黄土沟壑区小流域景观格局演变及生态服务价值响应

以黄土沟壑区典型小流域泥河沟为研究区,基于1986年的彩红外航空相片、2002年SPOT影像、2016年GF-1卫星影像的解译结果和社会经济统计数据,利用景观指数、土地利用程度、信息熵等方法分析了该流域近30年的景观格局演变规律,并借鉴生态服务价值当量估算法定量探讨了生态系统服务价值的变化特征。结果表明:(1)近30年来研究区土地利用景观格局发生了显著变化,除了林地和建设用地景观面积增加,耕地、园地、未利用地均有不同比例的减少。(2)流域内景观整体破碎度减少,优势斑块的连通性呈增加趋势。(3)土地利用程度整体呈上升趋势且高于全国平均水平231,土地利用信息熵先减少后增加,流域景观经历了"无序-有序-无序"的变化。(4)研究期内流域的总生态系统服务价值呈持续上升趋势,单项生态服务功能主要为土壤形成与保护、废物处理、水源涵养和生物多样性保护。高分辨率卫星影像为流域景观格局演变和生态服务价值分析提供了较为详细的数据支撑。

Landscape pattern changes and evaluation of ecological service values in a small watershed of the Loess Gully Region

A case study was carried out in Nihegou, a typical watershed in the Loess Gully region. Color-infrared aerial photographs taken in 1986, SPOT images created in 2002, results interpreting GF-1(Gaofen-1 satellite)images in 2016, and socio-economic data were collected and used in this study. The change in landscape patterns over the past three decades was characterized by the landscape index and land use level indices and analyzed using information entropy theory. The characteristics of the change in ecosystem service values are quantitatively assessed with a version of an equivalence estimation method, which was originally used for ecology service valuations. The results showed that over the past 30 years, land use and land cover in the studied areas have undergone significant changes, with the areas of arable land, orchards, and unused land decreasing and the area of woodland and developed land increasing. The overall fragmentation of the landscape patterns is decreasing and the connectivity of the dominant patches is tending to grow stronger. The level of land use is continuing to grow and is greater than the national average level, at 231. The information entropy of land use decreased and then increased, indicating that the landscape patterns changed from an originally disordered state to a more ordered state and then returned to a more disordered state. The aggregate value of ecosystem services in this area, with the major individual functions being soil formation and protection, waste disposal, conservation of water sources, and maintenance of bio-diversity, is tending to rise. High-resolution satellite images provide highly specific data in support of this characterization of the changes in the landscape patterns and the ecosystem service values of this watershed.