Magister Scientiae - MSc / We review a number of compartmental models in epidemiology which leads to a nonlinear system of ordinary differential equations. We focus an SIR, SEIR and SIS epidemic models with and without vaccination. A threshold parameter R0 is identified which governs the spread of diseases, and this parameter is known as the basic reproductive number. The models have at least two equilibria, an endemic equilibrium and the disease-free equilibrium. We demonstrate that the disease will die out, if the basic reproductive number R0 < 1. This is the case of a disease-free state, with no infection in the population. Otherwise the disease may become endemic if the basic reproductive number R0 is bigger than unity. Furthermore, stability analysis for both endemic and disease-free steady states are investigated and we also give some numerical simulations. The second part of this dissertation deals with optimal vaccination strategy in epidemiology. We use optimal control technique on vaccination to minimize the impact of the disease. Hereby we mean minimizing the spread of the disease in the population, while also minimizing the effort on vaccination roll-out. We do this optimization for the cases of SIR and SEIR models, and show how optimal strategies can be obtained which minimize the damage caused by the infectious disease. Finally, we describe the numerical simulations using the fourth-order Runge-Kutta method. These are the most useful references: [G. Zaman, Y.H Kang, II. H. Jung. BioSystems 93, (2008), 240 − 249], [K. Hattaf, N. Yousfi. The Journal of Advanced Studies in Biology, Vol. 1(8), (2008), 383 − 390.], [Lenhart, J.T. Workman. Optimal Control and Applied to Biological Models. Chapman and Hall/CRC, (2007).], [P. Van den Driessche, J. Watmough. Math. Biosci., 7, (2005)], and [J. Wu, G. R¨ost. Mathematical Biosciences and Engineering, Vol 5(2), (2008), 389 − 391]. / South Africa

A total of 60% of the area of Alagoas / Brazil is considered endemic to the occurrence of schistosomiasis and is not known the classification of clinical forms of the disease. This work has the objective of evaluating an endemic Schistosomiasis population in Alagoas, taking into account the prevalence, classification of the clinical forms and the results of laboratorial analysis. The sample was made of people from endemic areas of Rio Largo/Alagoas. The participants were submitted to a stool examination by Kato-Katz technique and the diagnostic was made after the reading of two microscopic slides for each sample. The patients positive for schistosomiasis mansoni were submitted to a clinical examination and blood collection. The positivity for Schistosomiasis observed in the population under study was of 8.11%. The medium parasite load was of 79,1+174,3 eggs. The clinical forms found were intestinal (90.57%) and hepatointestinal (9.43%), statistically significant at p<0.001. There were not found serious clinical forms. The present study shows results which update information on Schistosomiasis in the city of Rio Largo, data that, although referring to only three locations of this place, suggest the decrease of the parasite load and the clinical forms as well. / Em torno de 60% do território do estado de Alagoas é considerado área endêmica para esquistossomose mansoni, sendo observadas áreas de moderada a alta prevalência com mais de dois milhões de indivíduos expostos à infecção, não sendo conhecido o atual estadiamento das formas clínicas da parasitose. Este trabalho tem o objetivo de avaliar a população de uma área endêmica de esquistossomose no Estado de Alagoas em relação à prevalência, estadiamento das formas clínicas e dados de exames laboratoriais. A amostra foi constituída de moradores de três áreas endêmicas (Ilha Angelita, Lourenço de Albuquerque e Fazenda Riachão) do município de Rio Largo, Estado de Alagoas. Foram realizados 3.082 exames parasitológico de fezes através da técnica Kato-Katz, sendo o diagnóstico firmado após a leitura de duas lâminas para cada amostra. Do total das amostras, 249 foram positivos para Schistosoma mansoni , correspondendo a uma prevalência de 8,11%. Estes pacientes foram submetidos a exame clínico e coleta de sangue para realização de exames laboratoriais. A média da carga parasitária encontrada foi de 79,1+174,3 ovos. As formas clínicas encontradas foram a intestinal (90,57%) e hepatointestinal (9,43%) sendo uma diferença estatisticamente significativa (p<0,001). Não foram encontradas formas clínicas graves. O presente estudo apresenta resultados que atualizam dados sobre a esquistossomose mansônica no município de Rio Largo e embora sejam referentes a três localidades, sugerem haver uma diminuição da carga parasitária e das formas clínicas graves.

