Abstract: [Objective] The study was intended to understand characteristics of species diversity in forest dynamics plot (FDP) which located in subtropical evergreen and deciduous broad-leaved mixed forest community in Mulinzi National Nature Reserve, Hubei Province, and to analyze patterns of temporal and spatial changes of species diversity of subtropical evergreen and deciduous broad-leaved mixed forest, and further to provide a basis for exploring maintenance of species diversity, community dynamics, environmental heterogeneity and regulation of ecosystem functions.[Method] The 15 hm² (300 m×500 m) forest dynamics plot was established according to the protocol of the CTFS for field plots establishment in 2014 in Mulinzi National Nature Reserve, Hubei Province. All woody plants with diameter at breast height (DBH)≥1 cm were mapped and identified, and the species diversity were analyzed.[Result] In the 15 hm² FDP there were 84 189 individuals belonging to 228 species, 112 genera and 61 families. There were 11863 individuals belonging to 130 species, 71 genera and 44 families when 10 cm was the minimum measured diameter at DBH, and there were 1 721 individuals when 30 cm is minimum measured diameter, belonging to 67 species, 40 genera and 29 families. Species richness rapidly increased with the expansion of sampling area in the 0-3 hm² when 1 cm and 10 cm were minimum measured diameters, and over 80% of the total species were presented in 6 hm² size. Species richness also quickly increased with sampling area in the range of 0-0.2 hm² when 30 cm was the minimum measured diameter, and there was also over 80% of the total species were at 8 hm². The number of individuals was over 1000 from 18 species accounting for 7.89% of the total number of species, but the number of individuals of these species accounted for 70.63% of the total numbers in plot. These parameters would provide a scientific basis in determining the minimum sampling area of subtropical evergreen and deciduous broad-leaved mixed forest community. Cyclobalanopsis myrsinifolia and C. multinervis dominated the forest canopy, and the importance values were ranked the second and third. Eurya japonica occupied most of the understory, and showed the highest abundance. There was a high proportion of rare species in the plot, a total of 116 species, accounting for 50.88% of the total number of species, but the number of individual trees of rare species accounted for only 0.14% of the total number of individuals. Fagaceae and Theaceae were the important families in evergreen broad-leaved forest in Mulinzi. There were total 18 880 woody plants of 137 sprouting species, belonging to 76 genera and 42 families in the plot, accounting for 22.4%, 60.1%,62.8% and 65.6% of the total number of individuals, species, genera and families, respectively. All these woody plants, there was 1 073 individuals of 64 species, belonging to 43 genera and 26 families when 10 cm was the minimum measured diameter, and 46 individuals of 17 species, belonging to 15 genera and 9 families when 30 cm was the minimum measured diameter.[Conclusion] There were abundant species in subtropical evergreen and deciduous broad-leaved mixed forests in Mulinzi National Nature Reserve, mainly composed of Fagaceae and Theaceae. There were high proportions of rare species and sprouting species. The large number of sprouting species was probably closely related to human disturbance and special habitat conditions before establishment of the nature reserve.

Key words: Mulinzi forest dynamics plot, evergreen and deciduous broad-leaved mixed forest, species richness, sprout, rare species, curve of species richness against area, curve of species against richness