Structural succession and functional changes in the river ecosystem of the Yellow River estuary under the influence of ecological restoration measures

Abstract

Clarifying the changes in the structure and function of damaged river ecosystems in estuaries influenced by restoration measures is crucial for formulating regional ecosystem management and restoration strategies; however, research on the Yellow River estuary remains insufficient. This study aimed to construct Ecopath models of the river ecosystem in the estuarine section of the Yellow River across different historical periods, based on previous biodiversity data. The results indicated that the sum of all production and total system throughput increased 107.3t/km²·a and 1288.4 t/km²·a respectively from 2013 to 2014 to 2019–2022, and the ratio of total primary production to total respiration was close to 1, thus the ecosystem became more mature. Moreover, Lateolabrax japonicus and Pseudorasbora parva were replaced by Mugil cephalus and Parabramis pekinensis, and most functional groups displayed lower integrated trophic levels but greater biomass and higher ecotrophic efficiency. Concurrently, functional groups became more interconnected, resulting in a more complex food web structure. Our study shows that the ecological capacity of functional groups in the study area is unsaturated, so future conservation activities should consider enhancing the biomass of carnivorous and detritivorous fish to promote the river ecosystem in the Yellow River estuary. These findings affirm the effectiveness of long-term implementation of river restoration measures such as stock enhancement and ecological scheduling, and propose optimizing the direction of restoration measures from an ecosystem perspective.