Tourism Development and Regional Economic Resilience: Nonlinear Effects under Regional Innovation System Conditions

External shocks have renewed interest in how tourism development contributes to regional economic resilience. Drawing on Regional Innovation System (RIS) theory and panel data for 246 Chinese cities, this study uses fixed-effects, IV-GMM, and panel-threshold models to examine the average, heterogeneous, and nonlinear effects of tourism. Tourism significantly enhances regional economic resilience, with stronger effects on shock resistance and innovation and transformation than on recovery and adjustment. Its effect is also stronger under financial shocks than pandemic shocks and is driven mainly by domestic rather than inbound tourism demand. We further identify threshold effects conditioned by industrial structure advancement, industrial structure rationalization, and entrepreneurial vitality. These findings show that tourism's contribution to resilience is nonlinear and contingent on regional structural and entrepreneurial conditions, extending tourism-led growth logic and offering a more nuanced explanation of tourism's role in regional stability and development.