Submitted by Rômulo Aguiar (romulo.aguiar@ucsal.br) on 2018-05-10T14:38:39Z No. of bitstreams: 1 TESEMIGUELALMEIDA.pdf: 2536339 bytes, checksum: f42138012a9efc9972d05653bd85c536 (MD5) / Approved for entry into archive by Rosemary Magalhães (rosemary.magalhaes@ucsal.br) on 2018-05-10T14:47:18Z (GMT) No. of bitstreams: 1 TESEMIGUELALMEIDA.pdf: 2536339 bytes, checksum: f42138012a9efc9972d05653bd85c536 (MD5) / Made available in DSpace on 2018-05-10T14:47:18Z (GMT). No. of bitstreams: 1 TESEMIGUELALMEIDA.pdf: 2536339 bytes, checksum: f42138012a9efc9972d05653bd85c536 (MD5) Previous issue date: 2018-01-25 / Com o objetivo de investigar e identificar os fatores associados à prevalência endêmica da esquistossomose no município de Santa Inês/BA, foi realizado este estudo, de natureza qualitativa, em função de seu viés sociológico. Assim, este estudo teve como parâmetros a pesquisa das políticas públicas de saúde, adotadas no Brasil, e pesquisa de campo por intermédio de questionários e entrevistas na área estudada. Foram realizadas pesquisas bibliográfica, exploratória/explicativa e de campo. Na pesquisa de campo, foram aplicados 10 (dez) questionários a acometidos pela esquistossomose, residentes no referido município, e realizadas 03 (três) entrevistas, sendo 01 (uma) com a Secretária municipal, gestora de Saúde e 2 (duas) com os únicos profissionais que atuam no PCE, para atender toda a demanda municipal. Os resultados indicaram que os fatores relacionados à prevalência endêmica, estão associados à fragilização da saúde na área estudada. Falta de pessoal de saúde para atender às demandas do PCE no município, infraestrutura deficiente, falta de material e de veículos para atender às atividades operacionais de rotina, inexistência de uma política de educação em saúde, carência de medicamentos, de informação para a população, inexistência de parcerias entre a Secretaria de Saúde e outros órgãos públicos, estão entre os principais fatores identificados, que contribuem para a prevalência endêmica da Esquistossomose no município de Santa Inês/BA. / In order to investigate and identify the factors associated with the endemic prevalence of schistosomiasis in the of Santa Inês city / BA, this qualitative study was carried out in function of its sociological bias. Thus, this study had as parameters the research of the public policies of health, adopted in Brazil, and field research through questionnaires and interviews in the studied area. Bibliographic, exploratory / explanatory and field research were carried out. In the field survey, 10 (ten) questionnaires were applied to the schistosomiasis patients, living in referred county, and three (03) interviews were conducted, being one (1) the Municipal Secretary, Health Manager and two (2) with the only professionals working in the PCE, to meet all municipal demand. The results indicated that the factors related to the endemic prevalence, are associated to the weakening of health in the studied area. Shortage of health personnel to meet PCE demands in the municipality, poor infrastructure, lack of material and vehicles to attend to routine operational activities, lack of a health educational policy, scarcity of medicines, lack of information for the population, lack of partnerships between the Department of Health and other public agencies, are among the main factors identified, contributing to the endemic prevalence of Schistosomiasis in the Santa Inês county/ BA.

