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Relações entre aspectos do balanço hídrico e condições climáticas associadas à distribuição geográfica dos anuros brasileiros / Relations between water balance traits and climatic conditions associated to geographical distribution of brazilian anuransTiton Junior, Braz 04 September 2015 (has links)
Anfíbios anuros, de uma forma geral, são caracterizados por baixa resistência cutânea à perda de água por evaporação, altas taxas de reidratação a partir da pele e alta tolerância à desidratação. Entretanto, diferenças interespecíficas destes parâmetros do balanço hídrico podem estar associadas a características ambientais das áreas de ocorrência. No Brasil, encontramos biomas com características climáticas contrastantes e uma rica anurofauna, consistindo em um modelo interessante para o estudo da evolução do balanço hídrico em anuros. Através de uma abordagem comparativa, este estudo testou as hipóteses de que, quando comparadas às espécies de anuros que habitam ambientes mais mésicos, espécies de ambientes mais xéricos deveriam apresentar: (1) maior resistência à perda de água por evaporação, (2) maior taxa de reidratação, (3) menor sensibilidade do desempenho locomotor à desidratação e (4) maior sensibilidade do desempenho locomotor à temperaturas mais baixas e menor sensibilidade deste a temperaturas mais altas. As taxas de reidratação e a resistência da pele à perda de água por evaporação apresentaram relação alométrica respectivamente positiva e negativa com a massa corpórea, indicando a evolução de mecanismos compensatórios das modificações das relações entre área de superfície e volume corpóreo com a variação de tamanho. Anuros de ambientes caracterizados por maior restrição em disponibilidade hídrica e temperaturas mais altas apresentaram maiores taxas de reidratação, menor sensibilidade do desempenho locomotor a temperaturas mais altas e maior sensibilidade deste a temperaturas mais baixas, indicando padrões de adaptação fisiológica a características ambientais. A variação em sensibilidade do desempenho locomotor à desidratação apresentou padrões mais complexos de relação com variáveis ambientais, sendo esta relação dependente dos ambientes e grupos filogenéticos amostrados / Anuran amphibians, in general, are characterized by low skin resistance to evaporative water loss, high rates of hydration through the skin and high tolerance to dehydration. However, interspecific differences of these water balance traits can be related to environmental characteristics of the areas of occurrence. In Brazil, there are biomes with contrasting climatic conditions and rich anuran fauna, which constitute an interesting model for studies on water balance evolution in anurans. Through a comparative approach, this study tested the hypotheses that, when compared to anuran species that inhabit more mesic environments, species from xeric environments should show: (1) increased resistance to evaporative water loss, (2) higher rates of rehydration, (3) low sensitivity of locomotor performance to dehydration and (4) increased sensitivity of the locomotor performance at lower temperatures and lower sensitivity of it at higher temperatures. Rehydration rates and skin resistance to evaporative water loss showed, respectively, positive and negative allometric relations with body mass, indicating the evolution of compensatory mechanisms to changes in the relationship between surface area and volume with body size variation. Anurans from environments characterized by higher restriction in water availability and higher temperatures had higher rates of hydration, lower sensitivity of locomotor performance at higher temperatures and higher sensitivity of it at lower temperatures, indicating patterns of physiologic adaptation to environmental characteristics. The variation in sensitivity of the locomotor performance to dehydration showed more complex relation patterns with environmental variables. These relations were dependent on the environments and phylogenetic groups sampled
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Evolução do canto de anúncio nos gêneros Adenomera e Leptodactylus (Anura, Leptodactylidae, Leptodacylinae), com aplicação taxonômica a populações e espécies de Leptodactylinae / Evolution of advertisement call in the genera Adenomera and Leptodactylus (Anura, Leptodactylidae, Leptodacylinae), with taxonomic application to populations and species within LeptodactylinaeTavares, Thiago Ribeiro de Carvalho 27 April 2017 (has links)
As vocalizações em anuros são comumente conspícuas e, até certo ponto, estereotipadas. Nesse grupo, o principal sinal acústico emitido por machos (canto de anúncio) basicamente codifica dois tipos de informação: a atração de fêmeas coespecíficas e o anúncio da posição do macho em atividade de vocalização, especialmente relevante na orientação espacial e delimitação de sítios de vocalização em espécies territoriais. Mais modernamente, com o devenvolvimento de métodos computacionais para incorporar a informação filogenética disponível para um dado grupo de organismos, tornou-se factível explorar tendências evolutivas e testar hipóteses adaptivas para de maneira mais apropriada, levando em conta a dependência filogenética dos táxons. Leptodactylinae é um grupo de anuros Neotropicais rico em espécies (ca. 95 spp.), cuja distribuição está essencialmente compreendida na região Neotropical. Esse táxon apresenta uma diversidade notável de vocalizações. A diversidade de padrões acústicos em Leptodactylidae por si só ressalta o potencial desse táxon representar um bom modelo para estudos focados no entendimento dos padrões e processos macroevolutivos envolvidos na evolução acústica nesse grupo de vertebrados. Nesse estudo, foi realizada uma revisão detalhada dos sinais acústicos reprodutivos, i.e. canto de anúncio, pela primeira vez analisados para esse táxon através de procedimentos e configurações padronizadas e com quantificações automatizadas. Os resultados das análises acústicas foram então associados aos padrões morfológicos na investigação dos padrões de diversidade críptica e reavaliação taxonômica de algumas populações e espécies em Leptodactylinae, além da abordagem comparativa a partir dos resultados obtidos das análises