Environment Act introduces mandatory biodiversity net gain requirement

The Environment Act 2021, which was given royal assent on 9 November, will introduce a new mandatory biodiversity net gain requirement for development proposals. This will mean that developers will have to demonstrate measurable improvements to biodiversity habitats in association with their proposals.

The Act will introduce a statutory planning condition which will require local authority approval to a biodiversity gain plan. This must demonstrate that the development’s biodiversity value exceeds the pre-development biodiversity value of the on-site habitat by at least 10%. This will be quantified using a recognised biodiversity metric – measuring the biodiversity value of habitat according to its size, distinctiveness, condition and strategic significance.

The requirement can be satisfied by way of works carried out on-site as part of the development, or by way of off-site compensatory habitat creation provided or paid for by the developer. There will be a national biodiversity gain site register of land being used to deliver this, and a system of biodiversity credits whereby developers can buy a credit from the government to enable them to meet the objective.

The habitat enhancements secured through the mandatory net gain requirement will be maintained for at least 30 years after the development is completed. This will be by virtue of a condition, planning obligation or conservation covenant.

The Environment Act will provide for the creation, monitoring and enforcement, modification and discharge of conservation covenants. These are private, voluntary agreements between a landowner and a ‘responsible body’, such as a conservation charity or government body, that can secure long-term conservation and environmental benefits for the public good.

The new requirements are unlikely to become mandatory until 2023 and the detail is still to be set out in secondary legislation. However, some local authorities already require biodiversity net gain and developers need to ensure that they can satisfy these requirements when considering future development proposals.