Orientador: Maria do Carmo Estanislau do Amaral / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-10T06:25:59Z (GMT). No. of bitstreams: 1 Koehler_Samantha_D.pdf: 6443365 bytes, checksum: 6a01c884fb24c1fbf015cf1b2ab4e212 (MD5) Previous issue date: 2007 / Resumo: Não informado / Abstract: Not informed. / Doutorado / Biologia Vegetal / Mestre em Biologia Vegetal

Orientador: Fernando Roberto Martins / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-23T02:32:50Z (GMT). No. of bitstreams: 1 VanMelis_Juliano_D.pdf: 2552550 bytes, checksum: 8227a941fa221a10cce8b272ae92449f (MD5) Previous issue date: 2013 / Resumo: Apesar da importância que as trepadeiras apresentam em florestas tropicais, estudos sobre a montagem da comunidade de lianas (trepadeiras lenhosas e sublenhosas) que investiguem desde a contribuição dos fatores abióticos e bióticos até fatores intrínsecos (coexistência entre indivíduos) são escassos. O objetivo geral desta tese é pesquisar a estruturação da comunidade das espécies de lianas em uma Floresta Estacional Semidecídua (FES), investigando (1) a importância relativa dos fatores ambientais e espaciais para diferentes espécies de lianas, (2) a estruturação filogenética da comunidade de trepadeiras em diferentes ambientes, e (3) os efeitos diretos ou mediados das árvores e arbustos para o número de espécies e indivíduos de trepadeiras. Mostramos que (1) grande parte da variação na composição de espécies de lianas em uma FES é devido a fatores não investigados (fatores estocásticos) e o espaço (autocorrelação espacial). Portanto, concluímos que os maiores determinantes na variação da composição de espécies de lianas em uma FES é a aleatoriedade (sendo reflexo da variação estocástica das populações) e a limitação por dispersão (demonstrada pela alta autocorrelação espacial). No segundo capítulo (2), encontramos que uma maioria discreta das parcelas apresentou maior aproximação filogenética do que o esperado ao acaso na comunidade de trepadeiras amostrada. Houve pouca influência de variáveis relacionadas à dinâmica florestal na variação da aproximação filogenética, sendo que áreas com árvores mais altas e maior proporção de árvores do presente apresentavam maior aproximação filogenética que outras áreas. Concluímos que em áreas de dossel mais baixo e menor proporção de árvores do presente (clareiras) não apresentam menor sinal filogenético, pois todas as espécies de lianas apresentariam potencial de existirem nestas áreas, enquanto que nas áreas de floresta madura haveria a existência de filtros ambientais para a existência de poucos ramos filogenéticos. Por último (3), encontramos que os atributos da comunidade de árvores e arbustos são fatores importantes na variação dos atributos da comunidade de lianas, sendo parte dele decorrente do distúrbio no dossel. Mas o distúrbio no dossel como fator direto é mais importante na variação da abundância e número de espécies de lianas em uma Floresta Estacional Semidecídua / Abstract: Despite the fact that climbing plants present in tropical forests, studies which investigate the contribution of abiotic and biotic factors or intrinsic factors (coexistence between individuals) on community assembly of lianas (woody and sub-woody climbers) are scarce. The overall objective of this thesis is to research the community structure of liana species in a Seasonal Semideciduous Forest (SSF), investigating (1) the relative importance of environmental and spatial factors on community assembly of lianas, (2) the phylogenetic structure of climbing plants community along the forest development (treefall gaps to old-growth forest), and (3) the direct or indirect effects of trees and shrubs for the number of species and individuals of climbing plants. We show that (1) much of the variation in species composition of lianas in a SSF is due to stochastic factors and space. Therefore, we conclude that the major determinants of variation in lianas' species composition in a TSF are stochastic variance of populations, shown by the unexplained factors, and dispersion limitation, shown by spatial autocorrelation. In the second chapter (2), we found that a slight majority of the sample plots showed cluster phylogenetic structure in the climbing plants community. There was a slight influence of variables related to forest dynamics in the