古田山常绿阔叶林萌生特征及其与群落物种多样性的关系

Characteristics and effects of sprouting on species diversity in a subtropical evergreen broad-leaved forest in Gutianshan,East China

萌生更新是森林木本植物重要的生活史策略,能够促使萌生树种长时间占据原有空间,对物种共存、群落构建与生态系统稳定性有重要的潜在影响;同时,萌生更新的植株具有较强的资源获取与竞争能力。但萌生更新对群落物种共存的作用还远未被理解。本文基于古田山5 ha亚热带常绿阔叶林监测样地的调查数据,研究了萌生更新对群落物种多样性的影响及作用机制。结果表明:(1)古田山常绿阔叶林中萌生树种的丰富度比例较高(63.95%),已发生萌生的物种多度比例较高(38.53%),潜在萌生多度比例更高(59.51%);(2)萌生现象在各分类群普遍发生,壳斗科、杜鹃花科、金缕梅科、山茶科等类群的萌生能力较强;(3)萌生物种丰富度比例与群落物种多样性的关系不显著,萌生物种多度比例与群落物种多样性呈负相关关系。由此推测,作为古田山亚热带常绿阔叶林中一种占优势的更新方式,萌生更新在保证萌生树种持续存活从而增加群落物种多样性的同时,在一定阶段又能抑制群落物种多样性的发展,对群落物种共存、生物多样性维持起到了较重要的调节作用。

Sprouting, a life history strategy found in woody plant communities, enables woody plants to per- sist in situ through disturbance events. The ＇persistence niche＇ of sprouting has important influences on spe- cies coexistence, community assembly, and ecosystem stability. However, the mechanism of the ＇persistence niche＇ in maintaining species diversity is not well understood. Based on data collected in a 5 ha plot in a mid-subtropical evergreen broad-leaved forest in the Gutianshan National Natural Reserve of Zhejiang Prov- ince, China, we analyzed the characteristics of sprouting and their relationships with species diversity. Our results revealed that the sprouting species had a great proportion of 63.95% in richness and a high proportion of 38.53% in abundance, especially a higher abundance proportion of 59.51% of potential sprouting at the community level. Sprouting occurred in most taxa, and there was high ability of sprouting in Fagaceae, Eri- caceae, Hamamelidaceae, and Theaceae. There were significant negative correlations between abundance proportion of sprouting species and the biodiversity index of the community, despite no relationships between richness proportion of sprouting species and biodiversity index. Therefore, the sprouters could retain their po- sition in forests and reduce biodiversity of the forest community. This trade-off of sprouting may result in the maintenance of community stability.