漓江流域岩溶区檵木群落不同恢复阶段主要共有种生态位变化

Changes of Niche among Restoration Stages of Loropetalum chinense Communities in Karst Area of Lijiang River Valley

以空间代替时间的方法选取典型样地,采用群落学调查对漓江流域岩溶区立地条件基本一致的檵木群落不同恢复阶段主要共有种的Levins生态位宽度和Pianka生态位重叠进行研究,揭示檵木群落恢复过程物种的环境资源利用状况和种间关系、种群动态及群落稳定性,为漓江流域岩溶石漠化生态系统的植被恢复和重建提供依据。结果表明:(1)檵木群落不同恢复阶段乔木层主要共有种为檵木、小巴豆,灌木层主要共有种为檵木、红背山麻杆、龙须藤、火棘、白饭树、白马骨、扁片海桐、皱叶雀梅藤、亮叶崖豆藤。(2)乔木层主要共有种的生态位宽度和生态位重叠随着檵木群落的恢复呈现增大的趋势,而灌木层主要共有种的生态位宽度和生态位重叠变化趋势则相反。(3)在乔灌阶段的乔木层和乔林阶段的灌木层主要共有种的生态位宽度均小于1.0,灌木层中主要共有种对间的低生态位重叠值(0～0.6)的种对数随着群落恢复增多,而高生态位重叠值(0.8～0.9)的种对数减少。(4)乔木层中的主要共有种檵木和小巴豆协同发展,在相当长的时间内将共同主导群落的整体恢复方向;灌木层中的主要共有种随着群落的恢复对环境资源需求进一步分化或者生态位进一步分离,檵木的优势地位进一步削弱。

By adopting the concept of space as a substitute for time, we analyzed the changes of Levins＇ niche breadths and Pianka＇s niche overlaps of main common plant populations in different restoration sta- ges of Loropetalum chinense communities distributing in similar site condition in the karst area of Lijiang River Valley. The results showed that. （1） The main common plant populations in arborous layer in differ- ent restoration stages of L. chinense communities were L. chinense,Croton xiaopadou. However, the main common plant populations in shrub layer were L. chinense,Alchornea trezvioides, Bauhinia championii, P yracantha f ortuneana , Flueggea virosa , Serissa serissoides , P ittosporurn planiloburn , Sageretia rugosa , Callerya nitida; （2）As a whole,the niche breadths and niche overlaps of main common plant populations in the arborous layer had an increased trend with L. chinense communities restoration. However, the reversed results had occurred in the shrub layer. （3）The niche breadths and niche overlaps of main common plant populations in the arborous layer of shrub to tree stage and in the shrub layer of tree stage were all less than 1.0. The number of the low values of niche overlaps（0～0.6） between main common plant popula-tions in the shrub layer had an increased trend with communities restoration, but the reverse trend occurred with the number of the high values of niche overlaps （0.8～0.9） between main common plant populations in the shrub layer. （4）The main common plant populations of L. chinense and C. xiaopadou in the arborous layer had a status with synergetic development. These two main common plant populations will leading jointly the direction of communities restoration for a long time. The needs to environment resource among main common plant populations in the shrub layer detached or niche separated with community restoration, and the dominant role of L. chinense in communities weaken further.