利用1956—2009年祁连山北坡定位观测、遥感监测和实地调查的气象、水文、森林、草原资料及相关文献,采用回归与对比分析相结合的方法,综合分析祁连山北坡生态环境变化。结果表明: 1960年以来,祁连山北坡年气温的年际变化率为0.033 4 ℃·a-1,气温呈上升趋势,特别是1987年以后气候明显变暖; 年降水量的年际变化率为0.570 2 mm·a-1,降水量呈增加趋势,但增加趋势不太明显,在1976年气候由干旱向湿润转变; 1956—2006年,祁连山北坡石羊河、黑河、北大河、疏勒河、党河和哈尔腾6个内流区河流域及大通河流域冰川面积减少17.7%,冰川厚度减薄5~20 m,雪线上升100~140 m,河西内流区冰川冰储量减少11.4%; 东段冷龙岭有27条冰川在1972—2007年的35年间消失; 1956—2009年,祁连山北坡出山径流变化存在一定的区域差异,石羊河流域出山径流呈明显减少趋势,黑河流域略有增加,疏勒河流域增加趋势明显; 1958—1988年间,祁连山北坡毁林草开荒面积达10.0万多hm2; 1958—1980年,森林面积减少0.6万hm2; 1989年祁连山自然保护区建立以来,不断加强保护培育,森林逐步恢复,至2008年有林地面积较1989年增加9.4万hm2; 因受人为干扰特别是超载放牧影响,1958年以来,祁连山北坡有林地、灌木林及草原的质量一直处于退化状态,致使森林病虫危害严重,灌木林积雪和保水能力下降,草地产草量降低,水土流失加剧。祁连山北坡生态环境仍处于局部改善、总体恶化状况,亟待加强保护与治理。
Based on meteorological, hydrological, forest, and grassland data collected by location observation,remote sensing,field surveys and relevant literature during 1956 to 2009, the ecological environment change in northern slope of the Qilianshan Mountains was analyzed synthetically using regression and correlation analyses.The results showed that the temperature had an annual variation rate of 0.0334 ℃·a-1 in northern slope of the Qilianshan Mountains since 1960,and exhibited a raising trend, especially since 1987.The annual variation rate of annual precipitation was 0.5702 mm·a-1,indicating that the precipitation tended to increase. The climate had changed from arid to humid in this region since 1976.From 1956 to 2006,the glacier area of six inland river basin(Shiyanghe river,Heihe river,Beidahe river,Shulehe river,Danghe river and Halternhe river)and Datonghe river basin in northern slope of Qilianshan mountains decreased by 17.7%.Thickness of the glacier reduced about 5~20 m,and the snow line rose about 100~140 m.The Glacier ice reserves in inland river basin of Hexi decreased by 11.4%. From 1972 to 2007,27 glaciers in the eastern section of the Qilianshan Mountains disappeared.From 1956 to 2009,the runoff change in the northern slope of the Qilianshan Mountains was different in different regions. The runoff was reduced significantly in Shiyanghe river basin, increased slightly in Heihe river basin,and increased obviously in Shulehe river basin.From 1958 to 1988,the area of the deforest and farming was more than 10.0 million hm2,and the forest area was reduced 0.6 million hm2.Since the Qilianshan Mountain Nature Reserve was established in 1989,the forest was restoring gradually because of continual protection and cultivating,and the forest area was increased 9.4 million hm2 grom 1989 to 2008.Due to human interference,especially over-grazing impact,the quality of the wood-land,shrub-land and grass-land in northern slope of the Qilianshan Mountains were in a degraded condition,which resulted in serious harm of forest pests,decrease of shrubbery snow and water-retention capacity and exacerbation of soil erosion.The ecological environment in northern slope of the Qilianshan Mountains was improved in certain regions,but deteriorated in overall region, and the protection and management are needed to be strengthen.