Evolução temporal da cobertura vegetal do manguezal do Rio Tavares (Florianópolis - SC) empregando sensoriamento remoto e SIG

AUTOR(ES)
DATA DE PUBLICAÇÃO

2008

RESUMO

The Marine Extractive Reserve of Pirajubaé (REMP) is a pilot area located within the mosaic comprised of the coastal and marine units of Santa Catarina, and represents an ideal sample for the development of integrated actions in the biological, administrative and institutional fields. The aim of this study was to interpret the processes of colonization of the Rio Tavares Mangrove, as a support for environmental management decisions. The methodology used was based on a temporal analysis (1957 2007) of the Rio Tavares Mangrove, using remote sensing techniques, together with an adaptation of the process of Rapid Ecological Assessment (REA) of a land area or region, and GIS technology. A flexible, accelerated survey was carried out, focusing on the species of the mangrove found in the Pirajubaé Marine Extractive Reserve, using a combination of images from the remote sensing, aerial photographs, data collected from the field, and visualization of spatial information, to generate useful information based on photographic records of the study area, for use in conservation planning at various levels. The Rio Tavares mangrove is comprised of three species: Avicennia schaueriana, Rhizophora mangle and Laguncularia racemosa. It has a homogenous appearance in terms of vegetal cover, with a predominance of the species Avicennia schaueriana, as was observed in this study, when the vegetation index classifications (NDVI) were generated, supported by the field studies. The vegetal cover became more homogenous over the period studied. The processes of colonization of the clearings is highlighted, which requires further study and has a separate dynamic of occupation, with different speeds. In 1957, the clearings covered an area of almost 50 hectares, and by 2002, this area was reduced to nine hectares. The methodology also compartmentalized the area into four polygons, which were studied separately, presenting different characteristics in each, particularly in the comparison by area, number of clearings, and their outer edges. Polygon 1 represents almost 60% of the total area of the mangrove, and presents an area of progradation which is established by the colonization of individuals of Spartina alterniflora at the edge (coastline), with the advance reaching an area corresponding to approximately 12 hectares by 2007. Its increase in size occurred gradually over the years, unlike the other polygons analyzed, which demonstrated a reduction in area of almost 16% in relation to the area in 1957 The total area of the mangrove has decreased over the years, and remained practically stable between 1998 and 2002, approximately 5% smaller than 45 years ago. Also, the advance of urban occupation, which practically surrounds the mangrove swamp, is very marked. This can be clearly seen to the South in polygon 1, where the roads, over a period of several years, have entered the mangrove by more than 400 meters. It was also observed that as urbanization increased, the surface flow also increased, with the drainage channels being much better defined than previously. Finally, the information from the various sources was stored in a database, and four thematic maps of the study area were created, as a support for the management plans of the entities responsible for the Marine Extractive Reserve of Pirajubaé

ASSUNTO(S)

ndvi sensoriamento remoto vegetação - monitorização manguezais gis ndvi classification remote sensing classificação sig ciencias exatas e da terra mangrove swamps

ACESSO AO ARTIGO

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