1- The ecology of a population of the tropical palm tree Euterpe edulis Mart. was studied at the Municipal Reserve of Santa Genebra, Campinas (Sao Paulo, Brazil). This palm has been intensively exploited due to the quality of its heart of palm (palmito). The heart of palm corresponds to the apical meristem of the plant together with the developing new leaves. 2- The indiscriminate exploitation that this palm has been subject to over recent years in southern Sao Paulo may result in it becoming extinct in many forest fragments. The biodiversity of large animals in these forests has declined as a consequence of hunting, and the overexploitation of E. edulis has also led to a decline in the number of large frugiverous birds. The financial benefits generated by the sustainable exploitation of palmito can exceed those from a single extraction or those from forest conversion to agriculture. 3- The seed and seedling ecology of the population of E. edulis was examined. On average each plant produced approximately 1500 fruits and, there was a tendency for plants of intennediate size to be slightly more fecund. Most seeds were found in close proximity to adult plants; the distance of dispersal could be described by a negative power curve. Five species of birds belonging to the Family Turdidae were observed to feed on the fruits of E. edulis while on the tree, while subsequent dispersal along the gro':lnd was found to occur by water. The probability of surviving and growing to the next Sl~ class was inversely related to the number of seedlings. The maximum survival of seedlIngs and growth to the next size class occurred approximately 4 m from adult plants, indicating that the survival and growth of seedlings was suppressed in the immediate vicinity of conspecific adults. 4- The spatial pattern of the population of E. edulis, in the Municipal Reserve of Santa Genebra, was significantly clumped. The data indicate that the spatial distribution of individuals becomes less clumped with time as individuals develop. 5- The transition matrix analysis of the population revealed that the population is increasing at a rate of 14% year-I. The highest sensitivity was observed in the transition from size-class 1 (0-10 mm diameter) to class 2 (10.1 - 20 mm). According to the elasticity analysis, most of the value of the finite rate of population increase is accounted for by the probability of surviving and remaining in the same size class. The results from the haryesting simulations, indicate that it is possible to harvest E. edulis sustainably when harvesting is restricted to size class 6 plants (Le. reproductive adults). 6- The density-dependence observed for survival and growth of plants in the smallest size class was s~ong enough to affect the population dynamics of E. edulis. Elasticity analysis of the transItion matrix shows that the position of populations of E. edulis in G-L-F space moves towards the L apex of the demographic triangle as the density of plants increases.

The stretch from the riparian zone of a major river, through the mouth and upstream in tributaries forms a range of differing habitats. The aim of this study was to investigate the effect of these different habitats on the riparian frog community in primary rain forest in Borneo; i.e. examine whether any gradients could be demonstrated in terms of species composition, diversity and density of frogs, as well as which environmental characteristics that seem to be of most importance in forming habitats of high conservational value. A major river, Segama, and three of its tributaries were investigated. The surveys were carried out at night by searching for frogs visually and acoustically along the streams, from the shore of the Segama river and 400 metres upstream in the tributaries. In all transects 10 habitat variables were also measured. The results from the study show a significantly lower diversity and abundance of frogs along the shores of Segama and close to the mouths of the tributaries compared to further upstream, and a significant difference in species assemblage. Most species exhibited a negative correlation with the downstream transects or were not found there at all. The habitat characteristics waterfalls and boulders were found to be of most importance for the diversity and abundance of frogs, making these characteristics key components of habitats with high conservational value. Major rivers could also potentially form dispersal corridors for invasive species, which findings of the introduced species Fejervarya limnocharis along the shores of Segama shows.

Lic.-avh. (sammanfattning) Umeå : Sveriges lantbruksuniversitet, 2007. / Härtill 2 uppsatser.

Diss. (sammanfattning) Umeå : Sveriges lantbruksuniversitet, 2006. / Härtill 3 uppsatser.

