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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

?reas importantes para a conserva??o do ?ltimo grande herb?voro da caatinga potiguar: o veado-catingueiro (Mazama gouazoubira)

Mello, Daniel Bezerra de 23 June 2015 (has links)
Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2016-07-26T00:14:53Z No. of bitstreams: 1 DanielBezerraDeMello_DISSERT.pdf: 1169629 bytes, checksum: 58f09e2335bc84604b2c90327e81ff0a (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2016-08-05T23:14:19Z (GMT) No. of bitstreams: 1 DanielBezerraDeMello_DISSERT.pdf: 1169629 bytes, checksum: 58f09e2335bc84604b2c90327e81ff0a (MD5) / Made available in DSpace on 2016-08-05T23:14:19Z (GMT). No. of bitstreams: 1 DanielBezerraDeMello_DISSERT.pdf: 1169629 bytes, checksum: 58f09e2335bc84604b2c90327e81ff0a (MD5) Previous issue date: 2015-06-23 / Cerv?deo Mazama gouazoubira ? a esp?cie de veado que possui maior distribui??o dentre as esp?cies sul americanas. Aspectos da vegeta??o, preda??o, competi??o, ca?a e perda de habitat s?o fatores importantes para compreender a distribui??o espacial de herb?voros na paisagem. Dessa forma, considerando a falta de estudos de mam?feros de m?dio e grande porte na Caatinga, objetivamos compreender quais os fatores ambientais e antr?picos que influenciam a ocupa??o do veado-catingueiro (M. gouazoubira) na regi?o semi?rida do estado do Rio Grande do Norte, Brasil. O estudo foi realizado em 10 ?reas amostrais e utilizamos armadilhas fotogr?ficas para amostragem e modelos de ocupa??o foram constru?dos representando nossas hip?teses biol?gicas. Os modelos foram ranqueados atrav?s dos valores obtidos do AIC. As vari?veis cobertura vegetal de caatinga e densidade da vegeta??o mostraram maior efeito, j? a caatinga arb?rea mostrou um efeito menor, sugerindo que a esp?cie ? altamente dependente da vegeta??o para ocorrer, possuindo menor depend?ncia de caatinga arb?rea. Esperamos que nossos resultados possam ser utilizados como suporte para planos de manejo e cria??o de novas unidades de conserva??o no estado.
2

