Comparison of woody plant diversity in the evergreen broad-leaved forest in mid-subtropical China

Aims: The evergreen broad-leaved forest is a zonal vegetation type in the subtropical region of China. Evergreen broad-leaved forests are widely distributed in China, so a variety of vegetation subtypes are available. This study aims to discuss the differences between evergreen broad-leaved forest communities from the eastern coast to the western interior. Methods: We selected Tiantong, Gutian Mountains (GTS), Badagongshan Mountains (BDGS), Zhujiangyuan (ZJY), Diaoling Mountains (DLS) and Jizu Mountains (JZS) forest dynamics plots as the research objects. Based on nationally available data on woody plants in the six plots, we first unified the species’ names and counted the number of families, genera, and species of each plot. Then we investigated the distribution type and growth-form of all species. Based on these results, we compared the species composition and structure differences of six plots by Jaccard similarity analysis, the redundancy analysis, and the species–area curve analysis. Results: The results showed: (1) The richness of woody plants in the BDGS plot was the highest, followed by TT plot, GTS plot, JZS plot, DLS plot and ZJY plot. The species composition of evergreen broad-leaved forests in the eastern region of mid-subtropical China is significantly different from that in the western region, with species belonging to the same vegetation subtype being more similar. (2) On the composition of growth form spectrum, the woody plants in the plots of the eastern region mainly belong to tropical families and tropical genera, with most families and genera distributed in the Pantropic zone. In other plots, the woody plants mainly belonged to tropical families but most belonged to temperate genera within the tropical families, with the most genera distributed in the Northern Temperate zone. (3) Plots in the eastern and central regions hold more trees than shrubs, while in the western region, plots hold more shrubs than trees. Only the BDGS plot holds more deciduous woody plants (59.2%) than evergreen woody plants (40.8%), while in other plots, the opposite is true. (4) The BDGS plot differs the most in the richness of evergreens (97) and deciduous woody plants (141), while the DLS plot differs the most in the proportion of evergreens (69.8%) and deciduous woody plants (30.2%). Conclusion: Our results reflect the differences in community species composition, species diversity, and community structure among typical evergreen broad-leaved forests, mixed evergreen and deciduous broad-leaved forests, and semi-humid evergreen broad-leaved forests in mid-subtropical China. The study supplements the comparative analysis among multiple vegetation subtypes in evergreen broad-leaved forests and provides a scientific basis for revealing the species turnover characteristics and change patterns among evergreen broad-leaved forests from the eastern to the western region in mid-subtropical China.