【目的】探究徐州市典型石灰岩山地侧柏(Platycladus orientalis)人工林不同演替阶段植物群落组成及物种多样性,揭示物种替代和群落结构变化的规律。【方法】采用空间代替时间变化法及典型样地调查法,揭示徐州市4个不同演替阶段(灌草丛、针叶林、针阔混交林、阔叶林)的侧柏人工林群落特征及影响因素。【结果】①所调查的样地共有植物种类105种,隶属于58科96属,各演替阶段所出现的物种数分别为灌草丛14科18属20种、针叶林33科49属51种、针阔混交林43科59属64种、阔叶林27科44属45种;②不同演替阶段植物群落物种重要值方面,乔木层中侧柏的重要值均居于首位,灌木层中构树(Broussonetia papyrifera)的重要值均居于首位并呈现先下降再升高的趋势;草本层4个不同的演替阶段中,重要值分别位居首位的物种为马兜铃(Aristolochia debilis)、茅莓(Rubus parvifolius)、白英(Solanum lyratum)、常春藤(Hedera nepalensis);③不同演替阶段植物群落Shannon-Wiener多样性指数、Margalef丰富度指数、Pielou均匀度指数和Simpson优势度指数变化趋势较为一致,均随着演替的正向发展均呈现先上升后下降的趋势,其中,多样性指数在针阔混交林阶段达到峰值;④物种多样性指数与环境因子的相关性分析结果显示,郁闭度、坡位和坡向与徐州石灰岩山地侧柏人工林演替过程中物种多样性的变化关系密切,其中郁闭度与群落Shannon-Wiener多样性指数相关性最为显著(P<0.05)。【结论】徐州石灰岩山地侧柏人工林物种多样性在针阔混交林阶段达到最高值,其中郁闭度、坡位和坡向对物种多样性发挥着关键影响作用,研究结果可为该地区近自然林分改造与经营提供理论依据。

【Objective】This study explored the composition and diversity of plant communities at different succession stages of Platycladus orientalis in typical limestone mountainous areas of Xuzhou City, and revealed changes in species substitution and community structure.【Method】The community characteristics and influencing factors of P. orientalis in four different succession stages: shrub grassland, coniferous forest, coniferous-broadleaf mixed forest, and broadleaf forest were analyzed using a space-for-time substitution method and typical sample plot surveys. 【Result】 (1) A total of 105 plant species across the sample plots, representing 58 families and 96 genera. Species diversity across succession stages included: 14 families, 18 genera, and 20 species in shrub grasslands; 33 families, 49 genera, and 51 species in coniferous forests; 43 families, 59 genera, and 64 species in coniferous-broadleaf mixed forests; and 27 families, 44 genera, and 45 species in broadleaf forests. (2) Regarding importance values of plant species in different succession stages, P. orientalis consistently ranked first in the tree layer, while Broussonetia papyrifera ranked first in the shrub layer, showing a pattern of initial decline followed by an increase. In the herbaceous layer, the species with the highest importance values across the four succession stages were Aristolochia debilis, Rubus parvifolius, Solanum lyratum, and Hedera nepalensis. (3) The Shannon-Wiener diversity index, Margalef richness index, Pielou evenness index, and Simpson dominance index of community followed a similar trend, initially increasing and then decreasing as succession progressed. The diversity index peaked in the coniferous-broadleaf mixed forest stage. (4) The correlation analysis between plant diversity indices and environmental factors indicated that species diversity changes during the succession of P. orientalis forests in Xuzhou’s limestone mountains were significantly correlated with canopy density, slope position, and slope aspect, with canopy density having the greatest influence on the Shannon-Wiener diversity index (P< 0.05). 【Conclusion】 The plant diversity in P. orientalis forests in Xuzhou’s limestone mountainous area peaked during the coniferous-broadleaf mixed forest stage. The study identified canopy closure, slope position, and slope orientation as key factors influencing plant diversity. These findings provide theoretical bases for the transformation and management of near-natural forest stands in the region.