青海湖湖滨湿地演变与驱动因素分析

为了更好地应对气候变化的影响,对暖湿化气候下青海湖湖滨湿地的演变现状及其驱动因子进行研究。通过遥感影像解译和水文分析计算结合实地调查,发现21世纪气候暖湿化进程下,青海湖水位升高2.1 m,入湖水量显著增加。2003—2016年的年均径流量比1956—2002年的年均径流量增加了6.0亿m3,湖面降水增加了3.8亿m3,从最低水位到现状水位的湖滨淹没区面积为222 km2。湖滨区的地下水位抬升,地势较低的河谷区沼泽草甸面积扩大11.7 km2,溢出泉恢复,间歇性河流增加了近30条,间歇性湖泊(泡沼)恢复到1980年初的水平。同时,湖水位上升淹没了约23 km2的湖滨沼泽和鸟岛部分区域,植被腐殖质、食物碎屑和鸟类沉积粪便进入湖泊,加之畜牧业和旅游业的发展,牲畜粪便和垃圾流入青海湖,导致水深和光照适宜的湖滨区爆发刚毛藻水华。

Analysis of lakeside wetland evolution and driving factors around Qinghai Lake

In order to deal with the effects of climate change better, we clarified the current situation of wetlands evolution and its'' driving factors around Qinghai Lake. We found that the water level rose by 2.1m and the inflow into the lake increased significantly with the acceleration of climate warming and humidification in this century through the interpretation of remote sensing image and analysis of hydrological data as well as field investigation. The average annual runoff from 2003 to 2016 increased by 6.0 million m 3 compared with the average annual runoff from 1956 to 2002, and the lake precipitation increased by 380 million m³ The groundwater level in the lakeside area rose,and the marsh meadow area in the low-lying valley area expanded by 11.7km². At the same time, overflow springs recovered. The number of intermittent rivers increased by nearly 30,and the number of intermittent lakes (bog) recovered to the level of the early 1980s. Meanwhile, the lake level rose which submerged about 23km² of lakeside marshes and parts of bird Island. Vegetation humus,food detritus and bird detritus entered the lake. In addition,with the development of animal husbandry and tourism in recent years, pollutants such as livestock manure and garbage entered Qinghai Lake, leading to the outbreak of cladophora in the lakeside area where the water depth and light were suitable.