基于移动窗口法的豫西山地丘陵地区景观异质性分析

Landscape heterogeneity of mountainous and hilly area in the western Henan Province based on moving window method

研究典型区域景观异质性过程中,对特征尺度的判断尤为重要。基于3S技术,以豫西山地丘陵地区巩义市为研究区域,在分析其景观组分与结构的基础上,采用半变异函数和移动窗口相结合的方法,确定研究景观异质性的特征尺度,并在特征尺度下选取西北—东南方向和东北—西南方向两条样线,分析研究区不同干扰背景下景观异质性的空间特征。结果表明:豫西巩义地区总体上以旱地、建设用地、水浇地、草地和有林地景观类型为主,其中旱地所占比例最大(30.9%),沟渠所占比例最小(0.1%);根据特征尺度分析确定研究区巩义市景观异质性的合适尺度为1000 m;在特征尺度下,研究区景观破碎化以河谷平原和丘陵为主的巩义东部偏南区域最高,以人为干扰较少的南部低山有林地区最低,景观多样性分布特征则呈现4个聚集中心,分别为北部河谷平原农业区、城市建成区、南部低山区和东南丘陵区;不同干扰背景下,巩义地区景观异质性根据城市化程度呈现以市区为中心向外辐射发展的特征,同时受海拔高度因素影响较大,即在海拔200 m以下区域景观受人为干扰强烈,海拔200—500 m丘陵区域受海拔因子和人为干扰因子共同作用,海拔500 m以上区域海拔因子起主导作用。研究结果可为豫西山地丘陵地区及同类地区景观异质性的研究尺度、景观格局优化和土地的有效管理提供依据。

In analyzing landscape heterogeneity in a typical area,appropriate selection of characteristic scale is very important. In this paper,Gongyi City,located in mountainous and hilly area of western Henan Province,has been chosen as our study area. Based on 3S technology,the landscape composition and structure of this area are analyzed. Meanwhile,the characteristic scale of landscape heterogeneity is determined by using the semi-variable function and moving window method. According to the characteristic scale,we selected two sample lines,which extend from the direction of NW to SE and the direction of NE to SW. These two sampled lines are set to analyze the spatial characteristics of landscape heterogeneity under different disturbances. Finally,the results show that landscape of the study area mainly consists of dry land,construction land,irrigated land,grassland and woodland. Among these landscape types,the dry lands have the largest proportion,accounting for 30. 9% of the whole area,while the irrigation canals have the least area proportion,accounting for 0. 1% of the whole area. Based on the semi-variable function and the moving window method,the characteristic scale for analyzing landscape heterogeneity of the study area is 1000 m. Under this characteristic scale,the landscape fragmentation of the study area is mainly concentrated in the valley plain and hilly regions of the southeastern partof the Gongyi City. The lowest fragmentation regions are in the forestland of southern hilly area of Gongyi City. Landscape diversity of the study area is characterized by four gathering centers,which are the northern valley plain agricultural area,constructed urban areas,the southeast hills and the low mountains in southern area. The first center exhibits the highest landscape diversity,while the landscape diversity of the other three is of the lowest. Under the influence of different disturbances,the landscape heterogeneity of the study area show features of radiating from the city center to surrounding rural area. In addition,landscape heterogeneity is also related to altitude in hilly regions. We find that the landscape heterogeneity has dramatic changes below 200 m because of strong human disturbance. However,at the altitude of 200—500 m,human disturbance and altitude are combined to affect the landscape heterogeneity. In addition,at 500 meters above sea level,altitude is the dominant factor in influencing landscape heterogeneity. The results of this study can provide valuable guidance for further study on landscape pattern optimization and efficient management of land use in the mountainous and hilly area of western Henan Province.