甘青地区中晚全新世植被变化与人类活动

STUDY ON THE RELATIONSHIP BETWEEN THE VEGETATION CHANGE AND THE HUMAN ACTIVITIES IN THE GANSU-QINGHAI REGION DURING THE PERIOD FROM MID-TO LATE-HOLOCENE

史前时期人类对环境的影响是近几年来国际研究的热点。在甘青地区 ,全新世的孢粉资料比较多。但在中晚全新世 ,该区人类对环境的影响作用及其程度仍不清楚 ,许多孢粉分析资料中并没有充分考虑人类活动的影响。本文选取孢粉分辨率较高、代表性较好的青海湖、兰州、秦安大地湾三地的资料 ,着重研究了其中乔木成分的变化。分析发现 ,孢粉组合中乔木成分的变化与气候变化的趋势并不一致。通过对考古及历史资料的分析 ,笔者认为 ,该区的植被很早就受到人类活动的影响。自全新世中期 ,本区植被中的乔木成分波动下降。 5 0 0 0 - 30 0 0aBP期间 ,史前农业对植被的影响较大。 30 0 0 - 2 0 0 0aBP期间 ,植被略有恢复。 2 0 0 0aBP以后 ,人为影响加剧 ,植被中乔木成分迅速下降。研究者认为 ,依赖孢粉资料重建中晚全新世的气候变化历史应当慎重。

A great attention has been paid to the influence of prehistoric human activities on environment. The Gansu Qinghai region is one of the regions where the prehistoric culture was developed early in China. This paper discusses the relationship between the vegetation change and the human activities in this region during the period from mid to late Holocene based on the high resolving power spore pollen data, archaeological studies and historical documents. It is considered that the vegetation in the region has been influenced by human activities since very early time. In the vegetation in the region the proportion of arbors has decreased in a fluctuation way since mid Holocene. The vegetation was seriously impacted by the prehistoric agriculture during the period of 5,000~3,000 a B.P. and it was restored slightly during the period of 3,000~2,000 a B.P. The proportion of arbors in the vegetation has been sharply decreased with the increase of human activities since 2,000 a B.P. It is considered that it should be paid a great care to rebuild the climate during the period from mid to late Holocene with pollen data.