纵向岭谷区怒江流域生态变化之驱动力分析

The Main Factors to Effect the Ecological Changes in Nujiang Drainage Basin of Longitudinal Range-Gorge Region

利用纵向岭谷区怒江流域主要县市农业发展统计资料、森林资源调查数据、干流道街坝水文站径流量与输沙量数据和国土资源遥感综合调查成果等，采用趋势分析、主成分分析（SPSS）等方法综合分析了近40a间流域及上下游的生态变化，并揭示其主要驱动因子。结果表明：（1）国家和云南省林业和农业等相关政策是影响流域及上下游生态变化的主驱动力，它们控制着流域内森林资源、土地利用以及水土流失的变化趋势；（2）人口增长是影响流域土地利用变化的第二驱动力，其影响力表现为上游大于下游；（3）1968～2000年间由河道输沙量来看，流域内水土流失呈增长趋势，1999～2004年间从流域土壤侵蚀面积和侵蚀量上看，水土流失状况呈减少趋势；（4）流域水土流失加剧与自然因素、人为活动有密切相关关系；在影响程度上，自然要素的控制力大于人为活动。

Nujiang is the upstream of Salween which is one of the famous international rivers in Southeast Asia. In the recent years, its ecological changes and the effects to the local people and the ones living at the downstream have been brought highly attentions. And some former studies covered some issues on land cover, land use, the sustainable development. So, there were few concerns on the ecological changes, the characters and the main factors. In order to discover the integrated ecological situation of the Nujiang drainage basin, three aspects of forest coverage, farmland structure and, soil erosion and sediment load were analyzed. The statistics data on agricultural development in 1978 -2003 with 36 index, forest coverage survey data in 1960s, 1970s and 1980s, land resource surveying and remote sense monitoring data in 1987 -2000 of the major counties and cities and data of annual discharge and sediment load at the Daojieba hydrological station in 1968 -2000 were used, the ecological changes at the levels of the watershed, the upstream and the downstream during 40 years were analyzed, and the main factors are discovered. The main conclusions were found： （1） the relative national and provincial policies on forestry and agricultural development were the major factor to effect the ecological changes at the watershed, upstream and downstream, that controlled the changing tendencies of forest resource, land use and soil erosion; （2） population growth was the second factor to effect the land - using change of the watershed, and the force was more powerful at upstream than at downstream; （3） in 1986 - 1987, from the change of the sediment load, the soil erosion was getting heavy; in 1999 -2004, from the area and the amount of soil erosion, it was getting light; （4） the increase of soil erosion were controlled by natural elements and human activities, and the force of natural elements was more power than that of human activities.