深圳地区景观生态连接度评估

Landscape ecological connectivity assessment of Shenzhen City

以最新的土地利用变更调查资料为基本信息源,利用最小耗费距离模型和障碍影响指数、景观连接度指数计算方法,对深圳市的景观连接度进行综合评价,并分析导致景观格局变化的内在驱动机制,探讨连接度评价方法的使用效果。结果表明,林地和城市建设用地是导致工作区障碍影响指数空间分异的主要景观成分类型;全市生态资源用地类型呈现明显的碎裂化和孤岛状分布格局,而建设用地扩张过程中的无序性和不合理性是导致景观格局劣化的真正原因;摈弃以往不合理的土地开发模式,利用残存的生态资源辅助以必要的人工保护、恢复和建设工作来改善无连接区域内的景观连接度水平,强化建成区内的绿地建设工作,是提升深圳市景观连接度水平的3种有效策略途径。

Ecological connectivity is an important indicator for ecological relations among patches. Based upon the least-cost model, this paper conducted a systematic assessment of Shenzhen＇s landscape connectivity using the Barrier Effect Index （BEI） and Ecological Connectivity Index （ECI）. This new approach has assisted us revealing new driving mechanism of landscape dynamics. The results indicate that the two types of landscape -- natural vegetation and built-up areas are the very factors that affects the spatial configuration. Forests and agriculture have low influence, and are isles around lower hills and some reservoirs. Over half of the vegetation and farmlands are heavily disturbed by human beings, especially area around the built-ups. Based on the ECI results, no connectivity area （ECI = 1 ） accounts for more than 42% （with built-up areas dominate 97% ） whereas forest has relatively high connectivity, accounting merely 25% featured by an isle-like distribution. The relentless growth of built-up areas has been identified as the leading cause for landscape deterioration. We suggest three effective ways to increase Shenzhen＇s ECI and improve the ecological structure： to undertake a dramatic change in Shenzhen＇s development policy; to meliorate the no-connection areas using the remaining resources and necessary protection/restoration; to strengthen greenbelt construction in built-ups.