Spatiotemporal analysis of precipitation, vegetation cover, fire foci and burned areas in a dairy basin in Northeastern Brazil

Drought events combined with anthropogenic factors (e.g., agricultural activity) intensify the susceptibility of the Caatinga biome to wildfires and environmental degradation, and also directly affect local biodiversity, the natural properties of the soil, and, consequently, the natural water supply. Because remote sensing provides spatial and spectral attributes, it becomes a feasible technological alternative as a primary tool for temporal analysis of degradation in the Caatinga biome, enabling time-series assessments of vegetative activity in this biome. Accordingly, this study aimed to: (i) evaluate the spatiotemporal dynamics of vegetation cover using biophysical indices derived from Landsat-8/OLI imagery; (ii) characterize hotspots and burned-area scenarios; and (iii) assess the expansion of cattle farming in the dairy basin of Pernambuco (Northeastern Brazil) and its resulting impacts on the regional biome. The study region comprises 23 milk producing municipalities between 2016 and 2020. The study was conducted in the dry and rainy seasons. Vegetation indices were processed via technique in Google Earth Engine (GEE) and rainfall spatialization from the CHIRPS product. The thematic maps of Land Use and Land Cover (LULC), burned areas, and fire foci. In the 2016 rainy season there was less precipitation, followed by severe droughts. In the dry season the Soil Adjusted Vegetation Index (SAVI) showed lower spectral responses, a result of low precipitation and anthropic actions, while in the rainy season it showed high biomass activity (> 0.78). Due to the sensitivity of the corresponding chlorophyll, the Green Leaf Index (GLI) was not satisfactory for the spatial analysis of Caatinga. Fire frequency showed that anthropogenic activities in some sectors of the basin caused a change in LULC patterns and thus resulted in degradation, even in regions with higher precipitation. In the northern portion of the basin a high degree of degradation was identified in the pasture category as a result of anthropic actions. Correlated, the biophysical indices, maps of pasture quality, burned area and fire foci are able to characterize the degradation. In summary, the study points out socio-environmental demands, sustainability and preservation of the Pernambuco dairy basin. Regarding environmental public policies, the dairy basin needs sustainable practices via the community and management agencies regarding the environmental issues shown in the study.