关键词: 群落组成, 空间格局, 生物多样性, 演替动态, 天然次生林, 东灵山

Abstract

Community structure is one of the key features in the process of vegetation succession. Warm temperate mixed deciduous broad-leaved secondary forest is the main forest vegetation type in China’s warm temperate zone. In order to better study the mechanisms of succession and species coexistence in this forest type, we established the Donglingshan 20-ha forest plot (DLS plot) in 2009 and 2010 using the same protocol as the well-established plot on Barro Colorado Island in Panama. In the plot, all free-standing woody plants with DBH (diameter at breast height) ≥1 cm were mapped, tagged, and identified to species. Here, we address preliminary results on floristic characteristics, community composition, and size-class, vertical, and spatial structure of the DLS plot. These datasets will serve as baseline information accessible to a wide range of future studies. We tagged a total of 52,136 genotype individuals (103,284 individuals including branches of genotype individuals), belonging to 58 species, 33 genera and 18 families. All of these tree species were deciduous. Floristic characteristics of the community suggested a temperate flora, including some subtropical and tropical elements. There were very obvious dominant species in the plot. Five species comprised 61% of all individuals, and 20 species comprised 92% of all individuals, while the other 38 species comprised only 8% of all individuals. Vertical structure was composed of an overstory layer (19 species), midstory layer (18 species), and a shrub layer (21 species). The DBH size-class structure of all species in the plot generally fitted a “reverse J” distribution, indicating good regeneration across the community. The size-class structure of the main species in the overstory layer showed a bimodal or nearly normal distribution, while the most abundant species in the midstory and shrub layers showed “reverse J” or even “L” distributions. Spatial distribution patterns of the dominant species varied with size-class and scale and shifted from closer aggregation to looser aggregation from small to adult or old trees. The size-class spatial distribution patterns of the dominant species showed the different diameter levels of their own individuals occupied different spatial positions in the plot.

Key words: community composition, spatial pattern, succession dynamics, natural secondary forest, Donglingshan Mountain