The aim of this thesis is to describe the changes of bird species diversity along elevation gradient on six mounts in Cameroon and nearby Bioko island. The results of the analyses confirm most of the defined hypotheses, especially they show that species diversity declines with altitude and rises with area. Cluster analysis shows the similarity of individual mountains in particular altitude zones. Despite the original hypothesis, mount Cameroon is found to be most similar to mount Kupé, although high mountain assemblages of mount Cameroon and Bioko island are very alike as well. The absolutely highest diversity was detected on mount Cameroon and mount Kupé, but above 2100 m above sea level mounts Oku and Manenguba are the most diverse. The results of this thesis contribute to a clearer notion about factors influencing species diversity; however, more thorough data (particularly from mount Nlonako) and data extension for e.g. bird abundance would enrich the study and it would enable us to perform more detailed diversity analysis, especially an analysis of competition relationship among species. Key words Species diversity, Cameroon, bird assemblages, elevational gradient

The aim of this thesis is to describe the changes of bird species diversity along elevation gradient on six mounts in Cameroon and nearby Bioko island. The results of the analyses confirm most of the defined hypotheses, especially they show that species diversity declines with altitude and rises with area. The absolutely highest diversity was detected on mount Kupé and mount Cameroon, but above 2100 m above sea level mounts Oku and Manenguba are the most diverse. Other analysis showed that the biggest changes in beta diversity of bird assemblages along altitudinal gradients are on the lowest elevational belts which are on the edges of a degraded habitats and continuous undisturbed forests. Other important changes in bird assemblages happen around altitude 1200 m, where the assemblages of lowland rainforest change to assemblages of mountain forest. Analyses of affinity of bird species to forest habitat showed that the most affined assemblages to the forest are those found on mounts Kupé and Rata. On the other hand bird assemblages on mounts Manenguba and Oku are the one of least affined to the forest biotope. Analysis of habitat generalism and specialism did not show the expected outcome and for clearer results the design of analysis needs to be improved. The results of this thesis contribute to a...

Το γένος Bellevalia, (οικογ. Hyacinthaceae), αποτελείται από βολβώδη taxa, τα οποία παρουσιάζουν ιδιαίτερο ταξινομικό και κυτταρολογικό ενδιαφέρον. Στην Ελλάδα, οκτώ taxa του γένους έχουν καταγραφεί μέχρι σήμερα. Τρία από αυτά, η Bellevalia hyacinthoides, η B. brevipedicellata και η B. sitiaca είναι ενδημικά, ενώ τέσσερα, η B. dubia subsp. boissieri, η B. trifoliata, η B. romana και η B. ciliata είναι μεσογειακά στοιχεία. Επιπλέον, η B. edirnensis, γνωστή από την Ευρωπαϊκή Τουρκία ως ένα στενότοπο ενδημικό, βρέθηκε στην περιοχή του Έβρου στα πλαίσια της παρούσας μελέτης, προσθέτοντας ένα ακόμα είδος στην ελληνική χλωρίδα. Εκτός των ανωτέρω ειδών που απαντούν στον Ελλαδικό χώρο, μελετήθηκαν επιπλέον και τρία είδη της ανατολικής Μεσογείου, τα B. nivalis, B. flexuosa και B. longistyla. Πραγματοποιήθηκε ταξινομική μελέτη, χρήση της κλασσικής τεχνικής χρώσης των χρωμοσωμάτων για τον προσδιορισμό του χρωμοσωματικού αριθμού και των επιπέδων πολυπλοειδίας και στατιστική επεξεργασία των κυτταρολογικών δεδομένων, τόσο των taxa που απαντώνται στην Ελλάδα, όσο και ειδών της Ανατολικής Μεσογείου. Παράλληλα, έγινε για πρώτη φορά στο γένος Bellevalia μελέτη του γονιδιώματος με την χρήση Κυτταρογενετικής (χρώση με φθορισμό για τον εντοπισμό πλούσιων σε CG και ΑΤ ζωνώσεων), και Μοριακής Κυτταρογενετικής (in situ υβριδοποίηση φθορισμού –FISH– σε ριβοσωματικά γονίδια), καθώς και προσδιορισμού της ποσότητας του γενετικού υλικού με κυτταρομετρία ροής. Τα αποτελέσματα αυτής της προσπάθειας απαντούν σε σημαντικά ερωτήματα, σχετικά με την ταξινόμηση και φυλογένεση του γένους, τον προσδιορισμό του γενετικού υλικού, την οργάνωση του γονιδιώματος, το είδος και την προέλευση των πολυπλοειδιών, αλλά και την διαφοροποίηση των ειδών. / Bellevalia, an attractive genus of the Hyacinthaceae family, consists of small perennial geophytes interesting from both taxonomical and karyological points of view. In Greece, eight taxa of the genus had been recorded, three of which are endemic, i.e. Bellevalia hyacinthoides, B. brevipedicellata and B. sitiaca, while the remaining four, B. dubia subsp. boissieri, B. trifoliata, B. romana and B. ciliata, are Mediterranean elements. Additionally, B. edirnensis, one of the most localized endemics of European Turkey, was found in the framework of this thesis, adding a new species to the flora of Greece. In the present thesis three East Mediterranean species have been studied: B. nivalis, B. flexuosa and B. longistyla. Τhe above mentioned taxa of the genus were studied from a taxonomical point of view, as well as cytologically, with classical karyological techniques (squash technique) in order to determine chromosome number, ploidy level and karyotype morphology. Moreover, for the Greek taxa cytogenetic (staining with fluorochrome, in order to locate GC- and AT-rich areas) and molecular-cytogenetic techniques (fluorescence in situ hybridization, -FISH- in ribosomal genes). Cytogenetic, molecular cytogenetic studies and the determination of the genome size using flow cytometry are given for the first time for the genus Bellevalia. The results by this first attempt to study Bellevalia taxa, through the implementation of cytogenetic and molecular-cytogenetic techniques and statistical analysis, besides taxonomic and classical karyomorphometric analysis, provides valuable information on the taxonomic relationships among the species, the phylogeny of the genus, the origin of polyploids, as well as on chromosomal identification, genome organization and differentiation.

