Análise multicritério como instrumento para a definição de áreas de proteção florestal na bacia hidrográfica do rio Japaratuba - SE

Abstract

Brazil still does not have a consolidated National Forest Policy and its main Native Vegetation Protection Law is the Forest Code, updated in 2012 (Law No. 12,651 of 2012). The revision of this Law was surrounded by a series of conflicting discussions and promotions of changes classified as setbacks for forest protection in the country, especially the flexibilities of amnesty to deforesters, the reductions in the protection of the Permanent Preservation Areas (PPAs) and the extinction of the obligation to recover the Legal Reserve (LR) in small properties measured by the Fiscal Module. Despite the progress in establishing control instruments such as the Rural Environmental Registry, Environmental Recovery Plan and the Easement Quotas, regional difficulties are still observed in the implementation and monitoring of the instruments provided by law. Therefore, this research presented as problematic that the current criteria for implementation of regulatory instruments, PPAs and LR, are not sufficiently adequate for the definition of forest protection areas, as they are placed in the current norm. Thus the general objective of the research was to develop a multicriteria spatial model for the definition of priority areas for forest protection considering the Hydrographic Basin (HB) as an ideal Planning Unit (PU), as proposed in the National Water Resources Policy. To obtain the results, the Japaratuba-SE Hydrographic Basin was adopted as an experimental area and the following methodologies were used: a systematic review of the bibliographical production on the basin and the adoption of Strategic Environmental Assessment methods -SEA for the definition of Critical Decision Factors - CDF. Starting from the identified CDF and based on the specialized literature, nine criteria were selected and evaluated for the definition of forest protection areas: Proximity to hydrologic network; Proximity to protected areas; Soil erodibility (K factor); LS factor (declivity); Forest fragmentation; Groundwater recharge potential; Water balance; Mining activities; Distance from urban areas. The criteria were submitted to a Multicriteria Evaluation, for this, the Analytic Hierarchy Process - AHP methods were adopted, and for the map algebra the Weighted Linear Combination - WLC, resulting in the final synthesis map that represented a spatial model of priority areas for forest protection in the studied basin. A comparative analysis between the elaborated model and the provisions of the current law of protection of native vegetation (Forest Code) was also performed. The results showed that the selected criteria were adequate for the application of the prioritization process for forest protection areas. The basin has a high degree of deforestation, especially in riparian areas, only 14% of the riparian forests are preserved and there has also been an increase of 382% in water demand in the basin in the last 8 years. The intense use and occupation of the soil predominantly occupied by pastures and agricultural mosaics (84.1%) is one of the main pressure factors on the forest cover. The model indicated that about 36% of the total basin area should maintain and or recover its forest cover for future Sustainability, out of which only 8.9% of the areas still have forest cover, requiring recovery of 25.1% of the total area. However, when the scenario of the provisions of the current Forest Code is calculated, only 11.6% of the area would need to maintain its forest cover, according to the regulatory instruments APPs and RLs. This result demonstrated that the rules of the Code, when applied independently of other criteria, are insufficient to promote the sustainability of forest protection in the studied basin. The territorial model applied proved to be satisfactory and adequate for the context of river basins as planning units, and can be replicated to define macro-planning guidelines in other basins, adopting regional scales and observing the Critical Decision Factors for the area to be studied.