Relationship Between Groundwater Level and Rodent Community Structure Mediated by Nutrient Composition of Plants in Dongting Lake, China

The Dongting Lake wetland is an important habitat for rodents. In order to understand the structural characteristics of rodent communities and the effect of groundwater level on them, this study explored the changes in rodent community structure in four different habitats (Carex, Reeds, Carex + Reeds, and Poplar) from 2003 to 2023. Meanwhile, the relationships between groundwater level, nutrient composition of Carex brevicuspis, and structural characteristics of rodent communities were analyzed. The results showed that the advantages of rodent species in the four different habitats are different, and the community structure of rodents has undergone significant changes in recent years. A significant correlation between groundwater level and the nutrient composition of C. brevicuspis was found. Further analysis shows a significant correlation between the nutritional components of C. brevicuspis and the population structure of rodents. Crude protein, total phosphorus, and dry matter were three key plant nutrient indicators that were significantly correlated with both capture rate and the community diversity index (p < 0.05). Total phosphorus and crude protein were significantly negatively correlated with capture rate and Simpson’s index (p < 0.05), but significantly positively correlated with Pielou’s index and Shannon–Wiener’s index (p < 0.05), while the dry matter was completely opposite. The research conclusions suggest that different habitats and groundwater levels affect different characteristics of rodent community structures, and that plant nutrients are likely to be the mediator.