Abstract: Tropical evergreen broadleaf shrublands in low mountain and hilly areas represent the most extensive shrubland type in China. We surveyed 325 plots between 2011 and 2019 across three dominant vegetation associations to classify community types and quantify their floristic composition, structure, and distribution. Using classical Chinese vegetation classification and quantitative analysis, we identified three major shrubland types. (1) Baeckea frutescens shrublands occur from 18.4° N to 25.9° N and 105.2° E to 118.3° E, at elevations of 0–1,340 m. In 101 plots, we recorded 170 vascular plant species in 52 families and 124 genera, with 79.5% of seed plant genera showing tropical affinities; evergreen broadleaf woody species accounted for 90% of total importance value. This alliance comprises 5 association groups and 7 associations. (2) Rhodomyrtus tomentosa shrublands span 18.2° N to 26.2° N and 104.3° E to 118.8° E, at 4–700 m elevation. In 205 plots, we recorded 373 vascular plant species across 79 families and 241 genera, with 70.2% tropical genera and 85% importance value for evergreen broadleaf woody species. This alliance includes 4 association groups and 24 associations. (3) Psidium guajava shrublands, occurring between 22.1° N and 27.1° N and 101.7°E to 113.8°E, at 100–900 m elevation, were recorded in 19 plots, comprising 83 vascular plant species across 38 families and 76 genera, with 71.8% tropical seed plant genera, and an 81% importance value for evergreen broadleaf woody plants. This alien-dominated alliance forms 4 association groups and 5 associations. Baeckea frutescens and Rhodomyrtus tomentosa shrublands share similar community structures and habitat preferences, representing native, natural secondary communities with overlapping ranges. In contrast, Psidium guajava shrublands, dominated by alien plants, pose a growing threat to native vegetation and require urgent monitoring. Our results offer a comprehensive baseline for understanding the structure, function, and dynamics of tropical shrubland ecosystem in China.

Key words: community survey, vegetation classification, Baeckea frutescens shrubland, Rhodomyrtus tomentosa shrubland, Psidium guajava shrubland