岷江源区主要灌木种群生态位研究

对岷江源区植被及其环境因子系统取样调查的基础上,研究了30种主要灌木种群在土壤水分、全N、速效P、速效K、pH和土壤有机质6个资源维上的生态位特征。尖叶栒子、峨眉蔷薇、高山绣线菊、金露梅、南川绣线菊、窄叶鲜卑花、高山柳、甘青锦鸡儿的生态位宽度较高,对环境有较强的适应能力,形成了该地区的优势种群;伏地栒子、小果小檗、沙棘、沙柳、喜阴悬钩子、尖叶茶藨子、康定柳、山桃等种群的生态位宽度较小。生态位宽度较小的物种并非不是群落的优势种,取决于种群分布的范围和均匀程度。种群在各个资源维上的生态位宽度表明对不同资源空间的利用能力和适应性不尽相同,各个资源维上所有种群生态位宽度和的大小依次为速效K>速效P>全N>有机质>水分>pH,表明物种对土壤pH和含水量资源的利用能力较低,对速效K和速效P的利用能力较高。岷江源区主要灌木种群对不同资源的利用能力与干旱河谷植物种群有较大的差异。

Characteristics of Main Shrub Populations in the Original Area of the Minjiang River

This paper reports a field study on characteristics of shrub population niche in the original area of the Minjiang River to provide a scientific base for vegetation restoration and management.Niche breadths and overlaps of 30 main shrub populations along gradients of soil moisture,total N,available P,available K,soil pH,and organic matter were analyzed using Levins and Schoener indices.Cotoneaster acuminatus,Rosa omeiensis,Spiraea alpina,Potentilla fruticosa,Spiraea rosthornii,Sibiraea angustata,Salix cupularis,Caragana tangutica have higher niche breadth and adaptability to environment,which become the dominant species and play a vital role in maintaining the diversity and stability of plant community;niche breadth of each population in different resource dimension shows that different population has specific ability to use resources,so they have different ecological adaptability.The sum of niche breadth of all populations in different resource dimension is as the following order: available K>available P>total N>organic matter>soil moisture>soil pH.It indicates that the abilities of populations using soil moisture and soil pH were lower than that of available K and available P;not all species with low niche breadth were not dominant species in the communities,which depended on the range and evenness of species distribution.Compared with the main shurb populations of aried valley,the significant difference of using resource ability exited in the main shrub populations of the original area of the Minjiang River.