青海东部史前人口-耕地变化及其对植被演变的影响

Prehistoric Population and Cultivated Land Change in the Eastern Qinghai Province and Its Environmental Effects

集成青海东部考古数据和DEM,利用面积和墓葬相结合的估算法计算了区域史前人口数量,并利用GIS工具重建史前区域耕地面积的时空格局。结果表明：新石器马家窑文化时期区域人口、耕地迅速增加,并在晚期马厂时期达到新石器的顶峰,人口总数接近4万人,耕地面积达到462 km2,人口和耕地主要分布在黄河—湟水谷地内;齐家时期人口和耕地有一定幅度下降,在青铜时代人口和耕地有显著回升和增长,人口总数达61 000余人,耕地面积达到1 076 km2,约占区域适宜耕地总数的1/10。伴随人口与耕地的变化,人类活动的环境效应也逐步显现,5~4 ka B.P.人类活动导致研究区河谷地带乔木的减少,伴人植物增加,尤其是禾本科含量有较大幅度增加,与当时的粟作农业关系密切;4 ka B.P.后大范围的乔木减少是气候变化结果,其后人类活动加强,加速了乔木覆被面积的萎缩。

Integrated the archaeological and DEM data in the eastern Qinghai Province, using a combination of the area archaeological site and burials to estimate the regional prehistoric population, and apply the GIS tools to rebuild the regional cultivated land area of the prehistoric period for time and space. The results showed that regional population and cultivated land increased rapidly during the Majiayao culture of Neolithic Period, and the population had reached the peak during the late Machang culture regional of Neolithic period, in which the population had totally risen up to about 40×10^3 and the size of farm land was expanded to 462 km^2. The popula-tion and the farm land were mainly distributed in the valley area of the Huanghe River-Huangshui River. The population and farm land were decreased significantly during the Qijia culture period, but it was rebounded ob-viously during the bronze age, in which total population increased to 61 000 and the farm land was expanded to 1 076 km^2, about 1/10 of the total arable land area in the region. With the changes of population and farm land, the influence of human activities on the environment began to appear. In 5-4ka B.P., human activities lead to the reduction of the arbor in the study area, the increase of Androphile, especially Gramineae have sharply in- creased, as agriculture is closely related with the millet. After 4 ka B.P., a shape reduce of the arbor is due to the change of climate, while strengthening of human activities accelerated the shrinking arbor cover area.