acústicas a fim de explorar as principais tendências e processos evolutivos dos sinais acústicos nesse grupo de anuros. Os resultados revelaram que existem diferentes padrões de diferenciação fenotípica nesse táxon, apontando para a necessidade de revisões taxonômicas em diferentes clados de Leptodactylinae, com resultados contundentes para o clado L. melanonotus (a reavaliação de sinônimos juniores nesse clado indicaram que duas espécies devem ser revalidadas) e Adenomera (reconhecimento de diversidade críptica em A. hylaedactyla com base em evidência acústica). A exploração de métodos comparativos filogenéticos relevou tendências evolutivas interessantes, como, por exemplo, os surgimentos e desaparecimentos recorrentes de estruturas temporais (pulsos) e mudanças acentuadas na estrutura espectral dos sinais acústicos (deslocamento da frequência fundamental em algumas espécies de Adenomera), tais fenômenos sem relação aparente com tamanho corporal ou estrutura dos habitats ocupados por essas espécies. Os dados acústicos oriundos desse estudo se mostraram eficazes nas resoluções taxonômicas em várias espécies de Leptodactylinae. Estudos futuros focando em aspectos da morfologia do aparato vocal, e biomecânica de produção de som, podem informativos acerca do entendimento dos processos envolvidos em distintos padrões acústicos reconhecidos em Leptodactylinae / In anurans, vocalizations are usually conspicuous and stereotyped to some extent. In this group, the major acoustic signal broadcast by males (advertisement signal/call) basically encodes two kinds of information: the attraction of conspecific females and the advertisement of the position of a calling male, maintaining male spacing functioning as an auditory cue in the delimitation of calling sites in territorial species. More recently, the development of computational methods as a means of incorporation of phylogenetic information available for a given group of organisms allowed scientists to explore evolutionary trends and to test for adaptative hypotheses more properly, taking into consideration phylogenetic dependence among taxa. Leptodactylinae is a species-rich taxon (ca. 95 spp.), whose distribution encompasses the Neotropical region. This frog group exhibits a remarkable diversity of vocalizations. This pattern in Leptodactylinae draws attention to the fact that this group could be a promising model organism to studies focused on macroevolutionary patterns and processes involved in the acoustic evolution in this vertebrate group. In the present study, a comprehensive acoustic review was conducted, and it was the first time for this group that the analytical procedures and standardized settings were employed in an automated fashion for the quantification of acoustic traits. The results of the acoustic analysis was then associated with morphological patterns as a means to investigate the patterns of cryptic diversity and taxonomic reappraisals for some populations and species, as well as the application of comparative methods from the results obtained to explore the major evolutionary trends and processes of acoustic traits in this frog group. The results revealed that there are distinctive patterns of phenotypic differentiation present across Leptodactylinae clades, which indicate that taxonomic reassessments are required, particularly in the L. melanonotus clade (revaluation of the junior synonyms showed that two species should be relavalidated) and Adenomera (cryptic diversity was uncovered under the name A. hylaedactyla based on acoustic evidence). The phylogenetic comparative methods recovered interesting evolutionary trends as, for instance, the convergent appearances and losses of structures related to the time domain (pulses) and remarkable changes in the frequency domain (doubling of the fundamental frequency in some species of Adenomera), both phenomena being apparently unrelated to differences in body size or calling habitats. The acoustic data gathered here was efficient in species discrimination and should represent a good line of evidence to address species-level taxonomy in Leptodactylinae. Future research focused on aspects of the vocal apparatus and the mechanisms of sound production might tell us more about the evolutionary processes involved in the distinctive acoustic patterns that were recognized in Leptodactylinae
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Community structure of anurans along an altitudinal gradient: the role of topographic and climatic variables and their implications for conservation / Estrutura da comunidade de anuros ao longo do gradiente altitudinal: o papel das variáveis topográficas e climáticas e suas implicações para a conservaçãoMatavelli, Rodrigo Augusto 22 February 2019 (has links)
Montane ecosystems cover approximately 22 to 25% of land surface from sea level to more than 8,000 m a.s.l., harboring more than a third of the planet\'s biodiversity and includ half of global biodiversity hotspots. Among geographical gradients (latitudinal or altitudinal), the latitudinal species richness pattern is the most recognized and studied. Although not so intensively studied as latitudinal gradients, altitudinal gradients also provide great patterns of species richness distributions. Despite of the processes that driving the species richness patterns are still poorly understood, three main patterns have been reported along altitudinal gradients: 1) decreasing of species richness with increasing altitude, 2) increase in species richness with increased altitude, and 3) increasing species richness at intermediate altitudes (hump-shaped pattern), followed by a decreasing of species richness with increasing altitude. The hump-shaped pattern is considered the most common. A macroecological hypothesis that to explain species richness patterns along geographical gradients focusing in species range size is Rapoport\'s rule. This rule is a positive correlation between altitude and species range size distribution based on climate seasonality effects. Rapoport\'s rule prediz that species that can withstand broad climatic variability can become more widely distributed along geographical gradients. However, this hypothesis still has presented controversial results and this controversial results increased