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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
51

Les impacts de la dispersion historique sur la variabilité génétique à différentes échelles spatiales : connaître l'histoire pour mieux comprendre le présent

Cyr, Frédéric 08 1900 (has links)
No description available.
52

Influência da paisagem na estrutura e diversidade genética de uma espécie pioneira em fragmentos da Mata Atlântica / Influence of landscape on genetic structure and diversity of a pioneer species in Atlantic forest fragments

Gonçalves, Renata Fabrega [UNESP] 05 December 2017 (has links)
Submitted by RENATA FABREGA GONÇALVES null (re-ofs@hotmail.com) on 2018-04-19T12:12:21Z No. of bitstreams: 1 dissertacao_RenataFGoncalves.pdf: 3889454 bytes, checksum: f8a3b73bdac15a81960d45dfa7109f4d (MD5) / Rejected by Adriana Aparecida Puerta null (dripuerta@rc.unesp.br), reason: Prezada Renata, O documento "Influência da paisagem na estrutura e diversidade genética de uma espécie pioneira em fragmentos da Mata Atlântica" enviado para a coleção Instituto de Biociências Rio Claro foi recusado pelo(s) seguinte(s) motivo(s): - Capa: falta ao final da capa o nome da cidade e ano - Rio Claro e Abril 2018, conforme consta na Página de rosto. - Falta a folha de aprovação, que deve ser solicitada à Seção de Pós-Graduação e deve ser inserida após a ficha catalográfica. Elemento obrigatório. O documento enviado não foi excluído. Para revisá-lo e realizar uma nova tentativa de envio, acesse: https://repositorio.unesp.br/mydspace Em caso de dúvidas entre em contato pelo email repositoriounesp@reitoria.unesp.br. Agradecemos a compreensão e aguardamos o envio do novo arquivo. Atenciosamente, Biblioteca Campus Rio Claro Repositório Institucional UNESP https://repositorio.unesp.br on 2018-04-19T19:20:28Z (GMT) / Submitted by RENATA FABREGA GONÇALVES null (re-ofs@hotmail.com) on 2018-04-20T17:51:05Z No. of bitstreams: 1 dissertacao_RenataFGoncalves.pdf: 4060192 bytes, checksum: 24e6f0e6e47096c10a1f84f3a3206c5d (MD5) / Approved for entry into archive by Adriana Aparecida Puerta null (dripuerta@rc.unesp.br) on 2018-04-23T12:54:42Z (GMT) No. of bitstreams: 1 gonçalves_rf_me_rcla.pdf: 2991756 bytes, checksum: c544ce14a67ac400bd3b97498a9e3108 (MD5) / Made available in DSpace on 2018-04-23T12:54:42Z (GMT). No. of bitstreams: 1 gonçalves_rf_me_rcla.pdf: 2991756 bytes, checksum: c544ce14a67ac400bd3b97498a9e3108 (MD5) Previous issue date: 2017-12-05 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Florestas secundárias são produtos da degradação de vegetação primária e subsequente regeneração natural e se destacam como um componente florestal dominante em paisagens tropicais, contribuindo para o restabelecimento das funções ecológicas e com o fornecimento de serviços ecossistêmicos. Porém, a capacidade de restauração depende primariamente da chegada e estabelecimento de plantas pioneiras, enquanto a manutenção das populações florestais depende de condições ambientais propícias, como a ocorrência de dispersão de sementes e fluxo gênico entre os fragmentos florestais e regenerantes. Com o intuito de avaliar como espécies vegetais pioneiras abundantes respondem à composição da paisagem o presente estudo analisou a variação espacial genética de Cecropia hololeuca Miq. (Urticaceae) ao longo de uma região heterogênea e com diferentes graus de fragmentação. O estudo foi realizado em 18 paisagens ao longo de um gradiente de cobertura florestal de 21% a 90% dentro da região do Corredor Cantareira-Mantiqueira. A partir de oito marcadores microssatélites, foi possível identificar três grandes agrupamentos genéticos, indicando fraca estruturação genética de C. hololeuca ao longo da região estudada. Os atributos da paisagem que mais contribuíram à diferenciação genética entre os grupos de indivíduos (populações espaciais) foram distância geográfica, proporção de área urbana e presença de rodovias e, também contribuindo de forma positiva, mas em menor intensidade, o eucalipto. Embora a cobertura florestal tenha diminuído a diferenciação genética entre as manchas, contribuindo na conectividade entre elas, esta contribuição foi a mais fraca dentre as variáveis testadas nos modelos. Desta forma, é importante considerar estruturas relacionadas à urbanização ao se tratar de conectividade funcional, já que o fluxo gênico parece estar respondendo de forma negativa aos impactos antrópicos recentes. Ainda assim, a utilização de C. hololeuca em programas de restauração ecológica para esta região apresenta grande potencial de sucesso, desde o seu estabelecimento em áreas abandonadas, devido às sementes que podem ser dispersas a longas distâncias, até contribuindo com condições favoráveis para o desenvolvimento da sucessão ecológica. / Secondary forests are products of primary vegetation degradation and subsequent natural regeneration and stand out as a dominant forest component in tropical landscapes, contributing to the restoration of ecological functions and the provision of ecosystem services. Restauration depends first on the arrival and establishment of pioneer trees and second on favorable environmental conditions and maintenance of ecological processes such as pollen and seed dispersal from within and across forest patches. In order to evaluate how abundant pioneer species respond to the landscape composition, the present study analyzed the genetic spatial variation of Cecropia hololeuca Miq. (Urticaceae) along the heterogeneous region of the Cantareira-Mantiqueira Corridor, in Northeast São Paulo. The study was conducted in 18 landscapes, with forest cover varying from 21% to 90%. Using data on eight microsatellites markers we identified three genetic clusters, indicating weak genetic structure of C. hololeuca throughout the studied region. The landscape attributes that had the greatest contribution to genetic differentiation between groups of individuals (spatial populations) were geographic distance, proportion of urban area and presence of highways and, with a positive but with weaker effect, proportion of eucalyptus plantations. Contrary to our expectations, forest cover was considered less important to both genetic diversity and genetic differentiation between spatial populations. Recent anthropogenic land uses, such as urbanization, seem to affect more strongly the functional connectivity across the region. The utilization of C. hololeuca in ecological restauration programs holds great success potential. Pollen and seeds can travel long distances and transpose a myriad of land uses and covers, therefore can contribute significantly to the natural regeneration in abandoned and degraded pastures creating favorable conditions to ecological succession.
53

