Land use/land cover change geo-informative Tupu of Nujiang River in Northwest Yunnan Province

Abstract

Land Use/Land Cover Change (LUCC) is the core components of global change researches. It is significant for understanding regional ecological environment and LUCC mechanism of large scale to develop the study of LUCC of regional level. Nujiang River is the upper reaches of a big river in the South Asia--Salween River. Nujiang River is a typical mountainous river which is 3200 kilometer long and its basin area is 32.5 × 105 square kilometer. It locates in the core of "Three Parallel Rivers" World Natural Heritage. It is one of international biodiversity conservation center of the world, the ecological fragile zone and key ecological construction area, as well as a remote undeveloped area with high diversity ethnic. With the rapidly development of society and economy, the land use and land cover changed in a great degree. The function of ecosystem has being degraded in some areas which will not only impact on the ecological construction of local area, but also on the ecological safety of lower reaches -- Salween River. Therefore it is necessary to carry out the research of LUCC of Nujiang River. Based on the theory and methods of geo-information Tupu, the "Spatial Pattern" and "Change Process" of land use of middle reach in Nujiang River from 1974 to 2004 had been studied in quantification and integration, so as to provide a case study in local area and mesoscale in time. Supported by the remote sensing and GIS technology, LUCC Tupu of 1974-2004 had been built and the characteristics of LUCC have been analyzed quantificationally. The results showed that the built-up land (Included in this category are cities, towns, villages, strip developments along highways, transportation, power, and communications facilities, and areas such as those occupied by mills, shopping centers, industrial and commercial complexes, and institutions that may, in some instances, be isolated from urban areas), agriculture land, shrubbery land, meadow & grassland, difficultly/unused land increased from 1974 to 2004, the increased area of shrubbery land was the greatest, while the area of forest, artificial forest, waters, glacier and snow covered land decreased. The biggest decreased area was forest land. The biggest LUCC was the transformation from forest land to shrubbery land, the transformation from forest land to rangeland and agriculture land was the second. The main area of LUCC located at Nujiang River valley, between 2200-3700m of the east slope in the Gaoligong Mountain and 2800-3900m of the west slope of the Biluo Snow Mountain. From the valley to peak of mountain, the main land use type was transited from built-up land, agricultures land, artificial forest land to natural forest, shrubbery and grass land. The natural forest was the main land in the past 30 years. The main driving forces were the increase of population of local area, the governmental policies (Conversion of Farmland to Forests and Grass Land Projects, etc.) and urbanization. In order to accelerate the sustainable development of society economy and the ecological environment protection in this ecological fragile zone, strict management should be adopted to adjust the behaviors of human beings. Finally, VCM (variable clumping method) curve had been used to analyses the internal spatial distribution difference of land-use/land cover which shown that the landscape fragmentation was increased, the number of patches was added, the distance between patches was diminished during the past thirty years (1974-2004).