large étendue a été évaluée par la mise au point d’une méthode originale afin de caractériser et cartographier la diversité des segments de lisières. Les résultats remettent en cause les modèles théoriques antérieurs et ouvrent des perspectives pour une meilleure compréhension des principes d’organisation des communautés végétales en lisières de forêt. La complexité des patrons de réponse aux effets de lisière justifie de porter une attention plus soutenue à la diversité des lisières dans la perspective de mieux les gérer. / Forest edges are a challenge for land management. They contain high biodiversity, regulate ecological processes and provide environmental services to agriculture and forestry. Therefore, it is necessary to evaluate and quantify precisely edge influence on vegetation to propose management measures adapted to edge diversity. Referring to the literature asusmptions, this paper focuses on understanding the variation in the distribution patterns of forest plant communities in response to contrasted edge types in rural landscape. All vascular plant species of the understorey forest vegetation have been identified along 28 transects, pertaining to seven edge types of “coteaux de Gascogne”. Transects were perpendicular to the forest border and included 20 contiguous quadrats of 2 m × 2 m, towards forest interior. I tried to measure the depth of edge influence on vegetation using the two-phase linear regression method. Facing to high heterogeneity, I characterized the distribution patterns of plant communities by five continuous models for comparison. Edge effect structure the distribution of plant communities along a gradient from the border toward the forest interior. Response patterns to edge influence were more variable than expected and challenge the hypothetical response model pattern widely accepted in the literature. However, a common pattern of vegetation for all transects was identified using the k-tables STATIS method. Analysis of edge effects on a sub-sample of species was refined using on the one hand biological and ecological species traits and environmental variables at different spatio-temporal scales, on the other. The functional response of plant species better suited to the age and history of the edges than the distance from the border. Nevertheless, the hierarchy of environmental, landscape and historical context confirm the role of habitat quality on distribution patterns of forest vegetation. Temporal variability of edge effects has been addressed by monitoring hourly microclimatic variations over one year. The small differences in microclimate between edge and forest interior over seasons suggest a weak role of microclimate on the structure of plant species assemblages. Finally, the spatial variability of edges at the landscape level has been evaluated. An original method, Cartolis, has been developed to characterize and map the diversity of forest edge segments. Our results, calling into question the earlier theoretical models, provide opportunities for a better understanding of plant distribution patterns in forest edges. The complexity of responses obtained warrants to bring more attention to edge diversity for better management and conservation of plant species.

This study focused on the effectiveness of integrating traditional plant community analyses with landscape ecological analyses based on remotely sensed data. A temporal analysis of plant community diversity was conducted for major plant communities of the Ray Roberts Lake area using transect monitoring data collected between 1987 and 1997. Landscape analyses were performed with FRAGSTATS*ARC using classified SPOT satellite imagery for 1987 and 1997. Although the methodology developed in this work was exploratory, it was found that characterizing the dynamics of major plant communities in the study area produced a more effective and insightful analysis of Ray Roberts Lake area landscape dynamics.