Factors Determining the Abundance of Red Swamp Crayfish (Procambarus clarkii) in a Large Lake Connected to the Yangzte River

Abstract

Invasive species and habitat degradation are the main reasons for freshwater biodiversity loss. Reports on the habitat degradation and invasion ecology of Red Swamp crayfish (Procambarus clarkii) are few, although it is one of the most devastating invasive species in freshwater ecosystems. Based on a three-year investigation during 2017–2019 in West Dongting Lake, this study used Principal Component Analysis (PCA), Generalized Linear Model (GLM) and Bayesian model to analyze the relationships of P. clarkii stocks and environment factors in natural and modified wetlands. The results showed that the abundance of P. clarkii was positively correlated with total nitrogen, total phosphorus, water temperature, pH, water depth, and water transparency; while it was negatively correlated with dissolved oxygen and redox potential. The difference between P. clarkii stocks in natural and modified wetlands was nonsignificant. The P. clarkii stock decreased yearly, as levels in both 2018 and 2019 were significantly lower than in 2017. We concluded that inter-annual variation of the hydrological regime plays an important role in P. clarkii dynamics, and thus it is of great importance to ensure that the water level and flow velocity in summer to control the invasive P. clarkii.