ANALYSIS OF THE REGIONAL DIFFERENCES OF FLORISTIC COMPOSITION AND THE NATURE OF VEGETATION IN THE LOWER ZONE ON THE EASTERN SLOPE OF THE HELAN MOUNTAIN RANGE
贺兰山东坡低山区植被种类组成区域分异与植被性质的分析

In this paper, by using quantitative and qualitative methods, the regional differences of floristic composition and the nature of vegetation in the lower zone on the eastern slope of the Helan Mountain Range have been analysed, and the relationship between the species groups as a result of the ordination and ecological environments in the zone has also been discussed. The resuls of analysis show that all the main forms of vegetation in the zone have the common characters of desert or desertified steppe vegetation and the composition of the vegetation is different in the northern, middle and southern parts of the zone. Those differences reflect that, in the zone, the most humid area and the most arid area are respectively the middle part above the altitude of 1600 meters and the northern part below it. Therefore, in the zone,it is necessary to make use of and to conserve the vegetation resources in different ways.