Vegetation successions in response to Holocene climate changes in the central Tibetan Plateau

Alpine vegetation in the central Tibetan Plateau is vulnerable to climate change. Nine lacustrine pollen records with well-constrained chronologies and high-resolution data were reviewed to document regional and local patterns of alpine vegetation succession in this region, and to understand the climatic driving forces for these changes. According to the relationship between modern pollen distribution and climate condition in the central Tibetan Plateau, Cyperaceae is a moisture-favored and cold-resistant component in both the vegetation and pollen assemblages in the region, while Artemisia is a drought-tolerant and temperate component. Within an east west transect across contemporary alpine steppe zone and alpine meadow zone of the central Tibetan Plateau, Kobresia (Cyperaceae)-dominated alpine meadow expanded westwards to invade the alpine steppe (dominated by Artemisia and Poaceae), and to replace the Artemisia-rich temperate steppe on a regional scale during the mid-Holocene, probably driven by the enhanced precipitation. Vegetation within a south north transect, covered by alpine steppe and temperate steppe, underwent a turnover in steppe composition from a predominance of Artemisia during the first half of the Holocene to a predominance of Cyperaceae in the latter half on a regional scale, caused by a decline in the temperature. Furthermore, altitudinal vegetation belts in the central Tibetan Plateau shifted downwards in response to cooling climate since the early Holocene. Therefore, monsoonal precipitation and insolation-driven temperature changes may be the key climate driving forces for the Holocene vegetation successions in the central Tibetan Plateau. (C) 2015 Elsevier Ltd. All rights reserved.