关键词: 倍差法, 基本生态控制线, 深圳市, 景观生态风险

Abstract: The analysis of temporal and spatial variation and ecosystem service value assessment of green space system is of great significance to the optimization of green space system landscape pattern in large scale and to regional economic development and environmental management. Based on the theory of landscape ecology and the modified evaluation method of ecosystem service value, we analyzed the temporal and spatial variation of green space system and ecosystem service value (ESV) in Zhejiang Province from 1990 to 2015. There were substantial temporal and spatial changes of landscapes in the green space system. Forest land, as the main landscape type, increased first and then decreased. The transformation between green space landscapes and other land use types was characterized by obvious periodicity and directivity, with the landscape tending to be fragmented and heterogeneous. The overall ESV of green space system in Zhejiang Province continued to decline, with an average annual change rate of -0.62%. The ESV was dominated by the region with high ecological service value, and the proportion of extremely high ecological service value area was the smallest. In the first five years (1990-1995), the areas with high, extremely high, and low ESV increased, while the extremely low and middle grade areas showed a decrease trend. Afterwards, in addition to the sharp decrease of the extremely high ecological service value area, all the other grades tended to increase steadily and were extended to the mountain. The high ecological service value zones were gradually replaced by low grade zones. The ESV of all cities in Zhejiang Province had significant spatial differentiation, with the highest ESV being in Lishui, followed by Hangzhou. The overall trend of ESV of the cities was decreasing, with the rate of such decrease being decreased. The decrease rate increased after 2010, indicating that the green space system was not properly protected and managed during its development and utilization. Therefore, we should pay more attention to the environmental protection, seeking a balance between economic development and environmental protection.

Key words: difference-in-difference method, basic ecological control line, Shenzhen, landscape ecological risk