Fragmenta??o, conserva??o e restaura??o da caatinga

Fonseca, Marina Antongiovanni da 22 June 2017 (has links)
Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2018-01-24T12:36:44Z No. of bitstreams: 1 MarinaAntongiovanniDaFonseca_TESE.pdf: 4205215 bytes, checksum: df6f57417e4ce36d171d894870361a2d (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2018-01-29T11:36:33Z (GMT) No. of bitstreams: 1 MarinaAntongiovanniDaFonseca_TESE.pdf: 4205215 bytes, checksum: df6f57417e4ce36d171d894870361a2d (MD5) / Made available in DSpace on 2018-01-29T11:36:33Z (GMT). No. of bitstreams: 1 MarinaAntongiovanniDaFonseca_TESE.pdf: 4205215 bytes, checksum: df6f57417e4ce36d171d894870361a2d (MD5) Previous issue date: 2017-06-22 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / Informa??o confi?vel em larga ? essencial para tomadores de decis?o que lidam com conserva??o da biodiversidade, restaura??o de ecossistemas, manejos de recursos e pol?ticas ambientais. O bioma Caatinga, um ecossistema semi?rido espalhado por 826.000 km2 do territ?rio brasileiro, apesar de estar altamente fragmentado, ainda mant?m metade da sua cobertura vegetal original. Os remanescentes, no entanto, t?m sido perturbando h? s?culos por uma multiplicidade de amea?as antropog?nicas, incluindo sobrepastejo, extra??o madeireira, fogo e ca?a, entre outro. Apesar disto, a ?rea sobre prote??o est? abaixo do proposto por acordos internacionais e projetos de restaura??o t?m sido escassos. Baseado em m?ltiplas an?lises espacialmente explicitas, os quatro cap?tulos desta Tese tiveram como principais objetivos: (1) analisar quantitativamente a estrutura de fragmenta??o da Caatinga, (2) estimar o n?vel de perturba??o antr?pica cr?nica potencial dos fragmentos da Caatinga, (3) identificar as ?reas priorit?rias de restaura??o da Caatinga, baseado em conectividade da paisagem e na riqueza de esp?cies de plantas amea?adas e (4) comparar a perda de habitat e a taxa de desmatamento das ?reas Priorit?rias de Conserva??o da Caatinga, definidas pelo Minist?rio do Meio Ambiente (MMA), com as ?reas Priorit?rias dos outros biomas brasileiros. An?lises de Sistemas de Informa??o Geogr?fica, executadas sobre informa??es oficiais dispon?veis, evidenciam boas e m?s not?cias para o bioma. Apesar da fragmenta??o j? sofrida pelo bioma, o n?vel de conectividade funcional permanece relativamente alta entre fragmentos e metade da vegeta??o remanescente est? preservada em fragmentos grandes (? 50.000 ha), indicando a exist?ncia de preciosas oportunidades de conserva??o pr?-ativas. Em contraste, o n?vel de fragmenta??o ? intenso e 90% da vegeta??o remanescente ocorre em dist?ncias menores que 2,5 km da borda florestal, permitindo um f?cil acesso ao j? escasso habitat interior. Um ?ndice de Perturba??o Antr?pica Cr?nica (IPC), que sintetiza o efeito de perturba??o potencial de 14 vari?veis prim?rias, indicam que todos os fragmentos de Caatinga est?o sob algum n?vel de perturba??o. No entanto, uma importante heterogeneidade regional foi detectada, com fragmentos mais perturbados ocorrendo nas por??es norte, leste e central do bioma. Apesar do IPC m?dio dos fragmentos n?o estar correlacionado com a sua ?rea, o IPC declina n?o linearmente com a dist?ncia de borda mostrando ?reas relativamente est?veis ap?s 5 km. Simula??es de paisagens, testando a import?ncia de cada bacia hidrogr?fica para a conectividade da paisagem, permitiram a identifica??o de importantes ?reas para restaura??o. Cruzando este crit?rio com o n?mero de esp?cies de plantas amea?adas, foi poss?vel identificar um subconjunto de paisagens chaves para restaura??o que compreendem apenas 8% da ?rea desmatada do bioma. Estimando a taxa de desmatamento