基于生态系统完整性与连通性的生态保护红线优化探讨——以长三角为例

研究目的:生态保护红线正处于评估与优化阶段,尝试基于生态系统完整性与连通性提出简便且易操作的优化指标与阈值。研究方法:InVEST,CASA和RUSLE模型,STARS(Sequential T-test Analysis of Regime Shift)突变检验。研究结果:(1)长三角地区破碎度持续增加导致水源涵养、土壤保持、生境质量和净初级生产力(NPP)4类生态系统服务呈显著下降趋势,存在4个以上的显著下降突变点,生态保护红线破碎度优化阈值为0.2;(2)长三角地区连通度指数持续增大显著提升4类生态系统系统服务,存在3个以上的上升趋势突变点,生态保护红线连通度优化阈值为90;(3)基于破碎度(0.2)和连通度(90)作为生态系统完整性与连通性优化阈值,长三角生态保护红线约17.25%的面积需优化,其中生态系统完整性不满足的占9.01%,生态系统连通性不满足的占0.02%,两者均不满足的占8.22%。研究结论:(1)建议将破碎度(0.2)和连通度(90)作为生态保护红线的完整性与连通性的优化指标与阈值;(2)未来应加强从生态系统结构、功能与过程完整性、生态系统稳定性与弹性等多维度筛选关键表征指标,利用更多的景观指数及不同的阈值设定方案,建立一套更加系统科学、可操作的生态保护红线优化指标体系。

Optimizing Ecological Red Line Based on Ecosystem Integrity and Connectivity: A Case Study of Yangtze River Delta

The purpose of this paper is to establish a framework of ecological red line (ERL) optimization based on ecosystem integrity and connectivity, by taking the Yangtze River Delta as the study area, in that the ERL is currently at the stage of evaluation and optimization but lacks key indicators and technical guideline. The methods of InVEST, RUSLE and CASA models as well as STARS (Sequential T-test analysis of regime shift) were employed. The results show that: 1)the increasing degrees of division in Yangtze River Delta induces the decrease of four key ecosystem services, i.e., water conservation, soil retention, biodiversity conservation and habitat quality and net primary production (NPP) and incurs over 4 significantly decreasing regime shift points with an ERL optimization threshold for division of 0.2; 2)the increasing degrees of connectivity in Yangtze River Delta significantly amplifies the above 4 ecosystem services and incurs over 3 increasing regime shift points with an ERL optimization threshold for connectivity of 90; 3)given that the degrees of division (0.2) and connectivity (90) are regarded as the key indicators and thresholds for ERL optimization, approximately 17.25% of the total ERL area in Yangtze River Delta needs to be optimized, among which ecological systems lacking integrity take up 9.01%, ecological systems lacking connectivity take up 0.02% and a lack of both takes up 8.22%. In conclusion, 1)the degrees of division (0.2) and connectivity (90) should be taken as the key indicators and thresholds for ERL optimization. 2)In the future, the key indicators and thresholds for ERL optimization can be selected from the aspects of structures of ecosystems, integrity of functions and process, stability and resilience of ecosystems, and more landscape indicators and diverse threshold setting schemes should be used to establish a more systematic, scientific and feasible indicator system for ERL optimization.