迭山北坡云冷杉林火烧迹地灌木群落特征和物种多样性研究

Analysis of Shrub Community and Species Diversity in Burned Area of Picea asperata-Abies fabri Forest in the Northern Slope of Dieshan Mountains

为探究云冷杉林火烧迹地群落恢复与重建及其稳定性维持机制,以青藏高原东北边缘迭山北坡云冷杉林火烧迹地恢复15 a灌木群落为研究对象,针对不同坡位处典型群落,分析群落组成与结构特征和α物种多样性。结果显示:在坡位梯度上,从上到下可依次划分唐古特忍冬+扁刺蔷薇-密生薹草群落、箭竹-密生薹草群落和黑水柳-野草莓群落3种典型群落;在这3种典型群落中,共调查到27科49属60种植物,其中上坡位调查到23科28属32种植物,中坡位调查到21科27属33种植物,下坡位调查到25科40属49种植物;除下坡位高度结构呈双峰分布以外,火烧迹地灌木群落高度结构和径级结构均呈现出倒“J”型;各主要灌木种的高度结构和径级结构均呈现出倒“J”型、正态和多峰连续分散分布,高度结构在上、下坡位主要呈正态和多峰连续分散分布,中坡位呈倒“J”型分布,而径级结构在上、中坡位呈“J”型分布,下坡位主要呈正态和多峰连续分散分布;整个火烧迹地α物种多样性,除Pielou均匀度指数外,草本层物种多样性指数总体大于灌木层,灌木层下坡位植物种丰富度最高,Shannon-Wiener指数、Simpson指数和Pielou均匀度指数上坡位最高,草本层Shannon-Wiener指数随坡位上升而逐渐降低,Simpson指数中坡位最高,上坡位最低,Pielou均匀度指数中坡位最高,下坡位最低。研究表明:不同坡位处的典型群落、植被组成特征、群落结构特征和α物种多样性存在着明显的差异,造成这种差异的原因是坡度、坡位、干扰和生境异质性等多因素对火烧迹地植物演替进程中的综合作用,研究结果对科学指导火烧迹地群落恢复与重建以及维持其稳定性具有重要意义。

In order to research on the mechanism of the restoration and reconstruction of forest communities and its stability maintenance,the community composition and structure characteristics and α species diversity were analyzed for the typical communities in different slope locations,taking the restoration of 15a shrub community in the fire burning area of spruce forest on the northern slope of the northeastern margin of the Qinghai-Tibetan Plateau.The results showed that:from the top to the bottom,the three typical communities,namely,Lonicera tangutica+Rosa sweginzowii-Carex crebra community,Fargesia spathacea-Carex crebra community,and Salix heishuiensis-Fragaria vesca community,were divided from the top to the bottom.For 3 typical communities,a total of 60 species were investigated belonging to 27 families and 49 genera,among which,the upper slope had 23 families,28 genera and 32 species,the middle slope had 21 families,27 genera and 33 species,and the downslope had 25 families,40 genera and 49 species.The high-order structure and diameter class structure of the shrub community presented the bimodal distribution in the downslope,while it showed an inverted“J”shape in the upper and middle slpoe.The results indicated that the height structure was mainly normal and multi peak continuous distribution on the upper and lower slopes,the middle slope showed inverted“J”type,while the diameter class structure was mainly normal and multi peak continuous distribution on the upper and middle slopes;Except for Pielou evenness index,the species diversity index of herb layer was larger than that of shrub layer.The species richness of shrub layer was the highest in the lower slope,while the Shannon Wiener index,Simpson index and Pielou evenness index were the highest in the upper slope.The Shannon Wiener index of herb layer decreased gradually with the increase of slope position.The Simpson index was the highest in the upper slope and the lowest in the upper slope.In Pielou evenness index,the middle slope was the highest and the downslope was the lowest.There were obvious differences in typical communities,vegetation composition,community structure and α species diversity at different slope positions.The causes of differences were the comprehensive utilization of altitude,slope,slope position,disturbance and habitat heterogeneity in the process of plant succession in burned area.The analysis of shrub community characteristics and species diversity in the burned area of spruce fir forest on the northern slope of Dieshan mountains had the great significance in the restoration and reconstruction of burned area community and maintained its stability.