Developing a national level evidence-based toolbox for addressing freshwater biodiversity threats

Freshwater biodiversity is in a state of crisis. The recent development of a global emergency recovery plan to "bend the curve" for freshwater biodiversity lacks the necessary details for implementation in a regional context. Using Canada as an example, we describe a toolbox intended to equip decision-makers and practitioners with evidence-based tools for addressing threats to freshwater biodiversity. The toolbox includes two rubric-based scoring tools to inform users about the level of the reliability (e.g., transparent methods, critical appraisal) and relevancy to Canadian freshwater systems (e.g., habitat, species) of an evidence synthesis. Those scoring tools were applied to 259 evidence syntheses, also included in the toolbox, across fifty freshwater management actions. Habitat Creation, Invasive Species Removal, and Revegetation were found to have reliable evidence syntheses but there remain several actions for which the syntheses are not robust and where the evidence base is unreliable. We suggest the need for more rigorously conducted empirical tests of freshwater management actions, further evidence synthesis, and clearer conveyance of implications for decision-makers and practitioners. Decision-makers and practitioners should use the two scoring tools on syntheses outside this project and tailor them to their regions. Given the global interest in addressing the freshwater biodiversity crisis and the necessity to engage and empower decision-makers and practitioners on a regional basis, we anticipate this toolbox will serve as a model for regions beyond Canada. Future studies to understand if and how the toolbox is used will be needed to make refinements and ensure it benefits freshwater biodiversity.