Maintaining key ecosystem services under multiple development scenarios: A case study in Guangdong-Hong Kong-Macao greater bay Area, China

Effective land use management can better maintain ecosystem services, especially in urban agglomerations. However, rational urban scale systems and landscape patterns to maintain key ecosystem services (ESs) in highly urbanized areas remain poorly understood. Taking the Guangdong-Hong Kong-Macao Greater Bay Area (GBA) as a study area, we quantified the spatio-temporal change of key ESs from 2000 to 2020 by the Integrated Valuation of Environmental Services and Tradeoffs (InVEST) model, and simulated land use change prior considering ES conservation priority areas under different multiple development scenarios in 2050 by adopting the future land use simulation (FLUS) model. The main findings were as follows: (1) From 2000 to 2020, natural habitat, water retention and carbon sequestration decreased by 5.5%, 7.9%, and 3.9%, respectively, while the soil conservation increased by 63.7%. (2) The proportion of different conservation priority areas ranged from 10.6% to 22.6%, which were mainly located in the mountainous region. (3) The urban land area would increase from 4286.00 km2 to 4802.25 km2 between 2020 and 2050 in the GBA, with a growth rate of 12.05%. Under the simulation scenarios, the new urban land was mainly distributed in megacities and supercities. (4) Under the integrative conservation scenario, the habitat quality index, water conservation, soil conservation and carbon sequestration would increase by 0.036, 7 x 104 t, 5.11 x 106 t and 0.93 x 106 t, respectively. To maintain the key ESs, we recommend optimizing the urban scale system, making it compact at the city scale and scattered at the regional scale, and strictly restricting the conversion of forestland and farmland adjacent to megacities into urban land. These findings were beneficial to achieve regional high-quality development and sustainable development via rational urban system and landscape management.

Automated summary

Effective land use management is crucial for maintaining ecosystem services in urban agglomerations, but the understanding of rational urban scale systems and landscape patterns for key ecosystem services in highly urbanized areas is limited. Using models, the study quantified the change in key ecosystem services in the Guangdong-Hong Kong-Macao Greater Bay Area from 2000 to 2020, and simulated land use change under different development scenarios in 2050. The findings showed a decrease in natural habitat, water retention, and carbon sequestration, while soil conservation increased. It was recommended to optimize the urban scale system and restrict forest and farmland conversion to maintain ecosystem services.