[Spatial distribution patterns and intraspecific and interspecific associations of dominant shrub species var in Huangguan of Qinling Mountains, China].

In this study, the spatial distribution patterns of individuals with different diameter classes of dominant shrub var and the intraspecific and interspecific relationships were analyzed in Qinling Huangguan Plot. The results showed that the diameter class structure of var showed a pyramid shape, with a wide bottom and a narrow top. The number of small-diameter class individuals was the largest, showing a good state of renewal and a stable growth, which was conducive to community renewal and succession. Based on Ripley's function, using univariate and bivariate paired correlation functions, under complete spatial randomness model, heterogeneous Poisson model and antecedent condition model, all individual of the species and their diameter-dividing classes were mainly aggregated, and the aggregation degree decreased with the increases of research scale, and gradually tended to random distribution. Affected by habitat heterogeneity, diffusion restriction and negative density dependence, there was a positive correlation among different intraspecific dia-meter classes, and also a certain degree of no correlation, but without negative correlation. The interspecific relationship was complex. All types of association (no, positive and negative) were observed, but negative association and no association were dominated.