Farming expansion and land degradation in Western Bahia, Brazil

Abstract

Land degradation by soil erosion has called attention in tropical developing countries, particularly when natural vegetation is converted to farmland. Thus, the occupation of Brazilian savannas in Western Bahia is a matter of growing environmental concern. There are approximately 10 million hectares affected by this relatively recent land-use dynamics, but little is known about the temporal and spatial distribution of the process. To better understand such transformations, this paper addresses three related topics: land use/land cover (LULC) in 1985 and 2000; LULC dynamics between 1985 and 2000; and risk of land degradation by soil erosion as a function of farming expansion. The study area is located in Northeastern Brazil, between the coordinates 11º S and 46º 30' W and 14º S and 43º 30' W. All classes of natural vegetation cover decreased their areas during the period of study. Savanna (cerrado) lost 21.0% of its original area. Modern farming and irrigated areas increased 154.4 and 526.0%, respectively. Farming expansion reached 1,675,233 ha. Moderate risk of land degradation by soil erosion increased from 28.0 to 36.8% of the landscape mosaic between 1985 and 2000. The spatial and temporal dynamics observed reproduces development and land degradation examples of other savanna lands in Brazil. The integrity of native vegetation cover and the dissemination of soil and water conservation practices should be considered. This research contributes with an understanding of landscape transformations as a baseline for strategic environmental and land-use planning within the region.