Navegando por Palavras-chave "Ecologia De Paisagens"

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    Influência da matriz de pastagem na dispersão de espécies lenhosas de Cerrado
    (Universidade Federal de São Paulo (UNIFESP), 2020-03-26) Issii, Thais Martins [UNIFESP]; Vieira, Elisa Hardt Alves [UNIFESP]; Universidade Federal de São Paulo
    The landscape functional connectivity reduction can be caused by fragmentation processes, habitat loss, and anthropogenic activities of different types and intensities in the matrix. The pasture areas are examples of these anthropic influences that are responsible for the loss of most of the Cerrado in the São Paulo state, with the potential to modify the responses in the flora species dispersal. Given this problem, this dissertation aimed to understand the potential effects of the pasture matrix on the woody species dispersal in the Cerrado, with two approaches that aimed: i) to understand the correspondence relationships between landscape structural and functional connectivity measures in the conservation evaluation of Cerrado using Geographic Information System (GIS) environment; and ii) to identify dispersion distance threshold in the matrix, based on the quantification of the regenerating woody species establishment in loco and with an ex-situ propagation viability experiment in a controlled system. Three fragmented landscapes were selected in the Cerrado Domain with remnants of cerradão and the occurrence of seasonal Semideciduous Forest patches of the Atlantic Forest biome inserted in a pasture matrix. Landscapes mapping was carried out using ArcGIS® software. The GIS landscape analysis consisted of calculating structural and functional metrics in the Fragstats® and Conefor® programs. Surveys were carried out in stratified sample units to test the hypothesis that there is a decreasing habitat-matrix gradient for variables of composition (richness), structure (abundance, height, diameter, and volume) and diversity of woody flora. In the field, the soil was also collected for compaction quantification by measuring the soil total porosity, soil density, and carrying out a controlled experiment to evaluate the propagule's viability (germination and resprout). The results showed that all evaluated landscapes have low rates of coverage and functional connectivity (IIC) between habitats. The structural and functional metrics do not correspond and, sometimes, they had antagonistic interpretations. The application of functional connectivity metrics in conservation planning depends on the availability of species dispersal data, especially related to different land use and land coverages and the definition of representative species for a given area. The pasture matrix seems to reduce the flora functional connectivity, especially for zoochoric species. Although matrix condition influenced by Urochloa sp. and for trampling and foraging cattle does not avoid the plant establishment, it alters the plant community composition, prioritizing species that usually occur in Cerrado grasslands and with autochory dispersal. It was not possible to identify a habitatmatrix gradient for the study variables, which may have been masked by the greater soil compaction observed near the habitat’s edge and by the, possibly by the grass-leguminous mixture use. The dispersal by resprouting and by autochoric species germination from the pasture matrix seed bank fortified the potential of the Cercado’s woody flora for natural regeneration as a strategy for restoring the biome since it is accompanied by appropriate management actions.