Impactos socioambientais em áreas de várzea : transformações na paisagem pela perda de floresta na Amazônia Central

Abstract

The Amazon is globally renowned for its vast biodiversity and complex ecosystems, playing a pivotal role in regulating the global climate and preserving biodiversity. Within this immense region, the floodplains, particularly the várzeas, are notable for their ecological productivity and dynamic processes. Várzeas are floodplains shaped by sediment-rich whitewater rivers like the Amazon, Solimões, and Madeira, which periodically flood and deposit organic matter and nutrients, enriching the soil and boosting biological diversity. Historically, these areas have attracted human settlements due to their abundant natural resources, serving as crucial zones for the subsistence of riverine populations and regional economic development. However, with the advance of modernity and increasing anthropogenic pressures—such as deforestation, agriculture, and dam construction—the várzea landscape and the livelihoods of local populations have undergone significant changes. The loss of várzea forests not only threatens biodiversity but also weakens ecosystem resilience and essential environmental services, including fisheries and agriculture. In this context, the central objective of this thesis was to analyze the transformations in the landscape of the Central Amazon várzeas over recent decades and the resulting socio-environmental impacts, focusing on the relationship between environmental changes and the perceptions of riverine communities. To understand the transformation in the use of natural resources in várzea areas, a documentary and bibliographic study was conducted on the historical exploitation of fishery resources. The findings indicated that intensive use and the arrival of Europeans led to the overexploitation of resources such as pirarucu and manatee, contributing to the decline of these species. A systematic literature review was carried out to identify and describe the impacts of várzea forest removal, utilizing databases such as Science Direct and Scopus. The review identified impacts including changes in the hydrological cycle, increased sediment concentration, deforestation, and dam construction, all of which affect both ecosystems and riverine populations. Geographic data and satellite imagery were used to characterize the várzea landscape, analyzing geomorphological formations and river level variations within the study area. This characterization revealed significant changes in landscape structure, with direct implications for the region’s ecological dynamics. Remote sensing data, including satellite images, were employed to map and quantify landscape transformations over 20 years, correlating these changes with the ENSO index. The correlation analysis demonstrated that climatic events like El Niño are associated with increased wildfires and deforestation in the region. The perceptions of landscape changes among riverine populations were captured through structured questionnaires and the Likert scale, showing that communities clearly perceive the alterations in the landscape, corroborating scientific evidence of várzea forest degradation. These findings underscore the critical importance of the Amazon várzea areas and the urgent need for coordinated actions for their conservation and sustainable management. It is essential to adopt comprehensive measures to conserve and sustainably manage the Amazon’s várzea forests. This includes actions to combat deforestation, promote ecological restoration, encourage sustainable and low-carbon agricultural practices, and actively involve local communities in the management of natural resources.