京都大学 / 0048 / 新制・課程博士 / 博士(農学) / 甲第21470号 / 農博第2313号 / 新制||農||1064(附属図書館) / 学位論文||H31||N5165(農学部図書室) / 京都大学大学院農学研究科地域環境科学専攻 / (主査)教授 北山 兼弘, 教授 本田 与一, 教授 舟川 晋也 / 学位規則第4条第1項該当 / Doctor of Agricultural Science / Kyoto University / DGAM

Dans cette thèse, je reconstitue la dynamique de la circulation méridienne de retournement de l’Atlantique (AMOC) au cours des changements climatiques rapides de la dernière période glaciaire. Je trouve ainsi que le ralentissement de la cellule supérieure de l’AMOC commence 1420 ± 250 (1σ) années avant le déplacement vers le sud de l’ITCZ associé au « Heinrich Stadial » 2 et 690 ± 180 (1σ) années avant celui associé au « Heinrich Stadial » 4. Mes résultats confirment donc qu’un ralentissement de l’AMOC pourrait être à l’origine des migrations de l’ITCZ associées aux « Heinrich Stadials » et fournissent une première estimation précise du décalage temporel entre ces deux variables climatiques. Sur la base de ces résultats, je propose un mécanisme expliquant les différences entre les « Heinrich Stadials » et les « Dansgaard-Oeschger Stadials ».Je montre que deux cellules de circulation étaient probablement actives dans l’océan Atlantique pendant les périodes chaudes au Groenland (« interstadials ») : une cellule supérieure initiée par l’écoulement au-dessus de 2500 m d’une masse d’eau en provenance du nord et se dirigeant vers le sud, et une cellule inférieure initiée par l’écoulement au-dessous de 4000 m d’une masse d’eau en provenance du sud et se dirigeant vers le nord. Le taux de renouvellement de la masse d’eau profonde de la cellule supérieure était probablement plus faible que celle de la masse d’eau actuellement formée dans les hautes latitudes de l’océan Atlantique Nord. Au début des « Heinrich Stadials », la structure de l’AMOC a significativement changé et des eaux en provenance du sud ont probablement dominé l’océan Atlantique en-dessous de 1300 m de profondeur. / In this thesis, I reconstruct the dynamic of the Atlantic Meridional Overturning Circulation (AMOC) during fast climate changes of the last glacial period. I find that the AMOC upper circulation cell started to slowdown 1420 ± 250 (1σ) and 690 ± 180 (1σ) years before the southward shifts of the Inter Tropical Convergence Zone associated with Heinrich Stadial 2 and Heinrich Stadial 4, respectively. I therefore confirm that an AMOC slowdown could be at the origin of the ITCZ shifts that occured during Heinrich Stadials and provide the first precise estimate of the phasing between these two climate variables. Based on these results I propose a mechanism explaining the difference between Heinrich and Dansgaard-Oeschger stadials.Using modeling results, I show that the Atlantic Ocean circulation during periods of higher Greenland temperatures (interstadials) was markedly different from that of the Holocene. Two overturning cells were likely active in the Atlantic Ocean: an upper overturning circulation cell initiated by northern-sourced deep water flowing southward above ~2500 m depth at the equator, and a lower overturning circulation cell initiated by southern sourced deep water flowing northward below ~4000 m depth at the equator. The overturning rate of the upper overturning cell was likely lower than that of present-day North Atlantic Deep Water. At the onset of Heinrich Stadials, the structure of the AMOC significantly changed, and southern-sourced deep-waters likely dominated the equatorial Atlantic Ocean below 1300 m depth.

