濒危植物香果树(Emmenopterys henryi)种群结构与动态

香果树(Emmenopterys henryi)为我国特有种,属国家Ⅱ级重点保护植物。主要分布于江西、安徽等地亚热带中山或低山区的森林中。文中对武夷山自然保护区4个群落类型的香果树种群数量动态进行了系统研究,统计其径级结构、建立生命表,应用谱分析方法分析种群数量的动态变化,并对影响该种群结构的环境因子进行了分析。结果表明:(1)武夷山自然保护区香果树种群基本属于衰退型,幼苗少,中树、大树个体丰富。不同生境的种群密度存在差异,其中香果树纯林密度较大(8.45±0.818株.100 m^-2),幼苗数量较多,更新较好(幼苗密度1.05±0.326株.100 m^-2),针阔混交林中香果树密度较小(6.58±0.76株.100 m^-2),无幼苗;(2)香果树种群中树死亡率较高,其他各级死亡率较低;(3)香果树种群自然更新过程存在明显的周期。(4)对影响香果树种群结构的13个环境因子通过主成分分析(PCA)发现,较高的光强、土壤含水量、弱酸性土壤、土壤有机质、大气湿度、大气温度和适量的人为干扰对种群增长发挥有利影响,而高海拔、阴坡、陡坡度和大的乔灌层盖度对香果树种群增长则发挥不利影响。(5)充分利用香果树幼树喜荫、大树喜光的特点,加强现有林分的就地保护,特别是具有结实能力的母树,并就地采种育苗,扩大人工种群数量。

Population Structure and Dynamics of the Endangered Plant Emmenopterys henryi

Emmenopterys henryi is a national Class II protection plant endemic to China.It is mainly distributed in the forest of subtropical middle or low mountain areas of Jiangxi province,Anhui province,etc.Based on the investigation in Wuyishan Nature Reserve,the population dynamics of E.henryi in four types of communities was studied.The diameter structure was calculated,the life table was established and the population dynamics of it was predicted by spectral analysis method.At the same time,the relationship between E.henryi population structure and environment factors was analyzed.The result showed that the population of E.henryi in Wuyishan Nature Reserve belonged to a declining one because of the less young seedlings.The population density was different in various habitats.The biggest population(8.45±0.818 individuals·100 m^-2)was the E.henryi pure stands.Its’ seedling number was 1.05±0.326 individuals·100 m^-2 more than that of others.While the least one was in the forest mixed with conifers and broad-leaved trees,the average population density was 6.58±0.76 individuals·100 m^-2,and no seedlings were in it.There was higher death rate in medium tree,but lower in others.The spectral analysis of the population dynamics of E.henryi was made,which revealed that a marked regularity of periodic fluctuation was in the process of natural regeneration.Analysis on 13 ecological factors,we found that higher light,higher soil moisture,weak acidic soil,more soil organic matter,higher temperature,higher humidity,and appropriate human disturbance may produce positive influence on the population increase of E.henryi,while high altitude,shady slope,big slope digree and high-coverage of plant may have negative effect on it.In situ conservation should be taken as the most important management by making the best use of characteristic of E.henryi,and especially the mother trees which were in the fruit-bearing stage must be protected in order to promote their natural regeneration.In addition,the seed collecting and seedling nursing measures should be carried out in the original habitats of E.henryi,to expand artificial population number of it.