山西高原草地景观格局分析

在GIS的支持下,以《山西高原草地分类现状图》(1∶50万)为基础,通过对底图进行矢量化处理,设置样带并对其进行抽样,应用景观指数对山西高原草地景观格局特征进行研究。结果表明:①山西高原草地具有明显的纬度和经度梯度分布规律,即由南到北草地类型多样性呈现出由简单—最多—较多的变化特点。在山西中南部(34°52'～37°07'N)以喜暖灌木类草丛为优势草地类型,中部地区(37°07'～38°01'N)以喜暖灌木草丛和山地灌丛为优势草地类型,中北部(38°01'～39°22'N)草地景观多样性达到最大(6种草地类型均见于该区),最北部(39°22'～40°16'N)草地种类较少且面积有限。②草地斑块数量由西到东具有由极少—较多—少—极多的特点,且草地分布与海拔高度具有密切关系,最西边低地与中间盆地,基本无草地覆盖;在中海拔(1 000～1 400 m)地带,斑块数量最多、草地类型最为丰富;在高海拔(1 400～2 200 m)地带,草地成片出现。

Spatial Characteristics of Grassland Landscape in Shanxi Plateau

The spatial characteristics of grassland landscape in Shanxi Plateau were analyzed based on the Map of Grassland Types in Shanxi Plateau(1∶ 500 000).With the help of GIS technique,the map was vectored,and four transects were established and sampled,and a set of landscape indices were used to assess the latitudinal and longitudinal patterns of the grasslands.The results revealed that the grasslands had obvious distribution trends with the changes of latitude and longitude.From the south to the north,the grassland diversity changed from a low level to the highest and to the moderate.The temperate shrub grasslands were dominant in the south-central region(34°52′-37°07′N),both the temperate shrub grasslands and mountain shrub grasslands were dominant in the central region(37°07′-38°01′N),the grassland diversity reached the maximum in the north-central region(38°01′-39°22′N),while the diversity was very low and the area of grassland was very small in the northernmost(39°22′-40°16′N).From the west to the east,the number of grassland patches changed from extremely small to relatively large to small and to extremely large.Furthermore,the results showed that there was a close relationship of grassland distribution with altitude.There was less grassland in the middle basins and the west lowland of Shanxi.There were a large number of grassland patches and abundant types of grasslands in the areas between altitudes 1 000 m and 1 400 m.There were vast areas of grasslands in the high altitudinal zone(1 400-2 200 m).