Vegetation and climate change since the late glacial period on the southern Tibetan Plateau

Abstract

A well-dated pollen record from the Lake Mabu co, located on the southern Tibetan Plateau, provides a history of vegetation and climate change from the late glacial period to the Holocene. Before 17,090 cal yr BP, the vegetation type was alpine steppe desert with a cold and dry climate on the southern Tibetan Plateau. The high percentages of extra arboreal pollen (Pinus) indicate that the climate was mainly controlled by strong Westerlies. After 17,090 cal yr BP, alpine meadows mainly consisting of Cyperaceae were widely distributed in the study area. This shift in vegetation type may have been induced by increasing Indian Summer Monsoon (ISM) precipitation and atmospheric CO2 concentrations. The expansion of the montane mixed forests after 12,480 cal yr BP indicates that vertical migration of the vegetation belt occurred under the influence of a strong ISM and climate warming. These vegetation changes suggest that the climate has gradually become moister and warmer since the late glacial period, which is consistent with the intensified ISM and the summer solar insolation of the Northern Hemisphere.