Genômica de populações e genética geográfica de bovinos Pantaneiros e Curraleiro Pé-Duro com uso de polimorfismos de base única (SNP) / First report of population genomics in pantaneiro and Curraleiro Pé-Duro catle using single nucleotide polymorphisms (SNP) and a geographical genetics approach

Silva, Marcelo Corrêa da 21 September 2015 (has links)
Submitted by Luciana Ferreira (lucgeral@gmail.com) on 2016-04-18T10:48:49Z No. of bitstreams: 2 Tese - Marcelo Corrêa da Silva - 2015.pdf: 7209207 bytes, checksum: c24f13fb20a00a3bc5b7d242ee956d69 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2016-04-18T10:51:37Z (GMT) No. of bitstreams: 2 Tese - Marcelo Corrêa da Silva - 2015.pdf: 7209207 bytes, checksum: c24f13fb20a00a3bc5b7d242ee956d69 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Made available in DSpace on 2016-04-18T10:51:37Z (GMT). No. of bitstreams: 2 Tese - Marcelo Corrêa da Silva - 2015.pdf: 7209207 bytes, checksum: c24f13fb20a00a3bc5b7d242ee956d69 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Previous issue date: 2015-09-21 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Livestock production has played a major role in social-economic aspects of rural development worldwide. In South America the introduction of domestic breeds such as cows, sheep and goats occurred during Spanish and Portuguese colonization expeditions over five hundred years ago. The Pantaneiro and Curraleiro Pé-Duro cattle breeds originate from this exact context and resemble historic, cultural and ecological aspects of traditional cattle farming in Brazil. This is characterized by rough and extensive breeding systems placed in many ecosystems of this country. Small population sizes and severe loss of genetic diversity in livestock breeds are of great concern regarding the scenario of global warming, emphasis on the sustainability of farming activities, the need of alternatives to attend market trends and promote rural development in a local perspective. This study was undertaken to explore patterns of genetic diversity in Pantaneiro e Curraleiro Pé-Duro cattle, aiming to identify differences between groups reared in several regions of Central-West, Central, North and Northeast of Brazil. Animals were genotyped using a SNP (single nucleotide polymorphism) chip containing over fifty thousand markers. Different analytical procedures were carried out using differentiation index, estimates of common ancestry, simple and multivariate clustering, inbreeding coefficients, genetic and also geographical distances. Spatial analysis was developed to allow the identification of patterns of genetic variation, specific geographical regions and herds of greater genetic differentiation. The results furnish insights in order to develop strategies to preserve genetic variability in Pantaneiro and Curraleiro Pé-Duro cattle. / Os bovinos são tradicionalmente utilizados como fonte de proteína animal na alimentação humana em diversas regiões do mundo. Na América do Sul esta espécie foi introduzida por colonizadores espanhóis e portugueses e há mais de 500 anos tem sido disseminada no Brasil com importância alimentar e socioeconômica. Bovinos Pantaneiros e Curraleiro Pé-Duro são remanescentes de bovinos trazidos da região ibero-americana por meio de navios. Atualmente são considerados patrimônios históricos e culturais do país, com destaque à pecuária extensiva e tradicional que é praticada em diversos biomas do interior do Brasil, como o Pantanal, o Cerrado e a Caatinga. O baixo número de indivíduos existente, a demanda por uma produção animal mais competitiva e economicamente viável, com potencial de agregação de valor ou diferencial em termos de rusticidade, tem sido favoráveis para a discussão da conservação e maior utilização de raças localmente adaptadas. Isso tem tido maior destaque também em função do advento do aquecimento global e maior valorização de especificidades que caracterizam circunstâncias sociais, ecológicas e produtivas em escala local. Assim, este estudo foi desenvolvido a fim de explorar e compreender padrões de diversidade genética em populações de bovinos Pantaneiros e Curraleiro Pé-Duro, investigando-se diferenças e semelhanças genéticas entre indivíduos e rebanhos amostradas em diferentes biomas das regiões centro oeste, norte e nordeste do Brasil. Bovinos foram amostrados e genotipados com uso de um chip contendo mais de 50 mil marcadores polimórficos de base única (single nucleotide polymorphism, SNP). Diferentes técnicas de análise genética foram realizadas como o uso de distância genéticas, índices de diferenciação genética, estimativas de ancestralidade comum, endogamia e análises de dispersão e agrupamento uni e multivariados. Foram utilizados métodos de estatística espacial, que possibilitaram a identificação de padrões de variabilidade genética em função de distâncias geográficas e a identificação de descontinuidades genéticas, revelando uma compreensão inédita acerca da diferenciação entre grupos formados com base em um critério geopolítico ou com base em similaridade genética. Os resultados obtidos fornecem subsídios para a formação de grupos experimentais, a troca de material genético entre criadores, planejamentos participativos para a preservação e gestão sustentável desses bovinos junto às associações de criadores, entidades de pesquisa e demais atores envolvidos.
54