variation of the phylogenetic structure, and areas with tall trees and higher proportion of present trees had higher values of clustering in phylogenetic structure than other areas. We conclude that in areas of lower canopy and smaller proportion of present trees (treefall gaps) showed few phylogenetic branches, since all species of climbing plants would be existing in these areas, while areas of old-growth forest would demonstrate environmental filters for the climbing plants. Finally, we also found (3) that the community of trees and shrubs' attributes (abundance and species richness) are important factors in the variation of attributes liana community (species richness and abundance), being part of it due to the canopy disturbance. But canopy disturbance was the more important direct factor in variance of abundance and species richness of lianas in a Seasonal Semideciduous Forest / Doutorado / Doutor em Biologia Vegetal

Orientador: Carlos Alfredo Joly / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-20T14:31:26Z (GMT). No. of bitstreams: 1 Cavalin_PedroOrtman_D.pdf: 3253505 bytes, checksum: 2c0255c7d1c447ec6f4badb5c03b3993 (MD5) Previous issue date: 2012 / Resumo: Um grande número de espécies co-ocorre em florestas tropicais. Diferenciação de nicho e processos estocásticos são invocados como mecanismos que possibilitam essa coexistência de espécies. Recentemente, métodos filogeneticamente explícitos ou com base em atributos funcionais (considerados bons indicadores de nicho de regeneração, história de vida e tolerância ambiental) vem sendo usados para analisar tais mecanismos. No presente trabalho, estudei comunidades de espécies lenhosas no sub-bosque ao longo de um gradiente de altitude na Floresta Ombrófila Densa (FOD) Atlântica no Parque Estadual da Serra do Mar, SP, tentando relacionar a estrutura de comunidades com variáveis ambientais, e se tais relações variam de acordo com a altitude. Analisamos a estrutura filogenética em três sítios localizados em diferentes cotas altitudinais (FOD de Terras Baixas, 70 m; FOD Submontana, 370 m; FOD Montana, 1070 m). Em nenhum dos sítios foi observada estruturação filogenética, tampouco relações da estrutura filogenética com variáveis ambientais. Em seguida, analisamos a estrutura de comunidade baseada em atributos funcionais. Apesar de haver correlações entre atributos funcionais e variáveis ambientais no nível das espécies, as comunidades não apresentaram estrutura significativamente diferente do esperado pelo acaso, embora o conjunto de espécies comuns tenha apresentado boa correlação entre atributos funcionais e variáveis ambientais. Por fim, analisamos como a estrutura de comunidades, baseada em atributos funcionais, em um sítio (FOD Submontana) varia entre coortes de plantas de diferentes tamanhos. Em geral, plantas de menor tamanho são mais similares entre si do que o esperado pelo acaso, enquanto que plantas de maior tamanho não diferem do esperado pelo acaso. Quando árvores de dossel são analisadas em separado, nenhuma das classes de tamanho difere do esperado pelo acaso. Mortalidade causada pela abundância de vizinhos, e independente de suas identidades, pode ser responsável pela ausência de mudança na estrutura da comunidade baseada em atributos ao longo das coortes. Discutimos a ausência de variação na estruturação das comunidades ao longo do gradiente de altitude na FOD Atlântica, levando em consideração as características do mesmo, e propomos estratégias para o melhor entendimento da dinâmica dessas comunidades / Abstract: A large number of species co-occur in tropical forests. Niche differentiation and stochastic processes are commonly invoked to explain species co-occurrence. Recently, phylogenetically explicit or traitbased (functional traits are considered to be good proxies for regeneration niche, life history, and environmental tolerance) methods have been used to assess these mechanisms. In the present study, We have surveyed understory woody species communities along an altitudinal gradient on the Atlantic Dense Ombrophilous Forest at the Serra do Mar State Park, São Paulo State, Brazil, analyzing the relationships between community structure and environmental variables, and how these relationships vary along the gradient. Community phylogenetic structure was assessed in three sites differing in