Responses to Rapidly Shifting Waterscapes in the High Tropical Andes of Southern Peru

Research in tropical alpine areas provides a window into some of the most rapidly changing, yet least-studied, ecosystems on Earth. The Cordillera Vilcanota in the central Andes of southern Peru has been the focus of more than decade of research dedicated to understanding the biological and societal impacts of rapid climate change. Our multi-disciplinary approach bridging natural and social sciences highlights the parallel and interacting socio-environmental impacts of climate-driven shifts in high-elevation waterscapes.

High-elevation waterscapes face uncertainty surrounding the future timing of onset and duration of the wet season. We synthesized participatory observation of daily pastoral practices in a high-elevation herding community with reproductive phenology surveys of a high-elevation amphibian community to examine parallel responses to the strong 2015/2016 El Niño event, which caused a significant delay in wet season onset. We identify key strategies (i.e., flexible mobility for humans; reproductive plasticity in amphibians) for confronting unpredictable, extreme conditions in rapidly changing high-mountain environments.

Concurrently, rapid deglaciation and a surplus of glacial meltwater are substantially altering alpine wetlands. We assessed past, current, and future water availability by analyzing stable isotope signatures in synoptic water samples to identify habitats fed by glaciers, in conjunction with long-term observations of wetland vegetation cover change, and interviews with local herders. Our results suggest future reductions to connectivity between aquatic habitat and glacial meltwater may decrease the availability of suitable habitat for aquatic organisms and grazing areas for alpaca herds, the principal economic resource in this pastoralist community.

Taken together, our results suggest future precipitation and meltwater reductions could increase human-human and human-wildlife conflicts over diminishing water resources. As a living climate change laboratory, the Cordillera Vilcanota highlights the urgent need to create collaborative research approaches and adaptation strategies to make informed responses to changes that affect high-mountain areas worldwide in coupled human-natural systems.