Distribuição da variabilidade genética e fluxo de pólen em subpopulações de Annona crassiflora Mart. (Annonaceae) / Distribution of genetic variability and pollen flow in subpopulations of Annona crassiflora Mart. (Annonaceae)

Almeida Júnior , Edivaldo Barbosa de 21 December 2015 (has links)
Submitted by Luciana Ferreira (lucgeral@gmail.com) on 2016-09-09T13:51:21Z No. of bitstreams: 2 Tese - Edivaldo Barbosa de Almeida Júnior - 2015.pdf: 11899635 bytes, checksum: 81eb843ad44f05464a9ded05612db917 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Approved for entry into archive by Luciana Ferreira (lucgeral@gmail.com) on 2016-09-09T13:51:52Z (GMT) No. of bitstreams: 2 Tese - Edivaldo Barbosa de Almeida Júnior - 2015.pdf: 11899635 bytes, checksum: 81eb843ad44f05464a9ded05612db917 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) / Made available in DSpace on 2016-09-09T13:51:52Z (GMT). No. of bitstreams: 2 Tese - Edivaldo Barbosa de Almeida Júnior - 2015.pdf: 11899635 bytes, checksum: 81eb843ad44f05464a9ded05612db917 (MD5) license_rdf: 0 bytes, checksum: d41d8cd98f00b204e9800998ecf8427e (MD5) Previous issue date: 2015-12-21 / The Annona crassiflora Mart. species (Annonaceae) is a fruit plant native from Cerrado, widely distributed throughout the biome. The goal here was evaluate the spatial distribution of genetic variability in natural subpopulations of the species, geographically, and relate the genetic diversity levels with climatic and landscape profile, furthermore the pollen dispersal within a subpopulation. We used here six pair of microsatellite primers. To evaluate thedistribution of genetic variability we sampled 25 natural subpopulations, 30.6 plants per subpopulation, on average. We estimate the genetic diversity (He), allelic richness (Ar), fixation index (f), genetic structure, using coancestry coefficient (θ) and inbreeding coefficient of overall population (F). The spatial pattern the genetic variability was evaluated by Mantel test, Moran's I index and linear regression of genetic parameter with two spatial dimensions (latitude and longitude). We correlate He, Ar and f with climate suitability and the percentage of Cerrado vegetation around subpopulations. Furthermore we evaluated the pollen dispersal by paternity analysis, using 572 plants, including 460 seeds, 20 mother plants and 92 pollen donors candidate, within a natural subpopulation. The outcrossing rates were also evaluated in maternal families using the mixed mating model. The outcrossing rates indicate mating system with prevalence of allogamy. The assignment of paternity indicated that gene flow mainly occurs in short distances, until 360 meters, in the subpopulation evaluated. The 25 subpopulations have moderate genetic diversity levels and strong genetic structure. We found inbreeding due to the subdivision, but not in mating within subpopulations. The demes belongs to two consistent groups with genetic discontinuity between the northwest and southeast subpopulations distribution. The genetic diversity and allelic richness showed strong relationship with longitude, suggesting a range expansion in the southeastern direction. We noted that spatial distribution of genetic diversity and allelic richness are related to suitability at the last glacial maximum, by an indirect effect of geographical distances, whereas no relationship was observed regarding present suitability. The percentage of cover natural vegetation, in turn not explain the spatial distribution of genetic diversity, allelic richness and inbreeding coefficient. / A espécie Annona crassiflora Mart. (Annonaceae) é uma planta frutífera nativa do Cerrado, amplamente distribuída ao longo do Bioma. O objetivo do trabalho foi avaliar a distribuição espacial da variabilidade genética em subpopulações naturais da espécie, em um contexto geográfico e relacionar os níveis de diversidade observados com variáveis climáticas e da paisagem, além da distância de dispersão de pólen em escala local, em uma subpopulação natural. No presente estudo foram empregados seis pares de iniciadores microssatélites. Para avaliar a distribuição da variabilidade genética foram amostradas 25 subpopulações naturais, em média 30,6 plantas por subpopulação. Foram estimados os níveis de diversidade genética (He), riqueza alélica (Ar), índice de fixação intrapopulacional (f), estrutura genética, por meio do coeficiente de coancestria (θ) e coeficiente de endogamia da população total (F). O padrão espacial da variabilidade genética foi avaliado por meio do Teste de Mantel, I de Moran e regressão linear dos parâmetros genéticos com as duas dimensões espaciais (latitude e longitude). As estimativas de He, Ar e f foram relacionadas com métricas de adequabilidade climática e com a porcentagem de remanescentes de vegetação do Cerrado. A dispersão de pólen foi avaliada por meio de análise de atribuição de paternidade usando 572 plantas, que incluem 460 semente, 20 plantas matrizes e 92 candidatos a doadores de pólen, em uma subpopulação natural da espécie. As taxas de fecundação cruzada também foram avaliadas, nas famílias maternas, usando o modelo misto de reprodução. As taxas de cruzamento indicam sistema reprodutivo com prevalência de alogamia. A atribuição de paternidade indicou que o fluxo gênico ocorre, prioritariamente, em curtas distâncias, em até 360 metros, na subpopulação avaliada. As 25 subpopulações apresentam níveis elevados de diversidade e forte estruturação genética. Há endogamia devido à subdivisão, mas não em relação ao sistema de cruzamento. Os demes formaram dois grupos consistentes, com descontinuidade genética entre as subpopulações do noroeste e sudeste da distribuição. A diversidade genética e a riqueza alélica mostraram forte relação com a longitude, sugerindo uma expansão da distribuição na direção sudeste. Foi observado que a distribuição espacial da diversidade genética e riqueza alélica estão relacionadas com a adequabilidade climática no último máximo glacial, por um efeito indireto do espaço geográfico, enquanto que nenhuma relação foi observada com a adequabilidade no presente. A porcentagem de remanescentes da vegetação natural, por sua vez não explicou a distribuição espacial da diversidade genética, riqueza alélica e coeficiente de endogamia.
55

