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珍稀濒危植物疏花水柏枝种群结构与动态特征

Population structure and dynamic characteristics of the rare and endangered plant Myricaria laxiflora (Franch.) P. Y. Zhang & Y. J. Zhang

  • 摘要: 疏花水柏枝(Myricaria laxiflora (Franch.) P. Y. Zhang & Y. J. Zhang)是我国长江流域特有珍稀濒危植物,具有极高的生态价值。本研究以三峡大坝建设以来新发现的疏花水柏枝3个野生种群(长江上游2个、中游1个)为研究对象,开展疏花水柏枝种群调查、收集和种群生态学相关的数据,编制种群静态生命表、存活和生存分析曲线,采用数量化方法预测种群动态,揭示种群生存现状、种群结构及动态特征。结果显示:疏花水柏枝种群属于增长型,但具有衰退的风险;幼龄期死亡率偏高,数量动态变化指数VpiV´pi均大于0,但对外界干扰比较敏感;种群存活曲线介于Deevey-Ⅰ和Deevey-Ⅱ型之间。生存分析和时间序列预测结果表明,幼龄个体的缺乏、死亡率高是导致种群更新困难的主要原因。疏花水柏枝野生种群受到洪水、挖沙、砍伐、放牧、开荒等因素影响,种群的生存受到严重威胁,因此未来在加强原生境和幼苗管理的同时,还要加大保护力度、建立保护小区以实现对该物种的多方位保护。

     

    Abstract: Myricaria laxiflora, a rare and endangered species endemic to the Yangtze River Basin, holds critical ecological importance within riparian ecosystems. This study investigated three newly discovered wild populations of M. laxiflora distributed upstream and downstream of the Three Gorges Dam, aiming to assess their demographic status, survival patterns, and population dynamics. Based on extensive field surveys and quantitative analyses, including static life table construction, survival curve modeling, and time-series predictions, the population was classified as a growth type, although showing signs of potential decline. High juvenile mortality and limited seedling recruitment emerged as key constraints on population persistence. Population dynamic indices (Vpi and V´pi) were greater than 0, indicating positive growth potential, but also revealed high sensitivity to environmental disturbances. The survival curves exhibited characteristics intermediate between Deevey Type Ⅰ and Deevey Type Ⅱ models. Survival analysis and predictive modeling underscored the impact of seedling deficiency and early-stage mortality on population recruitment and demographic stability. Wild populations face serious threats from anthropogenic pressures, such as flooding, sand dredging, deforestation, grazing, and land conversion. Effective conservation of M. laxiflora requires integrated strategies encompassing habitat protection, seedling augmentation, public engagement, and the establishment of designated conservation zones to safeguard its long-term viability.

     

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