The comparative study of urban ecosystem health change in Asian and African coastal cities-Changle in China and Suez in Egypt

Urban Ecosystem Health (UEH) refers to the integrated capacity of urban ecosystems to both maintain and regenerate themselves and to provide ecological services for urban populations. Rapid global urbanization over the last two decades has generally led to a deterioration of regional UEH. Coastal zones are hot spots for economic and urban development, fragile in the ecosystem, and sensitive to climate change and sea levels. How does the UEH change in coastal cities from a global perspective? This paper proposes the Pressure-Vigor-OrganizationResilience-Service (P-VOR-S) modeling framework to study the UEH dynamics in Asian and African coastal cities. The results show that the UEH indexes (UEHI) of coastal cities in Asia and Africa vary significantly. Changle, a coastal city located in the subtropical ocean monsoon climate zone, was classified as the healthy UEH class with a decreasing UEHI from 2006 to 2022. While Suez, located in the tropical desert climate zone, was in the UEH sick class with an increasing UEHI during the same period. In Changle, from 2006 to 2022, the healthy area of UEH decreased by 61 km2 with a 9.04 % reduction in area proportion, while the sick area of UEH increased by 70.65 km2 with a 10.47 % rise in area proportion, the reason was directly related to the sprawl of build-up land on the forest and arable land. In contrast, during the same period, the area of healthy space in Suez increased by 129.13 km2 with a rise of 10.16 % of the whole area, while the area of sick space decreased by 160.95 km2 with a lack of 12.66 % in area percentage, the reason was the enlarged planting of the desert sparse forest. Moreover, the spatial dynamics of UEH in Asian and African coastal cities differed apparently. From 2006 to 2022, in Changle, UEH gradually deteriorated towards the eastern coastal region due to rapid economic development and local government planning policies, which would potentially stress the neighboring coastal ecosystem, while in Suez during the same period, UEH gradually improved along both sides of the Suez Canal due to afforestation, which will positively affect the ecosystem health of the Gulf of Suez and the Suez Canal. The results would provide examples for global comparative studies on coastal ecosystem health assessment and climate change.