Os ambientes terrestres têm sido gradativamente alterados pelo ser humano, mas a partir da Revolução Industrial, o homem começou a atuar de maneira mais intensa sobre o meio, fazendo com que as modificações ambientais tomassem proporções alarmantes, tanto em velocidade quanto em dimensão. As mudanças, como as climáticas, hídricas e biológicas, entre outras, ocorridas durante o século XX foram as maiores já registradas. As alterações ambientais associadas ao quadro demográfico do mundo contemporâneo, às condições socioeconômicas e à revolução técnico-científico-informacional que interligou o mundo, acabaram resultando em um cenário nunca vivenciado pela humanidade e ao mesmo tempo preocupante, tanto para saúde ambiental da Terra como para a humana. Se por um lado essa situação, baseada principalmente no avanço tecnológico, resultou numa verdadeira revolução nas taxas de mortalidade e na esperança de vida, por outro lado criou um ambiente que vem facilitando a emergência e reemergência de doenças, que pode comprometer o próprio futuro. Esse estudo tem por objetivo principal dar subsídios para o acesso a um conhecimento integrado, em escala global, tanto das alterações ambientais das áreas tropicais úmidas e do quadro socioeconômico dos países localizados nessa faixa tropical, quanto do surgimento e/ou expansão de quatro doenças infecciosas de caráter hemorrágico - dengue hemorrágica, febre amarela, marburg e ebola - no período de 1981 a 2005. No campo teórico-metodológico, a Geografia, mediante as suas características científicas de transitar pelos campos das ciências naturais e humanas, devido ao seu objeto de estudo, ofereceu a sustentação científica necessária para a realização, enquanto o avanço tecnológico das comunicações e da informática, associado ao processo de globalização pelo qual o mundo passa, proporcionou uma realidade de trabalho totalmente nova, permitindo a execução operacional do estudo. Foram realizados levantamentos bibliográficos e estudos sobre aquecimento global, mundo tropical, devastação das florestas tropicais úmidas, condições socioeconômicas dos países localizados nesta porção do globo e expansão das doenças citadas nos últimos 25 anos. O conjunto dos dados foi transformado em uma tabela síntese e em material cartográfico que retrata a situação atual desses países, destacando o nível das condições sócio ambientais e o risco saúde em que se encontram. / The terrestrial environments have been gradually altered by human being but from the Industrial Revolution on, this process has been even more intensive, resulting in environmental modifications of fast, huge and alarming proportions. The changes, such as the climatic, hydric and biological ones, among others, that took place in the 20th century, were the largest registered. The environmental alterations, associated to the current demographic panorama, to the socioeconomic conditions and to the technical-scientific-informational revolution - that have linked the whole world - resulted in a scenario never before experienced by humanity and, at the same time, very preoccupying for the Earth environmental health as well as for the humans. If on one hand that situation, based mainly on the technological progress, has resulted in lower mortality rates and higher life expectancy at birth, on the other hand it has also created an environment that made the emergence and re-emergence of diseases much easier to occur, so that future may be at risk. This study intend to bring up subsidies that allow for access to global integrated knowledge, not only about the environmental changes in the countries located in humid tropical areas and their socioeconomic conditions, but also about the influence of these alterations on the appearance and/or expansion of four infectious hemorrhagic diseases - hemorrhagic dengue, yellow fever, marburg and ebola - in the period from 1981 to 2005. In the theoreticalmethodological field, Geography - in face of its scientific characteristics of acting on the fields of both natural and human sciences, due to its object of studying - offered the necessary scientific support for the study accomplishment, while the technological progress in Communications and Computer Sciences, associated to the current world process of globalization, provided a new view of working, which allowed the operational execution of this study. The study was also based on bibliographical researches in world warming, tropical world, deforestation of tropical rain forests, socioeconomic conditions of the countries where the forests are placed and in the expansion of the mentioned diseases over the past 25 years. The set of data were synthesized in a table and in cartographic material that show the socio environmental conditions and the health risk of these countries.

