• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 1
  • 1
  • Tagged with
  • 2
  • 2
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 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.
1

Les coccinelles algériennes (Coleoptera, Coccinellidae) : analyse faunistique et structure des communautés / Algerian ladybirds (Coleoptera, Coccinellidae) : a faunistic analysis and community structure study

Saharaoui, Lounes 11 December 2017 (has links)
L'étude menée durant quatre années consécutives (2003-2007) a caractérisé écologiquement et faunistiquement le peuplement des coccinelles en Algérie. 48 espèces ont été répertoriées dont 46 sont des agents de lutte biologiques. Elles se répartissent dans huit sous-familles, 12 tribus et 23 genres. La richesse spécifique est très élevée dans les secteurs du nord d'Algérie. Cette zone est caractérisée par des bioclimats humide, sub-humide et semi aride regroupant 41 espèces. Elle est par contre très faible dans le secteur de l'Atlas saharien et le Sud algérien avec respectivement 12 et 16 espèces. L'étude des spécificités trophiques, spatiales et temporelles des principales espèces, nous a conduits à définir leurs niches écologiques dans les différents agro écosystèmes de l'Algérie. Ainsi, la distribution spatiale des espèces peut apparaître comme quelque chose de statique. Il s'agit en réalité d'un processus dynamique dont le moteur est la disponibilité d'habitat favorable qui abrite la proie préférentielle. La communauté de coccinelles fonctionne sur le principe de partage des ressources et les interactions entre espèces organisent la communauté en réseaux trophiques. L'analyse de la distribution des coccinelles à travers les différents secteurs géographiques montre que les espèces: C. septempunctata, H. variegata, S. punctillum et, H. argus présentent une forte valence écologique. En revanche, les espèces: P. ovoideus, P. numidicus, E. pubescent forme apicalis, H. marmottani, et Pullus sp semblent être spécifiques aux régions sahariennes et plus particulièrement au Sahara septentrional. / The study led during four consecutive years (on 2003-2007) shed light on the species composition, and habitat characteristics of the communities of ladybirds in Algeria. 48 species were listed among which 46 are biological control agents. They divide up in 8 sub-families, 12 tribes and 23 genera. The specific richness is very high in the sectors of the North of Algeria (41 species). This zone is characterized by bioclimates wet, sub-wet and semi-dry grouping. It is very low on the other hand in the sector of the Saharan Atlas and the Algerian South with respectively 12 and 16 species. The study of trophic interactions, spatial and temporal distribution of the main species, led us to define their ecological niches in the various agro-ecosystems of Algeria. So, the spatial distribution of the species can appear as something static. It is in reality a dynamic process the engine of which is the availability of favorable habitats that shelter ladybird preferential prey. Communities of ladybird works on the principle of division (sharing) of the resources and the interactions between species organize the community in trophic networks. The analysis of the distribution of ladybirds through the various geographical areas shows that the C. septempunctata, H. variegata, S. punctillum, and, H. argus present strong ecological valence. On the other hand, P. ovoideus, P. numidicus, E. pubescens forme apicalis, H. marmottani, and Pullus sp are specific to the Saharan regions and more particularly to northern Sahara.
2

Diversidade evolutiva de morcegos: padrões geográficos e aplicações em conservação / Evolutive diversity of bats: geographic patterns and conservation applications

