Interspecific Association and Environmental Interpretation of Dominant Species in Shrub Layer of Pinus Massoniana Community in Sandu Gulf Island, Ningde, Fujian, China

Abstract

The understory plant structure of artificial island forests is simple and not conducive to the stable development of the local community. The present study was conducted to understand the environmental adaptability and competition mechanism of dominant plants in the shrub layer of the Pinus massoniana community in the Sandu Gulf area of Ningde and provide a theoretical basis to restore the island environment and vegetation, optimize understory species composition of the artificial forest in islands, and rationally manage local pine forest. We used Pinus massoniana semi-natural forest found in the Sandu gulf area of Ningde as the research object, and the shrub layer plants of 160 quadrats in 40 plots of 6 islands were investigated by sample method. We used niche measurement, variance ratio method, χ2 test, Pearson’s correlation test, and Spearman’s rank correlation test were used to analyze the relationship between niche, interspecific association, and community succession. In addition, M. Gordon's stability was used to jointly verify the succession of the community. Simultaneously, redundancy analysis and other methods were used to analyze the relationship between the distribution of dominant species and environmental factors. The results showed that (1) Heptapleurum heptaphyllum had the largest importance value, which was the dominant species in the shrub layer. Smilax china had the largest niche breadth and the strongest environmental adaptability. (2) Overall, the dominant species showed a positive association in the shrub layer, which was slightly dominant in the three tests, indicating the stability of the community. (3) The overall association was insignificant. The positive and negative associations between species pairs were relatively small, the significant test rate was small, and the number of unrelated species pairs was small, indicating that the community is continuously evolving and has yet reached the most stable stage, which was consistent with the stability results of Godron. (4) The distribution of dominant species in the shrub layer was primarily affected by total potassium, pH, and available potassium. Moreover, Heptapleurum heptaphyllum and Melastoma malabathricum were significantly affected by light (canopy density). (5) Soil pH value decreased gradually with an increase in the distance from the coastline and the change of slope aspect from sunny slope to shady slope.

Keywords: island, Pinus massoniana community, Shrub layer, Niche, Interspecific association, Redundancy analysis