|Abstract or Summary
- The Biodiversity Impact Mitigation (BIM) hierarchy provides an overarching conservation framework for bycatch reduction, and more broadly for biodiversity conservation. This framework includes four steps, which are implemented sequentially to: (i) avoid and (ii) minimize impacts; (iii) rehabilitate/restore impacted biodiversity; and (iv), compensate such impacts, usually elsewhere. The first three steps are supposed to be implemented in that order to re-establish the biodiversity component to its pre-disturbance baseline or any other agreed upon “healthy state”. If this is not achieved despite having exhausted all possible conservatory efforts, a residual impact remains. Strict, application of the biodiversity impact mitigation through sequentially implementing each step will not generally give the most “bang for the conservation buck” and hence not allow as much conservation for a given budget as a more economically efficient (i.e., least cost) approach to achieving the same target. An economically efficient approach could use a combination of “avoid, minimize, restore, compensate”, but that combination would not necessarily (or generally) be the combination that sequentially pushes each of these approaches (“steps”) to its maximum limit. It would not be based on a strategy to first “avoid as much as possible” but rather on a strategy that would “avoid up to the point where the marginal benefit of further avoidance is equal to the marginal cost of further avoidance”, or, more specifically for cost-minimization, “avoid up to the point where the marginal cost of additional contributions to the stock through avoidance is equal to the marginal cost of additional contributions.