our interest in testing Rapoport\'s altitudinal rule in Atlantic Forest mountain ecosystems biome. However, patterns and process that drivres community assembly along altitudinal gradients have received little attention and remain controversial. Based on the anuran community strutucture variation (richness, composition and abundance) along altitudinal gradients, the present work aims to understand and disentangle the topographic and climatic effects on spatial patterns distribution and species altitudinal range size in the Atlantic Forest highlands, which will highlight how topographic and climate conditions acting in communities\' assembly along altitudinal gradients subside important rules to biodiversity conservation. / Os ecossistemas montanhosos cobrem aproximadamente 22 a 25% da superfície terrestre desde o nível do mar até mais de 8.000 m, abrigam mais de um terço da biodiversidade do planeta incluindo metade dos hotspots globais de biodiversidade. Entre os gradientes geográficos (latitudinais ou altitudinais), o padrão latitudinal de riqueza de espécies é o mais reconhecido e estudado. Embora não tão intensamente estudados como os gradientes latitudinais, os gradientes altitudinais também fornecem ótimos padrões de distribuição de riqueza de espécies. Apesar dos processos que impulsionam os padrões de riqueza de espécies ainda serem pouco compreendidos, três principais padrões tem sido relatados ao longo dos gradientes altitudinais: 1) decréscimo da riqueza de espécies com o aumento da altitude; 2) aumento da riqueza de espécies com o aumento da altitude and 3) aumento da riqueza de espécies em altitudes intermediárias (unimodal padrão), seguido por uma diminuição da riqueza de espécies com o aumento da altitude. O unimodal padrão é considerado o mais comum. Uma hipótese macroecológica que explica os padrões de riqueza de espécies ao longo de gradientes geográficos com foco no tamanho das faixas altitudinais das espécies é Rapoport regra. Esta prediz uma correlação positiva entre a altitude e a distribuição do tamanho das faixas altitudinais das espécies com base nos efeitos da sazonalidade climática. Rapoport regra prediz que as espécies que podem suportar um ampla variabilidade climática podem se tornar mais amplamente distribuídas ao longo dos gradientes geográficos. No entanto, essa hipótese ainda apresenta resultados controversos o que aumentaram nosso interesse em testar a Rapoport altitudinal regra em ecossistemas montanhosos na Mata Atlântica. Entretanto, os padrões e os processos que conduzem a montagem da comunidade ao longo dos gradientes altitudinais receberam pouca atenção e ainda permanecem controversos. Com base na variação da estrutura da comunidade de anuros (riqueza, composição e abundância) ao longo dos gradientes altitudinais, o presente estudo teve como objetivo compreender e desemaranhar os efeitos topográficos e climáticos nos padrões de distribuição espacial e tamanho das faixas altitudinais das espécies em ecossitemas montanhosos na Mata Atlântica, o qual realçará como as condições topográficas e climáticas atuam na montagem de comunidades ao longo de gradientes de altitude subsidiando importantes regras para a conservação da biodiversidade.
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Endokrin wirksame Stoffe (endocrine disruptors) und deren Wirkungen auf die Sexualdifferenzierung bei Amphib Xenopus laevisBögi, Christian 26 February 2003 (has links)
Die vorliegende Arbeit befasst sich mit der Erweiterung des etablierten Stu-dienmodells Xenopus laevis zur Untersuchung der Wirkung von endocrine disruptors auf die Reproduktionsbiologie von Amphibien. Um einen Einblick in die grundlegenden Mechanismen der sexuellen Differenzierung von Amphibien zu gewinnen, wurden die Konzentrationen bestimmt, mit denen androgene und estrogene Sexualsteroide während der larvalen Entwicklung in verschiedenen Stadien von Xenopus vorliegen. Parallel wurde das Auftreten der korrespondierenden Rezeptoren im Verlauf der Entwicklung untersucht, über welche die hormonelle Wirkung vermittelt wird. Auf der Basis der gewonnenen Erkenntnisse konnte eine neue Hypothese zur sexuellen Differenzierung von Amphibien entwickelt und vorgestellt werden. Sie stellt das Enzym 5alpha-Reduktase, das die Umwandlung von Testosteron in das potentere und nicht weiter aromatisierbare Androgen Dihydrotestosteron (DHT) bewerkstelligt, in den Mittelpunkt des Prozesses der Geschlechtsdifferenzierung. Abhängig von der genetisch bedingten Expression dieses Enzyms kommt es zu einem höheren oder niedrigeren Auftreten des DHT und damit zu Unterschieden im Verhältnis von DHT zu Estradiol (E2). Der Charakter dieses Verhältnisses scheint der entscheidende Auslöser für die Entwicklung eines weiblichen oder männlichen Phänotyps zu sein. In einem zweiten, anwendungsorientierten Teil wurde untersucht, in wie weit die bislang auf Laboruntersuchungen beschränkte Arbeit mit X. laevis auf Feldstudien erweiterbar ist und ob sich auf diese Weise gewonnene Daten auf die Situation heimischer Amphibien übertragen lassen. Parallele Expositionen des Krallenfrosches einerseits und des Grasfrosches (Rana temporaria) andererseits gegenüber realen Medien unter Freilandbedingungen bestätigten die hervorragende Eignung des Studienmodells X.laevis zur Beurteilung endokriner Belastungssituationen. Darüber hinaus konnte gezeigt werden, dass sich durch die Verwendung von Festphasenextrakten die endokrinen Wirkungen komplexer Matrizes unter standardisierten Laborbedingungen charakterisieren lassen. Rezeptorbindungsstudien sowie Untersuchungen zur Genexpression spezifischer Marker, histologische Betrachtungen von Gonadengewebe und die Bestimmung von Geschlechterverhältnissen ermöglichten Aussagen auf vielfältigen Nachweisebenen. Auf diese Weise konnte das Potenzial, mit dem Proben jeder Art, sowohl durch kurz- als auch durch langfristige Exposition, adverse Effekte auf das amphibische Hormonsystem hervorrufen können, umfassend und differenziert analysiert werden. / The presented work aims to contribute to the various opportunities of studying the effects of endocrine disruption on sexual differentiation in amphibians provided by the well established model Xenopus laevis. In order to gain insight into the basic mechanisms underlying the