Environmental Policy Simulation and Assessment under Rapid Urbanization: Case Study of Essential Area Policy in Shenzhen, China

Abstract

The balance between overall economic growth and protection of the environment is an important research topic of urban sustainable development. In 2005, Shenzhen promulgated the regulations, Administrative Regulations of Shenzhen Municipality on the Essential Area for Protecting Ecology [abbreviated as essential area policy (EAP)], which limited development to protect ecology. In order to evaluate the effects of this policy, a computer model was used to simulate land-use change based on a land-use change survey dataset of Shenzhen, a typical rapid urbanization area, under four scenarios. The writers aimed at developing a clear understanding of not only the effects of land protection policies for urban ecosystems but of a well-grounded prospect for regionally coordinated development as well. Five landscape structure metrics were chosen to describe the landscape pattern, including (1) number of patches, (2) mean patch area, (3) landscape shape index, (4) aggregation index, and (5) contagion index. In calculating and comparing these landscape metrics, the results support the conclusion that facing pressure from urban sprawl, agroecological land, water, and other nature-dominated areas shrink to high-altitude regions, and many small landscape patches disappear altogether, especially in the mixed periurban region in each scenario. The rapid growth of construction zones causes landscape fragmentation and renders the shape of the urban landscape more regular and smooth. However, EAP can keep small land patches from being developed into built-up areas; improve the percentage of agroecological land, water, and other nature-dominated areas within protected zones; and impel the relocation of these kinds of land-use from outside to inside the zone. The EAP affects the landscape pattern by increasing the mean area of each patch and the number of patches. If EAP were implemented in 2008, the number of patches and the landscape shape index would be relatively higher, whereas the aggregation and contagion indices would be lower than those resulting from nonimplementation. If EAP were implemented in 2008 but abolished in 2013, the number of patches and the landscape shape index would decrease, while the aggregation and contagion indices would increase. In contrast, if EAP were implemented in 2013, the number of patches and the landscape shape index would increase, while the aggregation and contagion indices would decrease. Delimitation of the boundary of an essential area is a critical factor in designing an effective policy. This paper enables land planners to understand the effects of EAP and highlights its importance as a tool for policymakers and stakeholders.