Biodiversity tradeoffs and offsets in impact assessment and decision making: can we stop the loss?

Abstract

The healthy functioning of ecosystems is fundamental to human wellbeing, but sustainable development policies have failed to reverse global decline in biodiversity and ecosystem services. Accepting loss of biodiversity as a tradeoff for socio-economic gains means that the global ecological deficit continues to grow, with attendant risks for human wellbeing. While impact assessment has become more effective at identifying potential impacts on biodiversity, it has generally retained a 'damage limitation' focus, rather than striving to sustain, or even enhance, important biodiversity and ecosystem services. This paper recommends changes in how biodiversity is addressed in impact assessment to avoid increasing the ecological deficit. It considers whether, and how, integration of biodiversity offsets, namely measurable conservation outcomes to compensate for significant residual loss of biodiversity, can achieve 'no net loss' outcomes for biodiversity. It also reviews some of the implementation challenges. These challenges include obtaining the information needed to assess impacts on biodiversity and ecosystem services at appropriate spatial and temporal scales, and recognizing when impacts might be impossible to offset or compensate in practice, thus setting limits to tradeoffs.