Studies On Plant Community Characteristics And Succession In Huang Bai Yuan Nature Reserve

This paper studied on the secondary succession of Giant Panda Nature Reserve in Huangbaiyuan by the method of trade space for time, according to the community physiognomy and structure characteristics. It gives some advices to utilize reasonablely and protect the plants of the nature reserve and to give pandas a more suitable residence. The major results are as follows:The secondary succession of Giant Panda Nature Reserve in Huangbaiyuan is mainly caused by man-made interference. It concluded five stages: Forbs community,Litsea community,Oak community,Populus and Litsea community and Fir community.Succession process is positive. In the succession process, the annual and biennial herb transit to the perennial herb, the sun plants transit to the shade plants, fast growing plants transit to slow growing plants. Forbs community mainly concludes annual and biennial sun herb such as wormwood and polygonum, when others mainly concludes perennial shade herb such as pteris, glechoma longituba, asarum and adenophora. Litsea shrub mainly concludes sun subarbor like litsea, but fir community mainly concludes shade plants like mock orange. Oak community mainly concludes sun arbor like sharp-tooth oak, when fir community mainly concludes shade arbor like abies fargesis.Bush niche breath law has been showed as followed: The niche breath of sun undershrub like litsea reduces gradually in the succession from litsea shrub to Fir community, when the niche breath of shade undershrub like sorbaria increases gradually. For the arbor, the niche breath of sun arbor like aspen reduces gradually, when the niche breath of shade arbor like abies fargesis increases gradually.Diversity index of communities: Fir community>Populus and Litsea community>Oak community > Forbs community > Litsea community. Homogeneity index has positive correlation with diversity index. Dominance index has negative correlation with diversity index. Species richness increase with increasing species in the succession from Forbs community to Fir community.It is showed that similarity index between Forbs community and other communities are all small in the succession from Forbs community to Fir community. Community composition changed greatly, so similarity index become smaller. Herb layer similarity index: Fir community > Populus and Litsea community > Oak community > Litsea community. Bush layer similarity index: Litsea community > Oak community > Populus and Litsea community > Fir community.