Abstract:The niche and interspecific association of main shrub species in Acacia confusa community in Langqi Island of Fujian Province were analyzed to explore the interspecific relationship and succession dynamics of the community. The results showed that Sageretia thea had the largest importance value and niche breadth, and had the strongest competitive advantage and environmental adaptability. The niche similarity and niche overlap of the main species in the shrub layer were small, indicating that there were great differences in the utilization and requirements of environmental resources among the species, showing a relatively stable interspecific relationship. The overall association of the main species in the shrub layer was significant positive association, the positive and negative association ratio between species was 1.72, and the significant rate was 7.35%, indicating that the degree of association between species was weak, the independence was relatively strong, and the species competition was not fierce. The community was in a relatively late and stable succession state. There is vertical complementarity between Castanopsis hystrix and many other species, the niche overlap was small, and the interspecific association was positive. The alien species Lantana camara competed with Elaeagnus oldhamii to some extent, and the competition between Lantana camara and other main shrub plants was less intense, so its impact on the community was relatively small. The Acacia confusa community in Langqi Island had developed into a zonal climax community, the species competition is not intense, and the interspecific relationship is stable. The harsh environment and the spread of alien species on the island will lead to the shortage of plant habitat resources, forcing species to gather in the same habitat coexistence, so that the degree of plant utilization of the environment is weakened. Therefore, it was necessary to control the number of alien species and improve the ecological environment of islands in order to maintain the stable development of island communities.
