广西珍珠湾红树种群结构与动态特征
Structures and dynamics of mangrove populations in Zhenzhu Bay, Guangxi
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摘要: 本研究以种群生命表为基础,对位于广西珍珠湾内的桐花树(Aegiceras corniculatum)种群、白骨壤(Avicennia marina)种群、秋茄(Kandelia obovata)种群和木榄(Bruguiera gymnorrhiza)种群采用径级法及匀滑技术,编制种群特定时间生命表,绘制种群存活曲线、死亡率和消失率曲线,进行种群数量动态变化和时间序列分析。结果表明:①白骨壤种群、秋茄种群和木榄种群年龄结构呈倒“J”形,种群趋于Deevey-II型,即增长型,主要集中在I龄级,存活曲线、死亡率和消失率曲线均呈现出更新层死亡率较高的特征;②桐花树种群年龄结构呈“金字塔”形,属于Deevey-I型,为衰退型,更新层个体数量少,种群总体不具备显著增长性幅度;③4种红树种群的数量变化动态指数Vpi和V′pi均大于0.00%,种群稳定但易受外部环境影响;④在未来2、4、6、8个龄级时间后,4种红树种群中老龄级个体能够得到不同程度的补充。Abstract: The specific life tables of populations of Avicennia marina, Aegiceras corniculatum, Kandelia obovata and Bruguiera gymnorrhiza in Zhenzhu Bay of Guangxi were compiled based on the population life tables and the survival analysis using diameter at breast height (DBH) class method and the smoothing out technique. The curves of survival rate, mortality rate and vanishing rate were drawn, and the population dynamics and the time sequences were also analyzed. The results indicated that the population age structures of Avicennia marina, Kandelia obovata and Bruguiera gymnorrhiza showed as an inverse shape of J, and mainly aggregated on age I class characterizing a higher mortality in the regeneration layer shown by curves of survival, mortality and vanishing. These populations belonged approximately to the class of Deevey〖KG-*6〗Ⅱ, the type of growing. The population of Aegiceras corniculatum belonged to the class of Deevey-I, the type of regression, characterizing less individuals in the regeneration layer with unstable population structure. The dynamic indices,Vpi and V′pi, of 4 mangrove populations were greater than zero, showing the type of stable-growth but sensitive to external disturbance. Time sequence model suggested that the old-aged individuals of 4 mangrove populations would be recruited in the age classes of 2, 4, 6 and 8 in the future.