Developing a resist-accept-direct (RAD) framework for managing freshwater fish species shifting in and out of political jurisdictions

Abstract

Factors including human dispersal, climate change and varied environmental stressors are altering fish species distributions. Range expansions are producing new records of freshwater species which were rare or previously absent from regional jurisdictions (states, provinces and territories). Simultaneously, species are facing declines and local extirpations in some areas of their distribution. The Resist-Accept-Direct (RAD) framework can provide guiding principles for how declining, newly arrived, or range expanding freshwater fishes should be managed and how range-wide trends can be considered in local management and conservation decisions. We examine the principles of the framework and provide an example decision tree which is applied to examples ranging from resisting the establishment of potentially harmful non-native fishes, to accepting and providing refuge to those species threatened in other parts of their ranges, to directing the migration of fishes which improve ecosystem services. Applying this framework may improve coordination between agencies aiming to improve the resilience of freshwater ecosystems.