Beyond the Ecological Boundary: A Quasi-Natural Experiment on the Impact of National Marine Parks on Eco-Efficiency in Coastal Cities

Abstract

National marine parks (NMPs) are a crucial form of marine protected areas that serve an essential function in safeguarding marine ecosystems and the related inland urban ecosystems. Though 30 coastal cities in China have established NMPs, little is known about the ecological benefits national marine parks contribute to surrounding areas. This study takes China’s coastal cities as an example and employs a multi-period DID model to investigate how eco-efficiency responds to the establishment of national marine parks, based on panel data from 2003 to 2020. The results show that the establishment of NMPs contributed to a 3.87% enhancement in the eco-efficiency of coastal cities. This finding remains robust after a series of robustness tests such as PSM-DID. In addition, significant heterogeneities are captured, with NMPs exhibiting a more substantial enhancement effect for cities along the East China Sea and South China Sea. NMPs with a large area increased the eco-efficiency of coastal cities by 5.18%, but small-area NMPs failed the significance test. A mechanism analysis further reveals that NMPs could improve the eco-efficiency of coastal cities by optimizing the industrial structure, enlivening the local economy, and inhibiting sewage pollution behaviors. This study provides evidence of the impact of NMPs on local eco-efficiency in developing countries.