Modeling the optimal ecological security pattern for guiding the urban constructed land expansions

Rapid urbanization has induced numerous ecological and environmental issues seriously threatening the ecological security. The ecological security pattern (ESP), an effective way for protecting the ecological security, is becoming increasingly important in reconciling the rapid urbanization and ecology protection in urban planning practices. Based on the cost-distance analysis method, we constructed a three-rank (basic, moderate and strict-rank) composite ESP of Gaoming (Guangdong, China) aiming at protecting the survivals and habitat securities of rare vegetations, wild animals and human beings. The proposed composite ESP is established on five equal-weighted individual ESPs (namely Geology-ESP, Hydrology-ESP, Atmosphere-ESP, Biodiversity-ESP and Farmland-ESP) for geologic disasters prevention, flood prevention and drinking water protection, air pollution prevention, biodiversity conservation and farmland protection, respectively. Our results show that under the basic, moderate, and strict- rank ESPs, the integration and connectivity of the ecological components are constantly improved, but the connectivity between neighboring urban patches decline gradually. The moderate-rank ESP proves to be the optimal spatial pattern for balancing the conflicts between urban development and ecological protection. Notably, the ESP that considers the security of atmosphere and farmland securities, which protects the regional farmlands better and well balance the expansions of industrial and residual lands, proves to be much more reasonable.