Made available in DSpace on 2016-06-02T20:20:30Z (GMT). No. of bitstreams: 1 3078.pdf: 3949929 bytes, checksum: 0375aaec7134412a51147cc0d80c7620 (MD5) Previous issue date: 2010-05-21 / The State of Maranhão is considered as a transitional area between northeastern semiarid and amazonian rainforest. Various perennial rivers such as the rivers Parnaíba, Itapecuru, Mearim, Pindaré and Gurupi are found in Maranhão. Distribution patterns analysis indicated the region as an endemism area for Neotropical freshwater fishes. However, only few studies have been performed in the region. Therefore the relationships between the hidrographic set and the respective neighbour areas are not fully comprehended. One complication is the insufficient cientific knowledge about the endemism level in the region due to insufficient establishment of taxonomic bounds for several species in the area. This study examines the hypothesis that freshwater fishes from Maranhão rivers are valid taxonomic unities, and whether its hydrographic set can be considered as an endemism area for Neotropical fishes. The study is focused on the analsis of genetic differentiation of Hoplias malabaricus and Prochilodus lacustris. The geographic variation of H. malabaricus was studied using sequences of the DNAmt control region as well by geometric morphometrics. Besides the mitochondrial marker, the variation analyses of P. lacustris employed sequences of the S7 intron 1. Both species exhibited high genetic variability which may be related to its own ecological features. The genetic diversity of H. malabaricus, a sedentary species, is influenced by drainage architeture. On the other hand, the migratory behavior of P. lacustris and the results obtained had suggested that the variability found was influenced by historical factors. Because the most resolution of the P. lacustris data, the molecular clock hypothesis was tested and divergence times between populations sampled were estimated. These estimates matching with geological informations enabled us to identify several putative events that may play an important role in differentiation of the maranhense ichthyofauna. Under the taxonomic point of view, the hypothesis that H. malabaricus is a species complex was reinforced and the analyses suggested that putative criptic species occur in the region. The P. lacustris specimens constitute a taxonomic unit, but did not support the hypothesis that the species is endemic for the Parnaíba and Mearim rivers. Considering these results, we suggest that the most closely indication of endemism areas could be the ecoregions established by Secretaria de Recursos Hídricos from Ministério do Meio Ambiente. / O Estado do Maranhão é geralmente considerado uma área de transição entre o semiárido nordestino e a floresta amazônica, onde está localizado um conjunto de rios perenes, tais como, Parnaíba, Itapecuru, Mearim, Pindaré e Gurupi. Análises baseadas em padrões de distribuição têm indicado que a região constitui uma área de endemismo para peixes neotropicais. No entanto, devido ao reduzido número de estudos, as interrelações desse conjunto hidrográfico com áreas vizinhas são pouco compreendidas. Uma das dificuldades que surge do esquálido conhecimento científico é a identificação do nível de endemismo que a região abriga, uma vez que há problemas na definição dos limites taxonômicos de várias espécies com ocorrência registrada na área. Assim, este trabalho teve como objetivo testar as hipóteses de que as espécies de peixes dos rios do Maranhão são unidades taxonômicas válidas e, consequentemente, o conjunto hidrográfico pode ser considerado uma área de endemismo. O estudo foi centrado na análise de diversidade genética das espécies Hoplias malabaricus e Prochilodus lacustris. Em H. malabaricus a variação geográfica foi estudada usando sequências da região controle do DNAmt e através de morfometria geométrica. Além do marcador mitocondrial, na análise da variação em P. lacustris foram utilizadas sequências do íntron 1 do gene S7. Ambas as espécies apresentaram alta variabilidade genética que parece estar associada às características ecológicas de cada uma. H. malabaricus, sendo sedentária, teve sua diversidade genética influenciada por arquitetura de drenagem. Por outro lado, dado o comportamento migratório de P. lacustris, os resultados sugeriram que a variabilidade observada foi influenciada por fatores históricos. A maior resolução dos dados em P. lacustris permitiu testar a hipótese de relógio molecular e estimar tempos de divergências entre as populações amostradas. Estas estimativas foram combinadas com informações geológicas disponíveis, possibilitando a identificação de vários eventos que provavelmente exerceram papéis importantes na diferenciação da ictiofauna maranhense. Do ponto de vista taxonômico, as análises reforçaram a hipótese de que H. malabaricus é um complexo de espécie, sugerindo a possibilidade de ocorrência de espécies crípticas na área. As amostras de P. lacustris, por sua vez, constituem uma unidade taxonômica, mas não são consistentes com a hipótese de que a espécie é endêmica para os rios Parnaíba e Mearim. Diante dos resultados obtidos, sugerimos que a indicação mais aproximada de áreas de endemismo seja a de ecorregiões definidas pela Secretaria de Recursos Hídricos do Ministério do Meio Ambiente.

