芦芽山亚高山草甸优势种群和群落的二维格局分析

种群和群落的二维空间格局研究能够更好地揭示群落的空间和结构特征,但在分析方法上有较大的困难。用垂直相交的两条样带在两个方向上同时取样的二维取样法,获得数据,用一维格局分析方法分别分析,可以得到各个种不同格局规模斑块的长、宽及面积,实现二维格局研究。用DCA排序和格局分析方法相结合,可以完成群落的二维格局分析。在山西芦芽山亚高山草甸应用的结果表明这样的垂直样带二维取样及分析方法较好地反映了种群和群落的空间特性,是非常有效的,并且该方法简单易做,具有较大的可操作性。所研究的草甸主要优势种格局斑块的形状比较规则,面积也较大。次要种斑块多为不规则形,面积也较小。群落格局与主要优势种的格局关系密切。

Two-dimensional pattern analysis for dominant species and community in mountain meadow of Luya Mountain, Shanxi Province, China

The spatial pattern analysis of population and community is important to understand community structure and has become one key topic in modern plant ecology. There are many techniques to carry out the analysis for one-dimensional pattern in ecological literature. Two-dimensional pattern analysis is better than one-dimensional analysis in the study of community spatial characteristics and structure. However it is hard to analyze these two-dimensional patterns for poor effective methodology. The two-dimensional sampling using two transects meet at right angles was applied to get quadrat data in this work. And then the two transects data were analyzed separately by one-dimensional pattern analysis method, two-term local quadrat variance. The length, width and area of patches at different scale of pattern for populations were resulted from the analysis. For community pattern, the Detrended Correspondence Analysis (DCA) was employed to summarize the species information firstly, and then the first DCA axis scores were analyzed to check its pattern. The application of this method to the pattern analysis of dominant populations and community for subalpine meadow (Comm. Polygonum viviparum Carex rigescens Kobresia bellardii) in Luya Mountains shows that it can release the characteristics of spatial pattern clearly and is a very effective technique. It is easy to use and time-saving method with obvious advantages, compared with the presented two-dimensional pattern analysis methods in the literatures, such as Four-term local variance analysis, Nine-term local variance analysis, two-dimensional paired quadrat variance, two-dimensional spectral analysis and so forth. In the study meadow, the patterns of main dominant species, Polygonum viviparum, Carex rigescens and Kobresia bellardii, are apparent and comparatively regular in shape with large areas of patches at the same scale compared with other species such as Fetuca spp. and Thalictrum petaloideum. There are two or three scales of patterns for each studied plant population. This is related to population features, the interaction with environmental factors and their dominant position in the community. The two scales of patterns for meadow community are clear. The pattern of community is closely correlated with that of main dominant species. The patches of dominant species are inter-distributed and overlapped, and form the community pattern together. This is beneficial for utilization of resources, and keeping community stable.