Evolving analysis of land use and land cover in the riacho do Poeta – Garopaba/SC sub-basin: methodological contribution to environmental studies

Abstract

The objective of this work is to present a methodological approach to analyze the dynamic of land use and land cover in a sub-basins, using remote sensing techniques. The study area is a sub-basin of the Siriú river located in the north sector of Garopaba county, Santa Catarina State, Brazil. Aerial photographies from 1956 and 1978 and satellite images acquired by Landsat 7 in 2001 were used. Land use and land cover mapping for the years of 1956 and 1978 was obtained through visual interpretation. Whereas, the map of 2001 was accomplished by IHS fusion and Decorrelation Stretch through enhancement. After this, the synthetic image was classified using the MAXVER classifier. The protection global index (Ipg) for the sub-basin was computed from the results obtained for each year which was estimated based on the values attributed to each class (Ipc). The percentage comparative analysis for each class and for the Ipg, indicated that vegetation cover increased resulting in an improvement of environmental conditions in the study area. The advanced secondary succession covered 27,5% of the sub-basin area in 1956 and 72,7% in 2001. This environmental improvement can be mainly attributed to environmental law enforcement, lack of agricultural incentives and rural exodus. Key words: Sub-basin; land cover and land use; protection index; remote sensing.