A esquistossomose mansoni apresenta-se como uma doenÃa parasitÃria de importÃncia para a saÃde pÃblica, nÃo sà por sua ampla distribuiÃÃo no mundo, mas tambÃm pelos impactos causados por ela nas atividades da populaÃÃo infectada. A esquistossomose deve ser analisada como um processo dependente da interaÃÃo de vÃrios fatores, como fatores ambientais, sociais e econÃmicos, importantes para reduzir a transmissÃo da doenÃa bem como para interromper o ciclo do parasito. O objetivo do estudo foi avaliar a influÃncia de fatores ambientais e socioculturais na transmissÃo da esquistossomose em Ãrea de baixa endemicidade no Estado do CearÃ, na localidade do Planalto do Cajueiro, atravÃs da anÃlise de questionÃrios aplicados no ano de 2009 e em 2012. O estudo foi desenvolvido em duas etapas. A primeira consiste em um estudo transversal, onde foram analisados 167 questionÃrios dos pacientes que forneceram material sorolÃgico para a realizaÃÃo do mÃtodo ELISA, que serviu como triagem. A segunda etapa consiste em um estudo de caso controle, onde foram aplicados e analisados questionÃrios em 54 indivÃduos ELISA reativo e nÃo reativo que entregaram amostra fecal para anÃlise. As anÃlises dos questionÃrios das 167 pessoas mostraram que a maioria delas eram adultos jovens (19,76% na faixa etÃria de 15 a 25anos e 29,94% entre 26 a 46 anos), do sexo feminino (67,66%) e que 29% nÃo eram naturais de Maranguape. Em torno de 52,5% dos pacientes que afirmaram utilizar Ãgua do rio, tiveram resultado Elisa reativo para esquistossomose. Na segunda etapa, observou-se que a diferenÃa entre os sexos masculinos e femininos era insignificante, nos casos positivos para esquistossomose. Com relaÃÃo à escolaridade, a maioria (68,32%) possuÃa apenas o ensino fundamental incompleto. Nas associaÃÃes entre variÃveis ambientais e resultado positivo para a doenÃa, observou-se que 34,2% dos indivÃduos responderam nÃo ter contato com coleÃÃes hÃdricas e 37,5% disseram que tiveram contato. Este ponto ainda està em anÃlise mais aprofundada. A comunidade do Planalto do Cajueiro em Maranguape-CE mantÃm caracterÃsticas ambientais semelhantes à de comunidades rurais (mesmo sendo peri-urbana) e a transmissÃo da esquistossomose sofre grande influencia dos fatores comportamentais. / Schistosomiasis mansoni is presented as a parasitic disease of public health importance, not only for its wide distribution in the world, but also the impacts caused by it in the activities of the infected population. Schistosomiasis should be analyzed as a process dependent on the interaction of various factors, such as environmental, social and economic importance to reduce transmission of the disease and to stop the cycle of the parasite. The aim of the study was to evaluate the influence of environmental and sociocultural factors in the transmission of schistosomiasis in low endemic area in the state of CearÃ, in the locality of the Planalto do Cajueiro- Maranguape-Ce, through the analysis of questionnaires applied in 2009 and 2012. The study was conducted in two stages. The first consists of a cross-sectional study, which analyzed 167 questionnaires from patients who provided material for the realization of the serological ELISA, which served as a screen. The second stage consists of a case-control study where questionnaires were applied and analyzed in 54 individuals ELISA reactive and nonreactive who delivered fecal sample for analysis. The analysis of the questionnaires of 167 people showed that most of them were young adults (19.76% in the age group of 15 to 25years and 29.94% between 26-46 years), female (67.66%) and 29% were not natives of Maranguape. Around 52.5% of patients reported using water from the river, had reactive ELISA result for schistosomiasis. In the second stage, it was observed that the difference between male and female sexes was negligible in cases positive for schistosomiasis. With regard to education, the majority (68.32%) had only elementary education. Associations between environmental variables and positive for the disease, it was observed that 34.2% of subjects reported not to have contact with water collections and 37.5% said they had contact. This point is still under further investigation. The community of Planalto do Cajueiro, Maranguape-Ce maintains environmental characteristics similar to rural communities (even as peri-urban) and schistosomiasis transmission is greatly influences behavioral factors.

