山西历山连香树种群动态研究

Dynamic study of Cercidiphyllum japonicumin Lishan,Shanxi province

[目的]为了解山西历山连香树种群未来的发展趋势,探讨其濒危的主要原因,为连香树保护提供一定的理论依据。[方法]采用"空间代替时间"的方法,对山西历山国家级自然保护区的沁水县和垣曲县连香树种群的年龄结构、静态生命表和存活曲线进行了研究,并对种群数量动态进行预测和分析。[结果](1)种群的年龄结构基本上呈幼苗和幼树较少,中老龄数量较多的"倒锥形",其中垣曲县种群的幼苗较沁水县多,种群也较年轻,两种群的径级都出现了断续,表明种群衰退程度较大;(2)种群的存活曲线基本呈DeeveyⅢ型,种群的个体数量少,呈衰退趋势;(3)在未来10年、20年,幼苗和幼树将急剧减少,老龄植株增多,两种群的个体数量都将减少,种群衰退加剧。[结论]其繁殖特性及其对生境苛刻要求是导致连香树濒危的主要原因。针对连香树的保护工作,垣曲县的测重点是尽可能的采取人工措施,繁殖和培育连香树幼苗;而沁水县除了采取措施,增加幼苗外,还要重点限制人类活动对其生长的干扰和破坏。

[Objective]The purpose of the study was to understand the developmental trend of Cercidiphyllum japonicum population in Shanxi,to explore the main reasons why species became endangered,and to provide a theoretical basis for the protection of Cercidiphyllum japonicum.[Methods]Using the method of ＂space instead of time＂,the age structure,static life tables and survival curves of the population of Cercidiphyllum japonicum were studied in Qinshui and Yuanqu counties in Shanxi Lishan National Nature Reserve,and the population dynamics were predicted and analyzed.[Results]The results showed that：（1）The age structure of the tree population was basically ＂inverted cone＂ shape with fewer seedlings and saplings,but more middle-aged groups,of which the number of seedlings in Yuanqu County were more than those in Qinshui County,（2）The survival curve of the population showed as Deevey Ⅲtype with less number of the population and declining trend;（3）In the next 10 to 20 years,seedlings and saplings population would be decreased drastically,and the number of aged plants would be climbed up.The number of individuals of the both populations in different counties would be reduced and the population density would be declined dramatically.[Conclusion]The reproductive characteristics and the harsh requirements on habitats are the main reasons to lead to species endangerment.For the protection purposes of Cercidiphyllum japonicum in Shanxi Lishan,the strategies should be focused on artificial measures as much as possible to breed and cultivate seedlings in Yuanqu County;while for Qinshui County,besides artificially increasing seedling numbers,restriction of human activities on the species habitats should be conducted to avoid any disturbance and destruction of tree population development.