Spatial pattern and habitat correlation analysis of dead trees in karst seasonal rainforest in southwestern Guangxi
枯立木是森林生态系统物质循环和能量流动的重要组成部分,对森林群落动态和演替具有重要作用。该研究以位于桂西南的弄岗北热带喀斯特季节性雨林15 hm~2森林动态监测样地为平台,以样地中2011年第一次植被调查数据胸径(diameter at breast height,DBH)≥1 cm的枯立木为研究对象,在充分考虑空间自相关的基础上分析其不同径级(小径级,1 cm≤DBH5 cm;中径级,5 cm≤DBH15 cm;大径级,15 cm≤DBH)的空间分布格局、枯立木多度与环境因子的相关性及生境关联性等。结果表明:枯立木所有个体和小径级分别在0~4 m和0~5 m尺度上表现为聚集分布,其它尺度为随机分布;中径级和大径级在0~30 m尺度上均为随机分布。大径级与凹凸度表现为显著负相关,所有个体和小径级与干旱度指数和样方内所有植株个体数为显著正相关,所有个体和小径级与样方内最大胸径和平均胸径呈显著负相关。所有个体和小径级与3种生境类型间的关联性并不显著;中径级与山坡呈正关联性、与山脊呈负关联性、与山谷无显著关联性;大径级与山谷呈正关联性、与山坡无显著关联性、与山脊呈负关联性。在喀斯特季节性雨林中,枯立木空间分布格局总体表现为随机分布,仅小径级在小尺度内聚集分布,而较大径级在样地中表现出一定的生境关联性;树木死亡过程可能是小尺度内密度制约、大尺度内生境过滤和个体自然衰老等生态学过程形成的。
Dead trees are an important part of the material cycle and energy flow of forest ecosystems, and play an important role in the dynamics and succession of forest communities. The study was based on a 15 hm ~ 2 forest dynamic monitoring plot in a tropical karst seasonal rain forest in Nonggang North, southwestern Guangxi, using the first vegetation survey data in 2011 at breast height (DBH) ≥1 The dead tree of cm is the research object, and its different diameter classes (small diameter class, 1 cm≤DBH5 cm; medium diameter class, 5 cm≤DBH15 cm; large diameter class, 15 cm≤DBH) are analyzed based on full consideration of spatial autocorrelation. ) Spatial distribution pattern, the correlation between the abundance of dead trees and environmental factors, and the relevance of habitats. The results show that all the individuals and small-diameter classes of the dead stand are clustered on the scales of 0 ~ 4 m and 0-5 m, respectively, and the other scales are randomly distributed; the middle and large diameters are on the scale of 0 ~ 30 m. Random distribution. The large diameter level and the unevenness showed a significant negative correlation, all individuals and small diameter levels were significantly positively related to the aridity index and the number of individual plants in the plot, and all individuals and small diameter levels were significantly larger than the largest and average breast diameters in the plot. Negative correlation. The correlation between all individuals and small-path levels and the three habitat types is not significant; the middle-diameter level is positively related to the hillside, negatively related to the ridge, and has no significant correlation with the valley; the large-diameter level is positively related to the valley, It has no significant correlation with the hillside and negative correlation with the ridge. In the karst seasonal rain forest, the spatial distribution pattern of dead standing trees generally shows a random distribution. Only the small-diameter classes are clustered and distributed on a small scale, while the larger-diameter classes show a certain habitat correlation in the plot; the process of tree death may be It is formed by ecological processes such as small-scale internal density constraints, large-scale intra-habitat filtration, and individual natural aging.
Abstract in Chinese and English; article in Chinese only.