紫楠天然群落优势物种生态位与种间联结性

Niche and Interspecific Association of Dominant Species in Phoebe sheareri Natural Community

[目的]探究紫楠天然群落优势物种种间关系和群落稳定性。[方法]基于野外样地调查,从物种组成、重要值、生态位宽度、生态位重叠指数、方差比率法和χ^(2)检验等方面研究紫楠群落乔木层、灌木层各优势物种的生态位特征和种间联结性。[结果]紫楠在调查群落中的重要值最大,且其Levins指数生态位宽度和Shannon指数生态位宽度均最大,说明在群落中资源利用程度较高,竞争优势强;紫楠群落乔木层优势物种间总体呈不显著正联结(VR=1.247,χ^(2)_(0.95)(12)>W>χ^(2)_(0.05)(12)),而灌木层总体呈不显著负联结(VR=0.674,χ^(2)_(0.95)(36)>W>χ^(2)_(0.05)(36)),说明乔木层稳定性较高,且高于灌木层;χ^(2)检验结果显示乔木层、灌木层优势物种间正联结种对数均多于负联结,正负联结比分别为1.8∶1和1.5∶1,且绝大部分种对联结性均不显著,表明紫楠群落大多数优势物种间的生态特征较一致。[结论]紫楠群落总体稳定性较好,但仍可进行适当的人工抚育,促进紫楠种群自然更新。

[Objective]In order to explore the interspecific correlations and the stability of Phoebe sheareri natural community.[Method]Based on field sample survey,the ecological niche characteristics and inter-specific associations of dominant species in the arbor layer and shrub layer of P.sheareri community were studied by through species composition,important value,niche breadth,niche overlap index,variance ra-tio method,and χ^(2) test.[Result]The important value,Levins niche breadth,and Shannon-Weaver niche breadth of P.sheareri were the largest in the investigated communities,indicating that both the resource utilization degree and competitive advantage were strong.The dominant species in the arbor layer showed an overall insignificant positive association(VR=1.247,χ^(2)_(0.95)(12)>W>χ^(2)_(0.05)(12)),while the shrub layer showed an overall insignificant negative association(VR=0.674,χ^(2)_(0.95)(36)>W>χ^(2)_(0.05)(36)),indicating that the stability of the arbor layer was higher than that of the shrub layer.The χ^(2) test result showed that the positively as-sociated species pairs were more than the negatively onepairs,and the ratio of positive to negative associ-ation of arbor layer and shrub layer were 1.8∶1 and 1.5∶1,respectively.The majority of species pairs were not significantly associated,indicating that the ecological characteristics of most dominant species in the P.sheareri community were relatively consistent.[Conclusion]The P.sheareri community was is relat-ively stable.However,appropriate artificial tending practices should be carried out to promote the natural regeneration of these P.sheareri populations.