Glaven Ecology
Biodiversity Net Gain Assessments

Biodiversity Net Gain Assessments

What is Biodiversity Net gain?

Now a part of UK legislation, biodiversity net gain (BNG) is set to become a mandatory consideration for all development projects in England, with very few exceptions.  This includes a mandatory Biodiversity Net Gain of 10% for most new developments.


Biodiversity Net Gain (BNG) is an approach to development that aims to leave biodiversity in a better state than before. Where a development has an impact on biodiversity it encourages developers to provide an increase in appropriate natural habitat and ecological features over and above that being affected.



How can Glaven Ecology help?

We are trained in using the DEFRA Statutory Biodiversity Metric (or The Small Sites Metric, where applicable) to calculate both the baseline and proposed biodiversity units for sites.


The following steps are used to calculate biodiversity net gain or loss


  1. A field survey is undertaken to collect pre-development habitat data.
  2. Post-development habitat data is defined using the landscaping plans.
  3. Pre-development habitat data and post-development habitat data is converted into ‘biodiversity units’ using a biodiversity metric.
  4. The Biodiversity Net Gain or Loss is calculated using the difference between the pre-development and post development habitat data. It is often presented as a percentage.
  5. Additional biodiversity units may be added to post-development data using offsite compensation or biodiversity credits.