成渝城市群城市收缩的空间格局与形成机制研究

文章利用第五次和第六次人口普查数据，以成渝城市群16座地级及以上城市行政单元为研究对象，对其收缩的空间格局、基本特征和形成机制展开全方位的测算和分析。结果显示：（1）成渝城市群16座地级及以上城市中有13座出现收缩现象，占城市总量的81.25%，主要集中于成渝城市群中部地区；3座处于非收缩状态，占城市总量的18.75%，重点分布于城市群两侧边缘；14个市辖区出现收缩现象，约占市辖区总量的29.79%；64个市辖县出现收缩现象，约占市辖县总量的65.98%。（2）收缩城市总体可以划分为全域式收缩、边缘式收缩和局部式收缩三种主要类型，其中全域式收缩主要包括5座城市，约占收缩城市总量的38.46%，均位于成渝城市群中部地区，且呈现连绵化发展趋势；边缘式收缩主要包括4座城市，约占收缩城市总量的30.77%；局部式收缩主要包括4座城市，约占收缩城市总量的30.77%，主要分布于成渝城市群的中部边缘地区，非收缩的市辖区（县）被收缩的城镇所包围。（3）少年儿童和劳动年龄人口减少的同时老龄人口不断增加，社会抚养负担持续加大；人口受教育程度呈现持续上升趋势，本科及以上学历人口占比均出现大幅度增加；第一产业就业人口占比出现大幅下滑，二、三产业就业人口占比则大幅上升，且第二产业就业人口占比上升幅度最大。（4）通过对城市收缩的形成机制分析，中心城市的虹吸效应、产业结构转换中的就业岗位不足、人口老龄化趋势加重、自然因素，以及政府适当的干预构成成渝城市群城市收缩的关键性机制。

Study on spatial pattern and formation mechanism of urban contraction in Chengdu-Chongqing city cluster

Based on the fifth and sixth census data, this paper takes 16 prefecture-level and above urban administrative units in Chengdu-Chongqing city cluster as the research object, and conducts comprehensive calculation and analysis of their shrinking spatial pattern, basic features and formation mechanism. The results show the following:1)13 out of the 16 cities of Chengdu-Chongqing city cluster are contracting, accounting for 81.25% of the total urban area, mainly concentrated in the central region of Chengdu-Chongqing city cluster. Three of them are in a non-shrinking state, accounting for 18.75% of the total urban population, and they mainly distribute on both sides of the urban agglomerations. The shrinkage of 14 municipal districts accounted for 29.79% of the total. The contraction phenomenon occurred in 64 city jurisdiction counties, accounting for 65.98 percent of the total number of cities jurisdiction counties. 2) The overall type of shrink city can be divided into three major types:global contraction, marginal contraction and local contraction. The global contraction includes 5 cities, accounting for about 38.46% of the total contraction cities, all located in the central part of Chengdu-Chongqing city cluster and showing continuous development trend. The marginal contraction mainly includes 4 cities, accounting for 30.77% of the total contraction. Local contraction mainly includes 4 cities, accounting for about 30.77% of the shrinking cities, mainly distributed in the central marginal region of Chengdu-Chongqing city cluster, non-shrinking municipal districts (counties) are surrounded by shrinking towns.3) The number of young children and working-age people has been decreasing, the number of the elderly population has been increasing and the burden of social support has been increasing; The population of education showed a trend of continuous increase, and the proportion of people with bachelor''s degree or above increased significantly. The proportion of the employed population in the primary industry has declined dramatically, while that of the employed population in the secondary and tertiary industries has increased significantly, and the proportion of the employed population in the secondary industry has increased the most. 4) Based on the analysis of the formation mechanism of urban shrinkage, the central city''s siphon effect, the lack of employment in the transformation of industrial structure, the increasing aging trend of population, natural factors and the appropriate interventions of the government constitute the key mechanism of urban contraction of Chengdu-Chongqing city cluster.