|Other Abstract||Under the background of global climate change, sea-level rise and human development activities, the scale and intensity of reclamation, land-based pollution, and coastal erosion are increasing. China’s coastal habitats are being or have been damaged to varying degrees. According to the relevant data, more than 50% of the coastal wetlands in China’s coastal zone have been lost. Coastal biodiversity and ecosystem health are facing serious challenges, and more and more coastal ecosystem products and services are showing unsustainable trends. Given this, it is urgent to carry out the research on the ecosystem services and their value assessment in china’s coastal zone, so as to provide some reference and scientific support for policy formulation, implementation and rational allocation of resources in the coastal zone region.
This research attempts to evaluate the macro-scale ecosystem services and their value of China's coastal zone in historical and future periods. The purpose of this study is to comprehensively understand the current situation of land use ecosystem and the evolution of its service and value in China’s coastal zone. Based on the basic characteristics of China’s coastal zone and referring to many research results, the classification system of China's coastal ecosystem services was proposed. Afterward, based on this classification system, the identification and diversity analysis of regional ecosystem services in China’s coastal zone are carried out, and the spatiotemporal change characteristics, transfer change characteristics and landscape pattern index change characteristics of land use landscape are analyzed based on China’s coastal zone land use dataset, so as to provide support for the subsequent estimation of ecosystem services in China’s coastal zone. Four typical coastal ecosystem services and their values in China from 2000 to 2015 were evaluated by using mainstream and mature universal estimation models or methods, and discusses the change rules of ecological services and their values in China’s coastal zone, and the change of coastal ecosystem services and their values was discussed. Then, based on the multi scenario land use data in 2025, the future ecosystem services and their value are simulated and evaluated, and the interaction between land use and ecosystem services value under multi scenario in the future is discussed. The main conclusion are as follows:
(1) Classification and identification of coastal ecosystem services in China are as follows: Based on the actual situation of China’s coastal zone, referring to many research results, a set of ecosystem service classification system suitable for China’s coastal zone has been established. Then, based on this classification system, the service identification and diversity of China’s coastal system are researched. From 2000 to 2015, the overall diversity of ecosystem service types in China’s coastal zone showed a downward trend, with the most dramatic changes in the land area within a 20-km radius from the coastline. The high value areas were mainly distributed in mountainous areas, coastal zones and estuarine delta wetlands with high vegetation coverage, while the low value areas were mainly distributed in construction land and its surrounding areas, which were severely disturbed by human activities.
(2) The spatial distribution of land use in China’s coastal zone exhibited an overall pattern of "shallow water — saltwater wetlands — human-made wetland (salt pan and mariculture) — terrestrial multi-type mixed region" from the sea to the land. The period from 2000 to 2015 was a period of significant anthropogenic development of land use in China’s coastal zone. The urban and rural land, mariculture, isolated industrial-mining land expanded significantly, encroaching on large amounts of farmland, shallow water, saltwater wetlands, reservoirs and ponds, etc. However, the intensity of the artificial development has slowed down over time. During the study period, the fragmentation of the overall fragmentation of land use landscape in China’s coastal zone was significant, the patch types were more complex and diverse, and some specific types of land use landscape patch agglomeration was obvious.
(3) The spatial distribution of NPP and water production in China’s coastal zone generally showed a decreasing trend from south to north during 2000-2015. The NPP value of terrestrial ecosystem was higher than that of shallow water ecosystem. The total amount of NPP and soil conservation in China’s coastal zone showed a downward trend in the four periods, with a decrease of 5.86 million tons and 9.56 million tons respectively in 15 years. During the four periods, China’s coastal water yield, mariculture production, salt pan yield under ideal conditions all showed a significant increase trend, while the offshore maximum sustainable catch decreased slightly.
(4) The total value of ecosystem services in China’s coastal zone showed a trend of continuous decline, decreasing by 35.46 billion yuan from 2000 to 2015. The value of different services in China’s coastal zone has changed differently. The value of material production has shown a significant increase, while the value of carbon fixation and oxygen release services, water conservation services and soil conservation services have all shown a continuous decline. In the four periods, the value of water conservation service was the largest in China’s coastal ecosystem, followed by the value of carbon sequestration and oxygen release service, while the value of material production service and soil conservation service accounted for a small proportion.
(5) The total value of ecosystem services in China’s coastal zone under the business-as-usual scenario and ecological protection scenario in 2025 decreased by 3179.17 billion yuan and 3191.73 billion yuan, respectively. Compared with 2015, the total value of ecosystem services under the two scenarios decreased by 24.52 billion yuan and 11.96 billion yuan respectively, and the total value of ecosystem services under the business-as-usual scenario decreased significantly. The value of material production service in China’s coastal zone increased under both scenarios, and it increased significantly under the business-as-usual scenario, while the value of carbon fixation and oxygen release service, water conservation service and soil conservation service decreased. The value of three services under the ecological protection scenario decreased slowly, while their value declined significantly under the business-as-usual scenario.|