Made available in DSpace on 2016-06-02T19:26:23Z (GMT). No. of bitstreams: 1 TOCHET_Caroline_2013_V_ 1.pdf: 367702 bytes, checksum: e45cebba8c597ec047bc77ddd848aef5 (MD5) Previous issue date: 2013-11-29 / Universidade Federal de Sao Carlos / The Cerrado biome is located in Central Brazil Plateau occupying 2,036.448 km². Its weather is characterized by seasonality and the landscape by a vegetation mosaic. Those factors contribute for Cerrado to be known as the richest savanna in the world. It is considered one of the 20 World Hotspots, because of its high level of diversity and threat. The Cerrado is still poorly known, especially in relation to its history, origin and distribution through time, which are important factors to comprehend its recent diversity. This project aims to determine the historically stable areas within Cerrado by modelling 14 marsupial and small rodent species potential distribution for past and present scenarios, to relate the detected areas with endemism levels, to compare the identified patterns with known biogeography hypothesis of other Cerrado organism groups, and to suggest priority areas for inventory. To generate the potential distribution maps I used the digital bases available by WWF and IBGE and the SIG ARCMAP 10.1 software. The potential distribution modelling was implemented by maximum-entropy algorithm (MAXENT), using WORLDCLIM 1.4 and PALEOCLIMATE MODELING INTERCOMPARISON PROJECT (PMIP) climate variables data. The open vegetation biomes of South America were the base area for modelling, with 2.5 layers resolution (ca. 5 km²). To statistically evaluate model performance, I used the area under the curve (AUC) of the receiver operating characteristic (ROC) plot. All models presented high AUC values. The hypothesis that during the Last Glacial Maximum (LGM) the open formations expanded and the forest ones retracted, while the open formations retracted and forests expanded during the Last Interglacial (LIG) were supported by 20 of the 28 proposed models. The historically stable areas include the Parecis , Chapada dos Guimarães, Chapada Diamantina and Central Brazil Plateaus, the western Minas Gerais and the Espinhaço range. Those areas agree to other historically stable areas and/or endemism areas already proposed for other taxa, such as birds, squamate reptiles, anuran, lepdoptera and plants. They also reflect lack of inventory data. So, the fauna of those areas should be better investigated and its material used in future phylogenetic and phylogeographic studies. Conservation should also be considered in the light of their climatic stability, resulting in the possible creation, increasing or maintaining of Conservation Units. / O bioma Cerrado localiza-se no planalto do Brasil Central e ocupa uma área de 2.036.448 km²; tem seu clima marcado pela sazonalidade e é constituído por um mosaico de diferentes fitofisionomias, um dos fatores que mais contribui para que seja a savana com maior riqueza de espécies do mundo. Por ser um bioma com alto nível de diversidade e estar dentre os mais ameaçados do planeta, é considerado um dos 20 hotspots mundiais. Apesar disto, pouco se conhece a respeito do Cerrado, em especial sobre sua história, incluindo sua origem e distribuição ao longo do tempo, fatores muito importantes para a compreensão da atual diversidade presente no bioma. Este projeto tem como objetivos determinar áreas historicamente estáveis no Cerrado a partir de modelos de distribuição potencial de 14 espécies de marsupiais e pequenos roedores para cenários passados e atuais, relacionar as áreas detectadas com aquelas que atualmente possuem maior concentração de espécies endêmicas, e comparar os padrões levantados em relação a hipóteses biogeográficas já propostas para outros organismos que habitam o Cerrado, além de sugerir áreas prioritárias para inventário. Para produzir os mapas de distribuição potencial foram utilizadas bases digitalizadas disponibilizadas pela WWF e pelo IBGE e o software SIG ARCMAP 10.1. Para a modelagem foi utilizado o algoritmo de máxima entropia (MAXENT). As variáveis climáticas foram obtidas a partir da base de dados do WORLDCLIM 1.4 e do PALEOCLIMATE MODELING INTERCOMPARISON PROJECT (PMIP) e a área considerada para gerar os modelos foi aquela que incluiu as formações abertas da América do Sul, conhecida como Diagonal Seca , com resolução das camadas ambientais de 2.5 (ca. 5 km²). Para verificar o desempenho dos modelos produzidos foi utilizada a análise da área sob a curva (area under the curve, AUC) ROC (Receiver Operating Characteristic). Todos os modelos gerados apresentaram alto valor de AUC. A hipótese de que durante os períodos glaciais, como o Último Máximo Glacial (Last Glacial Maximum LGM), as formações abertas teriam se expandido e as áreas florestadas se retraído, e durante os períodos inter-glaciais, como o Último Inter-glacial (Last Interglacial LIG), o oposto teria acontecido, isto é, expansão das formações florestais e retração das áreas abertas, foi corroborada por 20 dos 28 modelos propostos. As áreas historicamente estáveis geradas pelos modelos das 14 espécies incluem o Planalto dos Parecis e a Chapada dos Guimarães (MT), o Planalto Central brasileiro (GO e DF), o oeste de Minas Gerais, na região leste do Triângulo Mineiro, a Serra do Espinhaço (MG) e a Chapada Diamantina (BA). Essas áreas aqui identificadas condizem com áreas historicamente estáveis e/ou áreas de concentração de endemismos anteriormente propostas para outros táxons como aves, répteis Squamata, anuros, lepidópteros e plantas. Os modelos também apontaram estas áreas como áreas de lacunas de amostragem, representando regiões a serem melhor investigadas em campo quanto à sua fauna e possível fonte de material para estudos futuros de filogenia e filogeografia. Além disso, são importantes para conservação, tendo em vista sua estabilidade climática, representando possíveis áreas alvo de criação, ampliação e manutenção de Unidades de Conservação.

