狭域特有植物元江素馨的种群结构及动态特征

Population structure and dynamic characteristics of narrowly distributed endemic species Jasminum yuanjiangense

关键词:  元江素馨, 种群, 静态生命表, 存活曲线, 时间序列预测

Key words:  Jasminum yuanjiangense, population, static life table, survival curve, time sequence prediction

摘要:

元江素馨(Jasminum yuanjiangense)为云南省元江河谷狭限分布的特有植物,该研究采用典型选样法在元江素馨较为集中分布地布置4个样方,包含干热灌丛、稀树灌木草丛2个植被类型,调查分析种群年龄结构及存活曲线,量化种群结构类型,比较各局域元江素馨种群的差异性,并运用时间序列预测种群数量动态,以揭示元江素馨种群结构及动态特征。结果表明:(1)元江素馨种群属于增长型,V_pi'=0.004 1,表明该种群趋近于稳定型; 种群结构在发展过程中存在一定的波动性,种群生长前期个体数多于生长后期; 存活曲线趋于Deevey-Ⅲ型和Deevey-Ⅰ型; 幼苗充足,死亡率高,幼龄阶段到中龄阶段个体生长发育受阻。(2)时间序列预测分析表明,元江素馨种群具备一定的恢复能力,未来2、4个龄级时间后种群个体数均呈现小幅度的增加趋势。(3)各局域元江素馨种群结构存在差异,但依据其年龄结构大致可划分为两类,即样地1、样地2和样地4种群为增长型,存活曲线表现出Deevey-Ⅲ型; 样地3的种群为稳定型,存活曲线呈现出Deevey-Ⅰ型,稳定型种群生境较增长型种群生境更适宜于元江素馨的生长。

Abstract:

Jasminum yuanjiangense is an narrowly distributed endemic species in Yuanjiang River Valley of Yunnan Province. Four sample plots, belongs to two vegetation types including dry-hot shrubs and savanna were typically selected in the distribution area of J. yuanjiangense. The population age structure and survival curves were created and the type of population structure were analysed by Chen Xiaode's Quantification Method, and predicted population dynamics using time sequence model, and compared the population differences between different habitats. The results were as follows:(1)The population of J. yuanjiangense presented as a growing type and tend to stable(V_pi'=0.004 1). The populations had definite fluctuations during their growth dynamics, and the number of individuals in the pre-growth stage was more than that in the late growth stage. The survival curve of population approached to type Deevey-Ⅲ and Deevey-Ⅰ. The seedlings was abundant, but the mortality was high. The growth and development of individuals were limited from young to middle age.(2)The time sequence model predicted that the population of J. yuanjiangense was able to keep stable and the number of individuals would have a light rising tendency in the coming 2, 4 age classes.(3)The population structure of J. yuanjiangense varies greatly among different sites, but it can be roughly divided into two types according to its age structure. Sample plots 1, 2 and 4(Habitat 1)displayed growing type with Deevey-Ⅲ survival curve, Plot 3(Habitat 2)displayed stable type with Deevey-Ⅰ survival curve. The habitat of stable type is more suitable for the growth of J. yuanjiangense than the habitat of growing type.