1. Systematic conservation planning has been applied to terrestrial and marine systems for over a decade, but only recently been used for freshwaters. Of the various methods proposed, those that explicitly include the costs of, opportunities for and constraints on conservation actions are the most defensible because they allow transparent, rational decisions to be made about conservation priorities. 2. Applying these procedures to freshwater systems presents a number of challenges, including accounting for lateral, longitudinal and vertical connections, and the dynamism and resilience of freshwaters in space and time. Recent research on freshwater conservation planning contains an array of methods to address these issues. 3. The first step ...