Abstract: The study of changes in inter-species relationships would help reveal plant community succession and provide a basis for the mechanistic understanding of the ecological stability of communities and biodiversity maintenance. In 2015, a 1 hm² forest monitoring plot was established in the core distribution area of Hopea chinensis, a key species in the northern tropical valley monsoon rainforest of Shiwandashan, Guangxi. We assessed the changes of interspecific relationships of 22 major species in the community by comparing the data in 2015 and a reassessment in 2020, using the variance ratio (VR), Pearson correlation coefficient and Spearman rank correlation analysis. Results showed that: (1) The VR value of this community was 1.09 in 2015 and 0.98 in 2020. There was a significant VR deviation from 1 (with ω=108.75 and 97.78 in 2015 and 2020, respectively), both falling within the interval of \[77.93, 124.34\]. The overall interspecific associations were not significant. (2) Pearson correlation coefficient analysis showed that there were 28 species pairs with significant positive associations and 14 species pairs with significant negative associations in 2015. There were 35 species pairs with significant positive associations and 18 species pairs with significant negative associations in 2020. Spearman rank correlation analysis showed that there were 26 species pairs with significant positive associations and 19 species pairs with significant negative associations in 2015. The species pairs with significant positive associations in 2020 increased to 31 while those with negative associations remained similar (18 species pairs). (3) The correlation between Hopea chinensis and other species became stronger, with no change in significant positive association species pairs, and decreases in significant negative association species pairs. The ecological dominance of Hopea chinensis increased. In conclusion, the significant positive associations among species were enhanced with time. The associations among major species were complicated, but the changes within the 5-year period showed stability in the positive associations among major species, indicating that the community was in a positive stage of dynamic succession.

Key words: interspecific association, associative change, variance ratio, Pearson correlation, Spearman rank correlation