Orientador: Angela Borges Martins / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-15T02:27:30Z (GMT). No. of bitstreams: 1 Rodrigues_KarinaFidanza_D.pdf: 4546379 bytes, checksum: b708c32708ae62962fda2a676096bee2 (MD5) Previous issue date: 2009 / Resumo: Este trabalho trata da re-avaliação taxonômica do gênero Cambessedesia DC., com chave de identificação para todos os táxons, descrições, sinonímias, relação do material examinado, comentários sobre as afinidades taxonômicas baseados em caracteres morfológicos, a distribuição geográfica, acompanhados de ilustrações e mapas de distribuição para as espécies. Com base no estudo de cerca de 3.000 exsicatas provenientes de 17 herbários nacionais e 17 estrangeiros, associado a diversas observações de campo e a estudos inéditos para o grupo tais como a análise das sementes, tricomas, emergências e estames sob microscopia eletrônica de varredura, 27 espécies são reconhecidas, das quais três são novas. Foram efetuadas as seguintes alterações infragenéricas e infra-específicas: sinonimização de Cambessedesia sect. Cambessedesia e Cambessedesia sect. Pyramia; o epíteto de C. hilariana foi substituído pelo epíteto específico fasciculata, por ser prioritário; C. arenaria e C. tiradentensis foram consideradas sinônimos de C. corymbosa e, C. espora subsp. ilicifolia, sinônimo de C. espora; C. longifolia e C. bahiana foram elevadas ao status específico. Foram designados 13 lectótipos e quatro neótipos. O gênero Cambessedesia é caracterizado por apresentar espécies com folhas frequentemente adicionais axilares reduzidas e dispostas em braquiblastos (algumas vezes assumindo forma de fascículos) ou verticiladas apenas em C. weddellii, flores 5-(6-) meras, pétalas bicolores (predominantemente vermelho-alaranjadas com base amarela), ou monocromáticas (amarelas ou branco-amareladas), estames 10 (-12), (5 apenas em C. semidecandra); anteras com conectivo espessado dorsalmente e eventualmente com pequeno cálcar na base, sem apêndices ventrais; cápsulas com sementes depresso-ovais, densamente ou esparsamente tuberculadas, antirafe na maioria das vezes mais desenvolvida que a rafe. Este gênero é endêmico no Brasil, onde foram detectados três padrões gerais de distribuição geográfica de suas espécies: amplo, endêmico (endêmico na Serra do Espinhaço-MG, endêmico na Chapada Diamantina-BA, endêmico na Chapada dos Veadeiros-GO) e disjunto. Dentre as 27 espécies deste gênero apenas C. fasciculata e C. espora apresentam distribuição geográfica mais ampla. Os dados apresentados no presente trabalho poderão futuramente contribuir para outros estudos filogenéticos em Cambessedesia. / Abstract: A taxonomic re-evaluation of the genus Cambessedesia DC. is conducted, including identification key for all taxa, descriptions, synonymies, list of examined materials, comments about taxonomic affinities based on morphological traits, observations on habitat and distribution, as well as illustrations and distribution maps for all analyzed species. The studies were based on the analysis of 3.000 exsiccatae from 17 national herbaria and 17 herbaria of foreign countries, which was associated with diverse field observations and with inedited scanning electron microscopy examinations of seeds, trichomes, emergencies and stamens. A total of 27 species were identified and two of them were recognized as new The following infrageneric and infraspecific modifications were derived from the taxonomic re-evaluation: Cambessedesia sect. Cambessedesia and Cambessedesia sect. Pyramia are considered synonymies; the epithet C. hilariana was replaced by the epithet fasciculata, because of its priority; C. arenaria and C. tiradentensis were considered synonym of C. corymbosa and C. espora subsp. ilicifolia synonym of C. espora; C. longifolia and C. bahiana were elevated to the specific status. A total of 13 lectotypes and four neotypes were designated. The genus Cambessedesia is characterized by species with opposite leaves, frequently with additional axillary leaves that are small and arranged in brachiblasts, occasionally fasciculate, or verticillate in C. weddellii only. The flowers are 5-(6-) merous with bicolor petals that are red-orange colored and have a yellow base, or that are monochromatic yellow or white-yellowish; stamens 10(-12), 5 in C. semidecandra, and the anther connective is dorsally thickened, often with a calcar at the base, without ventral appendages. The capsules contain oval-depressed seeds that are densely or sparsely tuberculate and, almost always, the anti-raphe is more developed than the raphe. Cambessedesia is endemic to Brazil, where three general patterns of geographic distribution were identified for its species: widely distributed, endemic (Espinhaço Mountains (MG), Chapada Diamantina (BA) and Chapada dos Veadeiros (GO) and disjunct Among the 27 identified species, only C. fasciculata and C. espora are widely distributed. The data in the present work contributes to further understand the systematic of Cambessedesia and are potentially useful for future phylogenetic in this genus. / Doutorado / Biologia Vegetal / Doutor em Biologia Vegetal

