The Characteristics and Modes of Urban Network Evolution in the Yangtze River Delta in China from 1990 to 2017

In the context of regional integration development, research on the urban network in the Yangtze River Delta (YRD) has received extensive attention from academia. Existing research mainly uses listed companies to construct urban networks. However, most of China's listed companies are concentrated in large cities. Giving too much attention to the urban network composed of listed companies may cause small cities to be “off the map.” This article uses 8,061 financial companies of different sizes in the YRD from 1990 to 2017 as research data combined with complex network models to explore the evolutionary characteristics, modes, and influencing factors of urban networks. The findings show that the connection strength and resilience of the urban network are gradually increasing, and its evolutionary mode has changed from a single center to a multicenter network. The radiation and agglomeration capabilities of urban networks have strong asymmetry. Shanghai's network agglomeration capacity is only 1/22 of its radiation capacity, which implies that Shanghai has played a bridge function in urban network links. Notably, the networks of most peripheral cities continued to expand from 1990 to 2017, while Shanghai was in a state of contraction. This finding indicates that the overall urban network is developing in a balanced and coordinated direction. In addition, economic growth provides critical support for the urban network, and technological progress may improve the level of production management of companies, thereby promoting cooperation and exchanges between cities. Further, cities with similar industrial structures may have industrial synergy or complementary relationships and are likely to have spatial connections. Finally, we suggest promoting the expansion of urban networks in the YRD by forming a multicenter development model, transforming local government functions, exploring differentiated development, and strengthening infrastructure construction.