Five years of offsetting native vegetation: The challenge of achieving no-net-loss

Scatter plot showing the loss or gain in vegetation condition from developments and biodiversity offsets as a function of the initial vegetation condition of the development or offset. • We analysed the risk of achieving no-net-loss in NSW’s biodiversity offset scheme. • Compared to offsets, development sites tended to be smaller in lower-condition. • Active restoration in offsets was minimal, with most gains from management. • Offset-to-development ratios averaged 4.9:1, exceeding 10:1 in some cases. • Adoption of more active restoration could spread the risk of achieving NNL. As governments embrace the nature positive agenda, biodiversity offsets delivering no-net-loss (NNL) of biodiversity will play a fundamental role. New South Wales (Australia), has one of the oldest and most comprehensive biodiversity offset schemes in the world. It uses a vegetation condition metric as a surrogate for biodiversity, with offset gains predicted to occur over 20 years based on avoiding losses, managing threats (passive restoration) and active restoration. We examine the impact of development and offsetting on native vegetation across NSW, using 1,395 development and offset assessments spanning 2017–2023. We compared the area, condition, and vegetation types involved, and calculated the mean offset-to-development area ratio. Our results revealed: (i) Vegetation patches targeted for development tended to be smaller and in poorer condition compared to offsets; (ii) Active restoration was less than 20 % of the total offset area and 7 % of the total offset credits, with passive restoration of moderate condition vegetation dominating; (iii) Average offset to development area ratios were 4.9:1, similar to other schemes, but with a right-skew resulting in some offset ratios > 20:1. We could not determine whether NNL was achieved for individual trades due to data limitations, but conclude at the program level, NNL is unlikely to be achieved. Offset gains depend predominantly on managing threats, and we suggest a greater adoption of active restoration is necessary to spread risks. More fundamentally, the time-lag between permanent loss and offset gains accruing over 20 years mean that offset gains are unlikely to catch up while development continues.