Several updates and changes to guidance, policy and legislation have resulted in a new strategy used during developments in order to preserve and enhance biodiversity across the UK. Biodiversity Net Gain is an approach to development that leaves biodiversity in a better state than it was previously.
July 2018 – Changes to the National Planning Policy Framework (NPPF)
Updates to the NPPF introduced the requirement for every development to deliver a biodiversity net gain. This did not, however, offer any way of quantifying biodiversity. In lieu of standardised guidance, various metrics were devised by local authorities and non-profit orgranisations. These were largely based on the Defra Pilot Metric (Defra, 2012) document, which outlined some quantitative values for assessing site conditions.
March 2019 – Environment Bill amendment
The Government committed to requiring biodiversity net gain from all developments within the Environment Bill amendment. This amendment will make biodiversity net gain a legal requirement rather than a planning policy as it had been previously.
July 2019 – Biodiversity Metric 2.0 published
In response to the open consultation on biodiversity net gain, Natural England published the Biodiversity Metric 2.0, as an update to the 2012 Defra document, which provided some numerical values but was not provided as a working calculator. Currently in draft form, this provides a national standard metric that allows more consistency in what is required to achieve a biodiversity net gain. This stipulates that a minimum gain of 10% is required for every development.
The Metric does not provide quantitative values for features such as bat boxes, bird boxes, green roofs or green walls, which are often used as habitat enhancements. In this case, the professional opinions of ecological consultants and local authority is relied upon to determine the value of these enhancements.
Where a biodiversity net gain is not possible on site, which can often be the case with inner city developments, a contribution of ‘biodiversity units’ can be used. This is generally a financial contribution to the local authority for offsite biodiversity enhancements and acts as an alternative or an addition to onsite biodiversity net gain.
2020 – Final Biodiversity Metric 2.0 due to be published
Defra (2012) Biodiversity Offsetting Pilots: Technical Paper: the metric for the biodiversity offsetting pilot in England. Defra.