Land cover and soil loss multitemporal analysis: an application of geoindicators in the Pantanal Wetlands (Brazil)

In the last decades economic growth of developing countries involved population growth and need of new productive spaces: new urban areas, industries and agricultural lands were set up, often causing environmental troubles. Increase of "human pressure" without any evaluation concerning sustainable development makes the environment weak, reducing its productivity in the medium and long term. In South America, Brazil were strongly affected by such problems in the last three decades. Especially in the states located inside the Amazonas and Upper Paraguay rivers basins, natural areas were transformed into agricultural lands through deforestation. Forest and savanna were progressively cleared using both mechanical devices and fire, the latter being widely utilized because efficient and cheap. Forest clearing is one of the cause of desertification of tropical areas, global warming and the main cause of accelerated soil erosion. Especially in the highlands of the Mato Grosso do Sul State (Fig. l ), after forests clearing accelerated erosion developed and it is now threatening some urban areas and prevents the exploitation of wide lands. As a consequence, in the neighboring Pantanal wetlands, one of the largest continental alluvial fan of the world, the solid discharge increased, causing accelerated deposition in the channel beds, widening of floodable lands and reduction of productive territories. These facts suggest that geoindicators like land cover and soil erosion changes (Berger & Iam, 1996), represent key parameters for sustainable development evaluations and land management. In this work a multitemporal (years 1966, 1985, 1966) land cover database was created for a wide region of the Pantanal and the neighboring planaltos (highlands) (Fig. l ) by utilizing topographic data integrated with remotely sensed information. In a pilot area of the planaltos affected by appreciable land cover changes, GIS analyses and the USLE (Wischmeier & Smith, 1978) allowed to estimate the effects of changes on soil loss.