Niches and interspecific associations of dominant tree populations of Castanopsis carlesii (Hemsl.) Hay. in Wuyi Mountain

Taking the Castanopsis carlesii community in Wuyi Mountain as the research object, the dominant C. carlesii community species in the arbor layer were analyzed using niche determination and interspecific association methods. Results showed that C. carlesii, Dendropanax dentiger (Harms.) Merr., Rhododendron henryi Hance., and Engelhardtia fenzlii Merr. had higher niche breadths than other species. Niche similarity and niche overlap among populations were 0.36 and 0.42, respectively. Low niche overlap between dominant populations accounted for 71% of all species pairs, while high niche overlap only accounted for 9.67%, indicating that competition for common resources was not strong. The overall interspecific association in the tree layer was not significantly positive among dominant species. Pearson and Spearman rank correlation tests showed that the significantly correlated populations accounted for a relatively low proportion, with the majority found to be not significant. Negatively associated species pairs were greater than positively associated pairs. Based on principal component analysis ordination and interspecific association results, 25 dominant species were divided into four ecological species groups. In general, the C. carlesii community was in a relatively stable stage, and most species pairs showed no significant correlation or no correlation, with relatively strong independence.