sexual differentiation in amphibians, the concentrations of androgen and estrogen sexual steroids during several stages of the larval development of Xenopus were determined. In parallel, the ocurrence of the corresponding receptors, which mediate the effects of the respective hormones, was observed. Based on the results of the studies described, a new hypothesis regarding sexual differentiation in amphibians is presented, which assignes the enzyme 5alpha-reductase as the central element of sexual development. This enzyme converts the androgen testosterone into dihydrotestosterone, which can not be aromatized into estradiol. Depending on the genetic sex of the indivual, genexpression of 5a-reductase may differ and therefore lead to a characteristic ratio of androgens and estrogens. We suggest, that this ratio might be the essential trigger for amphibians to develop into a male or a female. A second part aimed to enlarge the Xenopus model to the use in field studies and to proof the transferability of such data to the situation of endemic amphibians. Exposure in parallel of Xenopus on one hand and the green frog Rana temporaria on the other to the effluent of a bavarian wastewater treatment plant revealed the exceeding suitability of the model to asess the endocrine charge of the environment. Furthermore, the use of solid phase extracts derived from natural samples allowed the characterization of the respective endocrine potential under standardized laboratory conditions. Rezeptor binding studies, detection of genexpression of specific biomarkers, histological examination of gonadal tissue and the determination of sex ratios provided the evaluation of effects on several levels of investigation. By this means the Xenopus model offers the opportunity to assess the ability of any kind of sample to cause endocrine impacts on amphibians after short time as well as after long time exposure in a broad and at the same time differentiated way.
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Influência do efeito de borda sobre a anurofauna do parque estadual Carlos Botelho (SP) / Influence of edge effects in frogs of parque estadual Carlos Botelho (SP)Adriano, Leonardo Ramos 14 September 2012 (has links)
Este trabalho teve como objetivo determinar a extensão do efeito de borda e sua influência sobre a riqueza e a abundância de anfíbios anuros em uma Unidade de Conservação de Mata Atlântica do estado de São Paulo, o Parque Estadual Carlos Botelho. Foram utilizados 28 transectos com seis parcelas de 4×4m paralelas à borda e distantes desta 0, 25, 50, 100, 200 e 300 m, totalizando 168 amostras nos arredores da unidade de conservação. Toda a amostragem ocorreu durante a estação úmida, tendo sido capturados 160 indivíduos de 28 espécies, distribuídas em 10 famílias. Nas mesmas parcelas, foram medidas as seguintes variáveis ambientais: Temperatura do Ar, Umidade Relativa do Ar, Cobertura do Dossel e Profundidade da Serapilheira (média de 10 pontos). No programa Ecosim 7.0 foi feita a estimativa de riqueza de espécies obtida pelo processo de rarefação, indicando que o esforço amostral empregado no trabalho foi suficiente. A variação na composição das espécies em relação à distância da borda foi representada com gráficos por meio de uma análise de gradiente, sendo as espécies Leptodactylus marmoratus, Ischnocnema guentheri e Haddadus binotatus as mais abundantes e distribuídas ao longo de todo o gradiente estudado e espécies raras como Macrogenioglottus alipioi e Chiasmocleis leucosticta foram capturadas em parcelas distantes 100 m da borda, o que pode indicar uma tolerância fisiológica e ecológica destas espécies, servindo como boas indicadoras da qualidade do ambiente nas áreas de borda do PECB. Análises de regressão simples e múltipla foram feitas para identificar relações entre as variáveis ambientais e a riqueza de espécies, sendo que a variável Cobertura do Dossel explica em 20% a variação na Riqueza de Espécies e as outras variáveis ambientais não determinaram a variação na Riqueza de Espécies . Também foi feita uma Análise de Variância Fatorial comprovando que não existem diferenças na Riqueza de Espécies entre as categorias de distância da borda e os diferentes cultivos agrícolas nas bordas do PECB. Todas as análises estatísticas foram feitas no software Systat 12 (P≤0,05). / This study aimed to determine the extent of the edge effect and its influence on the richness and abundance of amphibians in a conservation of the Atlantic Forest in the state of São Paulo, the Carlos Botelho State Park. We used 28 transects with six plots of 4 × 4 m apart and parallel to the edge of this 0, 25, 50, 100, 200 and 300 m, totaling 168 samples in the vicinity of the protected area. All sampling occurred during the wet season, having captured 160 individuals of 28 species belonging to 10 families. In the same plot, we measured the following variables: Air Temperature, Relative Humidity, Canopy Coverage and Depth of the Litter (averaging 10 points). In Ecosim 7.0 program was made to estimate species richness obtained by thinning process, indicating that the sampling effort was sufficient employee at work. The variation in species composition in relation to the distance from the edge was represented with graphs using a gradient analysis, and species Leptodactylus marmoratus, Ischnocnema guentheri and Haddadus binotatus the most abundant, and distributed throughout the gradient and rare species studied as Macrogenioglottus alipioi and Chiasmocleis leucosticta were captured in plots 100 m distant from the edge, which may indicate a physiological and ecological tolerance of these species, serving as good indicators of environmental quality in the areas of PECB edge. Analyses of simple and multiple regression were conducted to identify relationships between environmental variables and species richness, and the variable canopy coverage explains 20% variation in species richness and other environmental variables not determined the variation in species richness . Also we made a Factorial Analysis of Variance proving that there are no differences in species richness between the categories of distance from the edge and different crops on the edges of PECB. All statistical analyzes were performed in Systat Software 12 (P≤0.05).
