长白山风倒区植被恢复26年后物种多样性变化特征

Characteristics of plant species diversity in a windthrow area on Changbai Mountain after 26 years of natural recovery

20世纪80年代后期,长白山遭受了罕见的台风袭击,原始森林遭到了大面积破坏。为了弄清风倒区自然恢复26a后的植被恢复状况,通过调查和对比分析风倒区和相邻的原始林区(对照区)3种典型森林类型的物种多样性的特征,评估了风倒区植被的恢复状况。结果表明,与没有受到干扰的对照区相比,阔叶红松林风倒区乔木层物种丰富度和α多样性差异性不显著(P>0.05),而云冷杉林和岳桦林风倒区的乔木层物种丰富度和α多样性显著降低;阔叶红松林风倒区的灌木层物种丰富度和α多样性均呈降低趋势,且丰富度差异性显著,云冷杉林和岳桦林风倒区的灌木层α多样性显著升高;阔叶红松林和云冷杉林风倒区的草本层α多样性显著降低,但岳桦林风倒区草本层α多样性变化不显著。阔叶红松林乔木层更新恢复的较好,灌木层和草本层更新较差;云冷杉林和岳桦林均是乔木层更新较差,灌木层更新较好;云冷杉林草本层物种较单一,岳桦林变化不大。经过风干扰后的长白山不同海拔森林物种组成和多样性还需要较长时间才能恢复到干扰前水平。

Biodiversity forms the foundation of a vast array of ecosystem services that critically contribute to human well-being and sustainable economic development. Plant diversity is a key component of biodiversity; moreover, it is an important indicator of the biodiversity status and complexity of plant community structure and function in a specific area. Plant species diversity is considered as the most directly and easily observable component of ecosystem diversity, and therefore, it has been extensively researched. Disturbance is a ubiquitous phenomenon in nature and is regarded as the most important factor that contributes to plant species diversity. Wind disturbance is one of the most common natural disturbances in forest ecosystems. In 1986, a hurricane swept away a large area of primary forest on Changbai Mountain and caused widespread devastation. In the present study, we examined natural restoration 26 years after this wind disaster, by using contrastive analysis of plant species diversity in three forest types in the windthrow area and the corresponding undisturbed primary forest area （control）. In addition, we evaluated the characteristics of vegetation restoration in the windthrow area. We showed that the richness and α diversity of tree species in a broadleaved and Korean pine mixed forest （BKPF） in the windthrow area did not differ significantly from those in the control area; on the other hand, the richness and α diversity of tree species in a spruce-fir forest （SFF） and Erman＇s birch forest （EBF） were significantly lower in the windthrow area than in the control area. Additionally, in comparison with the control area, the windthrow area exhibited a significant compositional change in dominant tree species in the BKPF, but no significant compositional change in dominant tree species in the SFF or EBF. In the undisturbed primary BKPF, the dominant tree species were Pinus koraiensis, Tilia amurensis, and other precious hardwood tree species. On the other hand, in the corresponding windthrow area, the dominant tree species were Populus davidiana and Betula platyphylla, which are the dominant tree species during the early-successional stage of BKPF. The dominant tree species in the SFF （in the undisturbed and windthrow areas） were Picea jezoensis and Abies nephrolepis, whereas the dominant tree species in the EBF （in the undisturbed and windthrow areas） was Betula ermanii. According to the species richness, Shannon diversity index, and Simpson dominance index, the tree species was BKPF 〉 SFF 〉 EBF. Hence, 26 years after the wind disaster, natural restoration was fastest in the BKPF and slowest in the EBF; the SFF showed an intermediate rate of natural restoration. For shrubs in the BKPF, the species richness and α diversity were lower in the windthrow area than in the control area; however, the difference was significant only for species richness. On the other hand, for shrubs in the SFF and EBF, the α diversity was significantly higher in the windthrow area than in the control area. For herbs in the BKPF and SFF, the α diversity was significantly lower in the windthrow area than in the control; on the other hand, for herbs in the EBF, the α diversity did not differ significantly between the windthrow area and the control area. Our results indicate that when species compositions in the undisturbed primary forest were used as a reference, tree species in the BKPF recovered well in the windthrow area, whereas shrubs and herbs showed low recovery rates. Tree species in the SFF and EBF showed low recovery rates in the windthrow area, whereas shrubs and herbs recovered well. Interestingly, a single species was dominant in the herb layer of the SFF, and the dominant species in the herb layer of the EBF did not differ significantly from those of the undisturbed primary forest. Our findings suggest that natural recovery of forest in the windthrow area is incomplete and that full recovery will require a prolonged period.