Riverscape genetics in the endangered Mexican golden trout (Oncorhynchus chrysogaster) in Sierra Madre Occidental, Mexico / Génétique des paysages de rivière d'une espèce menacée : la truite dorée Mexicaine (Oncorhynchus chrysogaster) dans la sierra Madre Occidental, Mexico

Escalante Sanchez, Marco Alejandro 29 September 2017 (has links)
Les changements globaux provoquent une disparition accélérée des espèces endémiques. Il apparait crucial de quantifier les risques potentiels d’extinction en relation avec les changements climatiques liés à l’activité anthropique, et particulièrement pour les espèces dont l’aire de répartition est restreinte. Dans ce travail de thèse je me suis intéressé aux effets des changements globaux sur le complexe de la truite du Mexique qui vit dans le nord-ouest du Mexique. Ce complexe représente le groupe des salmonidés avec la distribution la plus méridionale au monde, avec seulement deux taxa décrits : la truite dorée mexicaine (Oncorhynchus chrysogaster) et la truite de San Pedro Mártir (O. mykiss nelsoni).En tant qu’espèce montagnarde d’altitude, ces salmonidés sont très vulnérables aux effets des changements globaux, et particulièrement au changement climatique et à l’introduction d’espèces exotiques pour l’aquaculture, comme la truite arc en ciel. Les objectifs généraux de cette thèse étaient de déterminer les relations entre les processus micro-évolutifs chez la truite mexicaine dorée, ainsi que la structure spatiale de leur habitat qui définissent les risques d’extinction engendrés par les changements globaux.Afin de répondre à ces questions, j’ai appliqué aux écosystèmes de rivières une approche de génétique du paysage intégrant différentes échelles spatiales à différents niveaux taxonomiques, ainsi j’ai appliqué des analyses de génétique des populations, des analyses de système d’information géographique et de modélisation de la distribution des espèces, ainsi que des simulations démo-génétiques.Initialement, les analyses de génétique des populations réalisées sur 11 loci microstallites nous ont permis de mettre en évidence une structure génétique spatialisée pour l’ensemble du complexe des truites mexicaines, ainsi qu’une introgression génétique chez la truite endémique. Ces résultats ont été confirmés par d’autres analyses utilisant un plus grand nombre de microsatellites et de marqueurs SNP. Une étude plus fine centrée sur O. chrysogaster et combinant simulations génétiques et distribution de l’espèce a permis de définir les caractéristiques des paysages de rivières comme les principaux déterminants de la structure génétique des populations natives, voire comme des barrières aux flux de gènes. Pour cette espèce, j’ai également généré une base de données de 9676 SNP grâce aux techniques de séquençage de nouvelles génération et mis en évidence une structure génétique cryptique chez O. chrysogaster. Une approche de génomique du paysage a révélé une influence significative des variables physiques des rivières sur la structuration génétique neutre et adaptative de la truite dorée mexicaine. / The combined effect of different threats has caused an accelerated loss of biodiversity in endemic species. Then, it is crucial to quantify potential extinction risks as consequence of global change related with human activities, especially in range restricted species. An example of that situation is represented by the native Mexican trout complex inhabiting the highlands of northwest Mexico and representing the group of salmonids with the southernmost distribution in the world, with the Mexican golden trout (Oncorhynchus chrysogaster) and the coastal nelson trout (O. mykiss nelsoni) as the only described species for this complex.However, as mountaintop species, these salmonids are highly vulnerable to global change effects, mainly by climate change and the introduction of the exotic rainbow trout for aquaculture purposes. The overall aim of this PhD project is to assess the possible relationships between microevolutionary processes of the Mexican golden trout, as well as the spatial structure of their habitat defining extinction risks derived by global change.To address those questions, a riverscape genetics approach was applied at different spatial scales and taxonomic levels including population genetics analyses based on neutral microsatellite markers and Next Generation Sequencing (NGS), G.I.S. (Geographic Information Systems; riverscape characterizations), species distribution modeling and demo-genetic simulations.Initially, population genetics analyses of 11 microsatellite loci revealed a spatial genetic structure for the entire Mexican trout complex as well as genetic introgression for native trout collected in aquaculture farm proximities, these results were corroborated by other using more microsatellite and SNPs markers. Moreover, focusing on O. chrysogaster, species distribution models and demogetic simulations defined riverscape as the main factor driving native population genetic structure, and as a boundary against exotic introgression. Additionally, 9,676 SNP’s were generated by NGS techniques defining a cryptic genetic structure for O. chrysogaster. Finally, landscape genomics approaches revealed a significant influence of riverscape factors on the neutral and adaptive genetic structure of the species.
56

