Fig. 1

Conceptual model linking changes in flow magnitude due to hydropower to potential changes in abundance and diversity of freshwater fish in flow regimes that are initially natural or previously altered by hydroelectricity production (i.e., where a change to, or modification in, the operational flow regime has occurred at an existing hydropower facility). Green pathway: maintenance of near-natural flow magnitude after hydropower production resulting in little effect on fish abundance/diversity; Blue pathway: an operational change/modification to flow magnitude at an existing hydropower facility to approach natural conditions resulting in a change (increase or decrease) or maintenance of fish abundance/diversity; Black pathway: alterations in magnitude from hydropower production from either natural or previously altered flow regimes resulting in a change (increase or decrease) or maintenance of fish abundance/diversity