Use of fuzzy systems in the elaboration of an anthropic pressure indicator to evaluate the remaining forest fragments

Abstract

The aim of the present paper is to develop a spatial analysis methodology with an inference fuzzy system using the geoprocessing techniques to generate an anthropic pressure indicator (API) based on two other indicators: Circularity Index (CI) and Edge Effects Index (EEI). This new methodology could indicate the remaining forest fragments exposition level after the anthropic action, considering the relationship between the geometry (CI) and the type of land use around the area (EEI) as the main factors. The studied area is located in the southwest part of Sao Paulo state, Brazil. The obtained results show that rivers are often found as limits between fragments, demonstrating the importance of the preservation and conservation of riparian forest. In total, 846 forest fragments were identified, occupying 6.19 % of the study area, totalizing 2775.7 ha. Out of the total fragments 48.7 % were in medium and advanced successional stage of regeneration presenting elongated shapes and 16 % were in a high fragility interval, consequence of the edge effects. Moreover, the map of API showed that 16.2 % forest fragments were in a moderate high anthropic pressure interval, which deserve special attention for being very elongated, limited and pressured in an intense way by different types of land use which affect its surroundings. Thereby, the study demonstrated that the understanding of pressure types imposed on the remaining forest fragments through an indicator can contribute to management programs and territorial planning, giving conditions to the forest restoration in areas of strong anthropic pressure, and that the employment of fuzzy logics and geoprocessing could contribute significantly to diagnosis and trouble characterizations.