浙江百山祖25 ha亚热带森林动态监测样地群落组成与结构特征

Community composition and structure of a 25-ha forest dynamics plot of subtropical forest in Baishanzu,Zhejiang Province

百山祖常绿林是亚热带中高海拔地区保存较好的森林类型,群落结构复杂。本研究以百山祖25 ha亚热带森林动态监测样地(简称百山祖样地)为平台,对样地内胸径(DBH)≥1 cm的所有木本植物进行调查和统计,分析了其物种组成、区系特征、径级结构和空间分布格局。结果表明:样地内DBH≥1 cm的木本植物独立个体有210,556株,分属43科85属163种。热带分布的科(20个)多于温带分布的科(17个),但在属水平上以温带性质为主(温带分布的属为47个,热带分布的属为33个)。常绿树种有90种,占总树种数的55.21%。样地内稀有种和偶见种分别占所有物种数的35.58%和25.77%。重要值≥1%的物种共有25个,分别占样地总个体数和总胸高断面积的85.84%和91.18%。重要值最大的3个物种分别是鹿角杜鹃(Rhododendron latoucheae)、黄山松(Pinus taiwanensis)和杉木(Cunninghamia lanceolata)。样地内所有个体的平均胸径为5.26 cm,整体径级分布呈倒“J”型,小径级个体较多,群落更新良好。样地内优势种在1–100 m尺度上呈聚集分布,且不同优势种表现出不同的生境偏好。本文可为后续开展亚热带中高海拔地带常绿林群落构建及生物多样性维持机制的研究提供科学基础。

Aim:This study surveys the species composition,floristic characteristics,size-class distribution and spatial distribution of dominant species within the subtropical evergreen forest of Baishanzu,Zhejiang Province,characterized by a complex community structure at medium-high altitudes,in order to lay a scientific foundation for the study of community assembly and species coexistence mechanisms.Method:Employing Forest Global Earth Observatory(ForestGEO)and the China Forest Biodiversity Monitoring Network protocols,we expanded the original 5-ha plot to a 25-ha forest dynamics plot within the Fengyangshan-Baishanzu National Nature Reserve in Qingyuan County,Zhejiang Province between 2014 and 2016.Surveying all woody plants with a stem diameter at breast height(DBH)≥1 cm,we meticulously analyzed species composition,floristic characteristics,DBH class distribution,and spatial distributional patterns within the plot.Results:The plot harbored a total of 210,556 individuals of woody plants with DBH≥1 cm,representing 163 species,85 genera,and 43 families.Notably,tropical floristic elements dominated at the family level(20 families)compared to families with temperate features(17 families).At the genus level,however,the floristic characteristics of the plant community were more temperate(47 genera of temperate floristic elements versus 33 genera of tropical floristic elements).Rare and occasional species contributed significantly to species richness(35.58%and 25.77%,respectively).Evergreen species constituted 55.21%of the total species richness,with 25 species having high importance values(IV)≥0.01,accounting for the majority of abundance(85.84%)and basal area(91.18%).Dominant species with the highest IV included Rhododendron latoucheae,Pinus taiwanensis,and Cunninghamia lanceolata.The plot exhibited successful regeneration,as indicated by an inverted“J”shaped diameter class distribution with a greater number of individuals in the smaller DBH classes.All the dominant species exhibited aggregated spatial distribution across scales(1–100 m)and exhibited habitat preferences.Conclusion:The majority of species presented in the forest dynamics plot are temperate floristic elements and evergreen species,which are the characteristics of medium-high altitude evergreen forest in East China.The dominant species in the plot have significant association with habitat,which suggests that habitat filtering plays an important role in the distribution of woody plants in this area.