Soil-water process interactions in a landscape context in the Andean páramo

A major concern for sustainable development in the Tropical Andes is the growing imbalance between ecosystem service supply and demand, particularly with regard to freshwater ecosystem services. Demographic growth, urbanization and evolving socio-economic conditions coupled with future projections of climate change in the Andes, call for urgent action. This thesis contributes evidence-based research on the conservation and restoration of young volcanic ash soils through an analysis of soil-water-plant interactions at the pedon, toposequence and landscape scales. The empirical data were collected over a 5-year period in the Jatunhuayco experimental site, located in the northern Ecuadorian Andes at 4200 m a.s.l. At the soil pedon scale, the vegetation type had a measurable effect on the soil water balance as well as on solute concentrations and chemical weathering rates. At the toposequence scale, the soil pore structure and hydraulic properties of the A horizon varied by vegetation type. This has implications for soil water storage in the topsoil and subsurface lateral flow. The hydrological connectivity of the geomorphic units at the landscape scale is time-dependent. As a result, the geochemical signature of the solute export varied strongly over time. The existence of strong interlinkages between plant functional types, soil and surface hydrology, and nutrient export has important implications for the sustainable management of high Andean ecosystems. The findings of this thesis can contribute to assess the potential impacts of vegetation conservation and restoration programs on water resources in the Tropical Andes.