环境因子对太白山锐齿槲栎林林下草本植物组成和多样性的影响

Effect of environmental factors on understory herbaceous composition and diversity in oak forests in Taibai Mountain

【目的】探索太白山锐齿槲栎林林下草本植物组成和多样性与环境因子的关系,为该区域森林保护、经营管理提供理论指导。【方法】基于太白山锐齿槲栎林林下草本植物野外调查及室内试验数据,采用CCA和偏CCA排序法分析环境因子对太白山锐齿槲栎林林下草本植物组成的影响,采用相关分析和多元逐步回归分析探索环境因子对其草本植物多样性的影响。【结果】环境因子能显著解释太白山锐齿槲栎林林下草本植物组成变异,海拔、坡向、坡度、pH、枯落物厚度和有机质、碱解N、有效P、有效K含量及郁闭度、灌木盖度11个环境因子共解释了物种组成变异的39.05%。其中,郁闭度、土壤有效P含量、pH值和海拔是影响林下草本植物组成的主要环境因子。海拔、郁闭度、有效P和有效K含量能够显著影响太白山锐齿槲栎林林下草本植物的多样性,海拔较高、郁闭度较大、土壤有效P和有效K含量较高的生境具有较好的草本植物多样性。【结论】在太白山锐齿槲栎林经营管理中,可通过适量施用P肥和K肥来促进林下草本植物发育,提高物种多样性。

【Objective】The relationships between understory herbaceous composition and diversity and environmental factors in the Quercus aliena var.acuteserrata forests in Taibai Mountain were investigated to provide basis for forest preservation and management.【Method】The characteristics and environmental factors of understory herbaceous plants in the Q.aliena var.acuteserrata forests were examined.Canonical correspondence analysis(CCA)and partial CCA were used to analyze the relationships between understory herbaceous composition and environmental factors,and correlation analysis and multivariate stepwise regression analysis were used to explore effect of environmental factors on herbaceous diversity.【Result】Environmental factors significantly explained variation in understory herbaceous composition in the oak forests in Taibai Mountain,with eleven environmental factors(elevation,aspect,slope,pH,litter thickness,organic matter,alkali-hydrolyzable nitrogen,available phosphorus,available potassium,tree canopy closure,herb cover)contributing to 39.05%of total variation in species composition.Tree canopy closure,soil available phosphorus content,soil pH and elevation were the main factors.The effects of elevation,tree canopy closure,soil available phosphorus content and available potassium content on understory herbaceous diversity were significant(P<0.05),and higher herbaceous diversity was associated with higher elevation,higher tree canopy closure,and larger contents of available phosphorus and potassium.【Conclusion】In the management of Quercus aliena var.acuteserrata forests in Taibai Mountain,moderate application of phosphorus and potassium fertilizers can promote understory herbaceous development and improve species diversity.