摘要
通过野外调查和数据统计,分析了桂西南喀斯特山地蚬木种群的数量动态过程;利用生存分析理论,编制了静态生命表,绘制了生存曲线并分析了生存函数变化。结果表明:(1)蚬木种群缺少大径级个体,幼苗幼树占较大比例,种群结构总体呈增长型,不同地段种群结构存在差异。(2)蚬木个体树高生长与胸径增长呈显著指数函数关系,胸径和树高分别为33 cm和13 m左右时是其生长过程中较为明显的转折点。(3)蚬木野生种群存活曲线的变化趋势经统计检验为DeeveyⅡ型,种群整体上处于一个动态稳定状态。(4)蚬木种群幼龄阶段的生存率逐渐下降,随后保持平稳;而累积死亡率逐渐上升,随后趋于平缓,说明蚬木幼龄植株受环境筛选作用,死亡率较高,生存率低,而种群后期相对稳定。(5)蚬木野生种群天然更新良好,该地种群濒危的主要原因在于人为干扰破坏。
Excentrodendron hsienmu is one of second-class rare and endangered plants in China, mainly distributes in tropical limestone mountainous seasonal rainforests of Guangxi and Yurman province. The numeric dynamic of E. hsienmu distributed in southwestern Guangxi province was analyzed. The static life table was worked out, and the curves of survival, survival rate, cumulative mortality rate, mortality density and hazard rate were drawn based on the field data and the theory of survival analysis. The results show that （1） the seedlings and saplings orE. hsienmu accounted for a higher proportion, so whole population was lack of large diameter-class individuals and demonstrated a growth-oriented type, and there were population structure differences among different plots were （p〈0.05）. （2） There was an obviously exponential functional relationship between tree height and diameter at breast height （DBH） and there was an apparent turning point in the growth when DBH and tree height were 33 cm and 13 m, respectively. Before the point, tree height grew faster than DBH, while the latter increased more rapidly than the former after the point, and tree height growth slowed down till stopped. （3） The curve of survival individuals tended to be the type Deevey Ⅱ , the whole E. hsienmu population was dynamic stable. （4）The survival rate of seedling and sapling of E. hsienmu population decreased gradually and then kept stable, while the cumulative mortality rate increased gradually and then became flat. The results show that the mortality rate of young E. hsienmu was higher and survival rate was lower because of the selective action by environmental sieve, while at the later stage the population was relatively stable. （5） The natural regeneration of wild E. hsienmu population is moderate in the study area and the anthropogenic factor may be the main endangered cause, so it is very urgent to take efficient measures to recover this endangered species and help it colonize successively.
出处
《中南林业科技大学学报》
CAS
CSCD
北大核心
2013年第3期1-8,共8页
Journal of Central South University of Forestry & Technology
基金
广西自然科学基金项目(2012GXNSFAA053042)
广西林业科学研究院基本科研业务费资助项目(林科201201号)
关键词
蚬木
树木年龄结构
生命表
存活曲线
生存分析
Excentrodendron hsienmu
age structure of trees
life table
survival curve
survival analysis
