Assessing grassland degradation and potentially salt-affected soils in the Paraguayan Chaco using multispectral data
Year: 2026
Type: article
Abstract: Dryland salinization and pasture degradation threaten livestock production in the Paraguayan Chaco, yet field-based ecohydrological assessments remain scarce as ranching is expanding into increasingly marginal environments. Bare land areas with <15% vegetation cover, locally called peladares , are increasingly emerging in the transformed landscapes of the Gran Chaco, leading to reduced rangeland productivity. We conducted a long-term analysis (2000–2025) of land-use change and spectral indices across a ~500,000 ha region in Boquerón, Paraguay, to assess whether these variables alone can explain the negative trend in NDVI (Normalized Difference Vegetation Index), or whether other unrelated factors contribute to their emergence. First, we identified bare land areas using a Random Forest classifier. Second, we analyzed when these areas were converted from native forest to pastures. In parallel, we evaluated whether peladares exhibit climate-aligned signals by analyzing long-term trends in NDVI (Landsat 7/8/9), evapotranspiration (MOD16A2GF) and a MODIS LST-based Crop Water Stress Index (CWSI; MOD11A2), using Sen’s slope. Finally, we used GAMs to remove cohort effects from NDVI trends and evaluated residual variation against salinity indices to rank their effectiveness as proxies for identifying peladares . This workflow provides a scalable baseline for screening secondary salinization risk and prioritizing field validation, pasture management and conservation planning in Chaco drylands.
Source: Cambridge Prisms Drylands
Language: English
Subfield: Ecology
Field: Environmental Science
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $3,893
OpenAlex ID: W7165771801
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