Biodiversity net gain will soon be a mandatory element for the planning and development industry. Whilst the national planning policy frameworks already encourage no net loss of biodiversity, the biodiversity net gain approach takes this further.

In practice, this means that planning applications will not only need to be supported by an ecology assessment, but they will have to demonstrate that the proposed development will result in biodiversity net gain using a recognised metric, such as DEFRA’s biodiversity unit calculation. This is based on the area (or length for linear habitats) x distinctiveness x condition of each habitat on the site. The total unit scores for the baseline conditions and post- development habitats are then compared.

A biodiversity net gain means that the proposed development will result in an increase in biodiversity units above the pre-development level. This may be achieved through increasing the area of natural habitats and ecological features on the site, or by providing higher quality, more cohesive or more appropriate habitats.