黔中天龙山典型喀斯特次生林地上生物量与环境因子的关系

Relationship between aboveground biomass and environmental factors of typical karst secondary forest in Tianlong Mountain, central Guizhou

关键词:  喀斯特, 地上生物量, 土壤厚度, 岩石裸露率, 坡度

Key words:  karst, aboveground biomass, soil thickness, rock exposure rate, slope

摘要:

为探究喀斯特次生林地上生物量与环境因子的关系,该文以黔中普定县喀斯特天龙山典型次生林样地为研究对象,采取单物种及不同径级组地上生物量模型计算优势种及群落生物量,采用空间分布图描述环境因子与群落地上生物量空间分布状况,利用相关性检验(Pearson)、一般线性模型(GLM)以及冗余分析(RDA)讨论群落、生活型、物种地上生物量与环境因子的关系。结果表明:(1)喀斯特次生林群落地上生物量总量为106.94 t·hm^-2,优势种地上生物量占整个样地的91.77%,其中常绿植物高于落叶,窄叶柯(Lithocarpus confinis)与化香树(Platycarya strobilacea)地上生物量在群落中占比最高,分别为34.23%和34.37%。(2)岩石裸露率空间分布呈现明显的上下梯度差异,上坡显著大于下坡,坡度与土壤厚度空间分布不连续,无明显规律。(3)群落地上生物量与土壤厚度呈显著正相关,二者空间分布趋于一致,土壤厚度是群落地上生物量的主要影响因子,岩石裸露率与坡度对群落地上生物量的影响较低。(4)对于不同生活型,岩石裸露率对地上生物量的影响程度最高,土壤厚度与坡度对常绿植物的影响大于落叶。(5)对于不同物种,环境因子与地上生物量的相关性复杂,大部分物种与土壤厚度呈正相关,化香树、刺异叶花椒(Zanthoxylum dimorphophyllum var. spinifolium)分别与岩石裸露率、坡度呈正相关。综上认为,该研究区次生林植被恢复缓慢,土壤厚度是群落地上生物量的主要影响因子,但对于不同生活型和物种而言,地上生物量对环境的响应会受到生活型差异、物种生境偏好及种间关系等生物因素的影响。

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(Pearson)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 follows:(1)The total aboveground biomass of karst secondary forest group was 106.94 t·hm^-2, and the aboveground biomass of dominant species accounted 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 had no obvious law.(3)There was a significant positive correlation between aboveground biomass and soil thickness, and their spatial distribution tended 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 var. spinifolium 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.