Land use change and water loss in the Upper Paraguay River Basin: Trends, future scenarios, and implications for the Pantanal

Résumé fourni par la source

The Upper Paraguay River Basin (UPRB), encompassing the Planalto highlands and the Pantanal, the world's largest tropical wetland, has undergone intense Land Use and Land Cover (LULC) transformations and recurrent droughts that threaten regional water security. This study analyzed LULC dynamics from 1985 to 2020 and projected scenarios for 2030, 2040, and 2050 using a hybrid modeling framework that combines Markov Chains, Cellular Automata, and a Multi-Layer Perceptron, based on annual satellite-derived LULC maps. Results show a drastic decline in water bodies (93.5 % reduction) and wetlands (71.2 % reduction) in the Pantanal, mainly converted to grasslands, and a sharp expansion of pasture (139.5 % increase) and agriculture in the Planalto. By 2050, pasture is projected to cover 34.7 % of the basin, grassland 17.8 % (683.0 % increase since 1985), and agriculture 9.0 % (202.0 % increase), while native vegetation will shrink from 76.4 % in 1985 to 53.9 %. Elevation, precipitation, and proximity to soybean crops and pasture were the most influential predictors in the model. These changes, driven by the combined pressures of climate variability, land-use intensification, and economic demand for agricultural commodities, threaten hydrological connectivity, biodiversity, and ecosystem services. Urgent, integrated, and spatially differentiated management strategies are essential to mitigate these impacts, including targeted conservation of wetlands and riparian zones, sustainable agricultural practices, and improved hydrological governance. While the CA-Markov-MLP approach provides spatially explicit projections useful for policy formulation and basin-wide planning, uncertainties remain, particularly for wetlands, due to class-specific misclassification and interannual variability in reference data. Therefore, projected magnitudes should be interpreted as indicative trends rather than precise forecasts.

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