Inferência geográfica para delimitação de corredores ecológicos: um estudo de caso para a Mata Atlântica do município de Tibau do Sul/RN

The Atlantic Forest biome occupies much of the Atlantic coast of Brazil, in addition to portions of Paraguay and Argentina. Due mainly to its biodiversity which falls in the group of global hotspots, i.e., areas that have high priority for conservation. Although currently there are some available devices that assist in their protection in the course of the history of occupation and exploitation of the Brazilian territory, this biome has gone, and is still going through, an intense process of devastation, caused mainly by the pressure from economic activities, culminating in a significant reduction of its area and consequent fragmentation of the landscape, which brings with hosts a series of problems at various scales and aspects. As in most municipalities included in the reach area of the biome, the situation of forest fragmentation in Tibau do Sul / RN is quite critical, reflecting on a truly diverse landscape with broad typology of land uses. Among the alternatives aimed at the conservation of this biome include the creation of protected areas and the creation of ecological corridors, the latter being more efficient by connecting the remaining forests, increasing landscape connectivity, providing significant gains in relation to biodiversity. However, a major problem on implementation of Ecological Corridors projects is related to the selection of areas for this purpose, in this sense Geography can provide important contributions through the integrated study of landscape in the light of the geosystemic approach and the use of Geographical Information System (GIS) in order to permit assessment of reality having as a base the integration of ecological, biological and man-made aspects. Thus, this research aims to indicate potential areas and propose scenarios delimitation of Ecological Corridors in the municipality of Tibau do Sul / RN through Geographic Inference techniques in GIS platform. Therefore, the methodology adopted is based on the Geosystemic approach. From these elements were created 4 models to indicate potential areas for implementation of Ecological Corridors from the environmental perspective (potential erosion), socioeconomic (cover and land prices), legislative (areas protected by environmental legislation) and integrated (combination of environmental factors, socioeconomic and legislative), which in turn served as a basis for proposing scenarios aimed at this purpose. The results showed that all models can be quite useful in indicating potential areas for the establishment of ecological corridors, especially when based on an integrated approach between environmental and anthropogenic. The Corridors delimitation proposes shown may perform duties beyond the establishment of connectivity between fragments, since they also may have usefulness in controlling erosion and protecting fragile environments. Among the models developed, the integrated constituted itself as the best option because it enabled the interconnection of a larger number of fragments from a better use of the potentialities present in the landscape

Fragilidade ambiental da bacia hidrográfica do Rio Punaú (RN) e área litorânea adjacente

Hydrographic basins always exercised a big fascination over humankind that attracted for its scenery beauty or for its richness in natural resources, had been acting in order to modify these important ecosystems without, therefore, considering the possible consequences of these changes. The attributed importance to the coast ecosystems, in eminence to the hydrographic basin of Punaú river and adjacent areas, is had when it s verified the diversity of the ecosystems that contemplate it. Hydrographic basin in evidence in Rio Grande do Norte state, occupies an area of nearly 652.71 km², being it sited in the homogeneous micro-region Litoral Nordeste, with a regional population estimated in nearly 75,188 inhabitants, according to the Anuário Estatístico do Rio Grande do Norte 2004. The region of the researched basin is formed by seven municipal districts related as it follows: Maxaranguape, Pedra Grande, Pureza, Rio do Fogo, São Miguel de Touros, Taipu and Touros, but Maxaranguape, Rio do Fogo, Touros and Pureza have a direct participation in the basin. Basin in study have it lands evaluated according to the agriculturist aptitude by the conventionally methodology practiced in the country, having as objective, then, a compara-tive analysis between the ambient unities, Aeolian littoral and coast tray, identified in the researched area. From the characterization of the physic way of the area in study and owning the kept data, it was proceeded the integrated analysis of the structural elements of the landscape which were evidenced that the fragile areas are associated with the areas of agriculture cultivation, such as the ones of irregular occupation. About the degradation, the ambient diagnostic of the basin indicated that the equivalent to the Aeolian Littoral Ambient Unit correspond to the bigger pledging of the ambient quality, in other words, high ambient fragility, being this result due to the use and occupation of the soil, propitiating this way, vulnerability in the vegetal cover of the area, despite it disposes of a low agriculture cultivation percentage. Already in the Coast Ambient Tray, is emphasized the medium ambient fragility, despite of the high index of cultivated area. In a general way, the total area of the hydrographic basin of Punaú river and adjacent areas presented ambient impacts over the tolerance limit, indicating the necessity of a review of the practices of use and handling of the soil, reforesting of the water courses edges, control of erosion and contamination of the aqueous in the perspective to reduce the effects of the impacts due to the use and occupation of the basin in regard. The present search evaluated the ambient impacts diagnosised in the hydrographic basin of Punaú river and adjacent areas, pointing the causes and the probable consequences of the damages caused by these impacts to the basin ambient. From the analysis of these data, if was possible to become explicit how they are fundamental as key elements in the process of decision taking in the ambient questions