Abstract:

[Objective] To investigate the diversity patterns of different plant growth forms and their responses to local environmental factors at the scale of a single permanent plot. [Methods] A 2-hm² permanent monitoring plot of Picea schrenkiana forest in the Tomur Peak National Nature Reserve, Xinjiang, was selected as the study site. Based on the baseline survey conducted in 2024, we analyzed species composition, α-diversity, and β-diversity patterns of woody and herbaceous plant communities, and compared their responses to topographic factors, stand structure, and spatial variables. [Results] The species composition of the community within the plot was relatively simple. Picea schrenkiana was the absolute dominant species among woody plants, with an importance value of 74.81%, whereas the herbaceous layer exhibited higher species richness but concentrated dominance. The α-diversity of herbaceous plants was significantly higher than that of woody plants (p < 0.001). The α-diversity of woody plants was significantly negatively correlated with mean diameter at breast height (DBH), mean tree height, and basal area (p < 0.01), whereas the α-diversity of herbaceous plants showed significant negative correlations with slope, stand density, and canopy closure (p < 0.05). The dominant components of β-diversity differed markedly between the two growth forms. The β-diversity of woody plants was primarily driven by the nestedness component (contribution rate: 72%), whereas herbaceous β-diversity was dominated by the species turnover component (contribution rate: 83%). Mantel tests and variance partitioning analyses revealed that spatial variables had relatively higher explanatory power for β-diversity of woody plants and its nestedness component. In contrast, topographic and stand structural factors better explained the β-diversity of herbaceous plants and its turnover component. [Conclusion] The results indicate the significant divergence in α- and β-diversity patterns and their underlying components among different plant growth forms. This study provides fundamental baseline data for long-term dynamic monitoring and community dynamics research on plant diversity in Picea schrenkiana forests.

Key words: α-diversity, β-diversity, topography, stand structure, growth form

摘要：

【目的】探讨单个固定样地尺度下不同生长型植物多样性特征及其对局域环境因子的响应。【方法】以新疆托木尔峰国家级自然保护区雪岭云杉林2 hm²固定监测样地为研究对象，基于2024年首轮调查数据，分析了木本与草本植物群落的物种组成、α多样性与β多样性格局，并比较了其对地形因子、林分结构及空间变量的响应差异。【结果】样地内群落物种组成较为简单，木本植物以雪岭云杉为绝对优势种（重要值74.8%），草本层物种丰富度较高，但优势种较为集中；草本植物的α多样性显著高于木本植物（p<0.001）。木本植物α多样性与平均胸径、平均树高、胸高断面积呈显著负相关（p<0.01），草本植物α多样性与坡度、林分密度、郁闭度呈显著负相关（p<0.05）；不同生长型植物β多样性的主导组分存在明显的分异。木本植物β多样性以嵌套组分为主（贡献率72%），草本植物β多样性以物种周转组分为主（贡献率83%）。Mantel检验与方差分解结果表明，空间变量对木本植物β多样性及其嵌套组分的解释率相对较高，而地形因子与林分结构因子对草本植物β多样性及其周转组分的解释率相对较高。【结论】在单个固定样地尺度下，不同生长型植物在α与β多样性格局及其组分贡献上存在明显的分异。研究结果可为雪岭云杉林植物多样性格局的长期动态监测与群落变化研究提供本底数据支撑。

关键词: α多样性, β多样性, 地形, 林分结构, 生长型