Demonstrating no net loss lies at the core of biodiversity offsetting. It requires a biodiversity loss and gain calculation and this biodiversity offsets accounting system will assist practitioners in making that calculation when designing good practice biodiversity offsets.

Biodiversity losses and gains in an accounting system

Demonstrating no net loss involves measuring biodiversity at matched impact and offset sites and then balancing predicted losses with anticipated gains at an offset site. No net loss is demonstrated when the losses and gains match, and a net gain is demonstrated when biodiversity gains exceed those lost. 

Because biodiversity offsets are based on a calculation of biodiversity losses and gains, it is not possible to demonstrate that gains match (ie, no net loss can be achieved), or exceed losses without this explicit calculation. This calculation requires an accounting system in which the losses and gains are compared and balanced. This means that a biodiversity offset consistent with the Guidance on Good Practice Biodiversity Offsetting in New Zealand must demonstrate a transparent accounting process.

A biodiversity offset accounting system

This web page provides a biodiversity offsets accounting system, a user guide and worked examples to assist practitioners demonstrate no net loss or a net gain. Its use is intended to be helpful and is voluntary.[1].  

Guidance on the development of currencies and use of accounting systems is provided by the:

We recommend you become familiar with these documents before using the biodiversity offsets accounting system.

This accounting system was developed through collaboration between DOC and the Catalyst Group Ltd working with Queensland University. It provides a rigorous but flexible approach to demonstrating no net loss or a net gain using a disaggregated area x condition currency incorporating the 'net present biodiversity value' concept of Overton et al. (2013 )[2]. It also provides for time preference discounting.

This accounting system is not the only method available or possible for demonstrating no net loss. As biodiversity offsetting approaches continue to develop, new and alternative methods are likely to emerge.

Download documents

Further reading

Maseyk FJF, L Barea, RTT Stephens, HP Possingham, G Dutson & M Maron (2016).
A disaggregated biodiversity offset accounting model to improve estimation of ecological equivalency and no net loss. Biological Conservation 204: 322- 332

A biodiversity offset accounting system, article from Decision Point Online

  1. Use of this accounting system does not prejudice DOC’s position on any development, activity or proposed biodiversity offset. 
  2. Overton, J. McC.; Stephens, R.T.T.; Ferrier, S. 2013. Net present biodiversity value and the design of biodiversity offsets. Ambio 42(1): 100–10.
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