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

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 m2 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.