Limits to the ability of carbon farming projects to deliver benefits for threatened species.

Australia has proposed a legislated market for biodiversity based on an existing carbon credits scheme which generates Australian carbon credit units (ACCU) from land-based projects. This provides a unique opportunity to assess the potential for markets to benefit biodiversity. We assessed the extent to which projects under the ACCU scheme overlap potential threatened species habitat, compared that to overlap afforded by protected areas, and compared the ability of different project types to deliver potential benefits to species most impacted by habitat loss. Projects are primarily located in low-cost, marginal arid lands, a pattern that reflects that of the protected area estate. Projects are smaller and fewer in number in more productive lands close to human populations. These lands also overlap most threatened species habitat, hence those species most in need of habitat restoration are the least likely to have their habitat restored under the ACCU scheme. Projects, however, do overlap the geographic range of 32% of the 1,660 threatened species assessed, including for 275 species with <17% of their range in protected areas. Biodiversity markets must incentivize actions in areas of high biodiversity value underpinned by regulations that align with national priorities for biodiversity conservation.