Topography regulates vegetation functioning by controlling water redistribution, microclimate, and solar exposure. In Mediterranean ecosystems, where water availability constitutes a fundamental limiting factor, vegetation functioning is also influenced by environmental drivers such as temperature, climatic seasonality, drought recurrence, and soil properties that interact with terrain heterogeneity. Understanding how these elements operate at the micro-scale is essential for interpreting the spatial variability of photosynthetic vigor and canopy water condition. This study evaluates the relationships between the topographic metrics Topographic Position Index (TPI), Terrain Ruggedness Index (TRI), and Diurnal Anisotropic Heat Index (DAH) and two spectral proxies of vegetation condition, the Normalized Difference Vegetation Index (NDVI) and the Normalized Difference Moisture Index (NDMI), in Los Nogales Nature Sanctuary (central Chile). Multitemporal Sentinel-2 time series (2017–2025) were analyzed using Generalized Additive Models (GAMs) with Gaussian distribution and cubic splines to detect non-linear topographic responses. All topographic predictors were statistically significant (p < 0.001). NDVI and NDMI values were higher in concave and less rugged areas, decreasing toward convex and thermally exposed slopes. NDMI exhibited greater sensitivity to topographic position and thermal anisotropy, indicating the strong dependence of vegetation water condition on topographically driven water redistribution. These results highlight the role of terrain in modulating vegetation vigor and moisture in Mediterranean ecosystems.

High-Andean wetlands are critical ecosystems for water regulation and carbon storage. This study analyzes the impact of climate variability on vegetation dynamics in eight wetlands located in the Estero Ortiga sub-basin, within the Los Nogales Nature Sanctuary (Metropolitan Region, Chile), between 2017 and 2024. We used time series of NDVI and NDCI indices derived from Sentinel-2 imagery (January 2017 to September 2024), along with monthly temperature and precipitation data from ERA5-Land (January 2016 to September 2024). Trends were assessed through linear regression, and vegetation–climate relationships were analyzed using Pearson correlations with a one-year lag. Results show a progressive decline in vegetation cover (slope: −2.04 × 10⁻⁵ NDVI) and chlorophyll content (slope: −1.15 × 10⁻⁵ NDCI), with strong positive correlations between annual precipitation and vegetation indices in the subsequent summer (R = 0.83–0.88 for NDVI; R = 0.84–0.90 for NDCI). Annual NDVI reclassification highlighted a reduction in healthy vegetation cover from 2020 onward. This research provides novel evidence linking climate trends and vegetation health in high-Andean wetlands, reinforcing the utility of satellite-based indicators for conservation monitoring.

Ravine forests are key to conserving biodiversity and maintaining ecosystem processes in fragmented landscapes. Here, we evaluated the phenology of plant species in the Los Nogales Nature Sanctuary (Lo Barnechea, Chile) using Sentinel-2 images (2019–2024) and the Alos Palsar DEM (12.5 m). We calculated the Normalized Difference Vegetation Index (NDVI), the Topographic Position Index (TPI), and Diurnal Anisotropic Heat (DAH) to assess vegetation dynamics across different topographic and thermal gradients. Generalized Additive Models (GAM) revealed that tree species exhibited more stable, regular seasonal NDVI trajectories, while shrubs showed moderate fluctuations, and herbaceous species displayed high interannual variability, likely reflecting sensitivity to climatic events. Spatial analysis indicated that trees predominated on steep slopes and higher elevations, herbs were concentrated in low-lying, moisture-retaining areas, and shrubs were more common in areas with higher thermal load. These findings highlight the significant role of terrain and temperature in shaping plant phenology and distribution, underscoring the utility of remote sensing and topographic indices for monitoring ecological processes in complex mountainous environments.

Difficult access and a lack of in situ data limit monitoring of high-Andean wetlands, which are key components of water regulation in central Chile. This study analyzes the multitemporal dynamics of vegetation in three high Andean wetlands of the headwater (1HW), lateral (2LW), and confluence (3CW) types in the Los Nogales Nature Sanctuary between 2018 and 2025. We integrated Sentinel-2 Level 2A images, annual accumulated precipitation from the ERA5-Land product (lag-1 year), and high-resolution UAV-derived boundaries to characterize six spectral indices (NDVI, EVI, NDRE704, NDRE705, NDWI, and SAVI) and their relationship with water variability. Annual precipitation ranged from ~420 to 780 mm during a regional megadrought. The headwater wetland showed the greatest climate sensitivity, with significant correlations between the previous year's precipitation and NDVI, NDRE705, EVI, SAVI, and NDWI (|R| ≥ 0.70; p < 0.05), while in the lateral and confluence wetlands, the relationships were moderate or weak. Multitemporal mosaics showed maximum vegetative vigor between 2018 and 2021, followed by a decline. Overall, the results confirm that integrating the Sentinel-2 series, climate reanalysis, and UAV delimitation is an effective tool for ecohydrological monitoring and management of high-Andean wetlands.