Introdução: A OMS recomendou às Américas, em 2004, implementar e aperfeiçoar sistemas específicos de vigilância epidemiológica das rickettsioses, caracterizando as áreas de transmissão dos diferentes agravos, investindo em vigilância epidemiológica e ambiental ativas. Estas são zoonoses relacionadas aos fatores fundamentais da expansão urbana, bem como ao aumento populacional de vetores e hospedeiros em contato com a população humana. Nas regiões do Vale do Paraíba paulista não há situação de endemia reconhecida, porém esta apresenta semelhanças ambientais e socioeconômicas com outras regiões ditas endêmicas, do Estado de São Paulo, não rara é a ocorrência de carrapatos das espécies descritas como vetores de doenças e ocorre importante intercâmbio de pessoas com objetivos de trabalho e lazer ao longo desta região, inclusive com freqüente fluxo internacional. Método: Avaliação do potencial de risco de transmissão de zoonoses por carrapatos em áreas selecionadas. Através de informações ambientais, prevalência de carrapatos transmissores de zoonoses e acessibilidade da população humana a áreas infestadas, criou-se uma escala para caracterização do risco. Resultados: Em 252 áreas das 6 microrregiões do Vale do Paraíba Paulista, no período de mai./2008 a mar./ 2009, foram encontrados 7.800 carrapatos adultos, além de ninfas e larvas, muitas das quais em criações familiares de coelhos e galinheiros. A classificação final apontou 42,5% das áreas inspecionadas em situação de risco iminente de transmissão de zoonoses por carrapatos. Outros 33% correspondeu ao risco limitado ou moderado. Nos restantes 24% da área estudada a classificação foi risco potencial para transmissão rickettsioses. Recomendações: Às áreas sob risco iminente, de situação de risco de transmissão de zoonoses por carrapatos, recomenda-se que os serviços de saúde locais mantenham uma vigilância acarológica programada e orientações à população. Às áreas sob risco limitado ou moderado, recomenda-se a manutenção de rotina de vigilância acarológica e inclusão da vigilância ambiental, com envolvimento da população. Às áreas sob risco potencial para transmissão de zoonoses, recomenda-se imediata elaboração de estratégias controle para as espécies encontradas, envolvendo os setores de saúde e a população. O aprimoramento da articulação com os serviços regionais e profissionais veterinários é de fundamental importância. Além disso, a estruturação dos serviços de saúde da região, adequação da área física, recursos humanos e materiais, são indispensáveis. / Introduction: OMS recommended America, in the year of 2004, implement and to improve specific systems of epidemic surveillance of the rickettsiasis, characterizing the areas of transmission of the different offences and investing in active epidemic and environmental surveillance. Those zoonosis are related to the fundamental factors of the urban expansion, as well as to the population increase of vectors and hosts in contact with the human population. In the areas called Vale do Paraíba from State of São Paulo there is no situation of recognized endemy, however this presents environmental and socioeconomic similarities with other recognized endemic areas of the State of São Paulo, no rare it is the occurrence of ticks described as vectors of diseases and it happens important exchange of people with work and leisure purposes there, besides with frequent international flow. Method: Evaluation of potential risk of zoonosis transmission by ticks in selected categorized areas. Through environmental information, the prevalence of vector ticks and accessibility of the human population to infested areas, a scale for characterization of the risk was build. Results: In 252 areas of the 6 districts of the Vale do Paraíba, in the Estado de São Paulo, on period between may/2008 and march/ 2009, they were found 7.800 adult ticks, also nymphs and larvas, many of which in family nurturing of rabbits and hen houses. The final classification pointed 42,5% of the inspected areas corresponding to the situation of imminent risk of transmission of zoonosis by ticks. Other 33% correspond to limited risk in the scale. In the remaining 24% of the studied area the classification went potential risk for transmission of tick related rickettsiasis. Recommendations: For the imminent risk areas, it is recommended that the local health services maintain proper vector surveillance and educational programmes for its populations. For the limited risk areas, it is recommended the maintenance of a proper vector surveillance routine and also the inclusion of an environmental surveillance. For the areas under potential transmission risk of those illnesses, priority elaboration of vectors control strategies is strongly recommended with proper engagement of all local health services, as well as the population. The enhancement of the articulation with the regional services and professional veterinarians is fundamental. Besides, an adequate structuring for the local health services administration, with rational and efficient managing of material and human resources, is indispensable.