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Déficit de connaissances de la biodiversité et biologie de la conservation : le cas de l’herpétofaune d’Algérie / Biodiversity shortfalls and biodiversity conservation : the case of Algerian herpetofaunaBeddek, Menad 30 November 2017 (has links)
L’Algérie est un cas d’école en matière d’ignorance en biodiversité. A ce jour, on ne dispose d'aucun inventaire complet pour aucun taxon ni aucun atlas à l’échelle du pays ! Pourtant, l’Algérie est d’une grande importance pour la biodiversité mondiale. La façade littorale de l’Algérie fait partie du hostpot de biodiversité mondial qui est le pourtour méditerranéen et compte plusieurs points rouges de biodiversité régionaux. Par ailleurs, la partie saharienne contient une diversité d’organismes endémiques adaptés aux fortes conditions de sécheresse. Les autorités algériennes déploient un projet ambitieux pour la conservation en fixant 50 % de la surface du pays comme objectif pour les aires protégées ! Mais, l’emplacement de ces aires protégées et leur gestion n’obéit pas à des critères basés sur une bonne connaissance de la diversité, mais sont plutôt panifiés à dire d’expert. L’objectif général de cette thèse c’est l’étude de la distribution de l’ignorance en biodiversité en Algérie en se concentrant sur les « Linnean, Wallacean et Darwinian Shortfalls » et de contribuer à les réduire. J’ai consacré un chapitre qui a pour but de réduire le Linnean Shortfall en proposant 1) une première checklist des reptiles et amphibiens d’Algérie qui est le fruit d’un examen précis des publications scientifiques sur ces taxons en Afrique du Nord. 2) une première pré-évaluation des statuts de conservations des reptiles et amphibiens d’Algérie pour la production de la première liste rouge nationale. La deuxième partie de ce manuscrit traite la question de l’ignorance de la distribution géographique des espèces. Le but de cette partie est de cartographier l’ignorance qui est la différence entre la diversité la richesse spécifique attendue et la richesse spécifique observée. La richesse spécifique attendue a été modélisée avec deux approches : 1 l’utilisation des modèles de niches avec la méthode de maximum d’entropie (MaxEnt) pour prédire les habitats favorables pour chaque espèce puis additionner les différentes couches binaires de présence des espèces pour calculer la richesse spécifique. 2) l’addition des couches des aires d’occurrences des espèces construite par la méthode du minimum convex polygon pour produire la carte de distribution de la richesse spécifique. Les deux approches ont montré la même tendance à l’échelle nationale, c’est-à-dire la concentration des zones les plus riches sur le long de l’Atlas Saharien et des hauts plateaux qui sont la zone de transition entre le Sahara et la partie méditerranéenne de l’Algérie. L’opposition de la partie saharienne globalement pauvre en espèce et la moitié nord plus riche. En fin, les massifs sahariens du Hoggar et Tassili forment une zone très distincte avec une richesse nettement supérieure par rapport au reste du Sahara. Pour ce qui est des lacunes, dans la Partie nord, la Kabylie, le parc national d’El Kala et la région d’Oran sont assez bien prospectées. Dans le Sahara, seuls quelques points sont assez bien prospectés comme Biskra, Béchar et quelques zones du Hoggar et Tassili. En fin, la troisième partie porte sur la distribution des lignées génétiques dans le Maghreb. Les objectif de cette partie est localiser les zones de sutures entre les lignées génétiques divergentes des populations de l’est et de l’ouest du Maghreb et d’essayer de comprendre les mécanismes qui ont conduit à ce patron de diversité génétique. Pour répondre à ces questions, j’ai effectué une phylogéographie comparées sur 11 espèces de reptiles et amphibiens à distribution continue et large dans le Maghreb. Deux zones de sutures ont été identifiées : une zone à la frontière de l’Algérie et du Maroc, l’autre EN Kabylie à l’ouest de la vallée de la Soummam. Les divergences entre les clades est et les clades ouest ont eu lieu entre la période pré-messinienne jusqu’au à la limite plio-pleistocène et se seraient maintenues dans des refuges climatiques à l’est et à l’ouest du Maghreb. / Algeria is a case study of biodiversity ignorance. To date, there are neither complete inventories for any taxa nor atlas across the country! Yet, Algeria is of great importance for global biodiversity. The coastal area of Algeria is part of the global biodiversity hostpot which is the Mediterranean perimeter and has several regional red spots of biodiversity. Moreover, the Saharan part encompasses a diversity of endemic organisms adapted to the strong conditions of drought. The Algerian authorities are deploying an ambitious project for conservation aiming to reach 50% of the country's surface as protected areas! However, the location of these protected areas and their management don’t obey to a scientific evidence based, but are rather based on experts opinion. The main aim of this thesis is the study of the biodiversity ignorance distribution in Algeria by focusing on the "Linnean, Wallacean, and Darwinian Shortfalls" and to contribute to reduce them. The first chapter aims at reducing the Linnean Shortfall by proposing 1) a first checklist of reptiles and amphibians of Algeria which is the result of an accurate review of scientific publications on these taxa in North Africa. 