沙漠化逆转的脆弱性及其成因机制研究

Land desertification is one of the serious ecological problems that many areas around the world have faced on. While a series of national ecological protection projects showing their effectiveness, new issues of desert science have to be studied now, which including the quantitative analysis of the vulnerability, sustainability, and management model of desertification reversion from the perspective of society-ecological system. This project is based on the frontier of international research on desertification and sustainable development. In the view of society-ecological system, the vulnerability of desertification reversion and its mechanism will be analyzed in this project. The objective area is Yanchi County, a typical desertification reversion area. Based on spatial analysis on the fusion of multi-source data, as well as the investigations of multi-stakeholders, the key researches are as follow: 1) The desertification reversion is evaluated quantitatively, which is mainly focus on the vulnerability and its spatial differentiation by using DPSIR framework. 2) Via OWA-GIS method and different development modes, the spatial differences on the vulnerability of desertification reversion are simulated. 3) An diagnosis system is built according to the SES framework to make contrast between the feature of typical social-ecological system and the interaction of key variables in the village. Also, the study is devoted to reveal the formation mechanism of the vulnerability. Thus, this study present the sustainable model and countermeasure of desertification reversion which will provide the theoretical basis and case support for ecological restoration and regional sustainable development in desertification reversion area.

土地沙漠化是世界诸多地区面临的严峻生态环境问题之一。随着我国一系列生态保护工程效果的显现，从社会—生态系统角度定量分析沙漠化逆转的脆弱性、可持续性及其调控管理模式，是当前沙漠科学亟待深入研究的新问题。本项目立足于沙漠化研究与可持续发展评价的前沿，从社会—生态系统视角，以宁夏盐池县沙漠化逆转过程为例，利用多源数据融合的空间分析和多利益主体的调查研究，重点开展：1）利用DPSIR分析模型，定量评价盐池县沙漠化逆转脆弱性及其空间分异；2）通过OWA-GIS方法，预景不同发展模式导向下沙漠化逆转脆弱性的空间差异；3）应用Ostrom的SES框架，构建诊断指标体系，对比研究典型村落社会—生态系统的特征及关键变量互动，揭示研究区沙漠化逆转脆弱性的成因机制。通过上述研究，提出沙漠化逆转的可持续模式及调控对策，为沙漠化逆转区生态恢复和区域可持续发展提供理论依据和案例支撑。

沙漠化逆转是沙漠化防治的愿景和践行绿色发展理念的目标，明确沙漠化逆转的脆弱程度和成因机制是确保沙漠化逆转可持续的关键。本项目以宁夏盐池县为例，紧扣沙漠化逆转脆弱性评价、成因机制分析、生态安全格局规划与调控这三个关键科学问题，基于社会-生态系统理论，从表象、系统及景观生态质量三维度分析了脆弱性的时空分异、致脆因子及未来趋势；明晰了该县社会-生态系统的资源系统、资源单位、管理系统、行动者的特点及其耦合互馈过程，探究了农户生计风险的多维特征与策略逻辑，阐明了禁牧政策的优化意见及逆转脆弱性的成因机制。研究发现：①禁牧政策实施后，盐池县植被覆盖度总体呈现稳中向好的趋势，沙漠化逆转脆弱性先增后降、现阶段逐年上涨、未来10年会平稳下降，生态治理、城镇化及产业结构是关键。②1990-2020年间，土地利用分布以草地和耕地为主，前者呈增加趋势而后者呈减少趋势，景观稳定性和生态质量先降后增，系统稳定性存在减弱的可能。盐池县一直处于幼童市场，现阶段牲畜数量及牧业产值下降明显。③基于平衡系统理论的禁牧政策忽视了生态系统的整体性和复杂性，在制度设计上存在理论偏差和假设偏差，并未形成“资本-行为-制度”相容的激励机制。81.25%地方领导、81.25%的学者、46.09%的农户认为应继续禁牧。④健康、灾害、市场和返贫是主要生计风险，灾害、污染和市场风险对后顾生计选择影响显著。⑤该县沙漠化逆转脆弱性的成因机制表现为一个6层级的递阶结构，牲畜需草量与产草量间的不平衡、生态治理投入不足是中层间接影响因素，而降水稀少是深层根源。本项目在理论上试图更新沙漠化治理研究的范式，方法上引入社会生态系统理论体系开展空间、村域、主体三个维度的研究，实践上提出了生态安全格局的规划方案与调控对策，可为未来我国沙漠化地区高质量发展及生态政策的制定提供科学支撑。