Small Sites BNG Metric
What is Biodiversity Net Gain?
Biodiversity Net Gain ensures a development leaves the natural environment in a better state than before.
The UK is one of the most nature-depleted countries in the world, with 56% of our species in decline. The UK government is expected to mandate the delivery of Biodiversity Net Gain with the adoption of the Environment Bill, and Cornwall Council has already mandated the delivery of at least 10% Biodiversity Net Gain from all major planning applications.
When can the small sites metric be used?
The small sites metric has been developed for use on minor development projects, whereas major projects must use the current version of the full DEFRA Biodiversity Net Gain metric.
The small sites metric can be used on projects that qualify as a minor development. Minor development is generally residential developments of less than 10 houses on a site of less than 1 ha, or any other development on a site of less than 0.5 ha. Note the small site’s metric can only be used where there are no priority habitats present, except hedges and/or arable field margins.
All major developments or minor developments on sites with priority habitats need to be assessed using the full DEFRA metric; please see our Biodiversity Net Gain page.
Any off-site measures to achieve the required Net Gain must also be assessed using the full DEFRA metric.
Who can do the assessment?
The small sites metric needs to be undertaken by a “Competent Person”. Although this does not have to be an ecologist, any Competent Person must be able to identify the habitat types present within the site pre-construction and must also be familiar with the management needed to create or enhance the proposed habitats to reach the desired outcome.
In practice, it is likely that for any site needing a PEA or Phase 1 habitat survey, this can be simply extended to cover the small sites metric.
If your site needs a small metric, CEC can undertake this to maximise the Net Gain of your project and help support your planning application.
