Andean wetlands: Seasonal variability and their interactions with the cryosphere

Study region: The Vilcanota Urubamba Basin in southern Peru includes fragile wetland ecosystems that play a key role in mountain hydrology and support grazing for Andean communities. Study focus: Mapping of wetlands variability is missing, limiting our understanding of their characteristics, seasonality and link with the cryosphere. We characterise wetland distribution, seasonality and persistence and evaluate their spatial association with glaciers and seasonal snow. Using Landsat 7 and 8 imagery, we build three-month seasonal land cover maps from 2013 to 2022 using a Random Forest classification and an Albedo Retrieval approach. New hydrological insights for the region: Wetland area decreases by 38% from the end of the wet season (October to December) to the end of the dry season (July to September). Pixel transitions indicate that wetlands primarily transform to and from agricultural and pasture lands. Highly persistent wetlands are located above 4600 m a.s.l. and closer to glaciers than less persistent wetlands. We identified three wetland seasonal drying patterns. Basins with delayed and slow dry-out wetlands were more common at higher elevations but were not always in glacierised catchments, suggesting meltwater may maintain wetlands in the early dry season. We provide the first large-scale picture of wetland seasonality, and the basis for modelling the processes that sustain wetlands in tropical high mountains.