大渡河上游生计方式的时空格局与土地利用/覆被变化

Livelihood succession and land use/cover changein the Upper Reaches of Dadu River watershed

该文以大渡河上游壤塘县、马尔康县和金川县为例,在野外考察、农户调查、历史资料分析的基础上,利用遥感、地理信息系统等多种手段,研究了该区1950～2000年生计方式的时空格局和1967～2000年的土地利用/覆被变化过程。结果表明:在河谷区、中山区、林区和牧区,居民生计方式的演变具有不同的特点。随着生计方式的演变,大渡河上游具有多样的土地利用/覆被变化过程。1980年代以后,该区不同地带劳动力向二三产业的转移具有显著的差异,居民对环境退化具有不同的响应方式。该研究还表明,生态脆弱区社会经济发展和生态重建的关键在于改变居民的生计方式,促进劳动力向二三产业转移。

Based on field survey, family questionnaire, historical datum analysis and interpretation of remote sensing data, this study presents livelihood succession during 1950-2000 and land cover change during 1967-2000 in Rangtang County, Maerkang County and Jinchuan County in the Upper Reaches of Dadu River watershed, by the combined using of geographic information systems (GIS) method and remote sensing (RS) method. The results show: there are different livelihood succession in the valley areas, middle-mountain areas, forest areas and pasture areas in the Upper Reaches of Dadu River watershed. At the collective economy stage, livelihoods of all the residents rest on agriculture and herds, which resulting in involution of agriculture. As labor forces transferred to the second and third industry to seek better livelihoods after the 1980s, livelihood of the whole region has diverse successions, as it is easier for the labor forces in valley areas to transfer to the second and third industry, harder for labor forces in middle-mountain areas, impossible for labor forces in pasture areas. As a result, involution cultivation system in the valley areas and middle-mountain areas is given up and agricultural structure is adjusted according to market needs, while the mountain nomadism has no marked changes. The residents in the valley areas and forest areas are positive to environmental degradation, while residents in the middle-mountain areas and pasture areas are passive to it. Driven by diverse livelihood successions, land use change successions and response models, the land cover change dynamics are also different in the four regions. This paper also shows that changing livelihood models and transferring the labor forces to the second and third industry are the key countermeasures for social and economic development and ecological rehabilitation of ecotone.