Abstract:
The evergreen and deciduous broad-leaved mixed forest is a typical vegetation type in the central subtropical region. In order to improve the biodiversity monitoring system of Shennongjia National Park (candidate area), to supplement the forest dynamic monitoring network in China, and to further study the mechanism of species diversity maintenance and forest dynamic of the evergreen and deciduous broad-leaved mixed forest in the middle subtropical zone, Wuhan Botanical Garden has established a forest dynamic plot of 5 hm
2 (250 m east-west, 200 m north-south, facing due north and south). The plot was established in the Shennongjia National Park in Hubei Province in 2023, following the standards of the Forest Global Earth Observatory (ForestGEO) and the Chinese Forest Biodiversity Monitoring Network (CForBio). Based on the plot survey data, a preliminary study was conducted on the community composition, basic characteristics, structure, and spatial distribution of woody plants (bamboo and liana not included) with diameter at breast height (DBH) ≥ 1 cm in the plot. The results show that there are 18, 450 surviving individuals in the plot, belonging to 164 species, 56 families and 101 genera of woody plants. Among them, there are 118 species of deciduous trees and 46 species of evergreen trees. There are 46 common species (>10 plant/hm
2), 80 occasional species (≥1 plant/hm
2, ≤10 plant/hm
2), and 38 rare species (< 1 plant/hm
2). The plot is a typical evergreen deciduous broad-leaved mixed forest. The proportion of evergreen and deciduous broad-leaved tree species are 73.90% and 26.10%, and the importance value are 53.25% and 46.75%, respectively. The flora is dominated by the northern temperate zone (33 genera), accounting for 32.67% of the total genera. It also has tropical components, with a total of 30 genera, accounting for 29.70% of the total genera. The forest layers are distinct, and the community is dominated by
Quercus oxyodon (
n=5147),
Quercus engleriana (
n=1041),
Carpinus viminea (
n=265) and
Fagus hayatae (
n=147), with importance values accounting for 15.57%, 6.13%, 2.52% and 2.19% of the total, respectively. Their basal area accounts for 15.30%, 9.73%, 4.42% and 4.66% of the total (159.51 m
2/hm
2), respectively.
Acer oliverianum and
Quercus multinervis are dominant species in the understory layer, while
Ilex pernyi and
Eurya nitida are dominant species in the shrub layer. In terms of size class distribution, the average breast diameter of individuals in the dynamic plot is 7.05 cm, and the overall size class shows an inverted "J" shape, with individuals with DBH≤5 cm being dominant (57.07%) with successful regeneration. And the community structure is stable with good species renewal. The 6 dominant species are all clustered distributed, and as the spatial scale increases, the degree of intra-species clustering decreases, tending towards a random distribution; a large-scale uniform distribution appears after excluding environmental heterogeneity.