Analysis On The Evolution Of Urban-town Landscape Pattern And Its Constraining Factors In Bazi Of Yunnan Province,China

Urbanization is a global trend for the modernization of human social development,which is challenged by urban environmental issues and urban sustainability.Researches on urban-town construction land pattern and temporal and spatial dynamics may reveal the rules and issues in urban expansion,as well as provide implication for urban-town planning and urban-town landscape optimization.Most of urban research focused on coastal and plain areas.However,12%global population lives in mountain areas covering25%land surface of earth.In China,two-thirds of the territory comprises less developed mountain areas,which contain larger populations than other countries and they are undergoing urbanization expansion at an unprecedented rate.Urbanization in mountain areas should be considered for its landscape changes,expansion modes,and related constraints.We chose inter-mountain basins(bazi),which is core areas for urban-town distribution and growth,as integrated research entities.Land use and land cover were deprived by interpreting remote sensing imageries.Urban-town landscape patterns and changes were elucidated in the basins large than 1 km2by hierarchical landscape analysis.Then regression model and random forest model were adopted to reveal the constraints on the urban-town landscape patterns and changes.The results indicted:(1)The capital of Yunnan Province,all 15 prefectures and 69.8%counties,and 30%townships were located inside a total of 1198 basins,with 1.0–1385.1 km~2 areas.(2)Urban-town landscape patterns were mainly controlled by basin area size,cropland,roads,and administrative levels.Topographical and climatic factors had less influences.(3)Development of urban-town systems in the basins were restrained by administrative levels.Urban-town areas were correlated more to the basin areas of high administrative levels.Physical factors were much more influential on urban-town landscape patterns in the basins of low administrative levels,i.e.towns and villages.(4)From 1990 to 2018,urban-town areas continuously grew and were constrained by basin areas.The constraint became more obvious in the late stage.(5)Expansion intensity of urban-town landscape grew with the basin areas,in contrast,the slope put negative effects on the expansion intensity.Meanwhile,the expansion intensity rose up with the administrative levels.Urban-town growth were simultaneously controlled by physical and social constraints.We found the relative big basins(>50 km~2)of town level had potential in future urbanization.It is essential that scientific urban-town planning and ecological capacity evaluation for urban sustainability and the reduction of environmental impacts in the mountain areas.