2) a first pre-assessment of the conservation status of reptiles and amphibians of Algeria for the production of the first national red list. The second part of this manuscript deals with the ignorance of the geographical distribution of species. The purpose of this part is to map the ignorance which is defined as the difference between the expected specific richness diversity and the observed specific richness. The predicted species richness was modelled with two approaches: 1 ecological niche modeling with the maximum entropy method (MaxEnt) to predict the suitable habitats for each species and then add the different binary layers of species presence to calculate the specific richness. 2) Minimum convex polygon method was used to create range maps of each species and were auditioned to obtain predicted species richness. Both approaches have shown the same trend at a national scale: the concentration of the richest areas along the Saharan Atlas and the high plateaux which are the transition zone between the Sahara and the the Mediterranean part of Algeria. The opposition of the Saharan with a low species richness and the northern part with a higher species richness. Finally, the Saharan massifs of the Hoggar and Tassili form a very distinct zone with a much greater wealth compared to the rest of the Sahara. In terms of gaps, in the northern part, Kabylie, El Kala National Park and the Oran region are fairly well surveyed. In the Sahara, only a few points are clearly well prospected as Biskra, Bechar and some areas of the Hoggar and Tassili. The third part deals with the distribution of genetic llineages in the Maghreb. The aim of this section is to locate the phylogeographic breaks between the divergent eastern and western populations of the Maghreb and to try to understand the mechanisms that led to this pattern of genetic diversity. To answer these questions, I carried out a comparative phylogeography on 11 species of reptiles and amphibians with continuous and wide distribution in the Maghreb. Two suture zones have been identified: one zone on the border of Algeria and Morocco, the other in Kabylia west of the Soummam valley. The divergences between the eastern clades and the western clades occurred between the pre-Messinian periods up to the plio-pleistocene boundary and were maintained in climatic refugia in the east and west of the Maghreb.
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Estudo da comunidade de anfíbios e répteis em um fragmento de Mata Atlântica e em áreas perturbadas no Estado de São Paulo: subsídios para conservação e manejo de áreas protegidas / Amphibian and reptilian community study on an Atlantic Forest fragment and on disturbed areas at São Paulo State: contribution for conservation and management of protected areasCarmona, Renata Uesugui 29 June 2007 (has links)
A Mata Atlântica é reconhecida internacionalmente como um dos 25 hotspots do planeta englobando áreas com elevada biodiversidade de espécies, elevado endemismo e fortes pressões antrópicas, constituindo a segunda floresta mais ameaçada do planeta que abriga muitas espécies ameaçadas de extinção. Anfíbios e répteis são animais abundantes e funcionalmente importantes em muitos hábitats terrestres e aquáticos. Sua maior diversidade ocorre em florestas tropicais úmidas, onde o processo de fragmentação pode causar diversos efeitos negativos como a remoção e a redução de populações. O presente estudo foi desenvolvido no Residencial Reserva Ibirapitanga, município de Santa Isabel, Estado de São Paulo. Trata-se de um projeto urbanístico, onde o proprietário de cada lote se torna sócio e responsável pela RPPN (Reserva Particular do Patrimônio Natural) Rio dos Pilões. Este é um modelo inédito no Brasil, pois os lotes foram planejados apenas em áreas desmatadas no passado onde ocorrem atualmente pastagens abandonadas. O trabalho teve como objetivos levantar as espécies da herpetofauna que ocorrem em quatro diferentes ambientes do Residencial Reserva Ibirapitanga: Mata Secundária ou Capoeirão, Capoeira, Capoeirinha e Campo Antrópico, através de dois métodos distintos (Armadilhas de Interceptação e Queda e Procura Ativa), além de caracterizar esses ambientes quanto à composição e abundância da herpetofauna e de identificar as espécies endêmicas, raras e ameaçadas de extinção. Dessa forma, o presente estudo pôde contribuir para a elaboração do Plano de Manejo da RPPN Rio dos Pilões. Durante o período de Setembro de 2005 e Julho de 2006 foram registradas 25 espécies de anfíbios anuros e 3 de répteis. A utilização de dois métodos de amostragem teve relevante importância, pois algumas espécies foram encontradas somente através de um ou outro método. No entanto, a Procura Ativa foi considerada o método mais eficiente, já que amostrou 23 das 28 espécies encontradas. Já através das armadilhas de interceptação e queda foi possível determinar as abundâncias relativas de espécies encontradas por este método. Assim, a espécie mais abundante na Mata Secundária e na Capoeira foi Chaunus ornatus; em Capoeirinha, Physalaemus cuvieri e em Campo Antrópico, a maior abundância relativa foi de Leptodactylus cf. bokermanni. Hypsiboas cf polytaenius e Physalaemus cuvieri apresentaram distribuição espacial mais ampla, ocorrendo em todos os ambientes amostrados. Um maior número de espécies foi encontrado na Mata Secundária, ambiente menos perturbado que apresentou então, 23 espécies. A Capoeira apresentou 15 espécies, Capoeirinha, 6 e Campo Antrópico 4 espécies apenas. Foram realizadas