Interspecific association, niche and community stability of the main tree species in Picea purpurea community in upstream of Taohe river

To study the niche, interspecific association and community stability of the main tree species in the community in order to understand the resource use habits of the species in the community and to understand the structure and stability of the community, which is of great importance for the sustainable management of forests, as well as for the restoration and reconstruction of degraded forests.

In this study, the natural forest community of Picea purpurea in the upstream reaches of Taohe river was taken as the research object. The niches, interspecific associations and community stability of the main tree species were analyzed by using Levins and Shannon niche breadth index, Pianka niche overlap index, variance ratio (VR), χ² test, association coefficient (AC), percentage of co-occurrence (PC), point correlation coefficient (PCC) and Godron stability.

The importance value and niche width of P. purpurea were the largest, and there was niche overlap with other main species, but the overlap index (O_ik) was less than 0.5. The overall performance of the main species in the community was not significantly positively correlated; the overall performance of the main tree species in the community was not significantly positively correlated, and the results of χ², AC, PC and PCC tests showed that the correlation between pairs of species in the community was not significant, and the correlation between species was relatively loose; the stability ratio of the tree layer in the community was (40, 60), which was far from the theoretical stability ratio (20, 80), indicating that the current purple spruce community was in a state of low stability.

The current P. purpurea community in the upstream of the Taohe river is unstable, and each species in the community shows an independent distribution pattern, and the correlation between the established species, P. purpurea and the other companion species is not high, and the competition is weak; Therefore, in the protection and restoration of P. purpurea community, species with similar ecological habits and biological characteristics should be selected to carry out artificial replanting measures to maintain interspecific balance and improve community stability.