Trame verte et papillons de jour en contexte agricole : influence du paysage sur la dispersion, la diversité génétique et la composition des communautés / Green veining and butterflies in farmland : landscape effects on dispersal, genetic diversity and composition of communities

Villemey, Anne 07 December 2015 (has links)
La mise en place Trame Verte et Bleue sur le territoire français a pour vocation de garantir la connectivité fonctionnelle entre habitats. C’est une des réponses politiques qui vise à enrayer le déclin actuel de la biodiversité, lie notamment à la destruction et à la dégradation des habitats. L’objectif de cette thèse est de quantifier l’effet de la connectivité, au regard d’autres facteurs environnementaux, sur la diversité des communautés et la diversité génétique des papillons de jour dans trois régions agricoles. Deux approches sont utilisées pour comprendre les processus qui sous-tendent ces patrons de diversité : i) l’étude de la communauté dans son ensemble et des groupes écologiques qui la compose, ii) l’étude de la résistance des milieux a la dispersion par génétique du paysage sur une espèce : le Myrtil (Maniola jurtina L.). Les résultats montrent que même si les caractéristiques locales jouent un rôle plus fort, la structure du paysage influence la composition des communautés. Ainsi, la quantité de terres arables réduit la richesse spécifique, la diversité génétique, et les flux de gènes chez le Myrtil. Les prairies hébergent des communautés diversifiées, incluant des espèces peu fréquentes. Les éléments linéaires enherbes supportent des communautés appauvries, mais favorisent la dispersion et la diversité génétique du Myrtil. La diversité des papillons est plus forte a proximité de boisements : les papillons pourraient bénéficier de ressources sur les lisières ; par ailleurs, les milieux boises semblent à la fois limiter les flux de gènes du Myrtil tout en accroissant sa diversité génétique. La complémentarité des milieux soulevée ici nous invite à repenser le modèle classique en ≪ sous-trames ≫ indépendantes de la Trame Verte et Bleue. Selon les enjeux de conservation, les espèces et les contextes paysagers, il est nécessaire de distinguer les situations ou, parmi un panel d’actions envisageables, améliorer la connectivité est une solution pertinente. / The implementation of the “Green and Blue Infrastructure” in France intends to ensure the functional connectivity of habitats (green veining). It is one of the nature conservation policies which aim to reduce the loss of biodiversity caused by the destruction and degradation of natural habitats. The objective of this work was to quantify the impact of connectivity, in comparison to other environmental factors, on the diversity of butterfly communities and their genetic diversity in three French agricultural regions. Two different approaches were applied to understand the underlying processes driving these diversity patterns: i) the study of the whole community and of the different ecological groups, ii) the study of landscape features resistances to butterfly dispersal using a landscape genetics approach on one species: the Meadow brown (Maniola jurtina L.). Our findings show that although local characteristics play a dominant role, landscape context does have an influence on community composition. Arable land cover decreases species diversity, and the Meadow brown genetic diversity and gene flow. Grasslands support more species rich communities, including non-frequent species. Grassy linear landscape elements host impoverished communities, but improve Meadow brown dispersal and enhance its genetic diversity. Species diversity is higher within grasslands in proximity to woody habitats: butterflies may benefit from resources on forest edges; moreover, woodlands seem to limit Meadow brown dispersal while increasing its genetic diversity. The habitat complementarity we evidenced here led us to question the classic model of ecological continuities as a collection of independent sub-networks, one for each type of habitat. According to conservation issues, species under interest and landscape contexts, we also need to identify situations where, among a broad panel of possible conservation actions, increasing connectivity is the most effective solution.
57

