Cloud dynamic contribution to high-elevation peatland growth during the Holocene (Escalerani, Central Andes, Bolivia)

Abstract

Changes in climate conditions during the Holocene are documented in different parts of South America, showing contrasting responses to global changes. This study was conducted in the wet puna at an elevation of 4040 m a.s.l. on the eastern side of the Cordillera Real in Bolivia near Lake Titicaca. Pollen, charcoal, and stable isotopes in a sediment core collected in the peatland of Escalerani were analyzed. Results revealed environmental changes during the past 7500 yr BP, with an increase in wet climate conditions from 5900 to 4700 cal. yr BP and 3500 to 1300 cal. yr BP, and two dry periods between 4700 and 3500 cal. yr BP and 1300 to 560 cal. yr BP. Changes in hydrological conditions ranged from local changes because of glacier melting to regional changes in annual rainfall variability, related to South American monsoon activity. Moreover, our results highlight the importance of cloud convective activity from the Amazon basin along the adiabatic gradient, which maintained moist conditions at high elevations even during the mid-Holocene dry phase. The last 70 years have been characterized by the degradation of the peatland because of human activity.