altitude (Lowland, 70 m; Lower Montane, 370 m; Montane, 1070 m). No phylogenetic structure was found in any site, nor correlations between phylogenetic structure and environmental variables. We then analyzed trait-based community structure. We observed no community structure, even though there were significant correlations between functional traits and environmental variables at specieslevel on a set of frequent species. Finally, we assessed how trait-based community structure varied between plant cohorts of differing sizes. In general, smaller plants were functionally more similar to each other than expected by chance, while larger plants showed no significant structuring. When only canopy trees are separately analyzed, no size-class cohort differs from the random expectation. This lack of change in structuring among cohorts may be due to mortality caused by neighboring stem density, irrespective of species identity. We then discuss the absence of community phylogenetic and functional structuring of understory woody plants communities along the altitudinal gradient on the Atlantic Forest, taking into account its peculiarities, and propose strategies that could advance the understanding of these communities' dynamics / Doutorado / Biologia Vegetal / Doutor em Biologia Vegetal

Le genre Psychotria est le plus vaste de la famille des Rubiaceae, avec plusieurs centaines d’espèces répandues dans toutes les régions tropicales humides. Les Psychotria sont principalement des arbustes (quelques-uns sont lianescents, herbacés ou arborescents) et entrent souvent pour une part importante dans la composition des sous-bois tropicaux. Certains montrent des adaptations remarquables comme la symbiose bactérienne foliaire ou l’accumulation d’humus. En raison de sa taille et des difficultés d’identifications, ce genre reste mal connu, notamment en Afrique occidentale et centrale où il n’a fait l’objet d’aucun travail d’ensemble depuis les années 1960.<p>Le présent travail a pour objectifs :1) la révision taxonomique du genre Psychotria pour l’Afrique occidentale et centrale; 2) une étude phylogénétique du genre, visant à reconstituer son évolution et améliorer la classification infragénérique ;et 3) une étude biogéographique régionale de ce groupe, afin de définir des centres de diversité et d'endémisme.<p>Notre travail de taxonomie, fondé sur l’examen des spécimens d’herbier et sur des missions de terrain au Cameroun et au Gabon, nous a conduit à reconnaître l’existence de 232 espèces en Afrique occidentale et centrale, ce qui fait de Psychotria le plus vaste genre de plantes dans cette région. Parmi ces espèces, 78 sont nouvelles.<p>Nos travaux phylogénétiques, basés sur l’étude de deux marqueurs nucléaires (ITS et ETS) et quatre chloroplastiques (rps16, trnG, matK et rbcLa), montrent que la classification de Petit (1964, 1966) est largement à revoir. Il apparaît notamment que les deux sous-genres (Psychotria et Tetramerae) reconnus en Afrique, et fondés sur la présence ou l’absence de nodules bactériens foliaires, ne sont pas monophylétiques, certaines espèces ayant secondairement perdu leurs nodules. Nos résultats soutiennent également le rattachement du genre monospécifique Peripeplus à Psychotria.<p>Le genre Psychotria montre une diversité remarquable, associée à un taux d’endémisme élevé, dans le domaine bas-guinéen (Cameroun et Gabon principalement) où plusieurs centres d’endémisme ont été identifiés. Ceux-ci sont localisés non seulement dans les massifs montagneux de l’intérieur, dont la flore particulière est bien connue, mais également dans les régions littorales. L’Afrique de l’ouest, moins diversifiée, montre cependant un fort endémisme localisé principalement dans deux centres, l’un situé au Liberia et dans l’ouest de la Côte d’Ivoire, l’autre vers la frontière Côte d’Ivoire/Ghana. Le bassin du Congo, comparable en diversité à l’Afrique de l’Ouest, est relativement pauvre en endémiques.