北京东灵山辽东栎(Quercus liaotungensis)林沿海拔梯度的物种多度分布

多度格局对理解群落结构具有重要意义。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),分乔、灌、草3层分别对北京东灵山辽东栎林进行了研究。结果表明:在乔木层,沿海拔梯度从低海拔到高海拔,能很好地反映物种多度格局变异的模型有由RAM、NPM向DPM过渡的趋势;NPM和BSM均能较好地模拟灌木层的绝大多数海拔段,但NPM的效果更好;草本层以BSM的模拟效果最好。生态位模型可以反映出辽东栎林乔木层物种多度分布沿海拔存在的明显变异,而灌木层和草本层物种多度分布沿海拔梯度无明显变化或很难由生态位模型反映出来,是否引入新的模型方法,如中性模型、近中性模型,还有待于进一步研究。

Species abundance distribution of Quercus liaotungensis forest along altitudinal gradient in Dongling Mountain, Beijing

Species abundance pattern plays a key role in understanding community structure.In this study,the species abundance patterns of tree,shrub and herb layers in a oak(Quercus liaotungensis) forest in Dongling Mountain,Beijing,China,were studied respectively with five niche models,including broken stick model(BSM),niche preemption model(NPM),overlapping niche model(ONM),random assortment model(RAM) and dominance preemption model(DPM).The models that well describing trees abundance patterns have a trend of RAM or NPM to DPM from the low to the high altitude.Most of the shrubs abundance patterns can be well fitted by both NPM and BSM,however the result of NPM is always better.While BSM is the only best fitting model for the herbs.It is obvious that the niche models are suitable in expressing the significant variation of tree species abundance along altitude,but they could not work well in those shrub and herb layers.Other models,such as the neutral theory,might be more suitable to explain the abundance distribution of the understory,which is worth to be considered in further studies.