Population Structure and Spatial Pattern of Parrotia subaequalis,a Rare and Endangered Species Endemic to China

The population structure of Parrotia subaequalis in Zhejiang and Anhui Province was analyzed by the method of spatial sere for time sere.By means of t-test of variance/mean value ratio,and four other aggregation intensity indexes,including I,K,CA,IPA,the spatial distribution pattern and dynamics of Parrotia subaequalis were studied.The results indicate that in terms of spatial distribution this species changes from aggregation to random distribution in the same process of seedlings to trees.However,aggregation distribution is the dominant in the plots.The reasons may be primarily the reproduction of sprouting,self-thinning,and habitat heterogeneity.According to the results of analysis of its population structure,survival curve,and static life table,the P.subaequalis population is generally declining type,and fluctuates,with poor stability and low ability to regenerate in the wild.