Vegetation geography of evergreen broad-leaved forests in Yunnan, southwestern China
Zhu Hua
Abstract
Aims Yunnan in southwestern China supports an extremely rich biodiversity and various vegetation types dominated by evergreen broad-leaved forest.Of these, three major types-monsoon evergreen broad-leaved forest (MEB), semi-wet evergreen broad-leaved forest (SWEB) and middle-montane wet evergreen broad-leaved forest (MMEB)-have not had a detailed scientific comparison.This article compares their floristic composition, species diversity, physiognomy, biogeography, and possible historical evolution, and gives suggestions for their conservation priorities.Methods Six 1 hm 2 sampling plots, representing the three evergreen broad-leaved forests in Yunnan, were set up based on the present distribution of primary forest.All trees in each plot were identified and their diameter at breast height (DBH) (minimum 5 cm) and height measured.In four plots, all plants, including understory shrubs, herbs, lianas, and epiphytes, were surveyed for life forms and biogeographical element analyses at plot level.Importance value indices (IVI) of tree species were calculated for each plot.At the vegetation level, all seed plants for the three major vegetation types were inventoried to compare their floristic composition and biogeography.Important findings At plot level, the three forest types differ considerably in species composition, diversity, 2 植物生态学报