Holocene changes in fire frequency in the Daihai Lake region (north-central China): indications and implications for an important role of human activity
详细信息 查看全文
- 作者：Xu Wang ; xuking@mail.iggcas.ac.cn ; xukingw@163.com ; Jule Xiao ; Linlin Cui ; Zhongli Ding
- 关键词：Fire history ; Climate change ; Black carbon ; Vegetation ; Human activity ; Holocene
- 刊名：Quaternary Science Reviews
- 出版年：2013
- 出版时间：3 January, 2013
- 年：2013
- 卷：59
- 期：Complete
- 页码：18-29
- 全文大小：962 K
文摘
Black carbon (BC) content in a sediment core from Daihai Lake, Inner Mongolia, was analyzed to reconstruct a high-resolution history of fires occurring in northern China during the Holocene and to examine the impacts of natural changes and human activities on the fire regime. The black carbon mass sedimentation rate (BCMSR) was disintegrated into two components: the background BCMSR and the BCMSR peak, with the BCMSR peak representing the frequency of fire episodes. Both the background BCMSR and the magnitude of the BCMSR peak display a close relation with the percentage of tree pollen from the same sediment core, suggesting that regional vegetation type would be a factor controlling the intensity of fires. The inferred fire-episode frequency for the Holocene exhibits two phases of obvious increases, i.e., the first increase from <5 to ¡«10?episodes/1000?yrs occurring at 8200?cal.?yrs?BP when the vegetation of the lake basin shifted from grasses to forests and the climate changed from warm/dry to warm/humid condition, and the further increase to a maximum frequency of 13?episodes/1000?yrs occurring at 2800?cal.?yrs?BP when herbs and shrubs replaced the forests in the lake basin and the climate became cool/dry. Both increases in the fire frequency contradict the previous interpretation that fires occurred frequently in the monsoon region of northern China when steppe developed under the cold/dry climate. We thus suggest that human activities would be responsible for the increased frequencies of fires in the Daihai Lake region in terms that the appearance of early agriculture and the expansion of human land use were considered to take place in northern China at ca 8000 and 3000?cal.?yrs?BP, respectively.