关键词: 景观格局, 农业土壤, 重金属, 珠江三角洲

Abstract: Studies on species composition and biodiversity pattern of Excentrodendron hsienmudominated communities in Karst Mountain can provide certain basis for the vegetation restoration, and the protection and reasonable use of E. hsienmu in karst area. We investigated the species composition and diversity characteristics of E. hsienmudominated communities at eight sites in Southwestern Guangxi, China. The results showed that there were 248 vascular species belonging to 95 families 164 genera in the communities of the eight sites with the tree layer species being more abundant. The main accompanying species were Orophea anceps, and Sterculia nobilis. In addition to species occurring in the tree layer, there were such species as Schefflera octophylla, Alchornea trewioides in the shrub layer. The pteridophyte was the dominant species in the herb layer while the main liane in the interlayer was legume plants. The Shannon, Simpson and evenness indexes maintained consistent trends in the different layers at the eight sites. The E. hsienmu forest communities at different sites showed certain similarity, and those who were geographically relatively closed showed higher similarity. The communities in Napo, and Longzhou Nonggang were more stable in terms of the biodiversity indexes of the tree layer.

Key words: landscape pattern, agricultural soil, heavy metal, Pearl River Delta.