秦岭东段洛河流域土地利用变化的地形梯度效应研究

Study on the Terrain Gradient Effect of Land Use Changes in the Luohe River Basin of the Eastern Qinling Mountains

明晰典型地势起伏区土地利用变化与地形因素的关系,对国土空间布局及区域协调发展具有重要现实意义。基于秦岭东段洛河流域多期土地利用数据及DEM数据,运用土地利用图谱法、标准差椭圆分析法和地形位分析法,揭示自2000年以来当地土地利用变化的时空分异特征,并探讨在不同土地利用变化下的地形梯度效应。研究结果表明:(1)20年间,土地利用变化多围绕耕地、草地和建设用地进行,且表现出显著的类型异质性及阶段差异性特点。(2)以耕地和林地为主的稳定型图谱面积占比达到88.17%,前期变化型和后期变化型分别为7.44%和3.51%,耕地被建设占用更偏向于无序化发展。(3)中低及其以上地形梯度的耕地逐渐趋向于低地形梯度区发展,林地的地形分布指数呈“S”型上升态势,草地则表现出中间高两边低的正态分布规律。(4)各图谱的地形分布指数随地形位增加表现出不同的趋势性规律,土地利用变化呈明显地形梯度效应。研究认为当地国土管理工作应重点关注反复变化型图谱和持续变化型图谱,并注意科学缓解和引导耕地水土流失及坡耕地开发利用问题。

The clear relationship between the land use changes and the terrain factors in regions with typical topographical variations has profound practical implications for the national spatial planning and the harmonious development of regions.This study focused on the Luohe River Basin in the eastern segment of the Qinling Mountains.By analyzing the multi-temporal land use data and DEM data,sophisticated methodologies such as land use mapping,standard deviation ellipse analysis,and terrain position analysis were employed to reveal the spatio-temporal nuances characterizing local land use changes since 2000 and investigate the terrain gradient effects under different scenarios of land use alterations.The results are as follows.(1) Over the past two decades,land use changes in the basin have primarily involved the cultivated land,grassland,and construction land,showing distinct heterogeneity in types and temporal disparities in change patterns.(2) The predominant land use pattern,dominated by the cultivated land and forest land,covers 88.17% of the total area in the basin.Early-change and late-change types constitute 7.44% and 3.51%,respectively.The conversion of the cultivated land to the construction land shows a tendency towards more disordered development.(3) The cultivated land in the basin,located at low to moderate terrain gradients,gradually shifts towards areas with lower terrain gradients.The terrain distribution index of forest land follows an upward “S” shaped trend,while the grassland displays a normal distribution pattern with higher values in the middle and lower values on both sides.(4) The terrain distribution indices of each land use pattern in the basin exhibit distinctive trends with increasing terrain positions,indicating a pronounced terrain gradient effect in land use changes.The study suggests that land management efforts in the Luohe River Basin should prioritize the land use patterns characterized by repetitive changes and continuous transformations.Additionally,careful attention should be given to scientifically mitigating and guiding issues related to the soil erosion in the cultivated land as well as the development and utilization of slope farmland.