我国特有珍稀植物七子花濒危原因分析

七子花被列为国家二级重点保护植物,目前仅间断分布于我国的浙江和安徽二省.为揭示其濒危原因,从地质历史时期的植物变迁、现代地理分布与资源状况、生物学和生态学特性及人为干扰的影响等方面对以往研究进行总结分析.研究表明:历史时期气候变迁可能导致七子花分布区大幅度缩小和种群数量急剧下降,加之后来人为干扰严重,从而造成如今资源稀少且呈片断分布的现状;种群片断化过程中的建立者效应和瓶颈效应造成了七子花的遗传多样性水平较低和种群间明显的遗传分化,并可能由此产生了有性生殖障碍,降低了其生态适应能力,即使强度不大的人为干扰,也对种群的生存构成威胁.因而在目前状态下,建议在种群规模大、遗传多样性高的七子花分布地设立自然保护区或保护点进行就地保护,对生境退化、规模较小的种群采取迁地的保护措施,并通过人工繁育七子花幼苗扩大种群规模.

Endangering Causes of an Endemic Plant Heptacodium miconioides in East China

Heptacodium miconioides is an endangered species mainly distributed in Zhejiang and Anhui Province, China. To understanding its endangering causes, previous studies were reviewed from aspects of plant migration in history, present geographical distribution and resources, biological and ecological characteristics and effect of human disturbance. The results showed that the strong climatic changes might result in a massive shrinkage of its distribution in history, which might be main cause for its modern habitat fragmentation and rare resources. Low genetic diversity due to the bottleneck and founder effect decreased its ecological adaptability. Moreover, its inherent characteristics, such as low genetic diversity, sexual reproductive obstacle and special status in forest, limited its population recruitment. To preserve this species, in situ conservation plan establishing nature reserve or spot and enlarging its population size were recommended.