Evolution on trade-offs and synergy of multifunction of rural landscape in metropolitan suburbs

The rural landscape function has obvious temporal and spatial heterogeneity, and exploring the relationship between landscape functions has become the focus of landscape ecology research. Aiming at the scientific representation of landscape function and the quantification of landscape multifunctional relationship, taking Qingpu district of Shanghai as an example, 6 kinds of landscape functions were constructed according to the functional framework of "production, life and ecology". Based on the data from 1980 to 2015, the variation characteristics of multi-functional trade-off and synergy relationships of rural landscape in 184 administrative villages in this area were studied by using the method of Spearman rank correlation coefficient analysis and bivariate spatial autocorrelation. The following results are obtained: 1) the agricultural production function of urban suburbs cannot replace the function of economic development. The economic development function of Qingpu district has become the leading functional. 2) The spatial and temporal differences of the multi-functional trade-off and synergy relationships of rural landscape in Qingpu district from 1980 to 2015 were significant. The production function- living function is led by the cooperative relationship, the space was spread along the central axis, the production function- ecological function was dominated by the trade-off relationship, the space was spread from the middle to the east, and the living function -ecological function trade-off the cooperative relationship was more balanced, The trade-off relationship was spread from the middle to the east and the synergy was spread from the west to the north and south. The contradiction between agricultural production function - economic development function (EDF), economic development function- ecological regulation function (ERF)/ environmental maintain function (EMF) was the inevitable contradiction in this area, and the economic development of this area was realized at the expense of ecological environment. There was a significant trade-off relationship between the EDF and landscape aesthetic function (LAF), and the pattern of the relationship between the two was the synergy of the eastern trade-off west, and the number of weighing areas was increasing. The relationship between EDF and spatial bearing function presents the pattern of eastern trade-off and western coordination, and the cooperative relationship area showed an increasing trend. The trade-off area between LAF-ERF/EMF was concentrated in Qingdong area, and the cooperative area was distributed in Qingxi area, and the number of weighing area increases at first and then decreases. The synergy area decreases at first and then increases. 3) The analysis method of temporal and spatial combination can accurately and comprehensively reflect the evolution characteristics of multi-functional trade-offs & synergies relationships of multifunctional rural landscape. The correlation analysis of multi-function and single time dimension of rural landscape cannot fully and accurately represent the change of multi-functional relationship, and there are differences in the pattern of space-time relationship. The relationship between spatial carrying function and ecological regulation function/environmental balance function was found to be compatible in time and tradeoff in space. And the results of time synergy and spatial tradeoff between agricultural production function and ecological regulation function/environmental balance function verify the scientific nature of using space-time model to analyze the multi-function tradeoff-synergy relationship of rural landscape.