Insights | Tunley Environmental

Biodiversity Metric is a tool used to measure changes in biodiversity

Written by Nora Von Xylander | 3 Nov 2023

The Biodiversity Metric 4.0 is a standardised tool used to measure changes in biodiversity. It focuses on habitats rather than individual species and incorporates factors such as habitat type, condition, connectivity, and significance.

To ensure the preservation and enhancement of biodiversity, this being is a critical aspect of our planet's health and resilience, the UK Department for Environment, Food & Rural Affairs (DEFRA) and Natural England have developed a tool known as the Biodiversity Metric 4.0. This metric enables the measurement and evaluation of changes in biodiversity resulting from land use changes and development projects, by providing a quantitative measure of the overall biodiversity gain or loss. Utilising this metric will assist businesses and organisations in making informed decisions to achieve Biodiversity Net Gain (BNG) and contribute to the conservation of our natural environment.

How does the biodiversity metric 4.0 tool work?

The Biodiversity Metric 4.0 is a standardised tool used to measure changes in biodiversity. It focuses on habitats rather than individual species and incorporates factors such as habitat type, condition, connectivity, and significance. By assigning a "unit value" to each habitat based on its relative importance for biodiversity, the metric calculates a biodiversity score. By using this tool, planning officers can evaluate the potential biodiversity outcomes of a project and ensure that the target 10% BNG required in England is achieved.

Calculating Biodiversity Score and Net Gain: The biodiversity score is determined by multiplying the distinctiveness, condition, significance, connectivity, and area of each habitat unit. This score provides a baseline measurement of a site's biodiversity value. Additionally, the metric allows for the calculation of predicted gain, considering new biodiversity elements and risks associated with development.

The Biodiversity Net Gain (BNG) is then calculated as the difference between the post-development score and the biodiversity score. This net gain measurement ensures that the positive impacts of development on biodiversity outweigh any negative effects.