La connaissance de la distribution spatiale des espèces et leurs déterminants constituent les principaux thèmes de la biogéographie et de l’écologie. Cette thèse a été réalisée sur les Fabaceae de l’Afrique Centrale :Burundi, République Démocratique du Congo et Rwanda. Composées de trois sous-familles (Caesalpinioideae, Faboideae et Mimosoideae), les Fabaceae sont présentes dans tous les biomes terrestres du monde. La présente étude a pour objectif d’évaluer et localiser la diversité spécifique, déterminer les zones de conservation des Fabaceae, identifier leur modèle de distribution spatiale et examiner l’impact potentiel de la déforestation sur les espèces indicatrices de cette famille. Les facteurs environnementaux déterminant la distribution des espèces endémiques de Fabaceae, les zones favorables à leur présence et l’évaluation de leur état de conservation ont également été analysés. L’étude a consisté à vérifier et à digitaliser tous les échantillons d’herbiers des Fabaceae conservés au Jardin Botanique National de Belgique et à l’Université Libre de Bruxelles. Les Systèmes d’Information Géographique ont été largement utilisés. Les analyses spatiales ont montré une distribution non uniforme de la diversité spécifique des Fabaceae. Les zones où la diversité spécifique coïncide avec celle des espèces endémiques ont été suggérées comme prioritaires pour la conservation. L’analyse de groupement appliquée sur le jeu de données des Mimosoideae a mis en évidence trois régions floristiques majeures. Ces trois régions correspondent aux régions phytogéographiques définies par White (1979, 1983). L’étude des Caesalpinioideae a confirmé l’existence d’espèces indicatrices de territoires phytogéographiques de Ndjele (1988). L’étude de cas réalisée au Katanga (R.D. Congo) a montré que la déforestation constitue une menace potentielle pour ces espèces, les plus vulnérables étant inféodées aux habitats forestiers. La distribution potentielle des espèces endémiques de Fabaceae (Caesalpinioideae) a montré une convergence entre les cartes de la distribution actuelle et celles issues de la distribution potentielle. Des sites où les espèces n’ont jamais été signalées ont été identifiés. La distribution potentielle a démontré le rôle des déterminants environnementaux dans la distribution des espèces endémiques. Cette étude a également prouvé que d’importantes proportions des zones de diversité des espèces endémiques ne sont pas couvertes par la conservation actuelle de l’Afrique Centrale. Cette thèse confirme que l’Afrique Centrale est une zone importante de conservation de la biodiversité. L’étude devrait être poursuivie en étendant la distribution potentielle aux Fabaceae non endémiques afin de définir leurs aires de distributions, critère indispensable pour évaluer le degré de vulnérabilité d’une espèce. La création de nouvelles aires protégées renforcerait le système actuel de conservation dans cette région./Knowledge of the spatial distribution of species and its determinants constitutes a principal theme in biogeography and ecology. This dissertation focused on the Fabaceae family of Central Africa: Burundi, the Democratic Republic of the Congo and Rwanda. Composed of three subfamilies (Caesalpinioideae, Faboideae and Mimosoideae), Fabaceae species are present in all terrestrial biomes of the world. The current study aimed to assess and locate Fabaceae species diversity, to determine potential conservation zones, to identify the spatial distribution pattern and to examine the potential impact of deforestation on some indicator species of this family. The environmental factors driving the distribution of endemic Fabaceae have been identified, as well as the potential areas of occurrence; their conservation status in the region has also been studied. The current study has verified and digitized all the herbarium samples kept at the National Botanical Garden of Belgium and the Université Libre de Bruxelles regarding the Fabaceae family. Geographic Information Systems have been used frequently. Spatial analysis showed an uneven distribution of Fabaceae species diversity. The zones where species richness depends on endemic species diversity are suggested to have priority for conservation. A cluster analysis applied to the dataset of Mimosoideae has highlighted three major floristic regions. These three regions correspond to existing phytogeographical regions defined by White (1979, 1983). A study on Caesalpinioideae species of Central Africa has confirmed the existence of indicator species of phytogeographic territories of Ndjele (1988). A case study conducted in Katanga (D.R Congo) showed that deforestation constitutes a potential threat for these species, the most vulnerable being those strictly confined to forest habitats. The potential distribution of endemic Fabaceae (Caesalpinioideae) showed a clear convergence between the current distribution maps and the potential distibutions. Sites where those species had not been reported before have been identified. The potential distribution enabled to identify the importance of the different environmental factors for each endemic species’ distribution. This study also showed that large regions characterized by important endemic species diversity are not covered by current zones of conservation in Central Africa. This dissertation confirms Central Africa as an important zone for biodiversity conservation. The current research should be completed by the potential distribution of non endemic Fabaceae species of Central Africa, an important criterion to evaluate their degree of vulnerability. Creation of new protected areas would reinforce the current status of conservation in the region. / Doctorat en Sciences / info:eu-repo/semantics/nonPublished

