秦岭西段天然油松种群的数量特征研究

Study on the Characteristics of Pinus tabulaeformis Carr.Population on the Western Section of Qinling Mountains

秦岭是我国南北气候和植被过渡带,油松群落是顶级群落之一,研究油松种群表现出来的特有结构和生命周期,将有助于深入理解在该区域油松能够成为主要建群种之一的机理。根据对秦岭西段油松种群的调查资料,利用生存分析理论,编制静态生命表,绘制生存曲线和死亡率曲线,同时应用谱分析方法分析种群数量的动态变化。结果表明:(1)油松种群存活曲线符合DeeveyⅢ,阳坡油松由于密度效应会导致种群自疏,出现"一张一弛"现象,阴坡油松种群在弱光照的胁迫下,弱化了密度效应的作用;(2)油松种群死亡率的波动周期为15 a,在时间格局上也一致,这对油松林的可持续经营具有理论参考价值;(3)谱分析表明不同坡向的油松种群生长周期不同(阳坡>阴坡),同时大周期内有小周期的波动。可见油松种群本身在结构上存在内调节机制,用以有效配置资源形成稳定种群。其研究结果有助于从种群学角度上解释油松群落成为顶级群落的稳定性。

Based on the investigation data on Pinus tabulaeforrnis Carr. population in the western section of Qinling Mountains, the theory of survival analysis and the method of spectral analysis, the static life table, the curves of survival and mortality rate were drawn in this paper. Meanwhile, authors also analyzed the population dynamics by the method of spectral analysis. The results showed that the curve of survival generally tended to the Deevey Ⅲ, and the competition would lead to self-thinning of the population by different degree. The fluctuation period of mortality was 15 year in all aspects and the temporal pattern was same. However, spectral analysis showed the fluctuation period of survival was different between sunny and shady slope （Sunny〉Shady）, and the minor period existed in the main period. In conclusion, the structure of Pinus tabulae formis Carr. population could keep stable through the efficient resource allocation adjusted by interior mechanism.