摘要
基于对贡嘎山海螺沟冰川退缩后形成的125 a的原生演替序列上不同森林群落类型的调查，以空间代替时间的方法，选取了7个典型样地（S0~S6），分别代表冰川退缩后第0、17、35、49、56、85和125年后的演替群落，探讨了不同演替阶段生态系统各组分生物量变化规律及分配特征。结果表明，群落生物量与演替阶段和乔木层优势种的组成密切相关。乔木层生物量与活植物体总生物量均随演替的进行呈显著的指数增长的趋势，分别从10.195 Mg·hm-2增至366.122 Mg·hm-2，从9.162 Mg·hm-2增至332.461 Mg·hm-2；不同演替阶段乔木层生物量在各个层次分配中占绝对优势（>89.871%），其他各层所占比例较小，总趋势为：灌木层>地被层>草本层，林下各层生物量分配受到群落环境影响较大。粗木质物残体量和年叶凋落物量也随着演替的进行不断积累，其中粗木质物残体量在针阔混交林阶段（S5）达到最高，年叶凋落物量则随演替的进行呈显著的指数增加的趋势。演替前60年（S0~S4），柳树（Salix rehderana)、沙棘（Hippophae rhamnoides）和冬瓜杨（Populus purdomii）等落叶阔叶树种对乔木层生物量贡献最大，演替后60年（S5~S6），乔木层生物量则主要来自冷杉（Abies fabri）和云杉（Picea brachytyla）等针叶树种（>93.070%）；乔木层生物量的器官分配以树干所占比例最高，为56.388%~72.658%，枝和根的比例次之，叶所占比例则最小。经过了125 a的演替，海螺沟冰川退缩区生态系统植被生物量已达到成熟林水平，生态系统结构与功能相对稳定，植被演替发展至顶级群落。
Abstract
In order to better understand the vegetation biomass changes and distribution characteristics of different components along time, seven sampling plots (S0~S7) representing different succession stages (bare land, 17 years, 35 years, 49 years,56 years,85 years and 125 years) were chosen through investigation of the 125-year-old chronosequence in Hailuogou glacier retreated area, Mt. Gongga. Results showed that stand age and plantation types were two main factors leading to biomass change. Total living biomass of the vegetation and biomass of the tree layer both presented an exponential growth pattern along time, separately ranged from 10.195 Mg·hm-2 to 366.122 Mg·hm-2, from 9.162 Mg·hm-2 to 332.461 Mg·hm-2. Tree layer contributed most to the total living biomass, which accounted for more than 89.871 percent during all stages; in contrast, biomass of the other layers only had little influence on the total biomass and showed a tendency of shrub layer > ground cover > the herb layer. What’s more, these underwood layers were more affected by the community environment. Biomass of the coarse woody debris and annual leaves litter also accumulated during the succession chronosequence, biomass of the coarse woody debris increase to the peak at S5, where the mixed broadleaf-conifer forest was growing while the biomass of the annual leaves litter fitted well with the exponential growth model during the whole succession chronosequence. In the former 60 years of succession, biomass of the tree layer mainly came from deciduous broad-leaf species such as Salix rehderana, Hippophae rhamnoides and Populus purdomii, in the last 60 years of succession, evergreen coniferous trees, for instance, Abies fabri and Picea brachytyla contributed most to the total layer biomass (>93.070%). As for biomass allocation related to various organs, the trunk occupied the greatest proportion of the tree layer, which made up 56.388%~72.658% of the total biomass,branch and roots came secondly, while leaves took up the least proportion among all the organs.
国家科技期刊平台
NSTL
维普
万方数据