Abstract:

Evergreen broad-leaved forest (EBLF) is climax vegetation in East China, and Jiangxi Province is located at the center of EBLF. Although many phytosociological studies have provided detailed descriptions on this forest at local and regional scales, knowledge on the high-level classification of EBLF and factors controlling their tree species composition and distribution are still lacking. We aim at providing a high-level classification framework for EBLF in Jiangxi and exploring the roles of topographic and climatic factors in driving their distributions. We investigated 205 EBLF plots covering the main alliances across Jiangxi Province. Two-way indicator species analysis (TWINSPAN) and detrended correspondence analysis (DCA) were used to distinguish the EBLF types. Diagnostic and indicator species were detected. The nonparametric Kruskal–Wallis test was used to compare the differences between the groups of EBLFs. We also used redundancy analysis and variation partitioning to estimate the effects of climatic, geographical and topographical factors on the distribution of EBLFs in Jiangxi. The EBLFs in Jiangxi were classified into four types based on the diagnostic taxa and verified by TWINSPAN, i.e. lowland, ravine monsoon, montane typical and dwarf cloud EBLF types. These four EBLF types are associated with climatic and topographic conditions, and their distribution pattern reflects biogeographic differences. Our study provides an important basis for the syntaxonomic classification of EBLFs and further in-depth studies on humid EBLFs in East China. We also emphasize the importance of conservation practices to protect these forests as diversified Tertiary relict plants.

Key words: subtropical, evergreen broad-leaved forest (EBLF), indicator species, diagnostic species, forest classification, ordination