Abstract:

Tropical montane rain forest is the most dominant vegetation type on Hainan Island. However, most tropical montane rain forest studies have been conducted at relatively small spatial scales, as large-scale permanent plots are scarce. In this study, we described the community characteristics of one 60 ha plot established in the tropical montane rain forest of Jianfengling, Hainan Island. The goal is to provide basic information to further understanding of biodiversity mechanisms in the tropics of China. Plot altitude varied from 866.3 to 1,016.7 m and the slope varied from 1.7° to 49.3°. A total of 439,676 stems, with diameter at breast height (DBH) ≥ 1.0 cm, belonging to 62 families, 155 genera and 290 species were recorded. The stem density including sprouts and branches was 0.7328 stem/m². Species richness varied from 32-120 species with an average richness of 80 species. There were 136 (88.3%) genera belonging to tropical flora. The plot was a mix of common and endemic species. For example, Rhamnus of Rhamnaceae has a global range while Parakmeria of Magnoliaceae is an endemic genus to China. Livistona saribus, Gironniera subaequalis, Cryptocarya chinensis, Alseodaphne hainanensis, Prismatomeris tetrandra and Nephelium topengii were the most dominant species with importance values greater than 2.0. Lauraceae, Fagaceae, Rubiaceae and Arecaceae were the most dominant families with importance values larger than 5.0. When the sampling area is larger than 7.5 ha or the sampling stems are larger than 20 thousand, 261 species and up to 90% of all species were counted in the plot by species-area and species-individual curves. The percentage of rare and occasional species was 20.7% and 37.6% of all species, respectively. The average DBH of all stems was 5.22 cm and the DBH size class distribution was a typical inverse-J distribution. This study provides basic information for further studies in the Jianfengling 60 ha plot. Jianfengling 60 ha plot is also a platform for monitoring dynamics of long-term biodiversity in the tropics.

Key words: Hainan Island, Jianfengling, forest dynamic monitoring, community structure, species composition, montane rain forest, biodiversity