【目的】钱江源-百山祖国家公园森林植物资源丰富、区系组成复杂,是我国重要的生物多样性保护和水源涵养生态功能区。本研究旨在探究园区森林群落植被层次结构及物种多样性沿海拔梯度的分布格局及变化规律,为亚热带森林植被恢复与生物多样性保护提供依据。【方法】在龙泉片区非旅游地带设置连续海拔梯度样带进行森林不同层次的植物群落调查,分析各层次结构、物种组成及物种多样性对海拔的响应差异。【结果】随海拔梯度的增加,杉木(Cunninghamia lanceolata)占比逐渐降低,黄山松(Pinus taiwanensis)以及甜槠(Castanopsis eyrei)、木荷(Schima superba)和鹿角杜鹃(Rhdodendron Latoucheae)等阔叶树种占比逐渐增加。乔木层负关联种对占比高,结构特征与多样性指数沿海拔梯度先增加后降低,在[1 100,1 300) m海拔范围达到峰值;灌木层对海拔梯度响应较弱;草本层仅在低海拔正关联种对占比较高,随海拔升高物种逐渐稀疏、矮小,多样性随之降低。【结论】海拔驱动森林群落各层次物种组成、种间关系、结构特征及多样性有序分化,中海拔为森林群落生长的最适范围,低海拔促进以杉木为优势种的针阔混交林与灌草本共生格局,高海拔促进物种共生、植株矮化。研究结果可为未来气候变化背景下钱江源-百山祖国家公园及其他亚热带森林生物多样性保护提供基础数据和科学依据。

【Objective】Qianjiangyuan-Baishanzu National Park is a key biodiversity conservation and water conservation area in China, characterized by rich forest plant resources and complex floristics. This study aimed to investigate the community structure, species composition, and diversity characteristics of different layers along the elevation gradients in the park, providing a basis for subtropical forest restoration and biodiversity conservation.【Method】Continuous elevation transects were set in non-tourist areas of the Longquan Section to investigate plant communities across different vertical layers of forests, analyzing the responses of structural characteristics, species composition, and species diversity to elevation.【Result】The relative proportion of Cunninghamia lanceolata gradually declined along the elevation gradient, while the relative proportion of Pinus taiwanensis and broad-leaved tree species (e.g., Castanopsis eyrei, Schima superba) gradually increased along the elevation gradients. Arborous layer showed the high proportion of negatively interspecific associated species pairs, and the structural characteristics and diversity of arborous layer initially increased with the maximum values in 1 100-1 300 m, then decreasing along the elevation gradients. The structural characteristics and diversity of shrub layer showed a weak response to the elevation gradients. Herb species were characterized by lower density, height and diversity, with positively associated species pairs predominantly distributed only at low-elevation areas.【Conclusion】Elevation regulated the orderly differentiation of species composition, interspecific relationships, structural traits and diversity in different layers. The mid-elevation areas were suitable for forest growth. Low-elevation areas promoted the coexistence pattern of coniferous-broadleaf forests dominated by Cunninghamia lanceolata as well as shrub and herb species. High-elevation areas led to species coexistence and plant dwarfing. Results could provide basic data and scientific basis for biodiversity protection in Qianjiangyuan-Bashanzu National Park and other subtropical forests under future climate change.