L’Afrique centrale atlantique (ACA) englobe l’ensemble du domaine bas-guinéen, les îles du Golfe de Guinée et une partie de l’archipel afromontagnard. Plusieurs centres d’endémisme ont été identifiés en son sein et sont généralement considérés comme liés à la présence de refuges forestiers durant les périodes glaciaires. Cependant, l’origine de cet endémisme, sa localisation et les méthodes permettant d’identifier ces centres restent controversées. La localisation de ces zones d’endémisme et des plantes rares qu’elles abritent, est pourtant un prérequis indispensable pour la mise en place de politiques cohérentes de conservation et demeure une priorité pour les organisations privées, institutionnelles ou gouvernementales actives dans la gestion et le maintien durable de la biodiversité.<p><p>Cette étude phytogéographique porte sur la famille des Orchidaceae et est basée sur l’analyse de la distribution des taxons endémiques de l’ACA. Elle s’appuie sur un jeu de données original résultant d’un effort d’échantillonnage important au Cameroun et d’un travail d’identification et de localisation de spécimens dans les principaux herbaria européens abritant des collections d’ACA. Durant cette étude, (i) nous avons tout d’abord identifié ces taxons endémiques et documenté leur distribution au travers de plusieurs contributions taxonomiques et floristiques, (ii) nous nous sommes ensuite intéressé aux nouvelles méthodes permettant d’analyser ces données d’herbier de plantes rares et donc pauvrement documentées, testant aussi l’intérêt des Orchidaceae comme marqueurs chorologiques, et finalement, appliquant ces méthodes à notre jeu de données, (iii) nous avons délimité des centres d’endémisme et identifié les territoires phytogéographiques des Orchidaceae en ACA.<p><p>(i) Une révision taxonomique des genres Chamaeangis Schltr. et Stolzia Schltr. a été réalisée respectivement. Sept nouveaux taxons ont été décrits: Angraecum atlanticum Stévart & Droissart, Chamaeangis spiralis Stévart & Droissart, Chamaeangis lecomtei (Finet) Schltr. var. tenuicalcar Stévart & Droissart, Polystachya engogensis Stévart & Droissart, Polystachya reticulata Stévart & Droissart, Stolzia repens (Rolfe) Summerh var. cleistogama Stévart, Droissart & Simo et Stolzia grandiflora P.J.Cribb subsp. lejolyana Stévart, Droissart & Simo. Plusieurs notes taxonomiques, phytogéographiques et écologiques supplémentaires ont également été redigées. Au total, nous avons identifié 203 taxons d’Orchidaceae endémiques d’ACA parmi lesquels 193 sont pris en compte pour l’étude des patrons d’endémisme.<p><p>(ii) Au Cameroun, les patrons de distribution des Orchidaceae et des Rubiaceae endémiques d’ACA ont été étudiés conjointement. Des méthodes de rééchantillonnage des données (raréfaction) ont été appliquées pour calculer des indices de diversité et de similarité. Elles ont permis de corriger les biais liés à la variation de l’effort d’échantillonnage. Un gradient de continentalité a été observé, les parties côtières étant les plus riches en taxons endémiques d’ACA. Contrairement à la région du Mont Cameroun et aux massifs de Kupe/Bakossi qui ont connu une attention particulière des politiques et des scientifiques, la partie côtière du sud Cameroun, presque aussi riche, reste mal inventoriée pour plusieurs familles végétales.<p><p>Cette analyse à l’échelle du Cameroun a également permis de comparer les patrons d’endémisme des Orchidaceae et des Rubiaceae. Les différences observées seraient principalement dues à la présence d’Orchidaceae terrestres dans les végétations basses et les prairies montagnardes de la dorsale camerounaise alors que les Rubiaceae sont généralement peu représentées dans ces habitats. Au sein des habitats forestiers, la concordance entre les patrons d’endémisme des Orchidaceae et des Rubiaceae remet en question l’utilisation des capacités de dispersion des espèces comme critère pour choisir les familles permettant l’identification des refuges forestiers et semble ainsi confirmer la pertinence de l’utilisation des Orchidaceae comme marqueur chorologique.<p><p>La distribution potentielle a été utilisée pour étudier en détail l’écologie, la distribution et le statut de conservation de Diceratostele gabonensis Summerh. une Orchidaceae endémique de la région guinéo-congolaise uniquement connue d’un faible nombre d’échantillons. Cette méthodologie semble appropriée pour compléter nos connaissances sur la distribution des espèces rares et guider les futurs inventaires en Afrique tropicale.<p><p>(iii) En ACA, les Orchidaceae permettent d’identifier plusieurs centres d’endémisme qui coïncident généralement avec ceux identifiés précédemment pour d’autres familles végétales. Ces constats supportent aussi l’utilisation des Orchidaceae comme marqueur chorologique. La délimitation des aires d’endémisme des Orchidaceae a ainsi permis de proposer une nouvelle carte phytogéographique de l’ACA. Les éléments phytogéographiques propres à chacune des dix phytochories décrites ont été identifiés et leurs affinités floristiques discutées. Les résultats phytogéographiques obtenus (a) soutiennent l’existence d’une barrière phytogéographique matérialisée par la rivière Sanaga entre les deux principaux centres et aires d’endémisme de l’ACA, (b) étendent l’archipel afromontagnard situé principalement au Cameroun au plateau de Jos (Nigeria) et (c) montrent l’importance de la chaîne montagneuse morcelée Ngovayang-Mayombe pour la distribution de l’endémisme en ACA. Cette chaîne de montagne, qui s’étend le long des côtes de l’océan du sud