Near‐term ecological forecasts to inform environmental flows: A case study on a long‐lived riverine fish in multiple rivers

Altered streamflow is a major threat to river ecosystems globally. Environmental flows aim to ameliorate the impacts of altered streamflow and are critical to the conservation and management of many freshwater ecosystems. Environmental flow deliveries are often guided by set‐and‐forget strategies based on predicted long‐term outcomes, which introduces considerable uncertainty when attempting to design flow deliveries robust to future climatic variability and management constraints. Here, we demonstrate how near‐term ecological forecasts can be used to guide the delivery of environmental flows in highly variable ecosystems. We illustrate our approach using a process‐explicit population model for Murray cod ( Maccullochella peelii ), a long‐lived riverine fish species that occurs across the Murray‐Darling Basin in south‐eastern Australia. Near‐term forecasts highlighted potential benefits of sustained baseflows in some rivers, but validation with independent data identified situations in which predicted population outcomes diverged from empirical data. Forecasts indicated that environmental flows may have small effects on Murray cod populations in some reaches, with population‐level responses taking several years to emerge. Synthesis and applications . Near‐term forecasts present an alternative to set‐and‐forget environmental flows strategies, providing managers with the information to adapt decisions in the face of changing environmental conditions, objectives or constraints. Near‐term forecasts are compatible with existing water planning frameworks and provide dual benefits of more nuanced adaptation to current circumstances and more frequent model updates to improve forecast accuracy. Used in this way, near‐term forecasts have considerable potential to increase the timeliness and effectiveness of environmental flows. Read the free Plain Language Summary for this article on the Journal blog .