Simulating the distribution of Corbicula fluminea in Lake Taihu by benthic invertebrate biomass dynamic model (BIBDM)

Benthic invertebrates play important roles in aquatic ecosystems, and their distribution are significantly affected by substrate conditions, such as substrate type, particle size, and riverbed stability. Traditional research mainly uses statistical methods based on field observation to analyze the relationship between benthic invertebrate distribution and environmental factors, while lacking the consideration of growth process mechanism. Meanwhile, the effect of bed surface morphology on benthic invertebrate biomass has rarely been evaluated quantitatively for shallow lakes. This study newly develops a benthic invertebrate biomass dynamic model (BIBDM), which is coupled to hydrodynamic and bed surface morphology models, simultaneously considering the processes of growth, excretion, and predation. The ripple height, which represents bed surface morphology, is adopted as key parameter in the growth equation. The proposed model was applied to Lake Taihu, which is the third largest shallow lake in China. Corbicula fluminea, the largest biomass species of benthic invertebrates in Lake Taihu, was selected as the research object. The model performs well in reproducing the temporal biomass growth process, and the spatial simulation also shows good agreement with the observed data. Meanwhile, results confirm the importance of bed surface morphology on benthic invertebrates, with the correlation coefficient of 0.81 between the biomass and the ripple height. The proposed model could be used to evaluate the effect of environmental factors on the benthic invertebrate growth process. Moreover, the model is highly capable of applying to other species with corresponding environmental factor as the key parameter.