Effects of reservoir regulation on downstream benthic invertebrate drift in dammed rivers: A review

Abstract

The drift of benthic invertebrates is closely linked to the stability of their community structure, exerting a direct influence on other aquatic biota and ecosystem functions. Driven by the growing demand for clean hydropower, dam construction and operation have disrupted riverbed structures, changed water properties, and affected flow regimes, leading to alterations in the natural drift pattern and significant loss of benthic invertebrate biomass. Therefore, this review summarizes, for the first time, the responses of benthic invertebrate drift to these changes, including habitat shift, sediment deposition, elevated water temperature, decreased dissolved oxygen levels, and, most importantly, flow fluctuations observed in both regulated rivers and experimental flumes. Furthermore, the development and procedure of a numerical simulation of invertebrate drift are summarised. Based on these processes, we suggest that future field sampling research on benthic invertebrate drift should be expanded to include Asian and high-altitude large regulated rivers. Invertebrate drift simulations could benefit from drawing on fish movement simulations and incorporating biomimetic techniques and tools, such as agent-based models.

Abbreviations: DO, dissolved oxygen; ABM, agent-based model.