湖北竹溪黑壳楠的种群结构与群落特征

Community Characteristics and Population Structure of Lindera megaphylla in Zhuxi,Hubei,China

为加强黑壳楠(Lindera megaphylla)种质资源的保护,了解其种群结构与群落特征,对分布于湖北省竹溪县的黑壳楠群落进行了全面的调查。研究群落的物种组成和物种多样性,绘制种群结构图,采用静态生命表和生存分析探明种群的生存现状,利用动态指数和时间序列预测分析其未来发展趋势。结果表明,黑壳楠群落的物种数量和多样性指数均较低,各层次的物种多样性指数均为灌木层>草本层>乔木层,乔木层物种单一;种群的径级结构为不规则金字塔型,高度级结构为金字塔型,黑壳楠种群为增长型种群,但幼龄个体较少,中老龄个体较多,对外界干扰的敏感性较高;静态生命表结果表明,黑壳楠的存活数量随着龄级的增加逐渐减少,个体期望寿命也逐渐降低;存活曲线趋向于Deevey-II型,前期死亡率平稳,但后期死亡率上升;生存分析表明,种群进入衰退期相对较晚,危险率曲线在V和VIII龄级出现陡增;时间序列分析预测,随着时间的推移,老龄个体数量增加,幼龄和中龄个体缺乏补充,种群在未来仍会面临衰退。在今后的保护工作中,应采用补植或人工促萌等措施增加幼苗数量,同时减少破坏性干扰,加强对黑壳楠种质资源的保护。

To better protect Lindera megaphylla and understand its community characteristics and population structure,we investigated the community of L.megaphylla in Zhuxi,Hubei,China.We studied the species composition and diversity of the community,drew the population structure map.We used static life table and population survival analysis to explore the survival status of the population,and used dynamic index and time series analysis to predict its future development trends.Results showed that,the species number and diversity index of the community were low.The species diversity index followed the rank of shrub layer>herb layer>tree layer,and L.megaphylla is the only species in the tree layer.The diameter class structure of the population was irregular pyramid type,and the height class structure was pyramid type.The population was a growing population,but there were fewer young individuals and more middle and old-aged individuals,which showed its high sensitivity to external disturbance.The static life table showed that the number and the life expectancy of individuals decreased with age.The population curves tended to be a Deevey-II type,and the mortality was stable in the early period,but increased in the late period.Survival analysis showed that the population entered the decline stage relatively late,and the hazard rate curve increased sharply at the age class of V and VIII.Time series analysis predicted that the population will continue to decline over time,as the number of older individuals increase over time and young and middle-aged individuals are not replenished.We suggest that,in the future conservation,measures such as replanting or artificial bud promotion should be adopted to increase the number of seedlings.Meanwhile,take measures to reduce destructive disturbances and to strengthen the protection of its germplasm resources.