八仙山不同类型松栎林群落主要特征分析

Main community characteristics of different types of pine and oak forests in Baxianshan Nature Reserve

关键词:  松栎混交林, 更新潜力, 多样性, 稳定性, PCA双序图

Key words:  mixed Pinus tabuliformis-Quercus variabilis forest, renewal potential, diversity, stability, PCA biplot

摘要:

为探究八仙山保护区不同类型森林群落的更新潜力、多样性程度以及稳定性水平,阐明三者间的关系,该文以保护区内油松林、蒙古栎林和油松-栓皮栎混交林(松栎混交林)3种不同类型天然次生林为对象,调查建群种径级结构和更新潜力,计算不同层次群落多样性,测定M. Godron稳定性,并采用主成分法建立评价模型。结果表明:(1)油松种群径级结构近似正态分布,处于成熟期,但幼苗较少; 栓皮栎、蒙古栎以及阔叶杂木的幼苗、幼树较多,更新潜力较大。(2)松栎混交林的乔木层多样性较高,而灌木层多样性最低,油松林的草本层多样性最低; 松栎混交林群落总体物种丰富度最低而均匀度最高。(3)M. Godron稳定性表明,蒙古栎林距离稳定点较近,而油松林偏离较远。(4)PCA双序图表明,M. Godron稳定性与种群更新潜力、Alatalo均匀度呈较强正相关,综合排序依次为松栎混交林、蒙古栎林和油松林。综上结果表明,建群种更新潜力和物种均匀度对群落稳定性影响较大,林地管理应注重对幼苗幼树的保护。

Abstract:

In order to explore the renewal potential, diversity degree and stability level in different types of Pinus and Quercus forests in Baxianshan Nature Reserve and to clarify their relationships, three types of natural secondary forests, Pinus tabuliformis forest, Quercus mongolica forest and mixed Pinus tabuliformis and Quercus variabilis forest were selected in Baxianshan Nature Reserve. The structure and renewal potential of constructive species were investigated, the diversities of different levels in communities were calculated and the M.Godron index was determined. The principal component analysis was used to develop an evaluation model. The results were as follows:(1)The DBH class structure of Pinus tabuliformis population distributed normally in the mature stage but with little seedlings. Few seedlings of P. tabuliformis were observed. The numerous seedlings and young individuals of Quercus variabilis, Q. mongolica and broad-leaved weed trees presented greater regeneration potential.(2)The diversity in arbor layer of mixed Pinus tabuliformis-Quercus variabilis forest was higher than other communities, while that in shrub layer was the lowest. The diversity in herb layer of Pinus tabuliformis forest was lowest. The overall species richness in the mixed Pinus tabuliformis-Quercus variabilis forest is the lowest with the highest evenness.(3)The M. Godron stability indicated that Q. mongolica forest was close to the stable point, while Pinus tabuliformis forest was far away.(4)The PCA biplot showed that M.Godron stability was positively correlated with population regeneration potential and Alatalo evenness index. The comprehensive characteristics of communities was ordered as mixed P. tabuliformis-Quercus variabilis forest, Q. mongolica forest and Pinus tabuliformis forest. It is concluded that the population regeneration potential of constructive species and species evenness take great influence on community stability, and the seedlings and young individuals of Quercus should be protected during the forest management.