Terrain units, land use and land cover, and gross primary productivity of the largest fluvial basin in the Brazilian Amazonia/Cerrado ecotone: The Araguaia River basin

Abstract

Integrity of most of tropical wetlands is threatened because they are often considered freely available resources of land and water. The Bananal, in the Araguaia River Basin, and the Pantanal in the Paraguai River Basin, are the two largest Brazilian wetlands influenced by the tropical seasonal floods. The purpose of this study is to integrate landscape structural and functional factors with the GPP dynamics over different terrain units present in the Araguaia River Basin. The study was conducted through the integration of different databases, including the topographic domains, protected areas and indigenous lands; land use and land cover map (year 2016); time series of GPP derived from the Moderate Resolution Imaging Spectroradiometer (MODIS) sensor (period of 2000–2015); Shuttle Radar Topography Mission (SRTM) digital elevation models (DEM); and precipitation data produced by the WorldClim version 2 dataset. GPP time series were processed using statistical methods of time series decomposition. The results show that, in the alluvial domains, we find grasslands (mostly), alluvial forests with the highest levels of GPP, and the largest legally protected areas. Spatial distribution of pasturelands across the entire basin is broad while croplands are concentrated mainly in geologically old and high plateaus. The time series analysis revealed the presence of intra- and inter-annual vegetation patterns and a continuous increase of GPP over time. The results contribute to the understanding of the linkages between land use changes and global carbon cycles by considering land use as a response of how the landscape is organized. The results may provide subsidies for public policies for the carbon budget equilibrium, conservation of biodiversity, and rational use of natural resources.