Subjects: Biology >> Botany >> Applied botany submitted time 2022-06-07 Cooperative journals: 《广西植物》
Abstract： In order to explore the relationship between the aboveground biomass of karst secondary forest land and environmental factors, we took the typical secondary forest sample of karst Tianlong mountain in Puding County, Central Guizhou as the research object, adopted the aboveground biomass model of single species and different diameter groups to calculate the biomass of dominant species and community, used the spatial distribution map to describe the spatial distribution of environmental factors and aboveground biomass of community, and used the correlation test (person) General linear model (GLM) and redundancy analysis (RDA) to discuss the relationship between community, life form, species aboveground biomass and environmental factors. The results were as follow: (1) The total aboveground biomass of karst secondary forest group was 106.94 t穐m-2, and the aboveground biomass of dominant species accounts for 91.77% of the whole sample plot. The aboveground biomass of evergreen plants was higher than that of deciduous plants. The aboveground biomass of Lithocarpus confinis and Platycarya strobilacea accounted for the highest proportion in the community, 34.23% and 34.37% respectively; (2) The spatial distribution of rock exposure rate showed obvious upper and lower gradient difference, the upper slope was significantly greater than the lower slope, and the spatial distribution of slope and soil thickness was discontinuous and has no obvious law; (3) There was a significant positive correlation between aboveground biomass and soil thickness, and their spatial distribution tends to be consistent. Soil thickness was the main influencing factor of aboveground biomass of the community, and the influence of rock exposure rate and slope on aboveground biomass of the community was low; (4) For different life forms, the influence of rock exposure rate on aboveground biomass was the highest, and the influence of soil thickness and slope on evergreen plants was greater than that of defoliation; (5) For different species, the correlation between environmental factors and aboveground biomass was complex. Most species were positively correlated with soil thickness. Platycarya strobilacea and Zanthoxylum dimorphophyllum were positively correlated with rock exposure rate and slope respectively. In conclusion, the vegetation restoration of secondary forest in the study area is slow, and soil thickness is the main influencing factor of aboveground biomass of the community. However, for different life forms and species, the response of aboveground biomass to the environment will be affected by biological factors such as life form differences, species habitat preferences and interspecific relationships.
Subjects: Biology >> Botany >> Applied botany submitted time 2020-10-20 Cooperative journals: 《广西植物》
Abstract：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。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。
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