The correlations between vegetation composition and soil characteristics in the riparian zone of Shengjin Lake

Exploring the effects of soil characteristics of lake wetlands on plant diversity is of great significance to understand how wetland vegetation distributes and maintains its function. We established sampling plots along a series of groundwater level gradients in the riparian zone of Shengjin Lake in the Anhui Province and measured the coverage, aboveground biomass of plants and soil moisture, soil organic carbon (SOC), total nitrogen (TN), and total phosphorus (TP) among other indicators. By using Pearson correlation analysis and redundancy analysis (RDA), we examined the effects of soil characteristics on plant community diversity. The results showed that as the groundwater level increased, the soil moisture and TN content increased significantly, whereas soil SOC and TP content decreased significantly. The contents of SOC, TP, and C ꞉ N were significantly and negatively correlated with soil moisture, whereas TN, N ꞉ P, and C ꞉ P were significantly and positively correlated with soil moisture. Collectively, soil moisture, TN content, C ꞉ P, and N ꞉ P were determined to be the key factors affecting plant diversity in the riparian zone, explaining 91.85% of the variation in plant diversity altogether. In conclusion, soil moisture could effectively determine plant community assemblage in the Shengjin Lake riparian zone, either directly or indirectly, by changing the cycling of N and the availability of P in the soil.