By Dingyu Xuan

Are glaciers the lifeline of high-mountain wetlands?

High-mountain wetlands are essential yet vulnerable ecosystems. They support local communities, regulate water supplies, and sustain biodiversity^1,2, but their future under climate change remains uncertain³. Glaciers are often considered to provide an important and relatively stable water source for these wetlands, particularly during the dry season^4,5.

As mountain glaciers are rapidly shrinking and may eventually disappear^6,7, their meltwater contribution is expected to follow a “peak water” trajectory: initially increasing as melting accelerates, before declining as the remaining ice becomes smaller⁸. Polk et al.⁹ proposed that wetlands might follow a similar trajectory with a time lag, potentially continuing to decline after glaciers have largely retreated. Local communities are therefore increasingly concerned about losing both the wetlands and the water resources on which they depend.

However, our recent study, combing satellite observations with statistical analysis, suggests a more nuanced picture –– at least in the high-Peruvian Andes. Glacier meltwater helps maintain year-round wet conditions in some wetlands close to the ice, but this influence weakens rapidly downstream. At broader spatial scales, wetland dynamics are controlled much more strongly by precipitation.

Figure 1. High-mountain wetlands in Cordillera Vilcanota, Peru. Field photos by Rike Becker.

Tracking wetlands from space

To investigate this relationship, we studied two contrasting regions in southern Peru: the still-glacierised Cordillera Vilcanota and the largely deglaciated La Raya range. Using satellite imagery collected between 2019 and 2025, we mapped monthly changes in saturated wetland extent¹⁰. We then combined these observations with precipitation and temperature data and examined whether wetland behaviour changed with distance from present or former glaciers.

Figure 2. Location and background of the two study sites¹¹. a) Overview of the study site within the Andes. b) Locations of the Cordillera Vilcanota (top) and La Raya (bottom) ranges in Peru. Glacier outlines from the Randolph Glacier Inventory, dated to ca. 2000 CE. c, d) Mean monthly precipitation and air temperature from January 2019 to February 2025 for the Cordillera Vilcanota (c) and La Raya (d)¹¹.

Rainfall dominates, but glaciers provide a local buffer

Across both regions, precipitation is the main control on wetland wetting and drying. Wetland saturation typically increased several months after the rainy season began, reflecting the time needed for rainfall to infiltrate, recharge groundwater and reach the wetlands.

Yet glaciers are not irrelevant. In the Cordillera Vilcanota, wetlands close to glaciers show smaller seasonal fluctuations and remained more consistently wet throughout the year. Glacier meltwater therefore appears to act as a buffer, helping nearby wetlands withstand seasonal dry periods.

This buffering effect is highly localized. It is strongest within a few kilometers of glacier margins, weakened downstream, and is no longer detectable at distances of roughly 10–12 km. Most wetlands at the landscape scale are therefore primarily dependent on rainfall and rainfall-recharged groundwater rather than directly on glacier meltwater.

Figure 3 Conceptual model of high‐Andean wetland dynamics at varying distances from glaciers¹¹.

What does glacier retreat mean for wetlands?

These findings do not mean that glacier loss is unimportant. Wetlands close to glaciers may become more sensitive to drought and rainfall variability as their meltwater buffer disappears. However, glacier retreat is unlikely to cause the widespread and simultaneous loss of all high-mountain wetlands. The more immediate consequence may be a shift from relatively stable, meltwater-buffered conditions towards stronger wetting and drying cycles.

The future of Andean wetlands will therefore depend not only on how rapidly glaciers retreat, but also on how rainfall patterns, groundwater storage, and local water management change in a warming climate.

Citation

Xuan, D., Becker, R., Vargas Valverde, M., Davies, B. J., Ely, J. C., King, O., et al. (2026). Spatial patterns of glacier-wetland hydrological connectivity in the rapidly deglaciating Peruvian Andes. Earth’s Future, 14, e2026EF008149. https://doi.org/10.1029/2026EF008149.

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About the Author

Dingyu Xuan

Dingyu is a hydrologist and PhD researcher in climate and carbon systems at Imperial College London. Her research explores how climate change affects water systems and ecosystem resilience, with her previous MSc research focusing on glacier–wetland interactions and high-mountain hydrology. She combines hydrological modelling, remote sensing, and climate data analysis to understand how ecosystems respond to environmental change and future climate scenarios.