Impacts Of Land Use In Alpine Settlement Onthe Boundary Of The Dry Valley In The Upper Reaches Of The Min River

Located at the transition zone between the Sichuan Basin and the Qinghai-Tibet Plateau, the dry valley is a sensitive and fragile area in the Upper Reaches of the Min River. Based on remote sensing data and the geographic information system, land use spatial pattern and the distribution of the dry valley in the Upper Reaches of the Min River was quantified. And the land use database in the Upper Reaches of the Min River is built. Furthermore, the land use change and driving forces, the changes of the area of the dry valley and its relationship with local environment, the differences of boundary displacements between settlement region and non-settlement region, and the impacts of land use change on the dry valley were analyzed. The study can provide references for vegetation restoration, rational use of resources and ecological development in the dry valley of the Upper Reaches of the Min River. The main contents and achievements of this paper are as follows:(1)GIS are used to processes remote sensing data, digital elevation model data, and image and document data, so that the basic data in the geodatabase are collected in a unified geographic coordinate system. Then, based on demand analysis and feasible analysis in the database, database architecture is designed and the land use database in the Upper Reaches of the Min River is built. In order to study spatial pattern change features of land use in the Upper Reaches of the Min River, this research focused on the using of several math model.(2)Based on the principal component analysis (PCA), the comprehensive evaluation index system of the land use is built up by selecting 21 indexes from the following three fields:nature, society and economy, combined with field investigation. The results show that the drivingfactor leading to land use changecan be generalized as four factors:the change of the natural environment, economic development, population growth and technical innovations in agriculture.(3)Based on the remote sensing data and field investigation results, the interpretation index can be set up, under the support of the geographic information system and the distribution of the dry valley in the Upper Reaches of the Minjiang River can be quantified.The changes of the area of the dry valley and its relationship with local environment, and the differences of boundary displacements between settlement region and non-settlement region were analyzed.(4)Considering three influencing factors, including elevation, slope and aspect, the impacts of land use change on the dry valley were analyzed. The results show that:Indifferent elevations and slopes, the decrease of the area and the boundary displacementsof the dry valley have maximum pertinency with the decrease of the area of farmland, and there are positive correlations.