Cameroun au Congo-Brazzaville et qui correspond à plusieurs refuges forestiers identifiés par de nombreux auteurs, est ici considérée comme une seule aire d’endémisme morcelée./<p>Atlantic central Africa (ACA) covers the Lower Guinean Domain, the four islands of the Gulf of Guinea and a part of the afromontane archipelago. Different centres of endemism have been identified into this area and are usually considered as related to glacial forest refuges. However, the origin of this endemism, the localization of the centres and the methods employed to identify these centres are subject to debate. Yet, the localization of these centres of endemism and the identification of the rare plants they harbor is an essential prerequisite to setting up rational conservation policies, and remains a priority for private, institutional and governmental organizations which are dealing with the sustainable management of biodiversity.<p><p>This phytogeographical study focuses on Orchidaceae and analyses the distribution of the taxa endemic to ACA. We use an original dataset resulting from an important sampling efforts and the identification of specimens coming from all the principal herbaria where collections from ACA are housed. During this study, (i) we first identified the taxa endemic to ACA and documented their distribution through several taxonomic and floristic contributions, (ii) we used and developed new methods allowing to correct for sampling bias associated with the use of rare and poorly documented taxa, testing at the same time the use of Orchidaceae as chorological markers, and finally, applying these methods to our dataset, (iii) we delimited the centres of endemism and identified the phytogeographical territories of Orchidaceae in ACA.<p><p>(i) A taxonomic revision of Chamaeangis Schltr. and Stolzia Schltr. respectively was carried out. Seven new taxa were described: Angraecum atlanticum Stévart & Droissart, Chamaeangis spiralis Stévart & Droissart, Chamaeangis lecomtei (Finet) Schltr. var. tenuicalcar Stévart & Droissart, Polystachya engogensis Stévart & Droissart, Polystachya reticulata Stévart & Droissart, Stolzia repens (Rolfe) Summerh var. cleistogama Stévart, Droissart & Simo and Stolzia grandiflora P.J.Cribb subsp. lejolyana Stévart, Droissart & Simo. Several additional taxonomic, phytogeographical and ecological notes were also published. We finally identified 203 Orchidaceae taxa endemic to ACA, among which 193 were used to study the patterns of endemism.<p><p>(ii) In Cameroon, the distribution patterns of both Orchidaceae and Rubiaceae endemic to ACA were studied. Subsampling methods (rarefaction) were applied to calculate diversity and similarity indices and to correct potential bias associated with heterogeneous sampling intensity. A gradient of continentality was confirmed in Cameroon, the coastal part being the richest in taxa endemic to ACA. The Cameroon Mountain and the Kupe/Bakossi mountain massifs have received a great consideration of politics and scientists. On the contrary, the Southern coastal part of Cameroon, though almost as rich as the Northern part, remains poorly known for several plant families.<p>This analysis also allowed us to compare patterns of endemism of Orchidaceae and Rubiaceae. The differences observed could be mainly due to the terrestrial habit of some Orchidaceae, which are only found in the grasslands of the highest part of the Cameroonian volcanic line where endemic Rubiaceae are rare. Within forest habitats, the concordance between the patterns of endemism of Orchidaceae and Rubiaceae question the widespread use of dispersal ability as a selection criterion for the families used to identify forest refuges. This also confirms the relevance of Orchidaceae as chorological marker.<p><p>Species distribution modelling was used of an in depth study of the ecology, the distribution and the conservation status of Diceratostele gabonensis Summerh. an Orchidaceae endemic to the Guineo-Congolian regional centre of endemism which is only known from very few collections. This method is proved to be appropriate to complete our knowledge on the distribution of rare plant species and to guide the future inventories in tropical Africa.<p><p>(iii) In ACA, an analysis of the distribution of endemic Orchidaceae confirmed the presence and location of several centres of endemism previously identified on the basis of other plant families. This result again supports the use of Orchidaceae as a chorological marker. The chorological study of the endemic Orchidaceae allowed us to propose a new phytogeographical map for ACA. Phytogeographical elements for each of the ten phytochoria described were identified and their floristic affinities were also discussed. Our results (a) support the existence of a phytogeographical barrier, materialized by the Sanaga River, between the two main centres and area of endemism of the ACA, (b) extend the limits of the afromontane archipelago to the Jos Plateau in Nigeria and (c) show the importance of the Ngovayang-Mayombe line to explain the distribution of endemism in ACA. This mountainous line, stretching along the ocean coast from Southern Cameroon to Congo-Brazzaville, corresponds to several forest refuges identified by many authors, and is here considered as an unique but discontinuous area of endemism.<p><p><p> / Doctorat en Sciences / info:eu-repo/semantics/nonPublished