As florestas tropicais representam grande parte do carbono armazenado na forma de biomassa. São caracterizadas por uma alta taxa de produtividade primária, no entanto, não é muito claro o entendimento de como as florestas tropicais respondem ao balanço de carbono com o avanço das mudanças climáticas. Um dos efeitos relacionados ao aumento de concentração de dióxido de carbono na atmosfera e ao aumento da temperatura ambiental, que pode contribuir para ocorrência de distúrbios na função de assimilação ou emissão deste composto dentro das florestas tropicais, é a temperatura. A temperatura tem sido apontada, como influenciadora nas trocas gasosas das plantas, afetando a fotossíntese e a respiração. Neste sentido, estudos que visam melhorar o entendimento dos processos fisiológicos das plantas, principalmente os que estão envolvidos com a ciclagem do C, são importantes para gerar informações sobre os efeitos das mudanças globais nos padrões de respostas da assimilação de CO2 das plantas ou ecossistemas. O objetivo deste trabalho foi determinar as respostas dos processos de fotossíntese e respiração em função da temperatura foliar de um indivíduo e comunidade em estudo. O trabalho foi desenvolvido na Floresta Nacional (FLONA) dos Tapajós (2º 51 Sul (S), 54º 58 Oeste (O)) localizada ao sul da cidade de Santarém, próximo ao marco km 67 e 83 da rodovia Santarém-Cuiabá BR-163. Para realização das medidas nas folhas das plantas na copa do dossel florestal foram utilizadas cinco torres. Para quantificação da fotossíntese e respiração foliar, utilizou-se um analisador de gás por infravermelho (IRGA) modelo (LI- 6400). Para cada folha observada, obteve-se uma curva de resposta da fotossíntese à radiação fotossinteticamente ativa (A-RFA) e quatro curvas de respostas da fotossíntese em relação a concentração interna de CO2 (A-Ci), em quatro grupos de temperaturas foliares (Tfoliar). As curvas de resposta a radiação fotossinteticamente ativa (RFA), Tfoliar e concentração interna de CO2 (Ci) foram realizadas entre os horários de 07:00 e 14:00 horas. Para o ciclo diurno quantificou-se a fotossíntese (A), condutância estomática (gs), transpiração (E) e déficit de pressão de vapor da folha (DPVf), as medidas foram realizadas ao longo de um dia entre 10:00 e 18:00 horas. A temperatura ótima média da fotossíntese foi de 29,9 oC, e a população apresentou taxa assimilatória líquida ótima de CO2 de 7,2 µmol.m-2.s-1. Valores de temperaturas foliares superiores a 32,9 oC e 32,5 oC, diminuíram a capacidade máxima de transporte de elétrons e a velocidade máxima de carboxilação, respectivamente. A eficiência de carboxilação começou a diminuir a partir de 31 oC. A concentração interna de CO2 diminuiu 32,6% aos 42 oC. Na avaliação do ciclo diurno A e gs decresceram significativamente a partir das 16:00 e 15:00 horas, respectivamente. Quando houve um aumento de 0,34 kPa no DPVf a transpiração diminuiu em 64%. A condutância estomática decresceu com o aumento da temperatura foliar e a respiração foliar foi positivamente relacionada com o aumento da temperatura foliar. / Tropical forests hold large stores of carbon as biomass. They are characterized by large net primary productivity, however, it is not well understood how carbon budgets of tropical forests respond to the advance of climatic changes. Temperature is one of the agents related to the increase of carbon dioxide concentration in the atmosphere and ambient temperatures can contribute to alterations in assimilation or emission of CO2 in tropical forests. Temperature has been pointed as responsible for gas exchange rates in plants, affecting the photosynthesis and respiration. Thus, studies aimed at better understanding of physiological processes of plants, particularly those which involve carbon cycling, are important to generate information on the effects of the global changes in the trends of CO2 assimilation response in plants or in ecosystems. The objective of this work was to determine the photosynthesis processes and respiration responses as a function of leaf temperature of an individual and of the community in study. The study was carried out at the Tapajós National Forest (FLONA, 2º 51` S 54º 58` W) located in the south of Santarém municipality, at kms 67 and 83 of the Santarém- Cuiabá highway (BR-163). Five towers were used to support