State Key Laboratory of Black Soils Conservation and Utilization, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun 130102, China.
State Key Laboratory of Black Soils Conservation and Utilization, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun 130102, China.
Water Res. 2024 Aug 15;260:121946. doi: 10.1016/j.watres.2024.121946. Epub 2024 Jun 14.
Landscape changes resulting from anthropogenic activities and climate changes severely impact surface water quality. A global perspective on understanding their relationship is a prerequisite for pursuing equity in water security and sustainable development. A sequent meta-analysis synthesizing 625 regional studies from 63 countries worldwide was conducted to analyze the impacts on water quality from changing landscape compositions in the catchment and explore the moderating factors and temporal evolution. Results exhibit that total nitrogen (TN), total phosphorus (TP), and chemical oxygen demand (COD) in water are mostly concerned and highly responsive to landscape changes. Expansion of urban lands fundamentally degraded worldwide water quality over the past 20 years, of which the arid areas tended to suffer more harsh deterioration. Increasing forest cover, particularly low-latitude forests, significantly decreased the risk of water pollution, especially biological and heavy metal contamination, suggesting the importance of forest restoration in global urbanization. The effect size of agricultural land changes on water quality was spatially scale-dependent, decreasing and then increasing with the buffer radius expanding. Wetland coverage positively correlated with organic matter in water typified by COD, and the correlation coefficient peaked in the boreal areas (r=0.82, p<0.01). Overall, the global impacts of landscape changes on water quality have been intensifying since the 1990s. Nevertheless, knowledge gaps still exist in developing areas, especially in Africa and South America, where the water quality is sensitive to landscape changes and is expected to experience dramatic shifts in foreseeable future development. Our study revealed the worldwide consistency and heterogeneity between regions, thus serving as a research roadmap to address the quality-induced global water scarcity under landscape changes and to direct the management of land and water.
人为活动和气候变化导致的景观变化严重影响地表水水质。从全球角度理解它们之间的关系是追求水安全和可持续发展公平性的前提。本研究通过对全球 63 个国家的 625 个区域研究进行连续荟萃分析，综合分析了流域景观组成变化对水质的影响，并探讨了调节因素和时间演变。结果表明，水中的总氮（TN）、总磷（TP）和化学需氧量（COD）是最受关注的，对景观变化高度敏感。在过去的 20 年中，城市土地的扩张从根本上降低了全球的水质，其中干旱地区的水质恶化更为严重。增加森林覆盖，特别是低纬度森林，显著降低了水污染的风险，特别是生物和重金属污染，这表明在全球城市化进程中森林恢复的重要性。农业用地变化对水质的影响大小具有空间尺度依赖性，随着缓冲区半径的扩大而先减小后增大。湿地覆盖与水中的有机物呈正相关，以 COD 为代表，相关系数在北方地区达到峰值（r=0.82，p<0.01）。总体而言，自 20 世纪 90 年代以来，景观变化对水质的全球影响一直在加剧。然而，在发展中地区，特别是在非洲和南美洲，仍然存在知识差距，这些地区的水质对景观变化敏感，预计在可预见的未来发展中会发生剧烈变化。本研究揭示了全球范围内不同地区之间的一致性和异质性，为解决景观变化下水质引起的全球水资源短缺问题提供了研究路线图，并为土地和水资源管理提供了指导。
