Changes in land use caused by human actions have generated major impacts on the landscape, including the substitution of natural areas for diverse uses and the fragmentation of forested areas. These impacts can be mitigated by land use and land cover monitoring, which uses spatial-temporal information to track changes occurring in the landscape. Currently, the best way to monitor these changes is through the use of multi-temporal remote sensing products that provide important data about environmental characteristics when used with Geographic Information Systems (GIS).
The Caatinga biome, located in Northeast Brazil, one of the most populated and biologically diverse semi-arid regions in the world, has been drastically altered by human developments since the onset of Brazilian colonization (Caatinga is both the name of the region and the type of vegetation that occurs there, composed of low trees, dense, thorny shrubs and grasses). Research by the Pernambuco Federal University (UFPE) and Paraíba Federal University (UFPB) has produced a detailed analysis of spatial-temporal dynamics of land use and occupation in Pernambuco State, a small watershed within the Caatinga biome. The research used classification of three Landsat-5 TM satellite imagery for the years 1991, 2000 and 2010. The images were used for the classification of transition matrices associated with the map algebra and landscape metrics.
The results showed changes between 1991 and 2010 characterized by an accelerated dynamic behavior of vegetation, with the gradual replacement of dense and open Caatinga vegetation by areas for grazing/agriculture areas. The transitions between fragments show that deforestation for the development of grazing and agricultural lands, in most cases, happens in the open Caatinga. Along with rapid growth of grazing and agriculture, the predominant landscape of native vegetation has been replaced by a landscape increasingly devastated, fragmented and heterogeneous, as shown by the maps above.
Read the entire paper Dynamic of land use/cover change processes in a Brazilian semiarid watershed/Dinâmica do uso e ocupação do solo em uma bacia hidrográfica do semiárido brasileiro in Revista Brasileira de Engenharia Agrícola e Ambiental (Portuguese).
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