面向水土生态系统服务协同的土地利用模拟

Land use simulation for synergistic water and soil ecosystem services

针对水土生态系统服务功能的相关成果难以应用到实际土地利用规划中的问题。本研究以黄土高原为研究区,使用K-means聚类算法在小流域尺度上划分土地利用结构,结合InVEST模型探究土地利用结构对水土生态系统服务功能的影响。以阳泉市为典型区,设置多情景,结合多目标优化算法和PLUS模型进行未来土地利用模拟。结果表明:在小流域尺度上,黄土高原的土地利用结构可以划分为6类。农地结构、林地结构、农地-草地结构、草地结构、农地-林地-草地结构、裸地结构,最优土地利用占比分别是0.6—0.7,0.5,0.45/0.4(农地/草地),0.75—0.85,0.15/0.4/0.25—0.35(农地/林地/草地)。各土地利用结构中生态系统服务之间的约束曲线基本上是驼峰型、凹波、半凹波和凸波。从未来的土地利用数量上看,3种情景下水域和灌木面积均处于较低水平。其中,对照情景中城建用地面积最大,基准情景次之,协同情景最小。3种情景下,阳泉市均以城市建设为中心,向外依次为耕地、草地和林地的层次分布特征。土地利用的发展过程中各种土地类型之间存在替代规律,即城市建设倾向于取代耕地和草地,草地则可能取代林地和耕地,而林地则可能与草地发生替代关系。研究成果对黄土高原土地利用规划有重要参考价值。

Given the challenges of integrating research on soil and water ecosystem services into practical land use planning,this study targets the Loess Plateau as its area of study.The K-means clustering algorithm classifies land use structures at the small watershed scale.The InVEST model is then used to explore the impact of these land use structures on soil and water ecosystem services.Taking Yangquan City as a typical case study,multiple scenarios are set,and future land use simulations are conducted using a combination of multi-objective optimization algorithms and the PLUS model.The results indicate that,at the small watershed scale,the land use structures of the Loess Plateau can be categorized into six types:agricultural land,forest land,agro-pastoral,grassland,agro-silvo-pastoral,and bare land structures.The optimal land use proportions are 0.6—0.7,0.5,0.45/0.4(agricultural land/grassland),0.75—0.85,and 0.15/0.4/0.25—0.35(agricultural land/forest land/grassland),respectively.The constraint curves between ecosystem services in each land use structure generally exhibit hump-shaped,concave wave,semi-concave wave,and convex wave patterns.In terms of future land use quantities,the areas of water bodies and shrubs are at relatively low levels under all three scenarios.Among them,the area of urban construction land is the largest in the control scenario,followed by the baseline scenario,and the smallest in the synergy scenario.In all three scenarios,Yangquan City is characterized by a concentric distribution pattern,with urban construction at the center,followed by agricultural land,grassland,and forest land.During the development process of land use,there is a substitution pattern among various land types,whereby urban construction tends to replace agricultural land and grassland,grassland may replace forest land and agricultural land,and forest land may be substituted by grassland.The research findings offer significant guidance for land use planning in the Loess Plateau.