关键词: 植物群落, 种群结构, 银缕梅, 极小种群植物, 安吉小鲵国家级自然保护区

Abstract: The Parrotia subaequalis is classified as a first-class protected plant species in China and represents a rare example of plant species with extremely small populations. The Zhejiang Hynobius amjiensis National Nature Reserve serves as one of the key distribution sites for this critically endangered plant species, and is also among the earliest sites to conduct research on Parrotia subaequalis. However, investigations into the population characteristics of Parrotia subaequalis in this reserve remain relatively sparse, and there has yet to be a systematic exploration of the community characteristics associated with its primary habitat. This study established 22 plots representing the primary habitat communities for this species in the reserve. Detailed investigations were conducted to assess both species composition and quantitative attributes of these communities, alongside an analysis of various community types and their respective characteristics. Furthermore, by examining the diameter class structure of the Parrotia subaequalis population, compiling static life table, constructing survival curve, and calculating indices for changes in population dynamics, this study delved the intricate aspects of population dynamics of Parrotia subaequalis. The results indicated that a total of 1,457 woody plants (including 121 individuals of Parrotia subaequalis) with a diameter at breast height (DBH) of ≥ 1 cm were examined, representing 106 species across 82 genera and 44 families. The 22 plant communities were classified into 14 formations. The population of Parrotia subaequalis exhibited a relatively low proportion of seedlings and saplings with DBHs < 7.5 cm, comprising only 22.31% of the total individual count. This observation suggests significant challenges in the renewal of the population. The species survival curve conformed to the Deevey-II type. Notably, there were significant differences in population dynamic indices between natural and disturbed conditions, revealing an insufficient capacity for the population to withstand external disturbances. In light of these findings, this study recommends enhancing in-situ conservation efforts for Parrotia subaequalis populations in the Zhejiang Hynobius amjiensis National Nature Reserve. It is also essential to implement management and protection measures specifically targeting seedlings and saplings of Parrotia subaequalis while conducting long-term monitoring of both its populations and their associated primary habitat communities.

Key words: plant community, population structure, Parrotia subaequalis, plant species with extremely small population, Zhejiang Hynobius amjiensis National Nature Reserve