Spatiotemporal Peatland Productivity and Climate Relationships Across the Western South American Altiplano

Abstract

The South American Altiplano is one of the largest, semiarid, high-altitude plateaus in the world. Within the Altiplano, peatlands locally known as ‘bofedales’ provide key water resources and ecosystem services to Andean communities and are important components of regional hydrology. Since bofedales are found near the upper-elevational limits for vegetation growth, they are highly sensitive to climate variability and change. Recent warming trends, changes in snow cover, and shifting atmospheric circulation patterns are among the differences that will likely affect peatland dynamics and regional hydrology. It is therefore urgent to better understand the relationships between climate variability and the spatiotemporal variations in peatland productivity across the Altiplano. Here, we use a recently developed inventory of bofedales, based on 31 years of Landsat data, to explore regional productivity patterns and climate influences on the dynamics of peatland vegetation. We focus specifically on the bofedal network in the Chilean Altiplano, the driest sector of the plateau, and use the satellite-derived NDVI (Normalized Difference Vegetation Index) as an indicator of vegetation activity. We develop temporally continuous NDVI products at the bofedal unit, 1 km2, and 5 km2 scales in order to evaluate relationships with climate variables over the past three decades. We conclude that cumulative precipitation from the current year to two years prior and snow persistence from two years prior are strongly associated growing season productivity, demonstrating the complex lagged relationships between climate and peatland productivity in the Chilean Altiplano. We also show that the recent jump in peatland productivity between 2013–2015 drives the increasing trend in NDVI and is likely a response to consecutive years of anomalously high snow accumulation and rainfall. A significant relationship between productivity and temperature does not emerge at the large-scale. Understanding the large-scale productivity dynamics and characterizing the response of bofedales to climate variability over the last three decades provides a baseline to more effectively monitor the responses of Andean peatlands to climate change.