Study On The Shrub And Herb Plants Under The Cold Temperature Coniferous Forest On Guancen Mountain

In this study the shrub and herb plants of the cold temperature coniferous forest on Guancen Mountain were investigated by using the methodology of quantitative ecology from the perspective of community ecology.The 82 sample plots of the shrub and herb plants were classified into 17 groups by TWINSPAN,which were named "undergrowth dominant species group"("dominant species group(DSG)" for short).They were changed into 20 DSGs based on the field survey,which were the main types of the undergrowth plants of the cold temperature coniferous forest on Guancen Mountain.The DCA ordination revealed that the elevation,slope and light were the dominant factors in the distribution pattern of the shrub and herb plants of the cold temperature forest in Guancen Mountain.The interspecies relationships of the undergrowth plants were examined by usingχ2 test,Pearson product moment correlation coefficient and Spearman's rank correlation coefficient.The results showed that the number of species pairs in negative association was more than that in positive association, which indicated that undergrowth plants were still in the succession stage. The positive association or correlation among the species pairs were mainly resulted from their similar biological characteristics,similar ecological adaptation to habitats and their separated niche.In contrast,the negative association or correlation among the species pairs were mainly caused by their different biological characteristics,different ecological adaptation to habitats and overlap niche.The significance of Spearman's rank correlation coefficient was 7.36%higher than that of Pearson correlation coefficient, which indicated that the sensitivity of the former was higher than the latter, and so it can make up for the weakness of the latter.The Shannon index,Simpson index,Patrick index and Hill Index were used in the analysis of species diversity of the undergrowth plants.The results from Patrick index,Shannon index and Hill index had a good consistency.According to the value of Shannon index,the species diversity of the 20 DSGs was in the following order:DSG-12＞DSG-17＞DSG-15＞DSG-11＞DSG-13＞DSG-18＞DSG-14＞DSG-6＞DSG-10＞DSG-5＞DSG-9＞DSG-20＞DSG-19＞DSG-4＞DSG-7＞DSG-3＞DSG-1＞DSG-16＞DSG-2＞DSG-8. Simpson index can reflect the status and the function of dominant species in the community.The values of Patrick index and Shannon index for herb layer were higher than those for the shrub layer,which showed that the species richness and species diversity of the undergrowth plants in the study area were mainly resulted from the species richness of herb layer.Elevation, slope and the density of tree layer can lead to some modification of a series of environmental factors such as temperature,humidity,soil moisture and light intensity etc,which will affect the species diversity of the communities.