Objective Human society and ecological environment have, through constant interaction, formed an indivisible and interrelated social ecological system. Environmental services and cultural services are two important subsystems of the social ecological system, which can respectively represent the value needs of ecology and society. However, with the development of human society, people's yearning for and pursuit of nature are becoming increasingly intense. Human beings have put forward higher requirements for the cultural services provided by urban ecosystems. Despite the high social demand, excessive human activities will pose a great threat to the natural environment to a certain extent, making it impossible to meet the ecological needs, while reducing the quality of cultural services provided by the natural environment for human beings. Therefore, understanding and analyzing the spatial visual coupling relationship between environmental services and cultural services, and identifying the hot and cold maps of environmental cultural services will help planners and managers clarify the trade-offs and synergies between social and ecological values, provide a new perspective for the optimization of ecological protection planning and management, and promote regional sustainable development, which is of certain theoretical and practical significance for regional planning management.

Methods Taking the Pearl River Estuary as an example, this research firstly adopts the InVEST model to evaluate environmental services, and the MaxEnt model to evaluate cultural services in combination with the location and comment information of public attractions/surrounding tourism channel resource points. Then the research adopts the coupling coordination model to discuss the relevancy and coordination between environmental services and cultural services in the research area. After that, the research figures out the difference between environmental services and cultural services in the spatial clustering of hot (warm/cold) spots through the superposition of their respective hot spots, and thus clarifies the spatial coupling mechanism of environmental services and cultural services. Finally, based on the results of coupling and coordination degree and hot spot analysis, the research, with the benefits from social and ecological synergy as the goal, proposes the strategies for ecological function regionalization and ecological management in the Pearl River Estuary area based on the evaluation of the coupling between environmental and cultural services.

Results 1) The overall coupling and coordination degree between environmental services and cultural services in the research area is 0.36, which is in the transition stage from maladjustment to coordination; the coordination type is the synchronous development of environmental and cultural services; the coupling and coordination between environmental and cultural services are different in different regions, and is relatively high in such regions as Hong Kong and Macao. 2) The hot spots of environmental services and cultural services in the research area vary greatly in space; the hot-hot spots are scattered in Hong Kong, Macao, Shenzhen, and Qi'ao Island, and there are also a few hot-hot spots in Humen and other places in the middle of the Bay Area; the cold-hot spots are mainly distributed in Shenzhen and Dongguan, while the hot-cold spots are mainly distributed in Hong Kong and Zhuhai. 3) Combined with the coupling and coordination in between and the hot spot analysis of environmental and cultural services, it is proposed that in the research area, the hot-hot, hot-cold, hot-warm and warm-warm spots covered by environmental and cultural services are ecological conservation spots, focusing on ecological conservation and restricted development; cold-warm, cold-hot and warm hot spots are ecological restoration spots, focusing on ecological restoration and cultural service optimization; cold-cold and warm-cold spots are general protection areas, focusing on comprehensive protection and appropriate exploitation of natural and cultural resources. In a word, the relationship between environment and cultural services should be rationally coordinated, and more refined and differentiated ecological management and control should be implemented in a modular and networked way. More importantly, the coupling and coordination between environment and cultural services can help give play to the natural education and ecological science popularization functions of the ecological environment, enhance the public's ecological and environmental awareness, guide the public to participate in ecological management and environmental protection, and form a joint force of government control and public participation in ecological management.

Conclusion This research not only provides a new way for spatial mapping of large-scale multi-cultural services, but also reveals the degree of spatial coupling between and clustering characteristics of environment and cultural services, clarifies the interaction results between society and ecology, and indicates that the bottom line thinking of terrestrial spatial planning prioritizing ecology is gradually moving towards the dimension of integration between social and ecological functions. The integration between society and ecology entails clarifying the relationship between various systems, and building a composite system for the integration between social and ecological functions with the two-dimensional interaction of social ecosystem as the governance model. This research can provide reference for sustainable planning and management of terrestrial space under the construction of ecological civilization.