初探青海湖地区生态环境演变的起因

PRELIMINARY STUDY ON THE CAUSE OF THE EVOLUTION OF ECOLOGICAL ENVIRONMENT IN QINGHAI LAKE AREA

本文根据遥感卫星图片资料,探讨了青海湖地区生态环境演变的特征。研究表明:干旱是造成该地区生态环境变化的主要原因。由于年蒸发量是年降水量的4倍,湖水水位1956—1986年间下降了3.16米,湖水面积缩小了279.4平方公里;1986年沙漠面积已达450平方公里,比1956年增加了115平方公里;沼泽面积1986年为193平方公里,比1956年减少了61平方公里。将古植被与现今植被演化进行分析对比得知,1982—1986年该区植被类型、种类组成均无显著变化。青海湖水位下降及生态环境的变化与上新世以来青藏高原巨大隆升密切相关。人类活动对生态环境有所影响,但强度有限,并非该区生态环境恶化的主导因素。

Based on the data from remote sensing satellite images, the paper deals with the characteristics of the evolution of ecological environment in Qinghai lake area. The research revealed that aridity was the main reason for the change in ecological environment in the area. Due to the annual evaporation in four times the annual precipitation, the lake level descended by 3.16 meters and the lake surface shrank by 279.4 km2 from 1956 to 1986; and the desert area was up to 450 km2 in 1986, which increased by 115 km2 as compared with that in 1956. The area of the wetland surrounding the lake was 193 km2 in 1986, reduced by 61 km2 as compared with that in 1956. Analysis and comparison of evolution between paleovegetation and modern vegetation led to the conclusion that both the vegetation type and species composition had no obvious change from 1962 to 1986. The drop in Qinghai lake water level and the change in ecological environment are found to be closely correlative to the great uplift of Qinghai-Xizang(Tibet) plateau since Pliocene epoch. human activity has the limited effect on the ecological environment, and is not the dominant factor to lead to the deterioration of ecological environment in the area.