comparações com taxocenoses de outras localidades, escolhidas de acordo com o método de coleta utilizado. Espécies como Aplastodiscus leucopygius, Proceratophrys boiei e Enyalius perditus, associadas a ambientes de mata, foram encontrados na área de estudo, enfatizando a importância da conservação deste remanescente florestal localizado na Serra da Mantiqueira. / Atlantic Forest is internationally recognized as one of the 25 hotspots on the planet which embodies high diversity and high endemism areas over strong anthropic influence, composing the second most threatened forest on the planet, representing an unique shelter for many endangered species. Amphibians and Reptiles are animals abundant and play an important role on many terrestrial and aquatic habitats. Its diversity occurs mainly within rain forests, where fragmentation processes may result on severe negative effects such as removal and population reduction. This study was developed at Ibirapitanga Residential Reserve, Santa Isabel municipal district, Sao Paulo State. The study deals about an urban project, where every plot owner becomes an associate responsible for the "Rio dos Pilões" RPPN (Particular Reserve of the Natural Patrimony) maintainance. This is a pioneer model in Brazil, since the residential plots were located within past devastaded areas, which are actually occupied by abandoned pastures. Herpetofauna species assesment was made at Ibirapitanga Residential Reserve within four different environments (Advanced Secondary Forest, Secondary Forest, Early Secondary Forest and Anthropic Field) using two distinct methods: pitfall traps and drift fences and active search. Environmental characterization was observed regarding herpetofauna species composition and abundance, besides the endemic, rare or threatened species occurrence. For this matter, this study contributes on the elaboration of the management plan for the "Rio dos Pilões" RPPN (Particular Reserve of the Natural Patrimony). From September 2005 to July 2006, 25 anuran amphibian species and 3 reptilian species were registered. The distinct sampling methods presented relevant differences, since some species were sampled exclusively by one or other method. However, active search was considered the best sampling method, since it sampled 23 out of the 28 studied species. Through pitfall traps and drift fences method it was possible to determine species relative abundance. The most abundant species found on Advanced Secondary Forest and Secondary Forest was Chaunus ornatus; on Early Secondary Forest it was Physalaemus cuvieri and on Anthropic Field the higher relative abundance was found for Leptodactylus cf. bokermanni. Species with enlarged distribution, occuring within every sampled environment, were represented by Hypsiboas cf. polytaenius and Physalaemus cuvieri. A higher number of species was found within Advanced Secondary Forest, which represent the less disturbed areas, with 23 different species. Secondary Forest presented 15 species, Early Secondary Forest 6 species and Anthropic Field only 4 species. Comparisons were made to assemblages from other localities, chosen accordingly to the sampling method applied. Species like Aplastodiscus leucopygius, Proceratophrys boiei and Enyalius perditus, commonly associated with forest environment, were found within the studied areas, pointing out the importance of this forest remnant conservation, located at Mantiqueira mountain range.
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Evolution des amphibiens et squamates de la transition Crétacé-Paléogène en Europe: les faunes du Maastrichtien du bassin de Hateg (Roumanie) et du Paléocène du Bassin de Mons (Belgique)Folie, Annelise 14 December 2006 (has links)
Les herpétofaunes du Maastrichtien du Bassin de Hateg (Roumanie) et du Paléocène Moyen du Bassin de Mons (Belgique) ont été analysées dans le but d’étudier l’influence de la crise Crétacé/Paléogène sur ces faunes en Europe et de contribuer à élucider leur origine biogéographique. Pour ce faire, nous disposions de 228, 56 et 19 spécimens provenant respectivement des gisements roumains de Pui-Islaz, Totesti-baraj et Nãlat-Vad ainsi que de 1054 spécimens provenant du puits de Hainin. Les herpétofaunes du Bassin de Hateg se composent d’au moins un allocaudate albanerpetontidé du genre Albanerpeton, de deux anoures discoglossidés, de deux lacertiliens paramacellodidés ainsi que du premier vrai téiidé identifié jusqu’au niveau spécifique en Europe et d’un serpent madtsoiidé. Les herpétofaunes du Bassin de Mons nous indiquent quant à elles que les caudates sont représentés par 3 nouvelles espèces de salamandridés, les anoures par un nouveau genre de discoglossidé ainsi que par une nouvelle espèce de palaeobatrachidé. La présence des lacertiliens est attestée par 2 nouveaux genres de scincoïdes ainsi que par 6 autres scincomorphes indéterminés, par un nouveau genre d’amphisbène et peut-être également par un anguidé apode. Les serpents sont quant à eux représentés par le plus ancien boidé d’Europe ainsi que par le plus ancien scolécophidien découvert jusqu’ici. Ces données paléontologiques ainsi que les données lithologiques des deux localités analysées, indiquent que le climat était tempéré chaud et humide avec des étendues d’eaux stagnantes. Ce travail permet également de conclure que la crise Crétacé/Paléogène n’a pas influencé les faunes européennes de manière dramatique.