卧龙自然保护区冷杉-铁杉林木本植物多样性在冷箭竹更新恢复过程中的变化特征

Woody plant diversity changes in Abies-Tsuga forests during the natural regeneration of arrow bamboo(Bashania faberi)in the Wolong Nature Reserve

为阐明冷箭竹(Bashania faberi)开花枯死后的自然更新恢复过程中,冷杉-铁杉林内木本植物多样性的变化特征,洞悉亚高山森林植被在群落内部扰动影响下木本植物的响应,以四川卧龙自然保护区"五一棚"区域内的森林固定样地为研究对象,采用常规群落学调查方法,分析冷杉-铁杉林内冷箭竹更新恢复前期与后期的木本植物多样性特征.结果表明,木本植物中乔木树种的种类组成、多样性指数在冷箭竹更新恢复前期与后期之间没有显著变化(P> 0.05),灌木植物的种类和同种植物的重要值以及多样性指数在前后期都有明显的变化,种类和多样性指数都略有增加(P <0.05);且不同样地在更新恢复的前后期,木本植物的多样性表现出不同的变化规律,海拔3 000 m以下的样地乔木树种的变化较小,海拔3 000 m以上样地有显著性变化;而灌木植物多样性在所有样地中都具有明显的差异,呈略微增长趋势;同时,不同样地之间在冷箭竹更新恢复前后期的乔木树种多样性,两两之间相差不明显,灌木植物在前期彼此相差较大,后期仅个别样地、个别指数有显著性差异,其余都无明显的统计学意义.本研究结果体现出演替顶级群落物种组成的稳定性,物种多样性在竹子更新恢复过程中的波动性,以及不同生活型植物(乔木树种、灌木植物)对环境变化适应的差异性,这为制定生物多样性保护与野生大熊猫栖息地生态恢复的策略提供了依据.(图3表4参54)

We examined the response of woody plants to internal forest disturbance during subalpine succession and its underlying driving mechanism by comparing changes in woody plant diversity of Abies-Tsuga forests after the flowering and die-back of arrow bamboo(Bashania faberi).We calculated species diversity indices(a-diversity andβ-diversity)for the survey data from six fixed plots in the area of the Wolong Nature Reserve,Sichuan Province,from 1984 and 2013 to understand changes in flora and species diversity over time,including the pro-phases and post-phases of the bamboo regeneration and restoration.The results showed that species and the diversity indices of the trees in the Abies-Tsuga forests did not change significantly before or after the regeneration and restoration of arrow bamboo but maintained relatively stable state(P>0.05).In contrast,species diversity and the importance values of shrubs changed significantly between the pro-phase and postphase of the regenerative and restorative periods,and the species composition and diversity indices of the Abies-Tsuga forests slightly increased(P<0.05).Variation was seen in woody plant tree diversity patterns,as changes in the tree species of the sample plots below 3000 m above sea level were small,but a significant change was seen in the sample plots above 3000 m above sea level.In contrast,the diversity of shrubs was significantly different among all plots and showed a slight increasing trend.At the same time,there were no significant differences in the tree species diversity of the Abies-Tsuga forests between different sites before or after the regeneration and restoration of arrow bamboo.Shrubs were significantly different with each other during the early stage.Only several plots and several indices were significantly altered during the later stage,and the rest presented no significantly statistical effects.In a word,these results reflect the stability of the species composition in climax communities,the variability of the species diversity of Abies-Tsuga forests during the process of bamboo regeneration and restoration,and the adaptation of diverse types of plants(e.g.,tree species and shrubs)to environmental changes.This provides a basis for developing strategies for biodiversity conservation and the ecological restoration of wild giant panda habitats.