Biodiversity Net Gain Assessments

What is Biodiversity Net gain?

Now a part of UK legislation, biodiversity net gain (BNG) is a mandatory consideration for all development projects in England, with a few exemptions.  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

River Condition Assessments

Our ecologist Carolyn Smith has accreditation to conduct River Condition Assessments as part of biodiversity net gain.

As part of your ‘Biodiversity Net Gain’ obligations, if a watercourse (i.e. river, stream, canal) falls within your application site or is within 10m of your application site boundary, then a formal River Condition Assessment will likely be required.

The River Condition Assessment comprises two components: a MoRPh field survey and a River Type desk-based study and forms an important part of ‘The Statutory Biodiversity Metric’ which in-turn is used to calculate ‘Biodiversity Net Gain’.

In accordance with ‘The Statutory Biodiversity Metric’ User Guidance, the River Condition Assessment must be undertaken by someone who has the relevant training and accreditation.