珍稀濒危植物黄杉种群结构与空间分布格局

Population Structure and Spatial Distribution Pattern of a Rare and Endangered Plant Pseudotsuga sinensis

摘要:

为了解珍稀濒危植物黄杉种群的生存现状和更新机制，对贵州省威宁县黄杉自然保护区内天然分布的黄杉(Pseudotsuga sinensis)群落的结构特征和空间分布格局进行了研究。结果表明，黄杉种群的中龄级个体数较多，幼龄级和老龄级个体相对较少，呈典型的“∩”型结构。种群结构动态指数V_pi(13.49%)和V'_pi(0.05%)均大于0，种群属于增长型，但增长幅度逐渐降低，对外界干扰敏感度较高。种群存活曲线趋于Deevey-II型，生命期望值单调下降，死亡率呈“V”型，有2个死亡高峰，第1个出现在I龄级，第2个出现在IX龄级。黄杉种群除部分样地(Q2和Q7)呈均匀分布外，大部分样地呈集群分布；随龄级的增加，空间分布格局由集群分布逐渐趋向于均匀分布。因此，黄杉种群濒危的主要因素是幼树个体无法及时补充种群，建议加强对幼苗的抚育和通过适度干扰，促进黄杉种群的更新。

Abstract:

In order to understand the survival status and regeneration mechanism of Pseudotsuga sinensis population, the community structure and spatial distribution pattern in Weining County Nature Reserve for P. sinensis of Guizhou Province were studied. The results showed that the diameter class structure of the population was a typical single-peak type, with more middle-aged individuals and fewer young and old individuals. The dynamic indexes (V_pi=13.49%, V'_pi=0.05%) of population structure showed a growth type, But the growth rate gradually decreased, and the sensitivity to external interference was higher. The survival curve of population tends to Deevey-II type, with the life expectancy decreased monotonously. The mortality rate showed a "V" type with two death peaks, the first appeared in I age class and the second in IX age class. Most of the sample plots showed cluster distribution, while Q2 and Q7 plots showed uniform distribution. The spatial distribution pattern changed from cluster distribution to uniform distribution along the age. Therefore, the main factor of endangered population of P. sinensis was the failure of young individuals to replenish population in time, it was suggested to strengthen seedling tending and promote regeneration of P. sinensis population through moderate disturbance.