坡位对北京东灵山辽东栎林物种多度分布的影响

Effects of slope position on species abundance distribution of Quercus wutaishanica community in Dongling Mountain of Beijing

海拔与坡位是气象因子和立地因子的综合表现。坡位影响环境因子在空间上的分布状况,与海拔共同营造物种生存的小生境,形成群落多度格局。本文选用5个描述种-多度关系的生态位模型(断棍模型BSM、生态位优先占领模型NPM、生态位重叠模型ONM、随机分配模型RAM、优势优先模型DPM),对北京东灵山辽东栎林的乔、灌、草3个层沿海拔梯度分别在上、中、下坡位进行群落多度格局调查。结果表明:在乔木层,从低海拔到高海拔、从下坡位到上坡位,能很好地反应群落多度格局变异的模型有由RAM、NPM向DPM过渡的趋势;能很好地拟合灌木层群落多度格局的生态位模型依次是NPM、BSM、RAM,DPM在高海拔地段拟合的效果也很好;BSM在草本层的拟合效果最好,其次是NPM和ONM。协方差分析表明,海拔和坡位都没有对辽东栎林的群落多度格局产生显著影响。

Slope position and altitude are the integrative reflections of meteorological and site factors.Slope position affects the spatial distribution of environmental factors,and with the altitude together,builds species existent small habitats and shapes the community abundance patterns.In this paper,the species abundance patterns in tree layer,shrub layer,and herb layer of Quercus wutaishanica community at the upper,middle,and lower slopes along an altitude gradient in Dongling Mountain of Beijing were studied,based on five niche models,i.e.,broken stick model（BSM）,niche preemption model（NPM）,overlapping niche model（ONM）,random assortment model（RAM）,and dominance preemption model（DPM）.Among the five models,the models that could well describe the species abundance pattern in the tree layer from low altitude to high altitude and from lower slope to upper slope were the RAM or NPM to DPM.The NPM could best simulate the species abundance pattern in shrub layer,followed by BSM,and RAM.The DPM could also well simulate the species abundance pattern in shrub layer at high altitude.The BSM could be the first choice to simulate the species abundance pattern in herb layer,whereas the NPM and ONM could be the second and third choice.Covariance analysis suggested that both slope position and altitude had no significant effects on the species abundance patterns of Quercus wutaishanica community in the study area.