BBOP

Biodiversity offsets are an increasingly popular yet controversial tool in conservation.  Their popularity lies in their potential to meet the objectives of biodiversity conservation and economic development in tandem, the controversy lies in the need to accept ecological losses in return for uncertain gains. The offsetting approach is seeing widespread adoption, even whilst methodologies and the overriding conceptual framework are still under development. This review of biodiversity offsetting evaluates implementation to date, synthesizing the outstanding theoretical and practical problems. We begin by outlining criteria that make biodiversity offsets unique, and then explore the suite of conceptual challenges arising from these criteria, whilst indicating potential design solutions. In practice, we find that biodiversity offset schemes have been inconsistent in meeting conservation objectives. This is as much due to the challenge of ensuring full compliance and effective monitoring as it is to conceptual flaws in the approach itself. Evidence to support this conclusion comes primarily from developed countries, though offsets are increasingly implemented in the developing world. This is a critical stage at which biodiversity offsets risk becoming a response to immediate development and conservation needs, without an overriding conceptual framework to provide guidance and evaluation criteria. We clarify the meaning of the term 'biodiversity offset', and propose a framework that integrates the consideration of theoretical and practical challenges in the offset process. We also propose a critical research agenda for specific topics around metrics, baselines and uncertainty.