Zhu Mingyong, He Wenming, Zhang Quanfa, Xiong Yongzhu, Tan Shuduan, He Hongming
School of Geography and Tourism, Jiaying University, Meizhou, 514015, Guangdong, China.
School of Chemistry and Environment, Jiaying University, Meizhou, 514015, Guangdong, China.
Heliyon. 2019 Dec 12;5(12):e02985. doi: 10.1016/j.heliyon.2019.e02985. eCollection 2019 Dec.
Soil erosion is an important environmental problem in the area of the upper and middle of the Yellow River (AUMYR), China, one of the most severe soil erosion areas in the world. It is significantly influences on the ecological security and sustainable development of the region. Soil conservation (SC) service, as one of the most important regulating services provided by ecosystems, can alter soil and water processes and improve ecosystem services that ensure human welfare. Investigations of spatial and temporal characteristics of SC service play important roles in soil erosion control and ecosystem protection in AUMYR. In the past several years, restoration projects (e.g. the Grain-for-Green project) were implemented to improve SC in most of AUMYR. It is needed to evaluate the change of SC service brought about by the projects. This study carries out quantitative spatial analysis of SC services through Universal Soil Loss Equation (USLE) model and geographic information system (GIS) manipulation based on various datasets, such as remote sensing image, digital elevation model (DEM), climate, and land use/cover maps. Soil retention calculated as potential soil erosion (erosion without vegetation cover) minus actual soil erosion was applied as indicator for SC service. The results are like these. (1) The total amount and mean capacity of SC service in AUMYR were 7.22 billion t/a and 142.2 t/hm·a in 2000 and 10.19 billion t/a and 200.8 t/hm·a in 2010, respectively. South-east AUMYR exhibited a much higher capacity of soil retaining than the north-west. (2) Forest ecosystems displayed higher SC capacity than other types of ecosystems. Moreover, the SC capacity of ecosystems increased with the increasing of slope gradient. (3) Variations of SC rate (the ratio of SC to potential soil erosion in percentage) in different units (ecosystem, slope zone and city) were relatively small and ca. 90% of potentially eroded soil was retained in AUMYR. (4) The spatial characteristics of SC service in AUMYR were primarily controlled by topography at the regional scale. Vegetation cover restoration significantly improved the capacity of SC service in AUMYR in the midst year of 2000 and 2010. The results revealed that ecological restoration efforts significantly enhanced SC service of ecosystem in the study area.
土壤侵蚀是中国黄河中上游地区的一个重要环境问题，该地区是世界上水土流失最严重的地区之一。它对该地区的生态安全和可持续发展有着重大影响。土壤保持服务作为生态系统提供的最重要的调节服务之一，可以改变水土过程，改善确保人类福祉的生态系统服务。研究土壤保持服务的时空特征对黄河中上游地区的土壤侵蚀控制和生态系统保护具有重要意义。在过去几年里，黄河中上游大部分地区实施了一系列生态恢复工程（如退耕还林工程）以改善土壤保持状况。有必要评估这些工程所带来的土壤保持服务的变化。本研究基于多种数据集，如遥感影像、数字高程模型（DEM）、气候数据以及土地利用/覆盖图，通过通用土壤流失方程（USLE）模型和地理信息系统（GIS）操作，对土壤保持服务进行了定量空间分析。用潜在土壤侵蚀量（无植被覆盖时的侵蚀量）减去实际土壤侵蚀量计算得出的土壤保持量作为土壤保持服务的指标。结果如下：（1）2000年黄河中上游地区土壤保持服务总量和平均保持量分别为72.2亿吨/年和142.2吨/公顷·年，2010年分别为101.9亿吨/年和200.8吨/公顷·年。黄河中上游东南部地区的土壤保持能力远高于西北部地区。（2）森林生态系统的土壤保持能力高于其他类型的生态系统。此外，生态系统的土壤保持能力随坡度的增加而增加。（3）不同单元（生态系统、坡度带和城市）的土壤保持率（土壤保持量与潜在土壤侵蚀量的百分比）变化相对较小，黄河中上游地区约90%的潜在侵蚀土壤得到了保持。（4）黄河中上游地区土壤保持服务的空间特征在区域尺度上主要受地形控制。植被覆盖恢复在2000年至2010年期间显著提高了黄河中上游地区的土壤保持服务能力。结果表明，生态恢复措施显著增强了研究区域生态系统的土壤保持服务功能。