de todas as ?reas Priorit?rias para Conserva??o dos biomas terrestres brasileiros, foi poss?vel demonstrar que a Caatinga e o Cerrado exibiram as maiores taxas de perda de habitat, demonstrando novamente a vulnerabilidade do bioma. Espera-se que as informa??es aqui disponibilizadas possam ajudar tomadores de decis?o, nacionais e estaduais, a avan?ar pol?ticas para a conserva??o, restaura??o e manejo da biodiversidade. / Reliable landscape information at large spatial scale is essential for decision makers dealing with biodiversity conservation, ecosystem restoration, resource management, and environmental policy. The Caatiga biome, a semiarid ecosystem that spreads over 826,000 km2 of the Brazilian territory, despite being highly fragmented, still holds half of its original vegetation cover. The remnants, however, have been disturbed for centuries by a multitude of different anthropogenic threats, including overgrazing, logging, fire, hunting, among others. Despite that, the area under protection is below international agreements and restoration endeavors have been scarce. Based on a multitude of spatially explicit analyses, the four chapters of this Thesis had as main objectives: (1) to analyse quantitatively the fragmentation structure of the Caatinga biome, (2) to estimate the level of potencial cronic anthropogenic disturbance of the Caatinga fragments, (3) to identify the priority areas for restoration in the Caatinga biome, based on landscape connectivity and number of endangered plant species, and (4) to compare habitat loss and deforestation rates of Conservation Priority Areas of the Caatinga, defined by the Ministery of Environment (MMA), with those in other Brazilian biomes. Geographic Information System analyses, performed on officially available information, show both good and bad news for the biome. Despite the fragmentation already experienced by the biome, the level of functional connectivity remains relatively high among fragments and half the remaining vegetation is preserved in large fragments (? 50,000 ha), indicating the existence of precious pro-active conservation opportunities. In contrast, the fragmentation level is intense and 90% of the remaining vegetation occurs at distances lower than 2.5 km from the forest edge, allowing an easy access to the already scarce Caatinga core area. An Index of Chronic Anthropogenic Disturbance (IPC), which synthesizes the potential perturbation effect of 14 primary variables, indicates that all Caatinga fragments are under some degree of perturbation. However, important regional heterogeneity was detected with more disturbed fragments occurring in the Northern, Eastern, and Central regional of the biome. Although the mean IPC of the fragments is not correlated to its area, IPC drops non-linearly with edge distance, showing relatively stable core areas after 5 km. Landscape simulations, testing the importance of each watershed for landscape connectivity, allowed the identification of relevant areas for restoration. By crossing this criterion with the number of endangered plant species in each watershed, we were able to identify a subset of key watersheds for restoration that hold only 8% of the deforested area of the biome. By estimating the deforestation rate of all Priority Areas for Conservation of the Brazilian terrestrial biomes, it was possible to demonstrate that the Caatinga and the Cerrado biomes exhibited the higher rates of habitat loss, further demonstrating the vulnerability of the biome. Hopefully, the information here provided can help national and state decision makers to advance biodiversity policies for biodiversity conservation, restoration, and management.
3

