Abstract:The research on the interspecific relationship, niche status and community stability of dominant plants in evergreen broad-leaved forests in special habitats can provide scientific basis for the conservation of regional biodiversity and the conservation and management of nature reserves. Based on the filed investigation data of long-term plots in Guangdong Grand Canyon and 2×2 correlation tables, the importance value, niche width and niche overlap of dominant species were determined. The index of interspecific associations, OI index and DI index for dominant species were analyzed by using variance ratio method and χ2 test. Moreover, the community stability was evaluated by Godron method. The results showed that there were 104 species, belonging to 39 families and 74 genera, in which the importance value and niche width of Schima superba were the biggest, followed by Machilus chinensis, Heptapleurum heptaphyllum, Diospyros morrisiana and Engelhardia roxburghiana. These five species occupied a dominant position in the competition for community resources and had a high niche overlap with other plants in the community (67.16% of the total). In 325 pairs of 26 dominant species, negative associations were greater than positive associations. χ2 test showed that the species were relatively independent and loosely connected. However, the five dominant species showed close correlation, and the concomitant occurrence rate was high. Godron method analysis showed that the community was in an unstable state and there was a significant negative correlation between species. Therefore, it was revealed that the interspecific association of the community in broad-leaved evergreen forests in Guangdong Grand Canyon had weak interspecific association and unstable community, which needs to be strengthened for conservation and management.
