关键词: 毛竹扩张, 常绿阔叶林, 竹阔界面, 物种多样性, 生态系统功能, 自然保护区

Abstract

The expansion of Phyllostachys edulis into the adjacent secondary evergreen broad-leaved forest (EBF) is obvious and greatly affects its ecological function. Little research has examined its effects on community structure and biodiversity. We comparatively analyzed the characteristics of species composition, community structure and diversity before and after the expansion of P. edulis forest (PEF), P. edulis-broad-leaved mixed forest (PBMF) and EBF along a gradient of P. edulis expansion in the Jinggangshan National Nature Reserve in Jiangxi Province using a space for time substitution method. Results indicated that: (1) The Bray-Curtis similarity index values of the tree layer, shrub layer and herb layer between PEF and EBF were 0.003, 0.046 and 0.030, respectively. (2) The PEF vertical structure showed a “>” type and the abundance percentage was 33.3% in 12-14 m interval, its diameter at breast height (DBH) class structure concentrated distribution in 5-10 cm interval, whose percentage was as high as 90.0%; while the EBF vertical structure showed a “L” type and the abundance percentages was 54.3% in 2-4 m interval, its DBH class distribution range was relatively wide, the average percentage of four larger diameter grades was 10.3%. (3) The Shannon-Wiener index value in the tree layer declined from 2.56 in EBF to 0.06 in PEF, with a reduction of 98%. In the shrub layer, the index value dropped from 2.58 to 2.03, declining 21%. We suggest that the expansion of P. edulis simplified the community composition and structure of the secondary evergreen broad-leaved forest and reduced species diversity, which can cause adverse impacts on forest ecosystem functioning.

Key words: Phyllostachys edulis expansion, evergreen broad-leaved forest, bamboo and broad-leaved forest interface, species diversity, ecosystem function, natural reserve