Neste trabalho, é apresentada a revisão taxonômica dos Pyrgotidae pertencentes à fauna do Novo Mundo, atualmente composta por 66 nomes válidos de espécies distribuídas em 15 gêneros. A revisão taxonômica resultou na descrição de dois novos gêneros e de duas novas espécies e na sinonímia de quatro gêneros e 18 espécies e uma espécie foi revalidada. De acordo com esses resultados a fauna de Pyrgotidae do Novo Mundo possui 51 espécies válidas dispostas em 12 gêneros. Análises filogenéticas foram processadas com o intuito de testar o monofiletismo dos gêneros e estabelecer o relacionamento entre suas espécies, além de testar o desempenho dos caracteres contínuos na filogenia de Pyrgotidae. Com este propósito foram levantados 54 caracteres morfológicos dos adultos, sendo 14 contínuos e 40 discretos. Os caracteres contínuos e discretos foram analisados separadamente e em evidência total. As análises em que se utilizaram apenas caracteres discretos e as que utilizaram os caracteres em evidência total, resultaram em topologias muito semelhantes entre si, divergindo apenas nas posições entre três terminais. Na topologia obtida em evidência total, o suporte dos ramos aumentou na maioria dos ramos o que demonstra que os caracteres contínuos são filogeneticamente informativos para serem utilizados em Pyrgotidae. / This work presents a taxonomic revision of New World Pyrgotidae, currently composed of 66 valid species names distributed in 15 genera. The taxonomic revision resulted in the description of two new genera and two species, synonymy of four genera and 18 species and revalidation of 1 species. According to these results, the Pyrgotidae of the New World contains 51 valid species arranged in 12 genera. Phylogenetic analyses were conducted to test the monophyly of the genera, establish the relationships among their species, and test the performance of continuous characters in the phylogeny of Pyrgotidae. Fifty-four morphological characters of adults were coded and divided as: 14 continuous and 40 discrete. Continuous and discrete characters were analyzed separately and under total evidence. The analyses using only discrete characters and in total evidence each resulted in one tree, which were very similar, diverging only in the positions of three terminals. In the tree obtained using total evidence, the branch support increased in more branches, which demonstrates that continuous characters are phylogenetically informative for use in analyses of the Pyrgotidae.

Ips typographus est le principal ravageur de l'épicéa en Europe, s’attaquant en masse aux arbres vivants en période d’épidémie, par le biais d’une communication chimique. Comme de nombreuses autres espèces de scolytes « agressives », le typographe se reproduit uniquement sur des arbres affaiblis ou des chablis en périodes d’endémie, quand les densités de population ne sont pas suffisantes pour surmonter les défenses des arbres vivants. Ces ressources sont en général présentées dans la littérature comme étant dispersées et imprédictibles dans le temps et l’espace. De plus, ces ressources affaiblies sont sans doute disponibles pour de nombreuses espèces compétitrices. Ces caractéristiques imposent des contraintes importantes sur la dynamique de population et l’écologie du typographe et principalement sur sa stratégie de prospection. Cela dit, cette espèce et ces questions sont très peu étudiées en période d’endémie.Durant ma thèse de doctorat, je me suis attelé à tout d’abord caractériser les facteurs déterminant la distribution spatio-temporelle des chablis, qui va influencer l’évolution des stratégies de dispersion. Cet aspect s’est prolongé par l’étude de la « durée de vie » des chablis, c’est-à-dire la période durant laquelle ils sont colonisables par les scolytes après déracinement. Cet aspect a été mis en parallèle avec les capacités de défenses de ces mêmes arbres et leurs effets sur la sélection de l’hôte et le succès des scolytes. Enfin, les données obtenues par ces études ont été intégrées à un modèle spatialement explicite visant à valider les hypothèses comportementales relatives à la prospection pour les ressources chez le typographe, à savoir une dispersion aléatoire à grande distance suivie d’un recrutement au niveau des ressources nouvellement trouvées.Les résultats obtenus au cours de cette thèse confirment l’importance de la prospection sociale et de l’agrégation dans la découverte et l’exploitation de ressources dispersées, dont la dégradation intrinsèque représente une faible contrainte temporelle. Ces comportements ont sans doute été développés chez des insectes saproxyliques en raison de l’avantage qu’ils apportent en termes de découverte de ressources. Dans un second temps, ces comportements auraient pu permettre l'attaque d‘arbres vivants, notamment en réponse à une pression de compétition inter-spécifique importante sur des ressources peu défendues. / Option Biologie des organismes du Doctorat en Sciences / info:eu-repo/semantics/nonPublished

Doctorat en sciences médicales / info:eu-repo/semantics/nonPublished

