Land cover change in two protected areas of Guinea-Bissau (1956-1998)

摘要

The objective of this work was to quantify and spatially characterize land cover change in the regions of the Cacheu and Orango protected areas (Guinea-Bissau). Land cover maps from 1956 and 1998 were co-registered and rasterized to the same spatialresolution in a geographic information system (GIS) and the land cover classes of both maps aggregated to a new common legend. Classification of Landsat Thematic Mapper images and field checking were used to generate the 1998 map. Comparisons between the two dates indicate that major changes have occurred in the Cacheu area, both in the extent and the spatial distribution of some vegetation classes, with decreases in areas of mangrove, dry forest and palm grove, and large increases in mudflats and savanna. In Orango, changes are less extensive, but the onset of some of the trends verified in Cacheu can be identified. The results are interpreted, taking into account land use practices in the two study regions, and will hopefully become a management andconservation tool for the local park authorities.