LAUSR

P. syluestriformis is an endemic plant in Changbai Mountain area of China. Some sample plots were set up in natural distribution communities of P. syluestriformis. Based on the survey data of the plots, the spatial distribution pattern of P. syluestriformis population was studied by the aggregation index. The niche breadth of Levins, Hurlbert and the Pianka niche overlap methods were used to analyze the niche characteristics of P. syluestriformis population in different communities. The results showed that in the pure forest of P. syluestriformis at about 700 m above sea level, P. syluestriformis population was in an aggregate distribution state, and in the scattered community of P. syluestriformis, P. syluestriformis population was randomly distributed in different forest stands under natural conditions, P. syluestriformis population had obvious advantages in each resource location. The maximum niche breadth of Levins was 5.3094. In the aspect of niche overlap index, there was a large niche overlap between the population of P. syluestriformis and U. japonica, which had obvious sharing advantages. Followed by L. olgensis, A. tegmentosum, Q. mongolica, A. nephrolepis. P. syluestriformis population and the above-mentioned associated species had the same or similar requirements for the same resource, and competition would occur when the resources were insufficient. The succession dynamics of P. syluestriformis populations were mainly characterized by narrow geographical distribution and narrow habitat, few populations, no individual seedlings and saplings, and lack of self-renewal ability, so they belonged to the recession-type populations.