Species Composition and Community Structure of Typical Subtropical Evergreen Broad-leaved Forest and Subtropical Montane Elfin Forest in Shimentai National Nature Reserve in South China

To study species composition and community structure of typical subtropical evergreen broad-leaved forest (EBLF) and subtropical montane elfin forest (MELF), we established 1 hm² EBLF plots and 1 hm² MELF plots in Shimentai National Nature Reserve in Guangdong, South China. Using all woody plants with DBH ≥ 1 cm, including trees, shrubs and lianas in each plot, the species composition and community structure of the plots were analyzed based on species community, density, diameter at breast height (DBH) class structure and plant height structure of the area. Results showed that dominant species differed between EBLF and MELF, with a Srensen similarity index value of 0.41, but dominant families (Theaceae and Ericaceae) were similar. The mean densities of seedlings (1 cm ≤ DBH < 2.5 cm) and saplings (2.5 cm ≤ DBH < 12.5 cm) were lower in EBLF than those in MELF, while there were no differences in density of small trees (12.5 cm ≤ DBH < 25 cm) and adult trees (DBH ≥ 25 cm) between the two forest types. EBLF had higher mean DBH of seedlings and adult trees, but lower mean DBH of saplings than those of MELF, while there were no differences in mean DBH of small trees between the two forest types. Mean height of small trees and adult trees were higher and mean height of seedlings were lower in EBLF than those in MELF, but there were no differences in mean height of saplings between the two forest types. Our results highlight the differences in community structure and species diversity between EBLF and MELF, which likely resulted from differences in structure and diversity maintenance mechanisms of these two forest types, with EBLF being more stable than MELF.