Ecohydrological Controls Across Elevation and Climate Gradients in the Andes

The Andes support critical mountain ecosystems and water resources that are highly sensitive to climate variability. Spanning multiple climate zones and steep topographies, Andean ecosystems exhibit distinct ecohydrological responses to changes in climate and land use across elevational gradients. However, interactions between vegetation dynamics and hydrological processes remain poorly understood at the scale of the Andean domain. This key knowledge gap is partly driven by local data scarcity and the limited representation of strong spatial heterogeneity. In this study, we investigate the spatial patterns of ecohydrological dynamics in the Andes using a hyper-resolution, physics-based ecohydrological modelling framework. Specifically, we develop a catchment selection scheme to identify representative catchments of all major climates and biomes across the entire mountain range of the Andes, quantify their hydrological and vegetation dynamics across elevational and latitudinal ranges. More specifically, we applied K-means clustering to all non-Amazon Andean catchments using key hydroclimatic, topographic, and soil variables. Four primary clusters were identified to represent the regional diversity: the North Tropical Andes, South Tropical Dry Andes, Central Dry Andes, and Extratropical Wet Andes. The North Tropical Andes cluster is located in Peru, while the remaining three clusters consist of Chilean catchments. Within each cluster, we analyse (1) vegetation dynamics and water balance components across elevation bands, (2) elevation-dependent plant water limitations and their variability among catchments, and (3) the relative importance of key drivers including precipitation, vapor pressure deficit, and air temperature in controlling evapotranspiration, gross primary productivity, and discharge, and how these relationships are modulated by topography. Through this integrated analysis, we aim to provide new insights into how climate, vegetation and hydrology vary systematically across the Andes.