205 resultados para Habitat Fragmentation
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Habitat loss and fragmentation of landscapes endanger the planet’s biodiversity. Strategies for identify priority areas for conservation and restoration of biodiversity rich areas becomes essential for the planning of the management of these landscape become successful. This study aims to propose a novel, transparent and replicable method for choosing priority areas for restoration, and includes the following steps: (a) identification of regional biodiversity hotspots for conservation; (b) identification of priority areas for restoration with the greatest potential to increase the connectivity of the fragments already existing; (c) estimate the potential richness of understory birds before and after restoration, analyzing the gain of species for the future scenario. In order to identify the corridors to be restored in a future scenario we considered the approach of multiple corridors, which aimed to connect the main fragments within the region through analysis of multi-paths. Already existing regression models were applied to estimate the richness of the landscape considering three models: a) species richness as a function of patch area of the fragment selected as hotspots; b) richness as a function of areas connected by structural corridors and c) connected area for species which are able to access nearby fragments within 20m. The gain of species for future scenario which consider the potential restoration of selected areas was estimated. Based on our results we observed that species that use corridors showed the highest increment of species richness of understory birds. As a result it had to restore corridors to model species with the ability to use forest corridors was the highest gain potential species richness of understory birds. The methods proposed method in this study appears provide new ways to ensures a better cost / benefit relationship for restoration projects by increasing the chances of better reach high levels of...
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Pós-graduação em Ciências Biológicas (Zoologia) - IBRC
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Cytogenetic analyses of triatomines are considered to be important taxonomic tools. Thus, we analyzed the pattern of constitutive heterochromatin in 7 species of triatomine with fragmentation of the sex chromosome X, focusing on the cytotaxonomy of these triatomines. The species analyzed included Triatoma vitticeps, Triatoma melanocephala, Triatoma tibiamaculata, Triatoma protracta, Meccus pallidipennis, Panstrongylus megistus, and Panstrongylus lignarius. The seminiferous tubules of the adult males were subjected to C-banding. P. megistus and P. lignarius showed differences in chromosome number and disposition of constitutive heterochromatin, as only P. lignarius showed C-blocks in autosomes. C-banding can differentiate these species, since one of the sex chromosome (X) is heterochromatic in T. vitticeps. T. protracta showed C-blocks in both ends of all autosomes, T. tibiamaculata showed terminal C-dots in some autosomal pairs and M. pallidipennis did not show constitutive heterochromatin in autosomes. Thus, we confirmed the heterochromatic pattern of 7 species of insects and emphasized the importance of cytogenetic techniques for C-banding for taxonomy studies of the triatomines, which are important vectors of Chagas disease.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Pós-graduação em Geografia - FCT
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Population genetics theory predicts loss in genetic variability because of drift and inbreeding in isolated plant populations; however, it has been argued that long-distance pollination and seed dispersal may be able to maintain gene flow, even in highly fragmented landscapes. We tested how historical effective population size, historical migration and contemporary landscape structure, such as forest cover, patch isolation and matrix resistance, affect genetic variability and differentiation of seedlings in a tropical palm (Euterpe edulis) in a human-modified rainforest. We sampled 16 sites within five landscapes in the Brazilian Atlantic forest and assessed genetic variability and differentiation using eight microsatellite loci. Using a model selection approach, none of the covariates explained the variation observed in inbreeding coefficients among populations. The variation in genetic diversity among sites was best explained by historical effective population size. Allelic richness was best explained by historical effective population size and matrix resistance, whereas genetic differentiation was explained by matrix resistance. Coalescence analysis revealed high historical migration between sites within landscapes and constant historical population sizes, showing that the genetic differentiation is most likely due to recent changes caused by habitat loss and fragmentation. Overall, recent landscape changes have a greater influence on among-population genetic variation than historical gene flow process. As immediate restoration actions in landscapes with low forest amount, the development of more permeable matrices to allow the movement of pollinators and seed dispersers may be an effective strategy to maintain microevolutionary processes.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)