Análisis multitemporal de la relación entre la cobertura vegetal y la humedad superficial mediante imágenes Sentinel-2 en la RFPN Cerro Vanguardia y la Cuenca Alta del Caño Vanguardia - Quebrada Vanguardiuno (2016-2025)

Abstract

This study evaluated the spatiotemporal dynamics of vegetation cover and surface moisture within the Cerro Vanguardia National Protective Forest Reserve and the Upper Vanguardia Stream-Vanguardiuno Creek watershed during the 2016-2025 period using Sentinel-2 imagery processed in Google Earth Engine and ArcGIS Pro. A total of 20 seasonal satellite mosaics corresponding to dry and wet seasons were generated, from which 40 spectral indices were derived (20 NDVI and 20 NDMI products). Subsequently, both indices were normalized, integrated through weighted overlay analysis, and spatially assessed using the Global Moran’s I statistics to evaluate the spatial organization of environmental conditions. The results revealed a strong relationship between precipitation, vegetation vigor, and surface moisture availability, confirming that hydroclimatic variability constituted the primary driver of the reserve’s ecohydrological dynamics. Environmental conditions remained predominantly favorable throughout the study period, reaching their optimal state during the 2018 wet season, when 97.67% of the study area was classified under the “Good” environmental condition category. In contrast, the 2016 dry season represented the most critical scenario, with the proportion of areas classified as “Good” decreasing to 75.41%, while the combined “Regular” and “Poor” categories expanded to 24.59% of the total area. Similarly, degraded areas reached approximately 19% of the study area during the 2022 dry season. Spatial autocorrelation analysis yielded high and statistically significant Moran’s I values (0,8066-0,9298; p-value=0,0001), demonstrating the presence of highly clustered spatial patterns and rejecting the hypothesis of random environmental distribution. A progressive increase in spatial aggregation was observed, reaching its maximum during the 2025 wet season. Furthermore, the findings suggested the occurrence of ecological hysteresis processes, evidenced by the expansion of degraded areas during 2024 and 2025 despite the partial recovery of precipitation regimes. Overall, the results provided valuable scientific evidence to support environmental monitoring, ecosystem conservation, and water resource management strategies within this protected area of the Colombian Llanos foothills.