<p>Seuls les allocaudates albanerpetontidés, les lacertiliens polyglyphanodontinés et les serpents madtsoiidés disparaissent après la crise tandis que les caudates salamandridés et batrachosauroididés, les anoures discoglossidés et palaeobatrachidés, et les lacertiliens scincoïdes et amphisbènes, ne semblent pas avoir été affectés par cette crise en Europe. Par ailleurs, les herpétofaunes du Maastrichtien européen ont subi une influence nord-américaine suite à une migration ayant eu lieu durant le Crétacé Supérieur. Une vague de migration se serait également produite au Paléocène Supérieur, entre le MP1-5 et le MP6, et une autre au début de l’Eocène correspondant à celle déjà mise en évidence pour les mammifères. Cette dernière vague serait responsable de l’arrivée de nombreuses familles modernes de lacertiliens tels les agamidae, geckonidae, varanidés, helodermatidés et lacertidés. / Doctorat en Sciences / info:eu-repo/semantics/nonPublished
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Diversidade, biologia, filogeografia e taxonomia molecular de tripanossomas de anuros da família Leptodactylidae. / Diversity, biology, phylogeography and molecular taxonomy of trypanosomes of frogs in the Leptodactylidae Family.Sato, Lyslaine Hatsue 12 June 2015 (has links)
A fim de avaliar a diversidade genética, morfológica e filogeografia de tripanossomas de leptodactilídeos, analisamos diversos isolados encontrados em amostras de sangue e fígados obtidos no Brasil (Amazônia, Caatinga, Cerrado, Mata Atlântica e Pantanal), na Colômbia e na Venezuela. Inferências filogenéticas baseadas em marcadores moleculares (V7V8 SSUrDNA e gGAPDH) demonstraram uma complexa associação entre clados, biomas e hospedeiros vertebrados. Nossos resultados corroboram a monofilia dos trypanossomas de anuros e sugerem a existência de, ao menos, seis clados (An01-06) nesse grupo com 12 candidatos a novas espécies. O clado An01 compreende tripanossomas de leptodactilídeos e hilídeos de todos os biomas. Os clados An02, An05 e An06 são formados, predominantemente, por tripanossomas de leptodactlídeos de diferentes biomas brasileiros, da Colômbia e da Venezuela. O clado An03 é formado por tripanossomas de leptodactilídeos, bufonídeos e flebotomíneos, todos do bioma amazônico. O clado An04 agrupa apenas tripanossoma exóticos da América do Norte, África e Europa. / Aiming to investigate the genetic diversity, the morphology and the phylogeny of leptodactylid trypanosomes, we analyzed a number of trypanosomes from blood and liver samples from Brazil (Amazonia, Caatinga, Cerrado, Atlantic Forest and Pantanal), Colombia and Venezuela. Phylogenetic analyses based on molecular markers (V7V8 SSUrDNA and gGAPDH) demonstrated a complex association between clades, biomes and vertebrate hosts. Our results corroborated the monophyly of anuran trypanosomes and suggested the existence of, at least, six clades (An01-06) inside the anuran clade with 12 candidate new species. Clade An01 groups trypanosomes from leptodactylids and hylids collected in all biomes. Clades An02, An05 and An06 are composed, mostly, by leptodactylid trypanosomes from several Brazilian biomes, Colombia and Venezuela. Clade An03 aggregates parasites from leptodactylids, bufonids and phlebotomines from Amazonia. Clade An04 groups only exotic trypanosome species from North America, Africa and Europe.
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Evolutionary ecology of ultraviolet-B radiation stress tolerance in amphibiansPahkala, Maarit January 2001 (has links)
<p>During the last decades many amphibian species and populations have experienced declines and extinctions in different parts of the world. Anthropogenic activities are believed to account for these declines, and one of the hypothesized causes has been the increased level of ultraviolet-B (UV-B) radiation due to depletion of the stratospheric ozone layer. </p><p>Although negative effects of UV-B radiation on development of many amphibian species have been demonstrated, a number of potentially critical issues around assessment of amphibian UV-B radiation tolerance have remained unexplored. For instance, next to nothing is known about geographic variation in UV-B tolerance and about possible carry-over effects of early UV-B exposure to later life-stages. Likewise, synergistic effects with other stressors, as well as sublethal effects on growth have received little attention. </p><p>The results from field and laboratory experiments show that <i>R. temporaria</i> and <i>R. arvalis</i> are relatively tolerant to even high levels of UV-B in terms of embryonic survival. However, it was found that even normal levels of UV-B can reduce early embryonic growth. In addition, the effects of early exposure to UV-B became manifested mostly or only after a considerable time-lag (i.e. at metamorphosis). Furthermore, it was found that the sublethal effects of UV-B may become manifested only in combination with other stressors, such as low pH, and this synergism may differ among different populations. No evidence for genetic differentiation in UV-B tolerance was found.</p><p>These findings suggest that even a relatively tolerant species, such as <i>R. temporaria</i>, may be sensitive to increased levels of UV-B radiation, but that this sensitivity may be highly population, environment and trait dependent. The observed carry-over effects over life-stages emphasise the importance of the early life environment on later life fitness.</p>
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