Muriquis e onde habitam: fatores que interferem na distribuição espacial de grupos sociais na Mata Atlântica fragmentada
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Data
2017-02-23
Autores
Centoducatte, Luana D'Avila
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Universidade Federal do Espírito Santo
Resumo
In a world of highly fragmented natural landscapes, it is convenient to identify different types of animal movement behavior and how they contribute to the understanding of dispersal processes and species distribution. Regional demand for agricultural products creates new patterns of land use and influences deforestation rates, changing the connectivity between habitats and therefore the degree to which animal populations are isolated or can maintain gene flow, and influencing the persistence of species in the landscape. In this context, this thesis addressed hypotheses about how habitat features affect the distribution and movement of the northern muriqui, an endemic, critically endangered primate, in an Atlantic Forest region, a hotspot of biodiversity. Using fieldcollected data, graph theory and individual-based spatially explicit models, we were able to analyze the muriqui’s population response to landscape variables, make inferences about the distribution of social groups, animal movement and population growth, and suggest conservation strategies that can be implemented in the region. We found that from 1970 to 2008, forest cover increased almost three-fold. The number of forest patches is diminished but the size increased, a reflection of the natural regeneration that connected some of the previously isolated patches. We found that patch size, connectivity and forest growth influence the distribution of muriquis, and their persistence in the landscape was probably ensured by forest regeneration and their ability to explore secondary forests. Empirical data showed that isolated forest patches produced a complete change of the typical behavior of muriquis, a primate with femalebiased dispersal pattern. At least five females stayed in their natal group and became sexually active and reproductive, while others left the group and became solitary. Forest patches functionally connected preserved that typical behavior, with dispersal of females from one group into another. Other than the expected female dispersal, we also recorded a fission of one group into two different social groups, in which the smallest one migrated to another fragment by crossing a road and an eucalyptus plantation. We developed the MPSG model (Muriqui Population Spread and Growth), which simulates movement behavior across the landscape by using population dynamics outputs as a trigger to regulate the events of migration. The simulation resulted in an average population increase of 2.4-fold in 50 years, with female migration playing an important role in that growth. More than 60% of females will probably have no success in finding a mating partner because their dispersal will lead to empty patches. We found that, for species with dispersal process such as the muriquis, connectivity may be as important as (or even more important than) habitat size. For conservation purposes, we proposed to improve the connectivity between patches, to establish a protected corridor of biodiversity, and the translocation of young females to other groups within the landscape. This study shows the importance of historical landscape analyses to understand potential population recovery of endangered species. Models that estimate the spatial behavior of populations in the landscape using spatial and population information can be a powerful tool to understand how past landscape features shaped present species distribution and to project the future persistence of this species.
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Palavras-chave
Habitat connectivity , Conectividade de habitat , Landscape heterogeneity , Heterogeneidade da paisagem , Forest regeneration , Regeneração florestal , Female-biased dispersal , Dispersão , Agent-based model , Modelos baseados no indivíduo , Brachyteles hypoxanthus
Citação
CENTODUCATTE, Luana D'Avila. Muriquis e onde habitam: fatores que interferem na distribuição espacial de grupos sociais na Mata Atlântica fragmentada. 2017. 73 f. Tese (Doutorado em Biologia Animal) - Universidade Federal do Espírito Santo, Centro de Ciências Humanas e Naturais, Vitória, 2017.