FIRE HISTORY IN ARID CENTRAL ASIA SINCE THE MIDDLE MIS 3 INFERRED FROM CHARCOAL RECORDS IN LAKE AILIKE,XINJIANG
Understanding the long-term evolution of fire and its influencing factors not only contributes to our comprehension of how fire responds to changes in vegetation and climate but also provides a scientific basis for modern fire prediction and management.The charcoal serves as the fingerprint of past fires in sediment and is a valuable indicator for reconstructing fire history.In this paper,we use 15 AMS 14C dating dates,pollen flux,and charcoal data from a sediment core Ailike-2019(4.49 m in length,location at 45.93°N,85.81°E),recovered from Lake Ailike in Xinjiang,AC A,to reconstruct the fire history of Lake Ailike over the last 40000 years.The results show that vegetation coverage was relatively low,and fire activity was less during the mid-late MIS 3(40.2～26.7 cal.ka B.P.).The vegetation coverage continued to decline with fewer fires during MIS 2(26.7～11.7 cal.ka B.P.).Subsequently,there was a significant increase in vegetation coverage and a corresponding increase in fire activity during the Holocene(11.7～0 cal.ka B.P.).These reveal that relatively less fire activity during the mid-late MIS 3,low fire activity during MIS 2,and a significant increase in fire activity during the Holocene.Fire activity in the Lake Ailike region has followed similar trends in vegetation coverage fluctuations since the middle MIS 3,suggesting that fire in the Lake Ailike region has been mainly controlled by vegetation coverage.This pattern of fire history with vegetation is also recorded in some charcoal records in ACA,indicating that fire on orbital timescales is influenced by combustible biomass in ACA.To further explore the factors influencing fires in the study area since the mid-late MIS 3,we compared the reconstructed fire history and vegetation coverage of Lake Ailike with other climate forcings.In conclusion,vegetation coverage is the primary influencing factor in controlling fires while climate change driven by solar radiation indirectly controls fire activity by influencing vegetation coverage.The expansion/contraction of vegetation coverage under warm-wet/cold-dry climatic conditions provide more/less combustible biomass,resulting in abundant/limited charcoal.However,it is important to note that during the late Holocene,there has been a notable increase in the relative occurrence of local fires,potentially influenced by human activities.
arid Central AsiaLake AilikeMIS3charcoalfire activity
万方数据
维普
