基于DCCA的蓟县八仙山土壤种子库特征分析

Analysis of Soil Seed Bank Characteristics in Baxian Mountain of Jixian County Based on Detrended Canonical Correspondence Analysis

[目的]通过研究天津市蓟县八仙山土壤种子库特征,为土壤种子库应用于植被恢复提供参考。[方法]采用除趋势典范对应分析(DCCA)方法探究土壤种子库与环境因子的关系。[结果](1)相比天津市其他样地,蓟县八仙山土壤种子库萌发物种丰富度较高,物种高达42种,但土壤种子库密度却最低,这与岩石裸露,土层薄弱,动物取食效应明显有很大关系;(2)土壤种子库的Sorensen相似性指数较低,但Simpson生态优势度指数、Shannon—Wiener多样性指数和Pielow均匀度指数却较高;(3)随着海拔逐渐升高,群落结构明显变化,木本植物数量增多。随着坡向逐渐向阳,植被类型由喜阴植物逐渐变成向阳植物。[结论]通过DCCA分析,土壤种子库物种呈现明显的3个聚类。影响土壤种子库主要的土壤因子为有机质、pH值和全磷。

[Objective]To study the characteristics of soil seed bank（SSB）in Baxian Mountain in Jingxian County of Tianjin City in order to provide reference for vegetation restoration using SSB.[Methods]As a new correspondence analysis method,the detrended canonical correspondence analysis（DCCA）method can overcome the arch effect and give better explanation between plant communities and environmental factors.[Results]（1）Compared with other plots of Tianjin City,the species richness of SSB was very high,reaching to 42 species,but the density of SSB was the lowest.The bare rock,thin soil and obvious animal feeding effect were main reasons for the low density.（2）The Sorensen similarity index was very low,but the Shannon—Wiener diversity index,the Simpson index and the Pielow index were very high.（3）With the increase of the altitude,the community structure changed rapidly,the number of woody plants increased.With the slope exposing to the sun,the type of plants changed from shade plants to light plants.[Conclusion]By DCCA analysis,three obvious clusterings were presented.Organic matter,pH value and total phosphorus were main soil factors which affected the distribution of SSB.