Ecohydrological Heterogeneity by Watershed in Dry Forest of the Coto de Caza El Angolo under ENSO Variability and Climate Change

Abstract

Dry tropical forests are highly sensitive ecosystems influenced by climate variability and regional warming trends, particularly those associated with ENSO. In northwestern Peru, a mosaic of watersheds is exposed to El Niño Costero precipitation pulses, which have increased in intensity and recurrence in recent decades. This makes it necessary to understand the relationship between these pulses and climate change, as well as their effects on ecosystems, in a sectorized manner. Meteorological variability, climate change, ENSO, and forest vigor were analyzed in the different watersheds of the Coto de Caza El Angolo from 1984 to 2025 to achieve this goal. Data from weather stations, ENSO measurements, and climate change measurements were processed to determine NDVI variation from Landsat images. The results revealed significant spatial heterogeneity, with higher NDVI values observed in the eastern watersheds (Tumbes and Chira) and arid conditions in the Pariñas watershed. Temporally, a sustained increase in NDVI was identified in all basins, exceeding 200% in the western basins (Fernández and Pariñas) due to greater wet year recurrence and reduced dry periods. The correlations indicate that the plant response is more closely related to minimum and average temperatures than to the El Niño-Southern Oscillation (ENSO) index. Intense ENSO events generate greening through hydrological pulses. Taken together, the results demonstrate that the ecohydrological response is heterogeneous and structurally differentiated by watersheds under a non-stationary climate regime. These findings provide empirical evidence of the importance of considering spatial heterogeneity when assessing ecosystems in the context of ENSO variability and regional warming.