[ES] Esta tesis investiga las oportunidades, desafíos y limitaciones para la investigación en el campo de la ecología vegetal, en el contexto de los acantilados mediterráneos. En concreto, las especies casmofiticas, cuyos hábitats naturales se caracterizan por su acusada pendiente. Las laderas de las montañas de piedra caliza en la proximidad del mar, en la parte central y occidental del área mediterránea se consideran objetos de estudio. Los estudios se llevaron a cabo en los cinturones costeros de montaña de las costas del noroeste de Sicilia y la costa diánica en la Comunidad Valenciana. El primer capítulo, titulado "The complexity of environmental factors: cliff microclimate", investiga la variabilidad del microclima del acantilado en tres áreas diferentes en Sicilia y España, analizando las condiciones ambientales creadas por el acantilado en una escala muy estrecha. Se recopilaron seis conjuntos de datos independientes y comparables que recogen las principales variables meteorológicas a lo largo de un período total de 18 meses. La gama resultante de condiciones ambientales se compara por pares a lo largo de dos gradientes ambientales principales: la orientación del acantilado Norte/Sur y la proximidad al mar. Además, los rasgos foliares intraespecíficos se utilizan para estudiar la variación en la respuesta funcional de las plantas que viven en las orientaciónes opuestas en una misma área de investigación. La variación resultante se correlaciona con la influencia de las condiciones microclimáticas creadas por la pendiente y el aspecto en los rasgos de la planta antes mencionados. El segundo capítulo, titulado "Compositional data and analyses of areas and plant communities in the coastal cliffs of the Valencian Community (Spain)", presenta una ordenación de los sitios de estudio y de las especies vegetales que habitan en las zonas de acantilados del cinturón montañoso a lo largo de las costas de la región diánica en el este de España. El estudio reveló correlaciones significativas entre las unidades de vegetación y los sitios con referencia a la amplia orientación geográfica Norte/Sur. Sin embargo, fue poco informativo con respecto a revelar las principales diferencias observadas en la estructura del conjunto de plantas relacionadas con laa variaciones microtopográficas registradas en el conjunto de datos. En el tercer capítulo, titulado "UAV (drone) surveys for the study of plant- microtopography relationships and for the conservation of rare species", se describe la metodología propuesta para investigar entornos verticales poco accesibles. También se analizaron los desafíos y las oportunidades de la investigación ecológica vegetal en estas áreas tipicamente inaccesibles. Un primer conjunto de datos comprende un censo visual parcial y total de dos especies endémicas de acantilados estrechos en las áreas de estudio españolas e italianas. Mediante el uso de la fotogrametría aérea de corto alcance y el modelado 3D, fue posible estudiar los efectos de la micro topografía en la segregación de nichos, tanto a nivel de comunidad como de especie. Se utilizaron métodos de ordenación para correlacionar las especies endémicas seleccionadas y conjuntos de plantas con factores ambientales como el aspecto local y global, la pendiente y la distancia desde los bordes de los acantilados. En el cuarto capítulo, titulado "Distribution, ecology, conservation status and phylogeography of Pseudoscabiosa limonifolia, a paleo-endemic chasmophytic species from Sicily (Italy)", se analiza en detalle la estructura filogeográfica de una especie endémica de acantilados, Pseudoscabiosa limonifolia (Caprifoliaceae, subfamilia Dipsacaceae), también considerando las relaciones filogeográficas con sus taxones más próximos. Además, su distribución total se determinó mediante observaciones de campo, caracterizando su hábitat y evaluando su estado de conservación como Vulnerable de acuerdo con las / [CA] Aquesta tesi va investigar les oportunitats, reptes i limitacions per a la investigació en el camp de l'ecologia vegetal, en el context dels penya-segats mediterranis. En concret, les espècies casmofitiques, amb hàbitats naturals que es caracteritzen pel seu acusat pendent. Les vessants de les muntanyes de pedra calcària en la proximitat del mar, a la part central i occidental de l'àrea mediterrània són considerats objectes d'estudi. Els estudis es portaren a terme als cinturons costers de muntanya de les costes del nord de Sicília i la costa diànica a la Comunitat Valenciana. El primer capítol, titulat "The complexity of environmental factors: cliff microclimate", investiga la variabilitat del microclima del penya-segat en tres àrees diferents de Sicília i Espanya, analitzant les condicions ambientals creades pel penya-segat a una escala molt estreta. Es recopilen sis conjunts de dades independents i comparables que reconeixen les principals variables meteorològiques a llarg termini durant un període total de 18 mesos. Les dades resultants de les condicions ambientals es comparen per parells al llarg de dos gradients ambientals principals: l'orientació del penya-segat Nord/Sud i la proximitat a la mar. A més, els trests foliars intraespecífics s'utilitzen per estudiar la variació en la resposta funcional de les plantes que habiten orientacions oposades dins d'un àrea d' investigació. La variació resultant es correlaciona amb la influència de les condicions microclimàtiques creades pel vessant i els aspectos funcionals dels trets vegetals esmentats. El segon capítol, titulat "Compositional data and analyses of areas and plant communities in the coastal cliffs of the Valencian Community (Spain)", presenta una ordenació dels llocs d'estudi i de les espècies de plantes que habiten a les zones de penya- segats del cinturó de muntanya al llarg de les costes de la regió diànica de España. L'estudi va a revelar correlacions significatives entre les unitats de vegetació