Interspecific Associations and Community Stability Changes of Dominant Woody Species of Natural Forest Communities in Mulinzi National Nature Reserve

Abstract:

In order to explore the changes of natural forest community structure in the national nature reserve, fourty-five 20 m×20 m plots were set up in three restoration stages, including original old forest (restored for 100 years or more), secondary forest restored for 40 and 25 years after clear-cutting. The interspecific association and community stability of dominant woody plants were studied by using Variance ratio (VR), χ² test, Pearson correlation test, Spearman rank correlation test and M-Godron stability test. The results showed that there was no significant positive association on the whole of dominant woody species in secondary forest restored for 25 and 40 years, but the significant positive association appeared in original aged forest restored for 100 years. The χ² test showed that the interspecific associations were not significant in 25 and 40 years plant communities, and only 2 species pairs in 100 years plant communities were significantly associated, and the interspecific associations were loose. The Pearson’s correlation coefficient test and Spearman’s rank correlation coefficient test also showed that the correlations among species pairs of most species were not significant, and displayed an independent distribution pattern. The M-Godron stability analysis showed that the plant community was in an unstable state at different stages, but the stability of the community gradually increased with restoration time. Therefore, interspecific correlation in the natural forest communities was weak at different restoration stages, and the species distributed independently and changed frequently, indicating that the community was still in the process of succession and was developing towards a stable stage.