Assessment on multi-functionality of land use in Tibet

Abstract: Judging from the change of land-use activities and planning formulations, multifunctional land use has been the inevitable trend in Tibet. It is an appropriate way to improve land use efficiency, also necessary for balanced eco-economic development in Tibet. The state of multi-functionality is the fundamental information for multifunctional land use and the aim of researchers. According to the present research and the land use situation of Tibet, the land use functions were divided into three layers: total function layer, single function layer and subfunction layer. There were 4 single functions: production function (PRF), economic function (ENF), ecological function (ELF), and social function (SOF), and 9 subfunctions. This paper established an assessment method on multi-functionality of land use, involving the characterization of land use function type, the establishment of an assessment indicator system, the estimation of weights and threshold values, the measurement of function value, and the indexes for reflecting the state and change of land use function, such as function value, dynamic degree, realization rate, standard deviation and dynamic dominance. The method was applied to measure the state of land use functions in 1990, 2000 & 2010, as well as the change between the 20 years in Tibet. The results show that the dynamic degree of total function was 2.0% and 5.7% during 1990-2000 and 2000-2010, which denoted that the total function of land use had improved slowly to a middle sustainable level. The standard deviations of single function and subfunction decreased gradually, which indicated that the harmony of multifunction was promoted progressively. With the decrease of the dynamic dominance, the direction of land use was changed from single function to multifunction. The function that changed the most was the production function during 1990-2000 and the economic function during 2000-2010. This change means that the centre of land use turned from production in the former period to economy in the latter period. The change characteristics between the functions were different. The sustainability of the production function was promoted from low-level to middle-level. The agricultural production function has undergone a rapid increase during 1990-2000, and a slow decrease during 2000-2010. Contrary to the fluctuation of the agricultural production function, the pastoral production function improved steadily and rapidly. The change of the economic function was on a low rise before 2000, and on a rapid rise after 2000 with the implementation of The Western Development. Though the industry and infrastructure facilities were improved greatly, the economic function was still in a low level. Influenced by the rapidly decreasing function of maintaining the balance of the ecosystem, the sustainability of the environmental function was retrograded from high-level to middle-level. It exhibited a low increase during 1990-2000 and a rapid increase during 2000-2010 for the social function, which was just promoted to the middle-level. The promotion of integral effect and harmony of multifunctional land use is the aim of land use in Tibet. It is suggested to stabilize the production function, step up the pace of improving the economy function, control the degeneration of environmental function emphatically, and promote the social function progressively. The assessment method established in this paper is about quantitative analysis, and is an enrichment of the research on multifunctional land use. The application of the assessment method provides the reference and instruction for land use decisions in Tibet.