秦岭北坡不同干扰条件下栓皮栎无性繁殖在其种群更新中的作用

Function of Vegetative Propagation on Population Regeneration of Quercus variabilis in Different Habitats on Northern Slope of Qinling Mountains

对秦岭北坡不同干扰条件下栓皮栎林径级结构及更新层的组成进行对比研究,同时采用Lotka-Volterra竞争方程研究栓皮栎林更新中实生个体与萌生个体竞争关系。结果表明:人为干扰较大种群A在更新时形成较大的萌生种群,顺利地通过瓶颈进行更新,保持群落的相对稳定;而人为干扰较小的种群B栓皮栎林的更新在其幼树阶段存在着明显的瓶颈现象。竞争方程平衡时,实生个体和萌生个体的相对优势度在种群A中为11.67%和88.33%,在种群B中为35.79%和64.21%,说明栓皮栎林更新由实生及萌生栓皮栎共优完成,在干扰条件下,萌生个体在更新中占优势。

A survey was conducted to study the variations in size class structure and species composition in the regeneration layer of Quercus variabilis forests on the northern slope of Qinling Mountains in different disturbed conditions.Moreover,the competition between seedling individuals and sprouting individuals were analysed during the regeneration of Q.variabilis forests by the Lotka-Volterra competition model.Results showed that the quantity of the sprouting individuals in Q.variabilis population A under a more heavily disturbed conditions was large enough to make up the shortage of saplings and complete the population regeneration,which ensured that the forest was able to maintain its stability.The size class structure of Q.variabilis population B under a slightly disturbed condition showed a clear bottleneck at the sapling stage during forest regeneration.The relative dominance of the seedling individuals and sprouting individuals in Q.variabilis population A was 11.67% and 64.21% respectively when the stand reached balance,those in the population B was 35.7% and 64.21% respectively.It shows that the seedling individuals and sprouting individuals can be jointly dominant in the regeneration layer of Q.variabilis forests,and the sprouting individuals are much favored in regeneration layer under disturbed conditions.