measurements in leaves in the forest canopy. An infra-red gas analyzer (IRGA, LI-6400 model) was utilized for quantification of leaf photosynthesis and respiration. For each observed leaf, a curve relating the photosynthesis response to the photosynthetically active radiation (PAR) was obtained together with four curves of photosynthesis response in relation to the internal CO2 concentration (Ci) in four groups of leaf temperatures (Tleaf). The response curves of PAR, Tleave and internal CO2 concentration (Ci) were obtained between 07h00 and 14h00. For the diurnal cycle it was quantified photosynthesis (A), stomatal conductance (gs), transpiration (E) and vapor pressure deficit of the leaf (VPDf), and measurements were carried out throughout one day between 10h00 and 18h00. The main optimum temperature of photosynthesis was 29.9 °C, and the community presented optimum CO2 net assimilation rate of 7.2 µmol.m-2.s-1. Leaf temperature values above 32.9 °C and 32.5 °C decreased the maximum capacity of electron transport and the maximum speed of carboxylation, respectively. The carboxylation efficiency starts to decreased at 31 °C. The internal CO2 concentration diminished 32.6% at 42 °C In the evaluation of the diurnal cycle, photosynthesis and stomatal conductance decreased significantly after 16h00 and 15h00 hours, respectively. An increase of 0.34 kPa in VPDf diminished transpiration in 64%. The stomatal conductance decreased with increase of leaf temperature and leaf respiration was positively related to the increase of leaf temperature.

O papel da Floresta Amazônica na ciclagem do carbono tem sido`freqüentemente relatado, no entanto, pouco se sabe sobre os aspectos que regula nos processos de assimilação e liberação de carbono da biosfera para a atmosfera. O objetivo deste trabalho foi descrever as respostas dos processos de respiração e fotossíntese com a variação da temperatura foliar, utilizando características biofísicas e dados micro-meteorológicos, para predizer a taxa assimilatória de CO2 de um indivíduo ou da comunidade em estudo. A pesquisa foi conduzida na Estação Experimental de Silvicultura Tropical (núcleo ZF-2), área de pesquisa da Coordenação de Pesquisa de Silvicultura Tropical (CPST) do Instituto Nacional de Pesquisas da Amazônia (INPA), utilizando-se de 4 torres para o acesso as copas. Os elementos climáticos foram monitorados por estações micro-meteorológicas Li-1401. As medidas de temperatura foliar foram realizadas com o auxilio de termopares de cobre-contantan, sendo a fotossíntese e a respiração avaliadas com um analisador de gases por infravermelho, com o qual foram obtidas curvas de respostas da fotossíntese a variação de radiação fotossinteticamente ativa (A-RFA), e a variação da concentração interna de CO2 em 4 diferentes temperaturas (A-Ci-T). Os resultados mostraram que: a temperatura foliar está relacionada com a radiação fotossinteticamente ativa (RFA) e a umidade relativa do ar (UR); a temperatura ótima da fotossíntese foi de 31,1 oC, onde a comunidade apresentou 7,6 µmol.m-2.s-1 de assimilação líquida de CO2, e a partir desta temperatura houve uma diminuição da fotossíntese máxima; valores de temperaturas foliares maiores que 34,5 oC diminuíram a velocidade máxima de carboxilação e as acima de 35,7 oC diminuíram a capacidade máxima de transporte de elétrons; a condutância estomática decresceu com o aumento da temperatura foliar, dentro do intervalo de temperatura estudado, indicando que a limitação estomática pode ser o fator que mais afeta a fotossíntese; e a respiração contribuiu para que o balanço de carbono fosse menor com o aumento da temperatura foliar devido a respiração estar positivamente relacionada com a temperatura foliar. A taxa assimilatória de CO2 foi diminuída devido a aumentos da temperatura foliar, sendo principalmente afetada pela diminuição da condutância estomática e do mesofilo e depois por aumentos da respiração foliar. / The role of the Amazon Rain Forest in the carbon budget has been often reported, however little is known about the aspects regulating the processes of carbon assimilation and its release from the biosphere to the atmosphere. The objective of this work was to describe the responses of respiration and photosynthesis processes related to leaf temperature variations by using biophysics characteristics