黄土高原水土保持工程措施的生态系统服务

黄土高原严重的水土流失是黄河泥沙的主要来源。自1950s以来大规模实施的水土保持工程建设是黄土高原水土流失治理的重要举措,在减少入黄泥沙方面做出了巨大贡献。水土保持工程措施通过直接或间接地作用于坡面、沟道的水文过程和物质迁移过程等,改变了水资源和土壤资源的时空分配格局,在土壤保持、粮食供给、水文调节等方面发挥了重要作用,对黄河流域生态安全具有重要贡献。本文系统综述了黄土高原水土保持工程措施的发展演变,阐述了水土保持工程措施对水土过程的作用机制及对关键生态系统服务的贡献,探讨了新形势下黄土高原水土保持工程措施建设面临的问题、挑战。在此基础上提出今后黄土高原水土保持工程措施应加强维护和管理,提升应对极端气候事件和自然灾害的能力,面向国家生态文明建设和区域社会经济发展需求,统筹工程措施与植被措施,进行科学的设计与合理的时空配置,以维护黄土高原及黄河流域生态安全、维持和提升区域生态系统服务功能及社会经济效益。

Ecosystem services of soil and water conservation measures on the Loess Plateau

Serious soil losses on the Loess Plateau are the main source of sediments in the Yellow River. Large-scale implementation of soil and water conservation measures since the 1950s is one of the key actions for decreasing soil and water losses in this region. Soil and water conservation measures can modify hydrological processes and soil loss processes on hillslopes or in channels by changing hydrological pathway, runoff velocity, and sediment transportation, and then change the spatial and temporal distribution of water and soil resources at corresponding scales. Different types of soil and water conservation measures played substantial roles in sediment trapping, hydrological adjustment, and regional food security maintenance on the Loess Plateau during the past decades. Soil and water conservation measures have a substantial contribution in reducing the sediment loads of the Yellow River, and are important for maintaining ecological security in the Yellow River Basin. This study aimed at (1) systematically summarizing the types and development of soil and water conservation measures on the Loess Plateau for the past seven decades; (2) revealing the effects of soil and water conservation measures on hydrological and soil processes and related critical ecosystem services and underlying mechanisms at multiple spatial scales; and (3) presenting the problems, challenges, and future prospects of soil and water conservation measures on the Loess Plateau. It is suggested that implementation of soil and water conservation measures on the Loess Plateau in the future needs to focus on their maintenance and improvement toward integrated benefits, strengthen their resilience to extreme climate events and natural hazard-induced disasters, and balance tradeoffs among social-economic-ecological benefits. Improvement in the effectiveness of soil and water conservation measures can help maintaining ecological security and enhancing regional ecosystem functions of the Loess Plateau.