桂林岩溶石山青冈群落主要乔木树种的种间关联

Interspecific associations of the main tree populations of the Cyclobalanopsis glauca community in Karst hills of Guilin,Southwest China

分析桂林岩溶石山青冈群落主要种群的种间关联性,揭示其种群间的共生关系,可为桂林岩溶石山植被的修复与重建、经营管理和生物多样性保护提供理论依据.基于样方调查,采用χ2检验、联结系数(AC)、共同出现百分率(PC)、Ochiai指数(OI)、Dice指数(DI)和主成分分析(PCA)等方法,对桂林岩溶石山青冈群落中重要值前22位的乔木物种进行种间关联测定和生态种组划分.结果表明:研究区22个主要乔木物种总体呈显著正联结,表明该地区青冈群落处于较稳定的顶极阶段;χ2检验结果显示,231个种对中有108个种对呈正联结,115个种对呈负联结,8个种对无联结,正负联结比为93.9%,绝大多数种对呈不显著联结,种对间的独立性较强,主要原因可能在于桂林岩溶石山较高的生境异质性导致物种间的生态位产生分化; AC、PC、OI和DI与χ2检验结果基本一致,种间关联性分析应以χ2检验为基础,辅以AC、PC、OI和DI等指数进行综合研究;根据PCA排序和种间关联关系,将22个主要乔木种群划分为3个生态种组,组内物种对生境具有趋同适应性,组间物种具有不同的生态要求.

Analyzing the interspecific association of major tree populations of Cyclobalanopsis glauca community and revealing the coexistence among the populations would provide theoretical basis for the restoration and reconstruction,management and biodiversity conservation of Karst hills in Guilin. Based on field survey,the χ2test,association coefficient( AC),co-occurrence percentage( PC),Ochiai index( OI),Dice index( DI),and principal component analysis( PCA) were used to investigate the interspecific association and eco-taxonomic classification of the top 22 tree species in Cyclobalanopsis glauca community in Guilin Karst Rocky Mountains. The results showed that there was a significant positive correlation between the interspecific associations of the 22 main tree populations,indicating that this community was in a stable climax stage. The results of χ2test showed that 108 pairs of 231 species pairs had positive associations,115 species pairs had negative associations,8 species pairs were unrelated,with the positive and negative linkage ratio being93.9%. The vast majority of species pairs showed no significant association. The strong independence between species might be mainly caused by the higher habitat heterogeneity of the Karst hills in Guilin which led to the differentiation of niches between species. The results of AC,PC,OI and DI were basically consistent with that of χ2test,indicating that the analysis of interspecific association should be based on the χ2test and supplemented by AC,PC,OI and DI indices. According to the PCA and evaluation of interspecific relationships,the 22 main tree species were divided into three ecological groups. The species within each group had the same adaptability to habitat but different ecological requirements.