贡嘎山海螺沟冰川退却迹地植被原生演替

海螺沟冰川末端前，近２０００ｍ冰川退却迹地植被原生演替经历了：裸地－草本地被、柳－沙棘－水冬瓜、水冬瓜、云冷杉－桦－杜鹃及云冷杉五个发展阶段。据树木年轮推测，１７０年来冰川末端位置变化显著。植被发展过程、冰川退却速度与气候变化密切相关。与冰川退却对气候变化的响应相比，植被对气候变化的响应更为敏感。

VEGETATION PRIMARY SUCCESSION ON GLACIER FORELAND IN HAILUOGOU,MT. GONGGA

Hailuogou Glacier is located at the east slope of Mt.Gongga in western Sichuan Province. A vegetation investigation on foreland area has been done along the glacial valley within about 2000m from the glacier tongue. 13 plots distributed from the end of the glacier(altitude from 2950m to 2800m)have been carefully studied.Further study indicates that the vegetation primary succession on foreland arca hasexperienced 5 stages:1.bare land-herds lasting 8 15a; 2.Salix-Hippophae-Populus lasting about35a; 3.Populus lasting about 60a;4.Picea,Abies-Betula-Rhododendron lasting about 30a;5.Picea-Abies as a climax in the succession. 1920s is a turning point in the process of deglaciation. During about 100a before 1920,theglacier retreated by 6m/a; but in the following 70a ,It obviously accelerated by 20m/a,which alsocan be refleeted by the distribution of end moraines. Corresponded analysis also revealed the similarities of the change tendancy both in rate ofdeglaciation and total basal area of vegetation. Within the distance of 1400 2000m from theglacier tongue,the glacier retreatell slowly , while the total basal area of plants kept changingfast ; but in the area within 0 1400m from the glacier tongue,the glacier began to accelaratelyretreat, as the change of total basat area of plants turned to slow down. In addition,evidencesaiso show that the responsebility of forest ecosystem is more sensitive to the climatic change thanthat of the glacier.