Becker et al. (2026) A map of high-altitude wetlands in the world’s major mountain regions

Identification

• Journal: Scientific Data
• Year: 2026
• Date: 2026-03-11
• Authors: Rike Becker, Jan Kropáček, A. Ross, Tom Gribbin, Fabian Drenkhan, Lilia Hernández Sotelo, Marc Martínez Mendoza, Bethan J. Davies, Jeremy C. Ely, Wouter Buytaert
• DOI: 10.1038/s41597-026-07020-w

Research Groups

• Department of Civil and Environmental Engineering, Imperial College London, London, UK
• British Geological Survey, Environmental Science Centre, Keyworth, UK
• Department of Physical Geography and Geoecology, Faculty of Science, Charles University, Prague, Czechia
• Geography and Environment, Department of Humanities, Pontificia Universidad Católica del Perú, Lima, Peru
• Grupo de Glaciología y Ecohidrología de Montañas Andinas (GEMS), Institute for Nature, Earth and Energy (INTE), Pontificia Universidad Católica del Perú, Lima, Peru
• City Planning Labs, The World Bank Group, London, UK
• Port de Barcelona, Barcelona, Catalunya, ES
• School of Geography, Politics and Sociology, Newcastle University, Newcastle-upon-Thyne, UK
• School of Geography and Planning, The University of Sheffield, Sheffield, UK
• School of Geography, Earth and Environmental Sciences, University of Birmingham, Edgbaston, UK

Short Summary

This study presents the first global high-resolution (30 meters) map of high-altitude wetlands across the world's major mountain regions, identifying a total area of over 134,700 square kilometers of these critical ecosystems.

Objective

• To create a high-resolution, global, and seamless map of high-altitude wetlands in the Andes, Rocky Mountains, Alps, and High Mountain Asia.
• To enhance the understanding of wetland distribution in remote mountain regions and their role in ecosystem functioning and water cycles, particularly in the context of climate change impacts.

Study Configuration

• Spatial Scale: Global, covering the Andes, Rocky Mountains, Alps, and High Mountain Asia, with a spatial resolution of 30 meters by 30 meters.
• Temporal Scale: The map represents the average wetland extent for the period 2019–2024, utilizing satellite imagery acquired between January 1, 2019, and December 6, 2024.

Methodology and Data

• Models used: Supervised classification using a Random Forest machine learning model (Google Earth Engine's 'smileRandomForest' function).
• Data sources:
  • Satellite imagery: Sentinel-1 SAR GRD (C-band synthetic aperture radar) and Harmonized Sentinel-2 MSI Level-2A (optical and multispectral imagery).
  • Topographic data: NASA SRTM 30m Digital Elevation Model (DEM) (v3).
  • Ecological data: RESOLVE global ecoregion map.
  • Training and validation data: National Bofedales Inventory (Peru), National Wetland Inventory (U.S. Fish and Wildlife Service for Rocky Mountains), Swiss REN-data set of wetlands (Alps), and manually delineated wetland occurrences (High Mountain Asia using VHR satellite imagery).

Main Results

• A total area of 134,700 square kilometers of high-altitude wetlands was identified across the four major mountain regions, with over 30,500 square kilometers classified with a probability of 90% or higher.
• The global classification achieved an overall accuracy of 85%–86% using k-fold cross-validation.
• Regional classification accuracies varied: Andes (91%), High Mountain Asia (93%), Rocky Mountains (83%), and Alps (76%).
• Leave-one-region-out (LORO) cross-validation indicated strong spatial transferability for the Andes (Balanced Accuracy = 0.78) and High Mountain Asia (0.74), but limited transferability for the Rocky Mountains (0.62) and Alps (0.54).
• Reliability diagrams showed good global calibration (Expected Calibration Error ≈ 0.05; Brier Skill Score ≈ 0.58), excellent calibration in the Andes and High Mountain Asia, moderate in the Rocky Mountains, and poorer in the Alps.
• The low certainty and accuracy in the Alps are attributed to fragmented, smaller wetlands, spectral resemblance to surrounding vegetation, steep terrain effects, and highly variable moisture contributions.

Contributions

• Presents the first global, high-resolution (30 meters), and seamless map of high-altitude wetlands, bridging the gap between coarse global land cover maps and limited local studies.
• Employs a unified supervised classification approach consistently applied across diverse mountain regions, capturing varied wetland characteristics.
• Enhances the understanding of wetland distribution in remote and inaccessible mountain environments.
• Provides a critical dataset to support research on high mountain water resources, ecosystem functioning, carbon storage, biodiversity, and the impacts of climate change.

Funding

• Natural Environment Research Council (NERC) highlight topic grant “Deplete and Retreat: the future of Andean Water Towers” (NE/X004031/1)
• NERC UKRI project RAHU (NE/S013210/1)

Citation

@article{Becker2026map,
  author = {Becker, Rike and Kropáček, Jan and Ross, A. and Gribbin, Tom and Drenkhan, Fabian and Sotelo, Lilia Hernández and Mendoza, Marc Martínez and Davies, Bethan J. and Ely, Jeremy C. and Buytaert, Wouter},
  title = {A map of high-altitude wetlands in the world’s major mountain regions},
  journal = {Scientific Data},
  year = {2026},
  doi = {10.1038/s41597-026-07020-w},
  url = {https://doi.org/10.1038/s41597-026-07020-w}
}