What does the science say about biodiversity offsetting?

In a bid to encourage economic growth without having detrimental effects on the environment, the UK government has recently proposed using biodiversity offsetting in England. Such a scheme would mean that developments could offset their environmental impact elsewhere, principally through the creation of new habitats or the restoration of existing ones. This developing policy has seen much controversy from a variety of interested parties, including environmental charities, scientists and even parliamentarians, with concerns ranging from the irreplaceability of habitats to the social values that could be affected. The BES has now produced a report to highlight what has largely been a neglected area of this developing policy: the role of ecological science.

In mid-September, following the release of Defra’s Biodiversity Offsetting Green Paper, the BES held a meeting to discuss the value of ecological science in informing biodiversity offsetting policy. Science is limited within the green paper, and attendees at the meeting feel that this is an important omission, particularly due to the high relevance ecology has to this policy area. The aim of the meeting and report was therefore not to agree or disagree with biodiversity offsetting as a whole but rather discuss the role that science could and should play in underpinning this policy. As such, our report summarises the discussions held and essentially highlights ‘what the science currently says’ and ‘what science could tell you’.

Using ecological science in biodiversity offsetting planning and decision making is vitally important for a number of reasons. Not only will using science make for a more evidence based and robust approach, but it will also help to inform the design, monitoring and assessment of offsetting practices. Ecological research can inform a number of areas including estimating habitat restorability, understanding uncertainty and risks as well as providing much data and information on habitats and species that a biodiversity offsetting approach will require. New emerging technologies, such as metabarcoding, are also allowing more efficient and quicker access to relevant information that would be useful to this developing policy. Our report therefore attempts to communicate these sources of information to those that are invested in biodiversity offsetting policy in order to show them the value of ecology and the role science should have in developing it.

The Environmental Audit Committee have also just released their report about offsetting as part of their Biodiversity Offsetting inquiry. Encouragingly, some of their concerns link to those highlighted in our report, such as the lack of an evidence based analysis to assess biodiversity gain and simplicity of the metrics proposed. Their report also argues that value judgments will play a big part in offsetting decisions, and as our own report shows this is an area where science could help to provide transparent and unbiased evidence to inform a choice made.

Defra’s own consultation into offsetting has just closed, and the responses to this are currently being analysed.  We also responded to this consultation which you can view here, using the outputs of the report to emphasize the importance of ecological science in informing and planning this offsetting policy. We will soon see whether the value of ecological science is regarded as much as it ought to be when Defra release their public response later this year.