## 1 Introduction  
As the point of interaction between sea and land, shoreline zones probably contain the most organically productive and diverse environments on our planet, such as coral reefs, estuaries and wetlands [1]. Seaside regions are significant and useful zones in light of their geographic location and plentiful regular assets that provide human existence and certain ventures [2, 3]. The proportion of the marine economy in the national GDP expanded from 3.8% in 2003, to 9.0% in 2019, according to the Statistical Bulletin of the Chinese Marine Economy (SBCME) [4]. The sharp expansions of the salt, agriculture and fishery industries have produced enormous financial development for China [5]. Meanwhile, coastal zones have higher population densities, higher population growth rates and higher rates of urbanization [6]. In particular, China's continuous and rapid economic growth can cause land shortage problems. As important reserve land resources, tidal flats can significantly alleviate land supply shortages and provide a large amount of land resources for coastal zones [7; 8]. Subsequently, the exploitation and growth of coastal zones have enormously expanded as of late [6], and many tidal flats have been converted into salt pans, ports [9] and aquaculture ponds [10; 11]. However, coastal environments are also economically and ecologically vulnerable areas threatened by various activities, such as sea level rise, pollution, reclamation and changes in storms associated with climate change [12; 13]. Coastal reclamation (CR) projects have a profound history and occur widely in coastal areas, which has resulted in extensive changes in the location of the coastline along the entire coastline of China [14; 15]. During this process, coastal environments and ecosystems have undergone serious intervention, and enormous coastal wetlands have been lost [14; 16]. From 1950 to 2010, CR brought about a loss of 70% of coastal wetlands, with an average of 40,000 ha/a, increasing particularly dramatically after 2006 to provide for rapid urbanization development [17]. In addition, there has been loss of salt marshes and mangroves [18], and habitat degradation [19]. A large number of studies have begun to evaluate the ecological risks of CR in order to establish a restrictive mechanism for these activities. [PERSON] et al. [20] detailed the extensive and enduring effect of rapid coastal development on international coastal environments, shadowing the delivery of significant marine ecosystem services. [PERSON] et al. [11] reported the dramatically expanding harm to natural habitat because of reclamation activities, in the past 20 years in Shanghai. [PERSON] et al. [21] surveyed eight kinds of ecosystem service value and found that the total ecosystem service value diminished by approximately USD 5 billion over 20 years. [PERSON] et al. [22] contrasted 16 worldwide megacities and the area of spread land, and found that seaside reclamation has decreased marine biodiversity and wetlands. [PERSON] et al. [23] recognized that trade-offs existed among material creation, environment quality, and carbon storage, in a study of the Yellow River Delta from 1989 to 2015. As exemplified above, prior cases shared a concern of the ecological impact of CR, but did not give a clear answer on how to control the scale of CR. [PERSON] et al. [24] proposed an estimation framework for reclamation area based on ecological and environmental cost, and analyzed the suitable area for CR. [PERSON] et al. [25] explored the progress of land reclamation in Hangzhou Bay over the past 30 years, analyzing the economic and ecological trade-offs of CR activities, with the hope of limiting reclamation activities. In 2012, the \"Some Suggestions on Strengthening the Management of Sea for Regional Agricultural Reclamation\" policy was announced [26], with strict guidelines adopted in the administration of ocean utilization for forestry, planting, animal husbandry and hydroponic projects.