木林子矮曲林优势种生态位与种间联结性

Niches and interspecific associations of dominant species in elfin forest of Mulinzi

以湖北木林子国家级自然保护区山顶矮曲林群落为研究对象,分析山顶矮曲林群落优势种生态位与种间联结性特征及群落稳定性,探究特殊生境下植物的资源利用策略与生存机制。在实地样方调查的基础上,采用生态位宽度、生态位重叠程度、方差比率法、χ^(2)检验,结合Spearman秩相关检验、Pearson相关检验、M.Godron稳定性测定法等对木林子山顶矮曲林群落优势种的生态位、种间联结特征及群落稳定性进行分析,结果显示:山顶矮曲林群落中青冈重要值与生态位宽度均最大,是群落中的绝对优势种,齿缘吊钟花、美脉花楸次之,是群落的主要建群种;重要值与生态位宽度大小排序差异较大。20个优势种组成的190组种对中,21.05%的种对生态位重叠指数大于0.5,50.00%的种对生态位重叠指数位于0.2~0.5之间,种群间存在普遍的生态位重叠现象,主要优势种与其它种群生态位重叠程度较高。群落总体关联性呈不显著正联结,χ^(2)检验结果显示98.95%的种对间呈不显著联结或不联结,Pearson相关检验与Spearman秩相关检验也显示大多数物种之间联结性不显著,各种群之间联结性较弱。山顶矮曲林群落大部分物种之间联结松散,各优势种对环境资源的竞争较弱,恶劣的环境条件改变了群落中各物种的生存与资源利用策略,群落结构适应了此类生境,对环境资源的利用更加充分,群落处于相对稳定状态。

Taking the elfin forest community on the top of the mountain in the Mulinzi National Nature Reserve in Hubei as the research object,the ecological niche,interspecific connection characteristics,and community stability of the dominant species in the elfin forest community on the top of the mountain were analyzed,and the resource utilization strategy and survival mechanism of plants in unique habitats were explored.Based on a field survey,the niche width,niche overlap index,variance ratio method,chi⁃squared test,Spearman′s rank correlation test,Pearson′s correlation test,and M.Godron stability assay were used to analyze the niche,interspecific connection characteristics,and stable communities of the dominant species in the elfin forest community at the top of Mulinzi Mountain.Quercus glauca had the highest significant value and niche width and was found to be the dominant species in the community.Enkianthus serrulatus,followed by Sorbus caloneura,were the main species in the community,but the order of importance and niche width were significantly different.Among the 190 species pairs comprising 20 dominant species,21.05%of the species pair niche overlap index values were more significant than 0.5,and 50.00%were between 0.2 and 0.5.There is a common phenomenon of niche overlap among populations,and dominant species have a high degree of niche overlap with other populations.The overall association with the community showed an insignificant positive association.The chi⁃squared test showed that 98.95%of the species pairs showed an insignificant or no association.Pearson′s and Spearman′s rank correlation tests also showed no significant association between most species,and the association between various groups was weak.Most species in the elfin forest community at the top of Mulinzi Mountain were loosely connected,and competition with the dominant species for environmental resources was weak.Harsh environmental conditions altered the survival and resource utilization strategies of various species in the community.Community structures have adapted to such habitats,and environmental resources have been utilized more fully.The community is relatively stable.