天山中段山地植被的生态梯度分析及环境解释

ECOLOGICAL GRADIENT ANALYSIS AND ENVIRONMENTAL INTERPRETATION OF MOUNTAIN VEGETATION IN THE MIDDLE STRETCH OF TIANSHAN MOUNTAIN

本文通过对天山中段植物群落的ＤＣＡ排序和ＴＷＩＮＳＰＡＮ等级制分类及其与３个土壤变量的ＣＣＡ典范对应分析，定量地研究了该区域植被分布与环境之间的相互关系。结果表明：天山山脉中段植物群落沿着温度和湿度两个梯度方向呈现以天山中段内部湿润植被为中心向北坡干冷荒漠植被和南坡干热砾石荒漠植被两个极点方向发展的分布格局。进一步研究发现，天山山脉中段南北坡植物群落，从大的宏观尺度上看，其类型与分布主要由降水量和温度所决定，而在中小尺度范围上，植物群落的分布与类型却与土壤湿度和土壤养分密切相关。该结果较好地解释了天山山脉中段内部，在地形地貌基本一致的情况下，植物群落类型分异很大的原因。建立了天山山脉中段植物群落梯度环境解释的数学模型和植物群落地理分布的数学模型。

In this paper, the relationship between the vegetation distribution and the environment of the middle stretch of Tianshan M. was quantitatively investigated with the methods of DCA ordination,Twinspan classification and CCA analysis.The spatial distribution of plant communities in this area has one center and two extreme points,that is,from one center(kinds of moist plant communities inside Tianshan M.)to the dry and cold extreme points of the northern slope and dry and hot extreme points of the southern slope.Further study found that types and patterns of plant communities in the studied region were determined on large scale by precipitation and temperature.On the middle and small scales the type and pattern were determined by soil humidity and soil nutrient.This conclusion explained why there were different plant community types where landforms were similar in inside Tianshan M.The spatial distribution of plant communities,the key environmental factors and environmental interpretation by mathematical models were presented in this paper.