From sambaquis (shell mounds) to plastic debris: a summary of the geological imprint of human occupation in the coast of São Paulo (Southeast Brazil)

In this work, we present a brief revision of the geological evidence of human activities in the coast of São Paulo (Southeast Brazil), from pre-historical times to the present. We analyze case studies in different sectors of the coast, identifying the main historical causes that resulted in environmental changes with their consequent imprint in the sedimentary column. There was a south-to-north trend inthe occupation at the colonization period (1500 onwards), essentially determined by differences in the geomorphology of the area. Finally, the accumulation of artificial radionuclides and plastic debris in the sediments is discussed

Characterization and monitoring of the flooding dynamics and seasonally flooded environments of the Volta Grande do Xingu through remote sensing

A região da Volta Grande do Xingu (VGX) se destaca por sua singular biodiversidade e riqueza ambiental. Com sua geomorfologia única, composta por diversos canais entrelaçados, cachoeiras e corredeiras, foi escolhida como local para abrigar o Complexo Hidrelétrico de Belo Monte. No entanto, esse megaempreendimento representa uma ameaça à viabilidade da Volta Grande do Xingu e aos ecossistemas que sustentam a vida. Além disso, as populações tradicionais que habitam a área também correm riscos. Esta pesquisa utiliza técnicas de análise por sensoriamento remoto para monitorar as mudanças na dinâmica de alagamentos e caracterizar os ambientes sazonalmente alagáveis pela influência do barramento do Rio Xingu na Volta Grande. A tese é composta por uma coletânea de três artigos, cada um abordando uma perspectiva diferente da Volta Grande do Xingu e seus desafios ambientais. O primeiro capítulo enfatiza a importância das ferramentas de sensoriamento remoto na monitorização dessas mudanças e ressalta a necessidade de combinar diferentes técnicas de classificação de imagens. O segundo capítulo introduz uma abordagem inovadora, utilizando modelagem 3D para caracterizar as áreas sazonalmente alagáveis na VGX. O terceiro capítulo se concentra nos impactos hidrológicos do Complexo Hidrelétrico de Belo Monte na VGX, com foco na extensão das áreas alagáveis e na elevação da superfície da água do Rio Xingu. Essa pesquisa oferece contribuições significativas para as Ciências Ambientais, pois a combinação de sensoriamento remoto, modelagem 3D e medições hidrológicas possibilitou uma análise abrangente da área de estudo, permitindo uma compreensão mais profunda das mudanças que estão ocorrendo, ampliando as possibilidades de monitoramento e preservação.The Volta Grande do Xingu area stands out for its unique biodiversity and environmental richness. With its distinctive geomorphology, featuring several anabranching river channels, waterfalls, and rapids, it was chosen as the site to build the Belo Monte Hydroelectric Complex. However, this mega-project poses a threat to the viability of the Volta Grande do Xingu and the ecosystems that supports life. Additionally, the traditional populations living in the area are also at risk. This research employs remote sensing analysis techniques to monitor changes in flooding dynamics and characterize seasonally flooded environments influenced by the damming of the Xingu River in the Volta Grande. The thesis consists of a collection of three scientific articles, each addressing a different perspective of the Volta Grande do Xingu and its environmental challenges. The first chapter underscores the importance of remote sensing tools in monitoring these changes and emphasizes the need to combine different image classification techniques. The second chapter introduces an innovative approach, utilizing 3D modeling to characterize the seasonally flooded environments in Volta Grande. The third chapter focuses on the hydrological impacts of the Belo Monte Hydropower Complex, with a focus on the extent of flooded areas and the elevation of the Xingu River\'s water surface. This research provides significant contributions to Environmental Sciences, as the combination of remote sensing, 3D modeling, and hydrological measurements has enabled a comprehensive analysis of the study area, allowing for a deeper understanding of the ongoing changes and expanding the possibilities for monitoring and preservation

A Comparison between Supervised Classification Methods: Study Case on Land Cover Change Detection Caused by a Hydroelectric Complex Installation in the Brazilian Amazon

The Volta Grande do Xingu (VGX) in the Amazon Forest of Brazil was chosen to analyze the land use and land cover changes (LULCC) from 2000 to 2017, with the aim of assessing the most suitable classification method for the area. Three parametric (Mahalanobis distance, maximum likelihood and minimum distance) and three non-parametric (neural net, random forest and support vector machine) classification algorithms were tested in two Landsat scenes. The accuracy assessment was evaluated through a confusion matrix. Change detection of the landscape was analyzed through the post-classification comparison method. While maximum likelihood was more capable of highlighting errors in individual classes, support vector machine was slightly superior when compared with the other non-parametric options, these being the most suitable classifiers within the scope of this study. The main changes detected in the landscape were from forest to agro-pasture, from forest/agro-pasture to river, and from river to non-river, resulting in rock exposure. The methodology outlined in this research highlights the usefulness of remote sensing tools in follow-up observations of LULCC in the study area (with the possibility of application to the entire Amazon rainforest). Thus, it is possible to carry out adaptive management that aims to minimize unforeseen or underestimated impacts in previous stages of environmental licensing