| The level of urbanization is an important indicator to measure the level of socio-economic development of a country or region.Since the 1990 s,China’s social and economic development has been rapid,especially in the 21 st century,the pace of urbanization is accelerating.In 2019,the No.1 document issued by the central government clearly stated that “China will deepen agricultural reform and revitalize the rural economy”,and “in the next five years,China’s rural urbanization will accelerate”.With the rapid development of rural urbanization,serious problems such as rapid resource consumption,water and soil pollution,and ecological environment deterioration have become increasingly prominent.Therefore,it is an urgent scientific problem to analyze the process,characteristics and dynamic changes of rural urbanization and coordinate the relationship between social and economic development and ecological and environmental protection in the river basin.Taking the Erhai Basin in Dali,Yunnan as the research area,using GIS and RS technology as the main methods,based on the Landsat satellite Remote Sensing Imagery in 1985,1995,2005,2015,and the basic data of the township social economy in the basin,1)the dynamic evolution characteristics of the land use landscape in the basin were analyzed.2)The evaluation index system of rural urbanization was constructed from the aspects of economic production,social life,spatial expansion and ecological environment.The entropy weight method was used to determine the weight of each index.The comprehensive evaluation model was introduced,the urbanization comprehensive index was calculated,and the process of rural urbanization in the research area was evaluated quantitatively.3)Based on the niche theory,the evaluation index system of rural landscape niche suitability was constructed from the aspects of agricultural production,social economy and ecological protection.By determining the index weights and using the comprehensive niche suitability model,the landscape niche suitability of each township in the basin was analyzed,and the township landscape function location and zoning control were carried out.The main conclusions of this paper were as follows:(1)From 1985 to 2015,the area of forest land,farmland and construction land in the Erhai Basin increased,while the area of grassland,water area and unused land decreased.In terms of the roll-out of various regions,the unused land had the highest roll-out rate,with a value of 74.08%.In terms of land use transfer,the transfer rate of construction land was the highest at 74.44%,followed by farmland and unused land.The center of gravity of the construction land in the research area moves to the southeast,with a distance of 7.32 km.(2)By calculating the single dynamic attitude,comprehensive dynamic attitude of land use,comprehensive index of land use degree and the change of the center of gravity of construction land in each township in the basin,it can be seen that,the changes of land use type area of Cibihu Town,Yousuo Town and Dengchuan Town are consistent with the changes of the whole watershed.The annual comprehensive dynamic degree of each township is mostly higher than the average level,and the comprehensive land use index shows an upward trend.In terms of the change of center of gravity,among the 16 towns in the basin,the center of construction of Shuanglang Town moved to the southwest,the farthest distance,is 2.89 km.(3)According to the correlation analysis between the urbanization evaluation index and the urbanization level,the proportion of non-agricultural population in the total population,per capita annual income,the proportion of construction land area,the proportion of forest land are positively correlated with the urbanization level,while the proportion of unused land is negatively correlated with the urbanization level.The urbanization level of Fengyi Town and Xizhou Town continued to rise,while that of Dengchuan Town decreased most significantly.From 1985 to 2015,the average growth rate of urbanization level in the basin reached 2.544%.The urbanization level of towns in the basin was divided into five levels,namely: low level urbanization area,lower level urbanization area,medium level urbanization area,higher level urbanization area and high-level urbanization area.The degree of coordination among different urbanization subsystems is mostly of the barely coordinated type.In addition to economic urbanization,the coordination degree of other subsystems in the valley between towns is in the range from barely coordinated to moderate coordinated.According to the urbanization-oriented analysis,in 2015,there are 7 towns that were eco-environment-oriented,with the largest number.(4)Based on the niche theory,the comprehensive niche suitability of Dali Town and Dengchuan Town shows a trend of increasing first and then decreasing,while the change of Niujie Town and Wanqiao Town are the opposite.Among them,the niche suitability level of Dali Town decreased from 0.542 to 0.495.Meanwhile,the niche suitability of towns in the basin still has much room for improvement.According to the niche suitability value of each type,there are 7 towns with agricultural production function,2 towns with social and economic function and 7 towns with ecological conservation function in 2015.According to the comprehensive suitability of niche,the towns were divided into four control modes: key development zones,moderate development zones,limited expansion zones and priority management zones,and according to various modes,corresponding township urbanization optimization proposals were proposed. |