<p>Ces résultats suggèrent que les forêts du Cameroun et du Gabon auraient relativement bien résisté aux périodes sèches passées, et remettent notamment en question l’hypothèse d’une disparition des forêts littorales du golfe de Guinée au cours du Pleistocène./Psychotria is the largest genus in the Rubiaceae family, with several hundred species in wet tropical areas worldwide. Psychotria spp. are mostly shrubs (a few being lianas, creepers or trees) and are often an important component of the undergrowth in tropical rainforests. Some show remarkable adaptations such as leaf bacterial symbiosis or litter gathering. Due to its size and identification problems, Psychotria remains a little-known genus, especially in West and Central Africa, where no major work has been done on this group since the 1960s.<p>The aims of the present work are: 1) a taxonomic revision of Psychotria in West and Central Africa; 2) a phylogenetic study of the genus, in order to trace its evolution and improve the infrageneric classification; and 3) a regional biogeographic study of the genus, to define centers of diversity and endemism.<p>Our taxonomical work, based on the study of herbarium specimens and field expeditions in Gabon and Cameroon, led us to recognise 232 species of Psychotria in West and Central Africa. Psychotria is therefore the largest plant genus in this area. Among these species, 78 are new.<p>Our phylogenetic work, based on two nuclear markers (ITS and ETS) and four chloroplastic markers (rps16, trnG, matK, rbcLa), shows that Petit’s (1964, 1966) infrageneric classification is in need of revision. In particular, we show that the two subgenera present in Africa (subg. Tetramerae and subg. Psychotria), which are defined by the presence or absence of leaf bacterial nodules, are not monophyletic: a secondary loss of the bacterial nodules has occured in some species. Our results also support the merging of the monospecific genus Peripeplus into Psychotria.<p>The genus Psychotria shows a remarkable diversity and a high level and endemism in the Lower Guinea domain (particularly Cameroon and Gabon) where several centers of endemism are identified. These are located not only in the inland hill ranges, which are well known for their particular flora, but also in littoral areas. West Africa is less diverse but also shows a high level of endemism, which concerns mostly two areas, one in Liberia and western Côte d’Ivoire and the other around the Côte d’Ivoire/Ghana border. The Congo basin, comparable in diversity to West Africa, has relatively few endemic species.<p>These results suggest that the rainforests of Cameroon and Gabon resisted relatively well during historical drier periods. They do not support the hypothesis of a disappearance of the Gulf of Guinea littoral forests during the Pleistocene.<p><p> / Doctorat en Sciences / info:eu-repo/semantics/nonPublished

Contrary to the other forest ecosystems in the Democratic Republic of Congo (D.R. Congo), semi-deciduous forests have so far attracted little attention and studies regarding their ecological aspects remain sketchy. Yet semi-deciduous forests are among the most important non-flooded ecosystems in the Congo Basin and their importance is high, both ecologically and economically. They are home to a variety of species, some of them being exploited for timber by forest companies acting in the region. There is a constant need to focus on their composition and diversity, and to understand factors shaping their communities.<p>Using a sampling method broadly inspired from the synusial phytosociology approach, we examined plant communities within each of the forest layers composing the overstorey (canopy and emergent trees) and the understorey (shrub and herbaceous layers). <p>The role of edaphic heterogeneity on plant communities in the considered semi-deciduous forests was examined. We mainly focused on:<p>- Floristic parameters within these ecosystems;<p>- Spatial structure of edaphic variables;<p>- Species responses to edaphic heterogeneity;<p>- Distance decay in the considered ecosystems;<p>- Phylogenetic patterns within plant communities.<p>Some of the species found in the considered semi-deciduous forests are more related to a type of soil than another, defining some “edaphic specialists” species while many others can be considered “generalists”. Spatial distance effect in the considered plant communities is marked by a decrease of floristic similarity with the geographical distance and all the forest layers showed a pattern of spatial phylogenetic clustering meaning that species cohabiting within a same plot are more related than species from distant plots.<p> / Doctorat en Sciences / info:eu-repo/semantics/nonPublished