The Great Escarpment forms a semi-continuous mountain system 5 000 km long, stretching from Angola in the north-west, south through Namibia, and into western, southern and eastern South Africa, including Lesotho and Swaziland. It is composed of a wide variety of geological suites but is unified in representing the edge of the African plateau and the passive Gondwanan continental margin. The Great Escarpment falls into all major climatic zones on the subcontinent, is a repository of palaeo- and neo-endemics, hosts more than half of southern Africa‟s centres of plant endemism, and has a rich suite of endemic fauna. In addition, the Great Escarpment is believed to be both a refugium and corridor for biological diversity. Despite the biological richness of the Great Escarpment, research to date has been fragmented and many sections of the Great Escarpment have not been studied. The aim of this study is to contribute to research on the Great Escarpment by undertaking a detailed floristic study of the southern Great Escarpment (the Sneeuberg, Nuweveldberge and Roggeveldberge). Together these mountains comprise approximately 1 000 km (one fifth) of the Great Escarpment, and occupy a transition zone between the summer rainfall zone in the east and the winter rainfall zone in the west. They are also the sections of Great Escarpment most closely situated to the Cape Floristic Region (CFR) and would thus be involved in hypothesised migration routes for lineages that also occur further north through the Drakensberg Alpine Centre (DAC) to the East African mountain chain. Detailed fieldwork of the southern Great Escarpment was undertaken over a period of four years in all seasons. Approximately 8 000 specimens were collected. Particular emphasis was placed on areas that may represent refugia, i.e. the highest plateaux and peaks, mesic areas and cliff-lines. An overview of each mountain range, together with their endemic plant species and phytogeography, is provided. Approximately ten new species have been discovered during this study, two of which have been described to date. Numerous endemics only known from their types have also been rediscovered. The Sneeuberg is defined as a new centre of plant endemism on the Great Escarpment (endemism of 2.3%), and the role of the Boschberg and Groot-Bruintjieshoogde (part of the Sneeuberg) as a nexus for floristic migration routes is discussed. The Nuweveldberge is shown to have low endemism despite a floristic tally similar to the Sneeuberg, while the Roggeveldberge are confirmed to be the most endemic-rich section of the southern Great Escarpment. The field data collected was augmented by available data in taxonomic revisions, and floras for the Sneeuberg, Nuweveldberge and Roggeveldberge were compiled. In order to floristically compare the southern Great Escarpment with other sections of the Great Escarpment and the CFR, a database of some 12 000 taxa was created using available floristic data for the CFR, DAC and Great WinterbergAmatolas, together with the data collated for the Sneeuberg, Nuweveldberge and Roggeveldberge. These data were analysed using phenetic methods and Parsimony Analysis of Endemicity (PAE). The results indicate stronger linkages in the east, particularly between the Sneeuberg and Nuweveldberge, and between the Sneeuberg and the Great WinterbergAmatolas. The relationship of the Roggeveldberge with the rest of the southern Great Escarpment remains ambiguous. In order to refine notions of connectivity and migration routes, 19 well-sampled phylogenies were assessed for sister-taxon disjunctions to explore CFRGreat Escarpment connections. Palaeo-connectivity between the CFR and southern Great Escarpment is most strongly supported for the south-eastern (SE) connection, and less so for the north-western (NW) and Matjiesfontein connections. There is support for the current (or recent) use of these three connections from numerous species that occur on both sides of the connections. Results of these analyses indicate that the southern Great Escarpment is a palaeo-corridor, the functioning of which has been broken by the aridification of the Nuweveldberge since the Last Glacial Maximum (LGM). Floristic connectivity is strongest in the east, from the Nuweveldberge to the DAC, and is less so in the west between the Nuweveldberge and the Roggeveldberge a finding attributed to the transition from a reliable winter rainfall regime on the Roggeveldberge to an unpredictable moisture regime on the Nuweveldberge. The mountains of the southern Great Escarpment are thus a series of refugia from a previous moister, cooler climate and are a corridor between the eastern and western components of the Great Escarpment. The SE connection is the primary link between the CFR and the eastern Great Escarpment Afromontane region in southern Africa. The implications of this research are that accurate conservation assessments and Red Data listings for many of the previously poorly-known endemics can now be made, and appropriate conservation measures implemented. Climate change remains the primary threat to these endemics and montane taxa in general, while degradation of wetlands is the primary threat to the water catchment service provided by the southern Great Escarpment. Future detailed research on the Great WinterbergAmatolas and Stormberg and a comprehensive flora of the HantamRoggeveldberge will further enhance our understanding of the floristics of the southern Great Escarpment, and provide the necessary data for comprehensive GIS-based models of proposed climate change scenarios for local, regional and national conservation planning.