Advancing our understanding of animal dispersal and functional connectivity in human-altered landscapes: conceptual considerations and their empirical and simulation-based demonstration

Pflüger, Femke 17 December 2019 (has links)
No description available.
58

Quantifier la perméabilité des domaines skiables pour la Grenouille rousse (Rana temporaria) : une approche combinant suivi GPS et génétique du paysage / Quantifying the ecological permeability of ski resorts for the European common frog (Rana temporaria) : an approach involving GPS tracking and landscape genetics

Boncourt, Etienne 09 April 2019 (has links)
La dispersion des animaux est un processus clé pour le maintien des populations et métapopulations. En particulier, les amphibiens se déplacent beaucoup durant leur cycle de vie fait de migrations saisonnières. Ceci les rend sensibles à la structure du paysage. En effet, les modifications anthropiques comme l’aménagement d’infrastructures linéaires peuvent constituer des barrières écologiques pour les animaux et limiter le flux de gènes dans le paysage. Si les effets des routes et des lignes chemins de fer sur les déplacements des animaux ont été largement étudiés, les effets des infrastructures liées aux activités de sport d’hiver comme les pistes de ski et les remontées mécaniques sont moins bien connus. Ainsi, la perméabilité des milieux de montagne anthropisés est peu connue. Cette thèse vise à quantifier la perméabilité écologique (ou connectivité fonctionnelle), des domaines skiables pour un amphibien de montagne largement répandu : la Grenouille rousse (Rana temporaria Linnaeus 1758). Pour ce faire, nous combinons un suivi individuel de déplacements et une étude de génétique du paysage pour mieux comprendre les facteurs influençant les déplacements de grenouilles et les flux de gènes dans le paysage. Le suivi individuel est réalisé au moyen de balises GPS et d’analyses de sélection de pas (step selection analysis). L’étude de génétique du paysage est réalisée en prélevant des échantillons d’ADN dans trois domaines skiables de Savoie ainsi que dans une zone témoin située dans le Parc national de la Vanoise. Nous avons testé l’influence de plusieurs variables paysagères liées à la topographie (pente, altitude…), les habitats (réseau de zones humides, couverture du sol…) ou les activités humaines (présence de routes, de pistes de ski) sur le flux de gènes. En utilisant une nouvelle méthode d’optimisation de surface de résistance, nous montrons l’importance du réseau de zones humides pour les amphibiens de montagne. D’une part, elles servent d’habitat préférentiel et d’autre part, un réseau dense de zones humides permet d’assurer une bonne connectivité des paysages pour la Grenouille rousse. Nous mettons également en évidence que l’hétérogénéité des tailles efficaces de populations dans un paysage peut fausser les distances génétiques mesurées entre populations et nous recommandons l’utilisation de techniques pour s’affranchir de tels problèmes. Nos travaux sont importants dans une perspective de gestion durable des domaines skiables, l’aménagement de pistes de ski ou autres infrastructures de loisir pouvant être accompagnée de destructions de zones humides. / Animal disperal is a key process for maintaining populations and metapopulations. In particular, amphibians move a lot during their life cycle made of seasonal migrations. This makes them sensitive to the structure of the landscape. Indeed, anthropogenic changes such as linear infrastructure can act as ecological barriers for animals and limit gene flow within the landscape. While the effects of roads and railways on animal movements have been widely studied, the effects of infrastructure related to winter sports activities such as ski slopes and lifts are less well known. Thus, the permeability of anthropized mountain environments is little known. This thesis aims to quantify the ecological permeability (or functional connectivity) of ski areas for a widely distributed mountain amphibian: the European common frog (Rana temporaria Linnaeus 1758). To do this, we combine individual movement tracking and landscape genetics studies to better understand the factors influencing frog movements and gene flow within the landscape. Individual tracking is carried out by means of GPS tags and step selection analysis. The landscape genetics study is carried out by gathering DNA samples from three ski areas in Savoie and a control area located in the Vanoise National Park. We tested the influence of several landscape variables related to topography (slope, altitude...), habitats (wetland network, land cover...) or human activities (presence of roads, ski slopes) on gene flow. By using a new method of resistance surface optimization, we show the importance of the wetland network for mountain amphibians. On the one hand, they serve as preferential habitat and, on the other hand, a dense network of wetlands ensures good landscape connectivity for the Common frog. We also highlight that the heterogeneity in effective population sizes in a landscape can distort the genetic distances measured between populations and we recommend the use of techniques to overcome such problems. Our work is important for the sustainable management of ski areas, the development of ski slopes or other recreational infrastructure that can be accompanied by the destruction of wetlands.
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Histoire évolutive d’une espèce menacée : la tortue d’Hermann (Testudo hermanni hermanni), de la phylogénie à la génétique du paysage