and micro-meteorological data in order to predict CO2 assimilation rates on individual or community level. The research was conducted at the Experimental Station for Tropical Forest research (ZF-2) of the National Institute of Research of the Amazon (INPA). For this study four towers were used to access the canopy. Climatic parameters were monitored by micrometeorological stations Li-1401. The leaf temperature was measured using copper-contantan thermocouples. Photosynthesis and respiration were evaluated with an infra-red gas analyzer, generating light and CO2 curves responses. The results showed that: the leaf temperature was related to the photosynthetic active radiation (PAR) and to the relative air humidity (UR). The optimal photosynthesis temperature was 31,1 ºC where the tree community presented 7,6 µmol.m-2.s-1 of net CO2 assimilation. Above this temperature a reduction of the maximal photosynthesis was determined. Leaf temperatures higher than 34,0 ºC decreased the maximal velocity of RuBP carboxilation and temperatures higher than 35,7ºC decreased the maximal capacity of electrons transportation. The stomatal conductance decreased with increasing leaf temperatures within the temperature interval studied. The results indicated that the stomatal limitation probably represent the main factor that effects photosynthesis. The respiration contributes to reduce the carbon assimilation due to the increase of the leaf temperature because respiration is positively related to leaf temperature. Thus, the CO2 assimilation rates decreased with an increase of leaf temperature and is mainly affected by a decrease of stomatal and mesophyll conductance and by an increase of leaf respiration.

La biodiversité des forêts tropicales humides (FTH) est inégalement répartie dans les trois principales régions des tropiques : les Néotropiques, l’Asie du sud-est et l’Afrique tropical. Même si les forêts africaines contiennent une diversité en espèces végétales et un endémisme importants, leur richesse spécifique reste faible par rapport aux autres massifs forestiers tropicaux. Cette disparité serait liée à l’impact négatif d’événements d’extinction durant le Cénozoïque plus intenses dans les forêts africaines. A l’échelle du bassin du Congo, les niveaux de diversité important et l’endémisme des forêts africaines seraient liés à l’hypothèse d’existence de forêts refuges du passé. Cette hypothèse suggère une contraction des forêts en ‘refuges’ durant les événements climatiques du Dernier Maximum Glacier (DMG, entre 24’000 et 12’000 Ans).L’objectif principal de cette thèse est d’étudier l’évolution des forêts africaines en réponse aux changements climatiques sur des pas de temps anciens (millions d’années) et plus récent (milliers d’années). Pour cela nous étudions deux groupes de palmiers Africains : les rotins de la sous-tribu des Ancistrophyllinae et le genre de sous-bois des FTH d’Afrique Centrale Podococcus composé de deux espèces P. barteri et P. acaulis. Le premier groupe nous renseigne sur les événements d’extinctions anciens durant le Cénozoïque, alors que le second permet d’étudier la réponse des FTH face aux changements climatiques du Pléistocène. L’approche utilisée dans cette thèse consiste à 1) reconstruire l’histoire évolutive des rotins, et 2) inférer la dynamique évolutive des deux espèces de Podococcus dans le temps. Cinq objectifs spécifiques structurant deux grandes parties de la thèse ont été retenus. Première partie : (i) reconstruire les relations phylogénétiques chez les Ancistrophyllinae à l’aide de marqueurs chloroplastiques et nucléaires, (ii) estimer les âges de divergences puis tester l’impact des événements d’extinction chez les Ancistrophyllinae. Seconde partie : (iii) construire les modèles de niches écologiques et inférer les zones de stabilité écologique des deux espèces de Podococcus depuis le DMG, (iv) reconstruire les relations phylogéographiques chez Podococcus à partir de plastomes entier obtenus avec du Séquençage Nouvelle Génération ‘NGS’ et (v) évaluer la concordance entre la diversité génétique et la stabilité écologique des populations de Podococcus.Les résultats suggèrent que les espèces d’Ancistrophyllinae se sont probablement diversifiées de manière constante mais avec un taux d’extinction assez élevé ponctué par un ou plusieurs événements