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Biodiversity Net Gain (BNG)

Biodiversity Net Gain (BNG)

Following the passing of The Environment Act in 2021, new developments must, by law, show that wildlife and the natural environment will be improved as a result of any project proposals. This is known as ‘Biodiversity Net Gain’. The new law came into effect in April 2024, and all new planning applications (unless otherwise exempt) are required to deliver net gains for biodiversity. Planning permission will only be granted where the proposal increases overall levels of biodiversity by at least 10%.

How Is BNG Measured?

Evidence of an increase in biodiversity will require a baseline assessment of what is currently present on a site, followed by an estimation of how the proposed designs will result in an overall increase in this level. The UK government has stipulated that new developments will now be required to demonstrate at least a 10% increase in biodiversity on or near the development site.


Biodiversity values are calculated using a system known as the ’Statutory Biodiversity Metric’, which attributes a score to the habitats on site based on their size, condition and rarity. Additional value is given to the retention and enhancement of existing habitats within the proposals, over the creation of new ones.

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Contains OS data © Crown copyright and database right (2022)

Durham Dales Ecology has been undertaking Biodiversity Net Gain calculations since their inception and implementation (including experience of different metrics), and has been trained to a high standard in their use. Where projects fall short of the 10% threshold, we have a strong background in land management and wildlife habitat creation, and will find deliverable, pragmatic and proportionate solutions, of value to both wildlife and people. Biodiversity Net Gain calculations are included with our Ecological Impact Assessment (EcIA) reports. Additional Biodiversity Management and Monitoring Plans can be produced to accompany BNG calculations, where necessary.

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