堵河源自然保护区四照花种群结构及动态分析

Population Structure and Dynamics of Dendrobenthamia japonica in Duheyuan Nature Reserve

【目的】探究堵河源自然保护区四照花(Dendrobenthamia japonica)种群的结构与动态,揭示其生存现状和数量动态趋势,为维护该区域四照花种群的稳定与发展提供科学依据。【方法】基于堵河源国家级自然保护区2个100 m×100 m动态监测样地数据,分析优势种四照花种群径级数量与动态,编制种群标准生命表,绘制种群存活曲线、死亡率和消失率曲线、生存函数曲线来描述种群结构特征,利用时间序列预测种群未来发展趋势。【结果】(1)四照花种群幼苗(Ⅰ龄级)数量占总株数的55.2%,中老龄级(Ⅳ~Ⅸ)个体仅占0.3%,数量动态变化指数V_(pi)>V′_(pi)>0,种群对外界随机干扰敏感性较弱,为增长型种群。(2)种群有“前期锐减,中期波动和后期趋稳”的特征,存活曲线趋向于Deevey-Ⅱ型;种群正处于生理较活跃期。(3)随着龄级增加,现有种群数量减少,存活的低龄级个体不断补充较高龄级的个体数量,进一步完善种群结构。【结论】堵河源自然保护四照花种群Ⅰ龄级个体数量较多,但种群前期死亡率较高,且缺乏中老龄个体,种群处于相对稳定的年轻化状态。在种群更新过程中,应提高幼苗存活并确保中龄个体的生存率,以保持种群稳定与发展。

【Objective】The structure and dynamics of Dendrobenthamia japonica populations in Duheyuan Nature Reservein were studied in order to reveal their survival status and population dynamics,and to provide a scientific foundation for maintaining the stability of existing communities and protecting species diversity in the region.【Method】Based on the data from two 100 m×100 m dynamic monitoring sample plots in the Duheyuan National Nature Reserve,the population size and dynamics of the prominent species D.japonica were analyzed,a standard life table for the population was established,survival curves were plotted,so were the mortality and vanish curves,and survival function curves to describe the population s structural characteristics,and time series was used to forecast the population s future development trend.【Result】(1)The number of seedlings(Age classⅠ)accounted for 55.2%of the total number of plants in the D.japonica population,while the number of intermediate and old(Age classⅣ-Ⅸ)individuals accounted for only 0.3%;the population dynamic change index V_(pi)>V′_(pi)>0;the populations were less sensitive to random external disturbances and were growing.(2)The population was characterized by a“sharp decrease in the first period,fluctuation in the middle period and then tending to a stable period”;the survival curve was typically of the Deevey-Ⅱtype;the population was in a more physiologically active stage.(3)As the age classes increased,the number of existing populations decreased,but the surviving individuals of the lower age classes continued to supplement the individual number of the higher age classes,improving population structure even further.【Conclusion】The population of D.japonica in Duheyuan Nature Reserve had a high number of individuals at age classⅠ,but the population had a high mortality rate in the early stage and lacked middle-aged and middle-old-aged individuals,and the population was relatively stable and young.In order to maintain population stability and development,we should improve seedling survival and ensure the survival rate of middle-aged individuals during the population renewal process.