Modeling trophic structure and energy flows in a typical macrophyte dominated shallow lake using the mass balanced model

Lake Gehu is located in the southern China and plays a significant role in the local societies. However, Lake Gehu has transferred from macrophyte-dominated to phytoplankton-dominated status in the last decades, and it is facing algal bloom problems. In order to restore the damaged ecosystem and characterize the need for developing an ecosystem-based management strategy, a mass balance trophic model of Lake Gehu was constructed by Ecopath with Ecosim software. Trophic structure and energy flows during 1986–1989 were analyzed. Results showed the primary production accounted for 90.93% of the total system production and macrophyte production accounted for 87.43%. Food chains in the lake included two main pathways: the grazing pathway and the detrital pathway. Primary production/respiration ratio (Pp/R), primary production/biomass ratio (Pp/B), Finnʹs index, system omnivory index (SOI), connectance index (CI) of Gehu ecosystem were 2.761, 1.76, 14.76, 0.086, 0.208, respectively. The present study revealed that Lake Gehu was a relatively mature ecosystem during the study period and provided a comparable database for further study.