Zenboudji-Beddek, Saliha 08 January 2016 (has links)
En plus des facteurs environnementaux et démographiques, les propriétés génétiques des populations sont devenues une préoccupation majeure pour préserver les populations en déclin de l'extinction. Afin d’acquérir des informations pertinentes pour la planification et la mise en œuvre des stratégies de conservation, les biologistes de la conservation ont réalisé le besoin d’avoir des connaissances en génétique des populations. Grace à l'acquisition de plus en plus rapide et de moins en moins chère d'une large gamme de marqueurs moléculaires, le recours a l’usage de l’outil moléculaire se répand de plus en plus. Ainsi, la génétique de la conservation se confirme comme une discipline à part entière qui est donc l’utilisation de la génétique dans la préservation des espèces comme entités dynamiques capables d'évoluer pour faire face aux changements environnementaux et afin de minimiser leur risque d'extinction. Par le biais de l’utilisation d’un large panel de marqueurs moléculaires (gènes mitochondriaux et nucléaires, microsatellites et SNPs), nous nous sommes intéresse à l’histoire évolutive à différentes échelles spatio-temporelles de la sous-espèce ouest méditerranéenne Testudo. hermanni hermanni (THH), qui présente une distribution insulaire et continentale très fragmentée. Le but de ce travail consiste à 1) comprendre les processus qui expliqueraient la distribution actuelle de la diversité génétique des populations et leur structure, 2) identifier l'origine des populations introduites (à Minorque et au Delta de l’Ebre), et 3) dater l’origine de la sous espèce THH. A l’échelle des populations, il s’agit d’identifier le nombre de groupes génétiques homogènes chez la tortue d’Hermann et le degré de différentiation génétique entre ces groupes afin de définir des unités de conservation évolutivement significatives (ESU) et des unités de gestion (MU). Enfin, nous nous sommes intéresses à l’étude des derniers noyaux de populations de THH dans le Var par des approches de génétique du paysage. Nos résultats ont révélé qu’une divergence par vicariance est à l’ origine de l’apparition de la sous-espèce T.h. hermanni. Ce scenario biogéographique s’expliquerait par les successions d’évènements glaciaires et interglaciaires qu’a connu le Pléistocène depuis plus de 2 MA provoquant un mouvement de retrait de l’espèce vers des zones refuges sur la frange côtière nord-méditerranéenne. Par ailleurs, le patron de différentiation mitochondriale Ile-continent observe et confirme par les microsatellites est très original par rapport à ce qui est connu chez d’autres espèces de reptiles partageant la même aire de distribution. Au vue de l’analyse phylogénétique confirmée par les microsatellites, on peut affirmer que la tortue d’Hermann n’est pas native sur Minorque et qu’elle a une double origine : la première, résultant d’une introduction à partir d’une seule source, probablement d’une population continentale génétiquement proche des Albères. La seconde d'origine insulaire, serait le résultat d’apports multiples, à partir de la Corse, de la Sardaigne ou de la Sicile. Enfin, l’isolement des populations de THH au sein de chaque région géographique reflète une structure génétique très forte. Par conséquent, six unités de gestion (MUs) sont proposées comme unités de conservation et de suivi sur le terrain. / In addition to environmental and demographic factors, the study of genetic properties of populations became inevitable issues in the conservation of declining populations. To acquire relevant information for conservation planning and implementing conservation strategies, conservationists have realized the need of population genetics tools. Moreover, this discipline has become more efficient with the development of a wide range of effective and relatively cheap methods for the characterization of a huge number of molecular markers. This led to define the conservation genetics as a separate discipline, which is the use of genetics in species preservation as dynamic entities evolving to cope with environmental changes and to minimize their extinction risk. Using a broad panel of molecular markers (mitochondrial and nuclear genes, microsatellites and SNPs), we interested in the evolutionary history at different spatial and temporal scales of the Mediterranean western subspecies Testudo hermanni hermanni (THH), which presents a very fragmented insular and continental distribution. The aim of this study is to 1) understand the processes that explain the current distribution of the structure and genetic diversity of populations, 2) identify the origin of introduced populations (Menorca and Ebro Delta) and 3) Dating the origin of the subspecies THH. At the population level, our study aimed to identify the number of homogeneous genetic groups of THH tortoise and the degree of genetic differentiation between these groups in order to identify evolutionarily significant units (ESU) and management units (MU). Finally, we were interested in the study of the last core populations of THH in the Var by landscape genetics approach. Our results revealed that a divergence by vicariance pattern explains the origin of the appearance of the subspecies THH. This biogeographic scenario is explained by the succession of glacial and interglacial events of the Pleistocene causing a withdrawal of the species toward refugia on the northern Mediterranean fringe. Moreover, the observed differentiation pattern (island vs continent) is very original compared to the reported diversity patterns of other reptiles sharing the same distribution range. According to our results, we may conclude that the Hermann’s tortoise is not native in Menorca and has a double origin: the first, is an introduction resulting from a unique source, probably from a continental lineage genetically close to Albera. The second, from an island origin, is the result of multiple contributions, from Corsica, Sardinia or Sicily. Lastly,the isolation of THH populations within each geographic region reflects a very strong genetic structure, therefor the six most relevant management units forconservation purposes are proposed on the basis that they represent a significant part of the evolutionary legacy of the species.
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Dispersion des graines de colza (Brassica napus L.) et origines des populations férales dans un agroécosystème / Dispersal of oilseed rape (Brassica napus L.) seeds and feral populations origins in an agroecosystem

