Thresholds, scale and strategy for biodiversity offsets in Australia: where to draw the line?

Biodiversity offsets continue to gain popularity around the world as a mechanism to compensate for the adverse environmental impacts of habitat destruction associated with development. In Australia, an offset programme has operated under national environmental protection legislation over the past decade and, in some state-level environmental assessment regimes, for even longer. The operation of these programmes has highlighted a range of important design and implementation issues. Whilst there have been notable improvements in ensuring more secure and well managed offsets, there remain ongoing difficulties in setting effective regulatory thresholds and decision guidelines to determine when loss or destruction of biodiversity is allowed, with or without offsets, and when it should be refused. Offsetting practice also highlights difficult issues of regulatory scale, with considerable tensions arising between strategic broad-scale and more local place-based conservation priorities. To enhance the effectiveness of biodiversity offsets and their ability to contribute to strategic conservation priorities, closer attention must be paid to establishing thresholds that limit removal of high value biodiversity and to developing a strong framework to guide the strategic use of offsets and balance losses and gains at various scales.