Deforestation drivers in the Brazilian Amazon: assessing new spatial predictors.

Researches on the deforestation of the Amazon have gained prominence in the last recent years, mainly with the change in the policy regarding the facing of this phenomenon by the Brazilian government. Therefore, an understanding about the causes that pressure the occurrence of deforestation remains relevant and has a leading role in the world. Therefore, the aim of this study is to perform the analysis of the spatial variability of the reasons for the deforestation in the Amazon Biome, in Brazil, (2010-2019). To achieve this goal, 14 variables were selected, the choice and adjustment of the regression model were determined and a diagnosis was carried out in order to verify the most appropriate model. To achieve this purpose, a geographic database was structured in a geographic information system environment. The main results revealed that the adjusted R2 of the Geographically Weighted Regression (GWR) was 0.96, that is, the GWR model explains 96% of the variations in deforestation. Therefore, it was observed a significant gain when using this model. In addition, it was also observed that the average variable of the number of oxen was, among those analyzed, the one that showed the highest correlation with deforestation. Thus, it was found that the livestock sector in southern Amazonia is the main economic agent that pressures large areas of deforestation, since stockfarming is practiced extensively. Finally, it was concluded that the municipalities with the largest areas of deforestation formed a cluster in the southern portion of the Amazon, in the arc of deforestation.

Impact of mining activities on areas of environmental protection in the southwest of the Amazon: A GIS- and remote sensing-based assessment.

The southwest Brazilian Amazon state of Rondônia has a relatively recent non-indigenous occupation, which subsequently develops a variety of human pressures and conflicts of interest presently identified in the region. Given such framework, it is worthwhile to note that there are 57 Conservation Units that must guarantee the biodiversity protection of Amazonia biome. However, due to the need for electricity and the international high demand for minerals, the highlighted scenario has dramatically changed in recent years. Official data from mining processes in the studied area demonstrated the existence of high interest for minerals, especially cassiterite and gold. Mining is indeed an essential activity for the nation mainly due to the generation of jobs and income. On the other hand, it produces several environmental and social impacts that vary accordingly to the peculiarities of the mining and with respect to the type of ore. Therefore, this research work investigated the concentration of mining projects in the state of Rondônia and complementarily evaluated the impact of such activities on areas of environmental protection. Landsat 8 OLI imageries were employed to map the diversity of land covers across the study area and also to evaluate the corresponding impact of mining activities. More than 500 processes have been identified within the Conservation Units. A significant part of the mining areas, covering about 26 km2, was observed inside one of the three types of evaluated areas (Integral Protection Sustainable Use Conservation Units and Damping Zone), clearly showing the development of the illegal activity, as defined in terms of the National System of Conservation Units. If deforestation is considered in this analysis, the area increases to about 6110 km2, representing more than 5.2% of the Conservation Units. In addition, we proposed the creation of the Mining Pressure Index (MPI), which allows classifying a Conservation Unit by the degree of pressure from mining activities. The proposed index revealed to be very efficient since it predicted high values over Conservation Units where it was expected a greater vulnerability. The index is a promising tool for public policy formulation and management of protected areas, as well as for enforcement action. The results provide a new horizon in terms of the perspective of importance and applicability of geotechnologies in the evaluation of environmental impacts, not restricted to mining activity.