Macroecologia e conserva??o de m?ltiplas dimens?es da biodiversidade

Oliveira, Brunno Freire Dantas de 26 July 2016 (has links)
Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2017-01-10T15:45:26Z No. of bitstreams: 1 BrunnoFreireDantasDeOliveira_TESE.pdf: 6640940 bytes, checksum: ad49d75685e2ea80ce1bd97392f6f888 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2017-01-11T16:14:37Z (GMT) No. of bitstreams: 1 BrunnoFreireDantasDeOliveira_TESE.pdf: 6640940 bytes, checksum: ad49d75685e2ea80ce1bd97392f6f888 (MD5) / Made available in DSpace on 2017-01-11T16:14:37Z (GMT). No. of bitstreams: 1 BrunnoFreireDantasDeOliveira_TESE.pdf: 6640940 bytes, checksum: ad49d75685e2ea80ce1bd97392f6f888 (MD5) Previous issue date: 2016-07-26 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / Determinar os mecanismos respons?veis pelos padr?es espaciais de biodiversidade t?m sido um dos maiores desafios para ec?logos e bioge?grafos. Durante a ?ltima d?cada houve um grande aumento no n?mero de estudos documentando padr?es de biodiversidade em larga escala. Atualmente, padr?es globais de riqueza de esp?cies s?o bem conhecidos para v?rios grupos de organismos. Entretanto, biodiversidade inclui v?rias dimens?es al?m da riqueza de esp?cies, como a diversidade filogen?tica e a diversidade funcional. Estas dimens?es s?o mais informativas do que simples medidas de riqueza de esp?cies e, consequentemente, podem permitir testes mais poderosos acerca de teorias de biodiversidade. Particularmente importante, conservar a biodiversidade em suas m?ltiplas dimens?es ? necess?rio para garantir a resili?ncia dos servi?os ecossist?micos e manter as hist?rias evolutivas das esp?cies. Neste contexto, a presente tese se configura na interface entre macroecologia e conserva??o, utilizando uma abordagem integradora que considera a conex?o entre mais de uma dimens?o da biodiversidade. No primeiro cap?tulo foram avaliadas hip?teses que invocam din?micas de equil?brio ou n?o-equil?brio para explicar a riqueza de esp?cies e diversidade funcional de mam?feros globalmente. Integrando informa??es sobre riqueza de esp?cies e diversidade funcional, eu abordo estas quest?es e clarifico os mecanismos que geraram e mant?m a diversidade de mam?feros e suas hist?rias de vida. O segundo cap?tulo representam uma base de dados sobre caracter?sticas biol?gicas de anf?bios globalmente: AmphiBIO. Esta base de dados centraliza informa??es sobre 19 caracter?sticas relacionadas ? ecologia, morfologia e reprodu??o de anf?bios. Os dados foram agregados a partir de mais de 1.500 fontes, e t?m potencial para auxiliar pesquisas mais amplas em ecologia de comunidades, evolu??o, biogeografia e conserva??o de anf?bios. No terceiro cap?tulo, utilizando o AmphiBIO, testo a suposi??o de que a perda de diversidade filogen?tica estaria associada ? perda de diversidade funcional. Para isso, a extin??o de anf?bios amea?ados foi simulada, as perdas de diversidade filogen?tica e funcional calculadas, e sua correla??o verificada. As perdas de diversidade foram analisadas atrav?s da filogenia dos anf?bios e do espa?o geogr?fico global. Esta tese contribui para um melhor entendimento dos mecanismos que originaram e mant?m os gradientes globais de riqueza de esp?cies, servindo de est?mulo para estudos futuros em ecologia e evolu??o, e para auxiliar decis?es pol?ticas visando a minimiza??o dos efeitos das extin??es sobre a perda de biodiversidade. / Determining the mechanisms underlying spatial variation in biodiversity has long been the main challenge for ecologists and biogeographers. The past decade has seen a veritable explosion of studies documenting broad-scale spatial patterns in biodiversity. Nowadays, broad-scale patterns of species richness (SR) are well documented for several groups. However, biodiversity encompass variation in several aspects beyond SR, such as phylogenetic diversity (PD) and functional (or trait) diversity (FD). These dimensions have been argued to aid more powerful tests of biodiversity theories because they can capture the diversity of life better than simple measures of SR. Particularly important, the conservation of biodiversity and its multiple dimensions have been advocated as necessary to ensure the resilience of ecosystem services and maintain important evolutionary history. The present thesis is set on the interface between macroecology and biodiversity conservation, and uses integrated approaches that consider the connection between more than one dimension of biodiversity. In the first chapter, I we evaluate four prominent hypotheses which invoke either equilibrium (more individuals, niche diversity) or non-equilibrium dynamics (diversification rate, evolutionary time) to explain species richness and functional diversity of mammals worldwide. While equilibrium and non-equilibrium hypotheses have received considerable attention in the literature and some empirical support, it remains unknown whether they can explain the diversity of species and their traits alike. By integrating information on species richness and functional diversity, I address these issues and shed light on the mechanisms that generated the diversity of mammals and their life histories. The second chapter represents a database on natural history traits for amphibians worldwide: AmphiBIO. This database centralizes information on 19 traits related to ecology, morphology and reproduction features of amphibians. Data were assembled from more than 1,500 sources, and has potential to support a more comprehensive research in evolution, community ecology, biogeography and conservation of amphibians. The third chapter uses information from AmphiBIO to test the assumption that loss of PD is associated with loss of FD. We simulated species extinction scenarios based on IUCN criteria, calculated the loss of PD and FD, and verified the correlation. Analyzes were carried out across the complete amphibian tree and across worldwide amphibian assemblages. This study highlights for the possible negative consequences of local amphibians extinctions that may impact the continuous provision of ecosystem services. This thesis adds to better understand the mechanisms on the origination of global gradients of species diversity. Finally, I hope this thesis can be used to stimulate future studies on ecology and evolution, and support political decisions on minimizing the effects of projected species extinctions on biodiversity loss.

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