Traditional agroecosystem transition in mountainous area of Three Gorges Reservoir Area

The Three Gorges Reservoir Area (TGRA) is a typical ecological vulnerable area with a characteristic of rural, mountainous and immigrant areas, therefore, it is of great significance to study the traditional agroecosystem changes in the TGRA for rural development and revitalization. According to the framework of "theoretical analysis - empirical study - trend prediction", this paper, taking the Caotangxi watershed as an example, analyzes the transition and trend of the traditional agroecosystem in the mountainous area of TGRA from the spatial change of man-land relationship by combining the Quick Bird high-resolution remote sensing images from 2012 to 2017, the natural resources and the farmers' behavior. The results show that: (1) the agroecosystem in the TGRA can be divided into four models by using buffer rings of 100 m interval, namely, the high-low-low, high-low-high, low-high-low and low-low-high. Different models, which represent the agricultural development stages in the TGRA, can reveal the trend of traditional agroecosystem transition from traditional way to modernization. (2) The agroecosystem in the TGRA is gradually transforming from the extensive agricultural land use to the intensive utilization way characterized by the rationalization of planting structure and species diversity within a range of 300 m around the settlements, through the ecological restoration way such as the abandonment of sloping farmland and the planting of economic fruit forest in the traditional farming area. (3) The traditional agroecosystem in the TGRA, represented by system elements such as farmers and sloping farmland, is undergoing transformation. Among them, the sloping farmland has mostly transformed from the type dominated by production function to the type with an equal emphasis on ecological and economic functions, the way of farmers' livelihood has tended to diversify, the ecosystem vitality of settlements system has gradually increased, and the change range of agroecosystem transition has basically migrated from high mountain area to valley flat area. Additionally, although there is a deficiency in study time limit, the results still have enlightenment for the rural land use, the control of soil and water loss and the improvement of rural living environment of the mountainous areas in the TGRA. © 2019, Science Press. All right reserved.