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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.
1

Filogeografia, hotspots evolutivos e conserva??o ao longo da diagonal de forma??es abertas da Am?rica do Sul

Fonseca, Emanuel Masiero da 16 February 2017 (has links)
Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2017-06-02T22:29:36Z No. of bitstreams: 1 EmanuelMasieroDaFonseca_DISSERT.pdf: 3761177 bytes, checksum: 9cdc6a52b6e1ddc96b241581dd9f53d7 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2017-06-08T22:43:43Z (GMT) No. of bitstreams: 1 EmanuelMasieroDaFonseca_DISSERT.pdf: 3761177 bytes, checksum: 9cdc6a52b6e1ddc96b241581dd9f53d7 (MD5) / Made available in DSpace on 2017-06-08T22:43:43Z (GMT). No. of bitstreams: 1 EmanuelMasieroDaFonseca_DISSERT.pdf: 3761177 bytes, checksum: 9cdc6a52b6e1ddc96b241581dd9f53d7 (MD5) Previous issue date: 2017-02-16 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico (CNPq) / Desvendar os processos e mecanismos envolvidos na gera??o e manuten??o da biodiversidade, atrav?s do tempo e espa?o, ? uma das quest?es centrais da biogeografia. O acesso as informa??es gen?ticas das esp?cies, conjuntamente com o progresso conceitual, metodol?gico e computacional t?m revolucionado a compress?o dos processos evolutivos. Como resultado, a reconstru??o da hist?ria evolutiva das esp?cies e o teste de hip?teses de diversifica??o (e.g. ref?gios, barreiras f?sicas, tempo de diversifica??o) t?m sido poss?vel em um n?vel de refinamento que outrora era irrealiz?vel. A diagonal de forma??es abertas da Am?rica do Sul estende-se de nordeste a sudoeste do continente e engloba tr?s grandes biomas: Caatinga, Cerrado e Chaco. Historicamente considerados biomas pobres e sem uma identidade evolutiva, tais regi?es tem testemunhado uma mudan?a de paradigma devido ao aumento das pesquisas e, atualmente, s?o consideradas dom?nios com uma expressiva riqueza, endemismo e hist?rias evolutivas ?nicas. Entretanto, o modo e o tempo de diversifica??o da fauna ao longo dessa regi?o ainda s?o um tanto quanto elusivos e o debate continua aberto. Essa disserta??o est? dividida em dois cap?tulos. (i) O primeiro, atrav?s de uma abordagem filogeogr?fica, testou os efeitos de eventos hist?ricos na diversifica??o ao longo da diagonal de forma??es abertas, utilizando o lagarto Polychrus acutirostris como modelo de estudo. A fim de alcan?ar tal objetivo n?s inferimos a estrutura populacional, as rela??es filogen?ticas entre as linhagens, a diversidade intraespec?fica, os padr?es de migra??o, a demografia e a hist?ria de difus?o espa?o-temporal. Finalmente, n?s testamos 12 cen?rios de diversifica??o usando computa??o Bayesiana aproximada (ABC). N?s recuperamos tr?s linhagens espacialmente estruturadas distribu?das na Caatinga, nordeste do Cerrado e sudoeste do Cerrado. A diversifica??o dessas linhagens ocorreu no Neogeno e foi marcada por um complexo cen?rio envolvendo diverg?ncia simult?nea, precoces est?gios de difus?o, um padr?o de migra??o sim?trico entre as linhagens vizinhas, mudan?as do tamanho efetivo populacional e efeitos distintos de barreiras f?sicas e ambientais. (ii) O objetivo do segundo cap?tulo foi identificar ?reas na Caatinga onde a diversidade gen?tica est? espacialmente concentrada (Evolutionary Hotspots) e propor ?reas que devam ser protegidas a fim de que a hist?ria evolutiva dessas regi?es n?o seja apagada. Com esse prop?sito, n?s utilizamos dados mitocondriais dispon?veis de seis esp?cies animais amplamente distribu?das na Caatinga, compreendendo: tr?s esp?cies de lagartos, uma de anf?bio e uma de aranha. N?s geramos, atrav?s de um m?todo de interpola??o, uma superf?cie de diversidade para cada esp?cie. Finalmente, as superf?cies de diversidade gen?tica de todas as esp?cies foram somadas a fim de determinar ?reas com alta diversidade gen?tica. No geral, as por??es sul, central e noroeste da Caatinga foram as regi?es com maiores valores de diversidade gen?tica. Entretanto, tais ?reas encontram-se fracamente protegidas por meio de unidades de conserva??o, o que ? um padr?o geral para a Caatinga. Os resultados apresentados nesse estudo real?am a complexidade da hist?ria evolutiva dentro da diagonal de forma??es abertas. Al?m disso, identificamos regi?es geneticamente diversas na Caatinga que s?o, portanto, de extrema import?ncia para conserva??o. / One of the main goals of biogeography is to unveil the processes and mechanisms involved on the generation and maintenance of biodiversity over time and space. Accessing species? genetic information, coupled with conceptual, methodological, and computational advances have revolutionized the comprehension of evolutionary process. These advances have enabled reconstructing the evolutionary history of species and testing diversification hypotheses (e.g. refugee, physical barriers, diversification time) in a refinement level that once was unfeasible. The diagonal of open formations stretches from northeast to southwest South America, encompassing three biomes: Caatinga, Cerrado, and Chaco. Historically considered speciespoor biomes with no evolutionary identity, these regions have witnessed a change in paradigm due to increase of research and, currently, are recognized as holding high levels of richness, endemism, and unique evolutionary histories. However, tempo and mode of fauna diversification throughout this region are still poorly known and the debate remains largely open. This dissertation is composed of two chapters. (i) In the first one, we used a phylogeography approach to test the effects of historical events on the diversification throughout the diagonal of open formations using the lizard Polychrus acutirostris as study model. In order to reach this goal, we inferred population structure, phylogenetic relationships between lineages, intraspecific genetic diversity, migration patterns, demography and the spatio-temporal diffusion history. Finally, we tested 12 diversification scenarios using approximate Bayesian computation (ABC). We recovered three non-overlapping lineages that are spatially structured in the Caatinga, northeastern Cerrado, and southwestern Cerrado. Diversification among lineages took place during the Neogene and was associated to a complex scenario involving simultaneous divergence, early stages of diffusion, symmetrical pattern of migration between neighbor lineages, distinct effects of physical and environmental barriers. (ii) The second chapter aimed to identify areas in the Caatinga biome where the genetic diversity is spatially restricted (Evolutionary Hotspots) and propose areas that should be protected in order to maintain the evolutionary history of those areas. For this purpose, we used available mitochondrial data for six animal species widely distributed in the Caatinga, including: three lizard species, one amphibian and one spider. We used an interpolation method to generate a genetic diversity surface for each species. Finally, we overlapped the genetic diversity surfaces of all species to determine areas that concentrate high genetic diversity. In general, southern, central and northwestern portions of Caatinga harbor the highest values of genetic diversity, despite being poorly represented within protected areas. Our results highlight the complex evolutionary history within the diagonal of open formations. Besides, we identified genetically diverse areas within the Caatinga that are of utmost importance for biodiversity conservation.

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