篦子三尖杉群落优势种群生态位和种间关系

通过对云南、贵州和江西3省天然分布的篦子三尖杉的野外调查,采用生态位宽度、生态位重叠和基于2×2联列表x²检验、联结系数和种间协变分析篦子三尖杉群落优势种群的种间关系。结果表明:篦子三尖杉是群落中重要值与生态位宽度最大的种群。群落中重要值与Levins指数的相关性分析表明,重要值越大,种群的生态位宽度越大。Schoener指数表明,有92.63%的种对不存在生态位重叠或生态位重叠较弱,其中,篦子三尖杉与其它优势种群之间存在较小的生态位重叠。x²-检验结果表明,中性联结的种对占64.74%,其中,篦子三尖杉与其它优势种群之间的种间联结均为中性联结;群落所有优势种群之间正负联结系数种对的比率为0.91,而负协变的种对也要多于正协变的种对,篦子三尖杉与杉木表现为显著的负协变,与其它种群之间则无显著地协变相关。群落中种群之间不存在较大的利用性竞争,这与篦子三尖杉长期适宜沟谷溪边较少受到外部干扰群落稳定性相对较高有关。

Niche and Interspecific Interaction of Dominant Tree Population in Cephalotaxus oliveri Communities

Based on investigation data of the naturally-distributed Cephalotaxus oliveri communities in Yunnan, Guizhou and Jiangxi provinces, the niche breadth, niche overlap, chi-square test, association coefficient (AC) and interspecific covariation based on 2×2 contingency table were used to analyze the interspecific relationship of dominant populations of C. oliveri communities. The results showed that the important value and the niche of breadth of C. oliveri in the communities were the highest. Relevant analysis results of important value and index of Levins showed the greater the important value, the greater the niche breadth of populations. The Schooner index showed that for 92.63% of the species, no or weak niche overlap were found, and the niche overlap was smaller between C. oliveri and other dominant populations. In chi-square test, species pairs of neutral connection were 64.74%, especially interspecific association between C. oliveri and other dominant populations. The ratio of species pairs of the positive and negative association coefficient between all dominant populations in community was 0.91. In the same way, the species pairs of negative interspecific covariation were more than that of positive interspecific covariation. C. oliveri and fir showed significant negative interspecific covariation, with the rest of the population, no significantly covariance correlation. The lager utilizing competition did not exist between populations in the community. Bbecause C. oliveri was appropriated valleys or stream sides and less external distractions, so its community stability was relative higher.