Watershed selection to support freshwater mussel restoration: an open-loop decision guide

Here, we outline questions to help guide a practitioner when selecting potential watersheds for population restoration. The questions follow an open-loop process in a ‘yes’ or ‘no’ format, whereby the options are to either proceed to the next question if the disturbance in question is negligible to mussel persistence or end the loop; each question ignores previous answers. Many posed questions may be associated with a high degree of uncertainty because of insufficient information and thus answering each question as ‘yes’ or ‘no’ could be considered an extreme simplification of complex information. Given this simplification, if the uncertainty around any question is too great, it is at the practitioner’s discretion to either end the open-loop question process or skip the question and proceed. While this process identifies watersheds for potential restoration, it does not prioritize among them. If practitioners are interested in selecting among multiple watersheds that make it through the open-loop process, then watersheds can be subsequently compared by calculating metrics that assess the relative quality of the watershed for restoration or by comparing information gathered in the open loop process—this step is not described in this open-loop process. Once a watershed is selected for potential mussel restoration, further reach-scale characteristics would need to be considered before population augmentation or reintroduction.