典型沙漠化逆转区的生态承载力与脆弱性评价

Land desertification, as a major issue in eco-environment and socio-economic field, seriously restricts regional sustainable development. With the appearance of the effects of a series of national ecological protection projects, the quantitative evaluation of the degree of ecological restoration and the ability of sustainable development in desertification reversion areas has become a key scientific problem needed to be solved currently. This project plans to select Yanchi County in Ningxia province, a typical desertification reversion area, as the study area. With social questionnaire investigation statistics and remote sensing images as the main data source, combining with the data on climate, environment and ground survey of study area, we will: 1) Explore the space-time dynamic change and its threshold range of ecological carrying capacity in the process of desertification reversion, and quantitatively evaluate sustainability level of desertification reverse areas; 2) Build an assessment index system on vulnerability of desertification reversion based on the model of “Human-environment coupled system analysis framework”, and to quantitatively evaluate the external disturbance factors, structure stability, and resilience of desertification reverse areas; 3) Propose a sustainable management model desertification reversion based on the comprehensive evaluation of the maximum interference-bearing threshold and anti-interference resilience of desertification reverse areas. This study will provide a scientific basis in our country for the desertification control and the build of a sustainable development model of the harmony between human and nature.

土地沙漠化作为生态环境和社会经济领域的重大问题，严重制约区域的可持续发展。随着国家一系列生态保护工程效果的显现，定量评价沙漠化逆转区域的生态修复程度及可持续发展能力，成为当前亟需解决的关键科学问题。本项目拟选取典型沙漠化逆转区宁夏盐池县为研究区，以社会问卷调查和遥感影像为主要数据源，结合研究区气候、环境和地面调查数据：1）探索沙漠化逆转过程的生态承载力时空动态变化及其阈值范围，定量评价沙漠化逆转区的可持续性水平；2）基于人—环境耦合系统分析框架，构建沙漠化逆转的脆弱性评价指标体系，定量评价沙漠化逆转区的外部扰动因子、自身结构稳定性及抗干扰恢复能力；3）通过综合评价沙漠化逆转区的最大干扰承受阈值及抗干扰恢复能力，提出可持续的沙漠化逆转管理模式。本研究可为我国的沙漠化防治，构建人与自然相和谐的可持续发展模式提供科学依据。

伴随一系列重大生态修复工程和生态保护政策的启动实施，许多生态脆弱区的沙漠化危害得到有效遏制并成功实现了逆转。探讨逆转区的生态恢复程度及可持续发展能力，对沙漠化逆转可持续管理模式的制定具有非常重要的理论和实践意义。本项目以宁夏盐池县为研究区，运用RS/GIS空间技术和多利益主体问卷调查，对沙漠化逆转过程的生态承载力及其脆弱性的时空动态变化进行了定量评价，并基于评价结果提出且论证了激励性的草原可持续管理模式的可行性。研究表明：（1）盐池县生态承载力在空间上呈现南高北低，主要集中于耕地（85%以上），其次是林地、草地和建筑用地（3%-6%）；随时间推移，耕地、林地和建筑用地的承载力主要转向草地，转出量分别占总转移量的92.47%、43.12%和58.18%；各土地类型的转移强度在2000年前后达到顶峰，耕地与林地和草地变化趋势相反。（2）盐池县生态系统平均脆弱性最强（0.267），其次为经济系统（0.194），最后是社会系统（0.186）；欠合理的产业结构、特殊的地理区位、生态治理力度和社会保障水平是研究区人地系统脆弱性的主要障碍因子；居民中以农村居民的脆弱性最高，而高收入、高文化程度及多种生计的居民脆弱性较低。（3）农户的生态环境意识趋向于短期性，随着生态环境好转，农户对生态政策的正向影响及接受态度由积极转为消极；相对于生态保护，农户更倾向于草地带来的短期经济利益。（4）从博弈论的视角论证了管理模式要讲究区域差异性；通过实行差别禁牧、差别补偿及产业结构调整等措施可确保生态政策效果的可持续。（5）提出了“放牧收费+基于结果的生态系统服务付费”的管理模式，且多数农户（85.23%）接受该模式；生计行为、草原产权及生态意识是影响农户接受该模式的关键因素。