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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.
| Identifer | oai:union.ndltd.org:IBICT/oai:repositorio.ufrn.br:123456789/24678 |
| Date | 22 June 2017 |
| Creators | Fonseca, Marina Antongiovanni da |
| Contributors | 75617633791, Guadagnin, Dem?trio Luis, 44800347068, Costa, Gabriel Correa, 90773306153, Ganade, Gislene Maria da Silva, 10250312883, Tambosi, Leandro Reverberi, 29520145826, Metzeger, Jean Paul, Fonseca, Carlos Roberto Sorensen Dutra da |
| Publisher | PROGRAMA DE P?S-GRADUA??O EM ECOLOGIA, UFRN, Brasil |
| Source Sets | IBICT Brazilian ETDs |
| Language | Portuguese |
| Detected Language | Portuguese |
| Type | info:eu-repo/semantics/publishedVersion, info:eu-repo/semantics/doctoralThesis |
| Source | reponame:Repositório Institucional da UFRN, instname:Universidade Federal do Rio Grande do Norte, instacron:UFRN |
| Rights | info:eu-repo/semantics/openAccess |
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