宝塔区土地利用的地形梯度效应与空间格局

Topographic gradient effect and spatial pattern of land use in Baota District

地形是多种地理因子中对土地利用变化产生重要影响的因素之一,黄土高原区域土地利用格局与资源配置深受地形因素的制约。为了给黄土高原地区未来土地利用、保护森林资源和经济健康发展提供依据,需要分析地形变化对土地利用影响。以黄土高原地区中部的宝塔区为讨论范围,采取2017年末土地利用矢量数据,选用坡度、高程、土地利用综合度和地形指数多项影响因子,全面剖析地形对土地利用类型分布的影响特征;在此探讨的结果下,利用分形理论探讨各土地利用类型的空间分布结构特点。结果表明:(1)宝塔区不同地形各地类分布表现出显著的空间分布差异,高程、坡度和地形位是宝塔区土地利用分布格局形成的重要影响因素。(2)水域、建设用地、耕地和未利用地的优势分布主要聚集在海拔<1200 m、坡度<10°的范围内,林地和草地的优势分布集中在高程>200 m、坡度>15°的区域内。(3)宝塔区土地利用程度综合指数随着地形位指数的增大而逐渐减小。土地利用程度较高的区域集中于人类活动频繁的区域,较低的区域集中于自然地貌区。(4)宝塔区各地类具备明显的分形特点,分维数处于1.2437~1.7360之间。宝塔区土地利用受地形制约,各地类受地形影响变化明显,本研究以期优化黄土高原土地资源配置,加快推进该地区经济发展速度。

Terrain is an important geographical factor affecting land use.Loess Plateau land resources and their development and utilization methods are deeply restricted by terrain conditions.Topography is one of the most important natural environmental factors determining land use patterns,and the land use patterns and spatial structure characteristics of the Loess Plateau are deeply restricted by topography.To provide a scientific basis for future land use,protection of forest resources,and economic development in the Loess Plateau,it is necessary to analyze the effects landform changes have on land use.This study analyzed land use data from the end of 2017 for Baota District.In addition,slope,elevation,topographic index,and other indicators were selected to explore land use mechanisms.On this basis,fractal theory is applied to analyze each land use type’s spatial structure characteristics.The results show that the spatial distribution of land use types in Baota District has obvious topographic gradient characteristics.Height,slope,and topography significantly influence the formation of land use patterns in Baota District.The predominant distribution of water,construction land,cultivated land,and unused land is mainly concentrated in a range where elevation is less than 1,200 m and the slope is less than 10°.The predominant distribution of forest land and grassland is concentrated in an area where the elevation is greater than 1,200 m and the slope is greater than 15°.With the increase of the topographic index,the comprehensive index of the land use degree in Baota District gradually decreased,thus terrain is the main factor affecting the comprehensive degree of land use in the study area based on this analysis.The comprehensive index of land use degree in Baota District is larger in areas where human activities are concentrated and smaller where vegetation coverage is concentrated.The distribution of land use types in Baota District shows obvious fractal characteristics,with fractal dimensions between 1.2437 and 1.7360.The water fractal dimension is the largest among these and the unused land dimension is the smallest.The large water fractal dimension is due to the complicated water boundaries,whereas the small unused land dimension is due to its simple structure.Land use in the Baota District is restricted by the terrain,and various types of land are affected by the terrain.This study aims to optimize the allocation of land resources on the Loess Plateau and accelerate economic development in the area.Efforts to optimize land resource allocation and promote poverty reduction in poor areas in the Loess Plateau should fully consider the effects of topographical factors,follow the principles of adapting to local conditions,guide the situation according to circumstances,and provide advantageous development by attaching importance to optimizing land use structure and layout.