黔中喀斯特次生林群落结构动态.

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 [ABSTRACT FROM AUTHOR]