d'extinction sévères au cours du Cénozoïque. Les Ancistrophyllinae ont divergé durant l’Eocène et la plupart des espèces sont apparues après 10 Ma durant la fin du Miocène et du début du Pliocène. Chez le genre Podococcus, une corrélation significative entre la diversité génétique unique et la stabilité écologique a été démontré appuyant l’hypothèse des forêts refuges. Les populations écologiquement stables et diversifiées sont principalement localisées dans les zones montagneuses comme les Monts de Cristal et les Monts Doudou au Gabon, mais aussi dans les forêts littorales atlantiques au Gabon et au Cameroun. Par contre la plupart des populations datent d’avant le DMG ce qui traduit une réponse des espèces sur plusieurs cycles glaciers. Les résultats de cette thèse montrent que les changements climatiques anciens et plus récents ont fortement influencé l’évolution et la dynamique des espèces forestières d’Afrique Centrale. De plus, nos résultats ont permis d’identifiés les forêts côtières comme prioritaires pour la conservation de la diversité en Afrique Centrale. / Tropical rain forests (TRF) biodiversity is not equally distributed between the three main tropical regions: Neotropics, South East Asia and tropical Africa. Even though African rain forests display high levels of diversity and endemism, this diversity is low compared to that of the other tropical regions. One of the main hypotheses advanced to explain this lower species diversity is that the African flora has undergone higher extinction rates during the Cenozoic. Across the Congo basin, high levels of species diversity and endemism is thought to be linked to the hypothesis of forest refugia. This hypothesis suggests a contraction of rain forests in 'refugia' during the Last Glacial Maximum (LGM, between 24’000 and 12’000 Years).The aim of this thesis is to study the evolution of African rain forests in response to climate change on ancient (million years) and more recent (thousands of years) time scales. For this we study two groups of African palms: the rattans of the sub-tribe Ancistrophyllinae and the understory genus of Central African TRF Podococcus with two species P. barteri and P. acaulis. The first group provides information about ancient extinctions events during the Cenozoic, while the second is used to study the response of TRF during Pleistocene climate change in Central Africa. The approach used in this thesis is to 1) reconstruct the evolutionary history of African rattans, and 2) to infer the evolutionary dynamics of the two species of Podococcus through time. The five specific objectives structuring two main parts of the thesis are: First part: (i) reconstruct phylogenetic relationships among Ancistrophyllinae using plastid and nuclear markers, (ii) estimate divergence times and test the impact of extinction events on Ancistrophyllinae. Second part: (iii) build ecological niche models and infer the areas of habitat stability of the two species of Podococcus from the LGM, (iv) reconstruct phylogeographic relationships of populations of Podococcus from whole plastomes obtained using Next Generation Sequencing and (v) assess the correlation between genetic diversity and ecological niche stability of all populations of Podococcus.Results suggest that Ancistrophyllinae has possibly undergone a constant diversification with a relatively high extinction rate punctuated by one or more severe extinction events during the Cenozoic. Ancistrophyllinae diverged during the Eocene with most species originating to the Late Miocene after 10 Ma. In the genus Podococcus, a significant correlation between the unique genetic diversity and habitat stability was demonstrated supporting the hypothesis of forests refugia in Central Africa. Ecologically stable and diverse populations are mainly located in mountainous areas such as Monts de Cristal and Monts Doudou in Gabon, but also in the Atlantic coastal forests in Gabon and Cameroon. In contrast, most of the populations predate the LGM reflecting that species respond over several glacial cycles. Results of this thesis highlight that ancient and recent climate changes have strongly influenced the evolution and dynamics of Central African forests. In addition, our results allowed the identification of African Atlantic coastal forests as an important conservation priority.