In order to reveal the influence of hydropower development on river ecology, we selected a number of research sites, including a natural channel (NC), a channel reservoir (CR), and a channel below the dam (CB) of a certain dam-type hydropower station on the Red River in China. We used the Ecopath model to analyze the differences in structures and energy characteristics of the three ecosystems. As indicated from the results, the energy flow in the three ecosystems of NC, CR, and CB mainly flows between trophic levels I and IV, and the overall transfer efficiencies of the three ecosystems are characterized by CR < NC < CB. The output of primary producers in the three ecosystems are, respectively, 852 t·km⁻²·y⁻¹, 3780 t·km⁻²·y⁻¹, and 1842.3 t·km⁻²·y⁻¹, and the recycling flows into the detritus are 49.37%, 48.46%, and 79.79% respectively. There are two major trophic transfer paths in the three ecosystem food webs, namely the detrital food chain and the grazing food chain. Through the comparison and analysis of the overall characteristics of the system, we found that the indicators reflecting system maturity – including total primary production/total respiration (TPP/TR), connectance index (CI), system omnivory index (SOI), Finn’s cycling index (FCI), and Finn’s mean path length (FML) – indicate that the maturity of the ecosystem of CB is lower than that of NC, and is much lower than that of CR. The results show that the ecosystems of CR, NC, and CB, respectively, are in basically mature, immature, and unstable “young” states. This trophic model analysis also provides a new research perspective on the studies of the influence of hydropower development on riverine ecology.
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