乌梁素海流域生态脆弱性时空变化及其成因分析

Spatiotemporal Changes and Causes of Ecological Vulnerability in Ulansuhai Basin

面对“碎片化”生态治理的挑战,全面了解流域生态系统的脆弱性及其演变规律成为生态环境综合治理的关键。乌梁素海流域作为全国示范意义的生态保护修复工程试点,经历了传统“治理湖泊”到系统“治理流域”的转变。本研究选择乌梁素海流域作为研究对象,构建了“敏感-恢复-压力”生态脆弱性评价指标体系,并以Google Earth Engine(GEE)云平台为基础,采用Mann-Kendall突变检验、Sen+Mann-Kendall趋势分析和变换轨迹等方法,对2000—2020年乌梁素海流域生态脆弱性时空演变进行分析,最后通过地理探测器进一步探讨了乌梁素海流域生态脆弱性的成因,并揭示了其主要驱动因子。研究结果表明:乌梁素海流域的生态脆弱性表现为“中间低、两边高”的格局。其中,西部乌兰布和沙漠以及东部乌拉山区生态脆弱性较高,而中部河套灌区则相对较低。2000—2020年,流域的生态脆弱性分级指数从2.44上升至2.59,揭示了生态脆弱性的轻微恶化趋势。2000、2009、2013、2017和2020年为突变节点,约59.82%的区域在评估期间生态脆弱性等级保持稳定,变化轨迹法显示2013年为显著下降的节点,2017年后下降趋势减缓。此外,地表干度是乌梁素海流域生态脆弱性的核心驱动因子,多个因素相互作用时对生态脆弱性的解释力超过单一因素。土地覆盖类型解释力最为显著,其次是气象类型、经济类型。本研究对长时序流域生态脆弱性的时空变化及成因进行了分析,为同类型的生态脆弱区域评估和生态保护与修复工程治理提供科学依据。

To meet the challenges posed by the"fragmented"nature of ecological governance,it is crucial to have a holistic understanding of the vulnerability of basin ecosystems and the underlying patterns of their evolution for comprehensive ecological management.The Ulansuhai Basin,serving as a pilot site for a representative ecological conservation and restoration project,has experienced a shift from traditional"lake management"to a more systemic"basin management".This study selected the Ulansuhai Basin as the study area and established a"Sensitivity-Recovery-Pressure"index system for ecological vulnerability assessment.Using the Google Earth Engine cloud platform,methods including Mann-Kendall test,Sen+Mann-Kendall trend analysis,and transformation trajectory were applied to analyse the spatiotemporal evolution of ecological vulnerability in the Ulansuhai Basin from 2000 to 2020.Moreover,geographical detectors were utilized to further investigate the causes of ecological vulnerability in the Ulansuhai Basin,and to identify the primary driving factors.The results indicated that the ecological vulnerability of the Ulansuhai Basin exhibited a“low in the middle,high on both sides”pattern,e.g.,the western region of the Ulan Buh Desert and the eastern Ula Mountain region had relatively higher ecological vulnerability,while the central Hetao irrigation area had lower ecological vulnerability.From 2000 to 2020,the basin’s ecological vulnerability grading index increased from 2.44 to 2.59,indicating a slight decline in ecological vulnerability.Abrupt changes of vulnerability were observed in 2000,2009,2013,2017,and 2020,with approximately 59.82%of the basin area maintaining stable ecological vulnerability grades throughout the assessment period.The transformation trajectory method showed that the decline of vulnerability peaked in 2013 and then began to slow after 2017.Additionally,surface aridity was identified as a key driving factor of ecological vulnerability in the Ulansuhai Basin,and the interaction of multiple factors showed a stronger explanatory power for ecological vulnerability than a single factor.Generally,land cover type exhibited the most significant explanatory power,followed by meteorological and economic types.This study analyzed the long-term spatiotemporal changes and causes of ecological vulnerability in basin ecosystems,providing a scientific basis for the assessment and governance of ecological conservation and restoration projects in ecologically vulnerable regions.