Peixoto, Franciele Parreira 18 March 2013 (has links)
Submitted by Erika Demachki (erikademachki@gmail.com) on 2014-09-23T21:19:16Z No. of bitstreams: 2 Peixoto, Franciele Parreira-Dissertação-2013.pdf: 995120 bytes, checksum: 365969ffce47a58af2a011eb0370ed04 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Approved for entry into archive by Jaqueline Silva (jtas29@gmail.com) on 2014-09-23T21:58:54Z (GMT) No. of bitstreams: 2 Peixoto, Franciele Parreira-Dissertação-2013.pdf: 995120 bytes, checksum: 365969ffce47a58af2a011eb0370ed04 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) / Made available in DSpace on 2014-09-23T21:58:54Z (GMT). No. of bitstreams: 2 Peixoto, Franciele Parreira-Dissertação-2013.pdf: 995120 bytes, checksum: 365969ffce47a58af2a011eb0370ed04 (MD5) license_rdf: 23148 bytes, checksum: 9da0b6dfac957114c6a7714714b86306 (MD5) Previous issue date: 2013-03-18 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / Aim: To investigate global patterns of phylobetadiversity (PBD) in bats, with the purpose to better understand the mechanisms underlying current biodiversity patterns. We also aimed to use a metric that allows partitioning PBD into two components to distinguish the relative roles of local (e.g. lineage filtering) and regional processes (e.g. speciation) in shaping broad-scale patterns of PBD. Furthermore, we analyzed the distance-decay relationship of phylogenetic beta diversity to provide more information about factors that act in the PBD patterns. Location: global, delimited by biogeographic regions. Methods: Using the global distribution of bats and a supertree available for most species, we calculated PBD using the complement of phylosor index. We used a null model to test if two assemblages were more or less phylogenetically dissimilar than expected by chance. In addition, we decoupled PBD into turnover and nestednessresultant components, providing information about two factors that produce differences in assemblage phylogenetic composition. We also performed a Mantel analysis to analyze the distance-decay patterns of PBD and its two components. Results: The most striking difference in PBD was found between the Old and New World “phylogenetic composition”. We found the lowest values of PBD between adjacent regions (i.e., Neotropical/Neartic; Indo-Malay/Paleartic), revealing a strong geographical structure in PBD. These values were even lower when the turnover component was analyzed, demonstrating the differences in the role of regional processes in shaping regional diversity. On the other hand, we found out that for some adjacent regions (e.g., Afrotropical/Paleartic), the observed PBD was higher than expected by chance and comparatively different from expected by the distance decay relationship. This value remained high, even when we analyzed just the PBD turnover component. This demonstrates that although these regions are relatively close in space, there are other factors driving phylogenetic differences between them (e.g. an environmental barrier). Main conclusions: Our analyses revealed differences in the expected patterns of bat PBD among regions, suggesting that at broad scales, besides the effects of distance and geographic barriers, we also have to consider the importance of environmental gradients when studying the phylogenetic origin of bat assemblages. / A abordagem mais comum no uso de PD (diversidade filogenética) para conservação é selecionar locais com maior diversidade evolutiva. Essa estratégia parte do pressuposto de que locais com maior quantidade de PD indicam maior potencial para respostas evolutivas a mudanças ambientais futuras. No entanto, há um crescente debate sobre se as prioridades de conservação deveriam também ser voltadas para locais com baixo valor de PD, que podem representar centros de diversificação de espécies ou “berçários de diversidade”. Alguns trabalhos têm testado se os hotspots globais de biodiversidade, baseados em riqueza, também representam locais de desproporcional concentração de história evolutiva. Nós testamos aqui se os hotspots contêm mais, menos ou igual diversidade filogenética (PD) que o esperado por uma amostragem ao acaso de espécies em qualquer posição na filogenia, para a ordem Chiroptera. Buscamos responder qual a real contribuição de cada hotspot para a conservação de padrões e processos relacionados à diversidade filogenética. Nós utilizamos uma supertree disponível para a maioria das espécies da ordem, e dados de distribuição das espécies. Nós calculamos o PD para cada hotspot separadamente e utilizamos um modelo nulo para obter os valores esperados dado a riqueza. De 34 hotspots, apenas um apresentou maior PD do que o esperado, treze apresentaram valores menores e o restante valores iguais ao esperado. Nós demonstramos que a relação entre PD e riqueza varia entre regiões biogeográficas, de modo que não há como fazer generalizações acerca da contribuição dos hotspots para a conservação de diversidade evolutiva. De modo geral nossos resultados demonstram que devido ao fato da história evolutiva variar regionalmente, também devem ser estabelecidas as prioridades de conservação nessa escala.

Page generated in 0.0934 seconds