Assessment of occupation of natural habitat by urban expansion and its impact on crucial ecosystem services in China’s coastal zone

Urban zones across the world have experienced a massive expansion in recent decades, affecting food production, carbon storage, and biodiversity, and further threatening the realization of the UN’s Sustainable Development Goals (SDGs), particularly SDG 2 (zero hunger), 13 (climate action), and 15 (life on land). These enormous impacts are even more worrying in coastal areas where urbanization has been continuously accelerated. However, we have a poor understanding about the magnitude of the reduction in natural habitat and crucial ecosystem services over time caused by urban expansion in coastal areas. Here we chose the coastal zone of eastern China using a high-resolution dataset of land-use/land-cover (LULC) to investigate the influences of urban growth on natural habitat and crucial ecosystem services from 1990 to 2018. The results showed that: (1) urban growth in China's coastal region resulted in an estimated reduction of 2061.14 km2 in natural habitat, 154.13 Tg C in carbon storage, 1.67 Tg C in cropland net primary production, and 148.02 × 103 in habitat quality; (2) cropland net primary production loss resulted in a 1.34 × 106 tons loss of crop production, which is comparable to meeting the basic food demands of 3.35 million hungry people for a year; (3) the overall degradation of habitat caused by urban expansion reached 1838.28 km2, with grade 1 degradation area accounting for the largest portion (801.18 km2), representing 43.58% of the total degradation; (4) the primary contributor to carbon storage loss (63.83%) was the large-scale conversion of cropland to urban areas, while habitat quality loss and degradation were primarily due to the occupation of forests by urban expansion (42.62%). Our results suggest that effective land-use planning must be implemented to coordinate urban growth, natural habitat protection, and cropland displacement in rapidly urbanizing coastal areas.