岷江干旱河谷植物群落分布特征及梯度效应

Distribution characters and gradient effect of species diversity of plant community in typical district of the arid valley in the upper reach of Minjiang River

为了探讨岷江上游干旱河谷典型地段植物群落结构与物种多样性梯度变化效应,采用物种多样性研究中常用的多样性指数、均匀度等指标测定茂县飞虹桥两岸植物群落不同海拔梯度物种多样性,分析了植物群落物种多样性梯度变化效应及坡向差异性。结果表明,飞虹桥两岸植物群落物种多样性梯度变化规律明显,随着海拔的下降,不论是阴坡还是阳坡,受焚风效应的影响程度不断加大,群落微生境产生劣变,物种数目、多样性指数、群落盖度、物种高度等指标均呈减小的趋势;因阳光直射时间长短的差异,阳坡的干旱效应影响范围高于阴坡。

The structure of plant communities and gradient change of species diversity in typical district （ Feihong Bridge in Mao County） of the upper reach of Minjiang River were studied. In sunny and shady slopes of Feihong Bridge, twenty four plots with 25 m^2 at different altitude were used for investigation. Based on the investigation, importance value, species diversity index and species richness index were analyzed for plant communities at different altitude. The results showed that as the altitude decrease, both sunny and shady slopes were affected greatly by fohn effect which caused the degradation of microhabitat and induced the decline of species richness, diversity index, community coverage, community height, etc. Therefore, due to the difference of sunlight duration, the range of fohn effect in sunny slope was superior to that in shady slope.