Bailleul, Diane 02 April 2012 (has links)
Les agroécosystèmes sont des mosaïques d’espaces cultivés, d’espaces naturels et semi-naturels et d’infrastructures humaines fortement imbriqués et donc intrinsèquement liés et dépendants. Les espaces semi-naturels sont confinés généralement aux bordures de champs et aux bordures de route où se côtoient biodiversités végétales cultivées et sauvages. Cette thèse se concentre principalement sur la dispersion des graines de colza (Brassica napus L.) vers ces espaces qui peut conduire à la formation de populations de colza dites férales. A l’échelle d’un agroécosystème, l’étude de données génotypiques couplées à des méthodes d’assignations aux variétés commerciales existantes, a permis de mettre en évidence un lien entre la diversité variétale des champs de colza cultivés et la diversité variétale des populations férales de l’année suivante. De surcroît, l’étude de ces diversités variétales a montré que les champs ne sont pas des entités uniformes comportant des plantes d’une seule variété et que les populations férales accumulent les variétés au fil des années grâce aux apports annuels des champs récoltés, à la survie dans la banque de graines et à l’autorecrutement au sein des populations férales. La modélisation des flux efficaces de graines par une méthode de maximum de vraisemblance a permis d’identifier des dynamiques de dispersion locales au sein des agroécosystèmes. Suivant la zone considérée et les axes de circulation vers le silo de récolte, les sources locales de graines varient et les apports extérieurs de graines sont plus ou moins importants. Nos données nous ont permis d’estimer que les semis de la même année (n), les champs récoltés l’année antérieure ou même les années précédentes (jusqu’à n-2) pouvaient contribuer de manière significative à la présence de populations férales (l’année n). Les distances moyennes de dispersion estimées varient de la dizaine de mètres au kilomètre. Enfin, une expérimentation in-situ nous a permis de quantifier les pertes de graines pendant la récolte liées aux bennes de récolte. Nous avons évalué ces pertes à 400 graines par m2 et nous avons mis en évidence de rares évènements de pertes massives de graines. L’analyse statistique des résultats de ces pertes nous a permis de les mettre en relation avec des caractéristiques du paysage, notamment les surfaces des champs et les axes de circulations principaux et secondaires. Dans le contexte de mise en culture de plantes transgéniques, ces résultats impliquent de prendre en compte la complexité du paysage dans les modèles qui prédisent les flux de transgènes à l’échelle des agroécosystèmes. / Agroecosystems are mosaics of cultivated areas where natural and semi-natural areas and human infrastructures are strongly nested and intrinsically linked and dependent. Semi-natural areas are generally confined to field edges and roadsides where wild and cultivated plants biodiversity are combined. This thesis focuses mainly on seed dispersal of oilseed rape (Brassica napus L.) towards semi-natural areas which can lead to establishment of feral oilseed rape populations. At the agroecosystem scale, the study of genotypic data coupled with assignment methods to existing commercial cultivars has highlighted the link between diversity of cultivars of oilseed rape cultivated fields with diversity of cultivar of feral populations the following year. Furthermore, the study of cultivar diversity revealed that fields are not uniformly composed of plants of a unique cultivar and that feral populations accumulate different cultivars over years consecutive of annual seeds rain of harvested fields, survival in the seed bank and self-recruitment in feral populations. Modeling the effective seed flow with maximum likelihood method revealed local dispersal dynamics within the agroecosystem. Local and extern sources of seeds differ according the area studied and the traffic roads to the silo. Our data have shown that both sowing of the same year (n), the fields harvested the previous year or even in previous years (up to n-2) could significantly contribute to the presence of feral populations (year n). The average dispersal distances estimated range from ten meters to kilometers. Finally, an in-situ experiment enabled us to quantify seed losses during harvest related to grain trailers. We evaluated these losses to 400 seeds per m2 and we highlighted rare events of massive seed deposition. Statistical analysis of these losses enabled us to relate them with landscape elements, including the traffic roads and. In the context of GM crops cultivation in agroecosystems, these results emphasize the need to introduce the landscape complexity in models predicting the presence and persistence of GM OSR feral populations.

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