黔中喀斯特次生林群落结构动态

Dynamics of phytoecommunity structure of karst secondary forest in Central Guizhou

关键词:  喀斯特, 群落结构, 多样性指数, 动态特征, 贵州

Key words:  karst, phytoecommunity structure, diversity index, dynamics characters, Guizhou

摘要:

喀斯特地区群落结构动态研究,是生态重建和石漠化治理中需解决的关键问题。该文基于黔中普定县6块永久监测样地在2013年、2015年和2019年的监测资料,分析了7年间喀斯特次生林重要值、物种消长结构、物种多样性、径级结构和垂直结构的动态特征。结果表明:(1)刺楸(Kalopanax septemlobus)、朴树(Celtis sinensis)等乔木种的优势度增大,更新率较高,竹叶椒(Zanthoxylum armatum)、杭子梢(Campylotropis macrocarpa)和火棘(Pyracantha fortuneana)等先锋种的重要值减少,且死亡率较高。(2)物种多样性指数各年间无显著差异,物种丰富度和Margalef丰富度指数呈先增加后减少的趋势,Shannon-Wiener多样性指数基本稳定,均匀度指数呈先减少后增加趋势,其在2013年和2019年之间差异显著。(3)径级和树高结构呈“倒J型”和“左偏正态”分布,各年间差异不显著,乔木层大径级(DBH≥10 cm)个体数增加,但高大乔木(H≥9 m)个体数和种数减少,灌木层中火棘、杭子梢和小冻绿树(Rhamnus rosthornii)等灌木种在0 m≤H<3 m和0 cm≤DBH<2.5 cm的个体数减少,而刺楸、朴树等乔木种个体数增加。喀斯特次生林的自然演替过程较缓慢且复杂多样,层次结构不明显,群落总体处于演替进展的中前期,群落更新良好,将进一步以乔木占优势的方向发展。

Abstract:

The dynamic study of community structure in karst area is a key problem to be solved in ecological reconstruction and rocky desertification control. Based on the monitoring data of six permanent monitoring sample plots in Puding County of Central Guizhou Province in 2013, 2015 and 2019, the dynamic characteristics of important value, species fluctuation structure, species diversity, diameter class structure and vertical structure of karst secondary forest in seven years were analyzed. The results were as follows:(1)The dominant degree and regeneration rate of Kalopanax septemlobus and Celtis sinensis increased, while the important values of Zanthoxylum armatum, Campylotropis macrocarpa and Pyracantha fortuneana decreased, and the mortality rate was higher.(2)There was no significant differences in species diversity indexes between different years. Species richness and Margalef richness index increased first and then decreased. Shannon-Wiener diversity index was basically stable, and uniformity index decreased first and then increased, the differences were significant between 2013 and 2019.(3)The distribution of diameter class and tree height showed “inverted J” and “left partial normal” distribution, and there was no significant differences in different years. The number of individuals of large diameter class(DBH≥10 cm)increased, but the number of tall trees(H≥9 m)decreased. In the shrub layer, the number of individuals of Pyracantha fortuneana, Campylotropis macrocarpa and Rhamnus rosthornii at 0≤H<3 m and 0≤DBH<2.5 cm, decreased, while the number of individual tree species such as Kalopanax septemlobus and Celtis sinensis increased. The natural succession process of karst secondary forest is slow and complex, and the hierarchical structure is not obvious. The community is in the middle and early stage of succession, and the community regeneration is good, which will further develop in the direction of arbor dominance.