i els llocs amb referència a l'amplias orientació geogràfica Nord/Sud. No obstant aixó, va ser poc informatiu per poder revelar les diferències observades en l'estructura del conjunt de plantes relacionades amb les variacions microtopogràfiques registrades al conjunt de dades Al tercer capítol, titulat "UAV (drone) surveys for the study of plant-microtopography relationships and for the conservation of rare species", es descriu la metodologia proposada per a investigar entorns verticals poc accessibles. També es van analitzar els reptes i les oportunitats de la investigació ecològica vegetal en aquestes àrees normalment inaccesibles. Un primer conjunt de dades inclou el cens visual parcial i el total de dues espècies endèmiques de penya-segats a les àrees d'estudi espanyoles i italianes. Mitjançant la fotogrametria aèrea a curt abast i el modelat 3D, va ser possible estudiar els efectes de la microtopografia en la segregació de nínxols, tant a nivell comunitari com d'espècies. Es van utilitzar mètodes d'ordenació per a correlacionar les espècies endèmiques seleccionades i conjunts vegetals sencers amb factors ambientals com ara l'aspecte local i global, el pendent i la distància de les vores dels penya-segats. En el quart capítol, titulat "Distribution, ecology, conservation status and phylogeography of Pseudoscabiosa limonifolia, a paleo-endemic chasmophytic species from Sicily (Italy)", que s'analitza en detall l'estructura filogeográfica d'una espècie endèmica de penya-segats, Pseudoscabiosa limonifolia (Caprifoliaceae, subfamilia Dipsacaceae), considerant tambè les relacions filogeogràfiques amb els seus taxons més propers. A més, la seva distribució total es va determinar mitjançant observacions de camp, caracteritzant el seu hàbitat i avaluant el seu estat de conservació com a Vulnerable, d'acord amb les directrius de la llista roja de la UICN. / [EN] This thesis investigated opportunities, challenges and limitations for plant ecological research in the context of Mediterranean cliffs. In particular, chasmophytic species, whose natural habitats are very steep, limestone mountain slopes in the proximity of the sea, in the Central and Western part of the Mediterranean area are considered as study objects. Studies were carried out in the coastal mountain belts of both North-western Sicily and Dianic coasts in the Valencian Community (Spain). The first chapter, entitled "The complexity of environmental factors: cliff microclimate", investigates the variability of cliff microclimate in three different areas in Sicily and Spain, analysing the environmental conditions created by the cliff at very fine scale. Six independent and comparable datasets including the main meteorological variables were compiled in a total period of 18 months. The resulting spectra of environmental conditions are compared pairwise along two key environmental gradients: North/South cliff orientation and proximity to the sea. Intraspecific leaf traits are used in order to investigate variations in the functional response of plants living on opposite orientations. The resulting variation is then correlated with the influence of microclimatic conditions created by slope and functional aspects of the aforementioned plant traits. The second chapter, entitled "Compositional data and analyses of areas and plant communities in the coastal cliffs of the Valencian Community (Spain)", presents an ordination of the study sites and of the plant species inhabiting the cliff zones of the mountain belt along the coasts of the Dianic region in Eastern Spain. The study revealed significant correlations between the vegetation units and the sites with reference to the broad North/South geographical orientation. However, it was poorly informative in respect to reveal the major differences observed in the structure of the plant assemblage related to the micro- topographic variations recorded in the dataset. In the third chapter, entitled "UAV (drone) surveys for the study of plant- microtopography relationships and for the conservation of rare species", a proposed survey methodology for investigating inaccessible vertical environments is described. Challenges and opportunities of plant ecological research in these typically inaccessible areas were also analysed. A first set of data is comprised of partial and total visual census of two narrow endemic cliff species in the Spanish and Italian study areas. Through the use of aerial close- range photogrammetry and 3D modelling, it was possible to study the effects of micro-topography on niche segregation, both at community and species level. Ordination methods were used to correlate selected endemic species and entire plant assemblages to environmental factors such as local and global aspect, slope and distance from cliff edges. The fourth chapter, entitled "Distribution, ecology, conservation status and phylogeography of Pseudoscabiosa limonifolia, a paleo-endemic chasmophytic species from Sicily (Italy)", is addressed to analyse in details the phylogeographic structure of a cliff narrow endemic species, Pseudoscabiosa limonifolia (VAHL) DEVESA (Caprifoliaceae, subfamily Dipsacaceae), also taking in consideration its closest sister taxa. Furthermore, its total distribution was determined by field surveys, characterizing its habitat, and assessing its conservation status as Vulnerable according to IUCN red list guidelines. / De Simone, L. (2020). Ecological aspects of plants inhabiting Mediterranean cliffs. Challenges and prospects of life in vertical environments [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/159877

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