Collington Winter Environmental

Biodiversity Net Gain Survey for Developments

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Following the introduction of The Environment Act 2021 through The Environment Bill, developers on all new development projects should now aim to protect ecosystems and existing habitats on site. Development projects should also align with local nature recovery strategies lnrs.

A biodiversity net gain survey should be carried out as early as possible within the development planning stages to identify and mitigate any potential habitat loss on the development site.

Mandatory biodiversity net gain will be introduced following the 2 year transition period in 2023 and will become a legal requirement. This will place a responsibility on developers to consider the environmental impact of a development in terms of biodiversity. However, the National Planning Policy Framework (NPPF) also requires a net gain approach which should be achieved in a measurable way.

The introduction of net gains for biodiversity also aims to ensure that the environment is left in a better state than before the development was completed. 

What is biodiversity net gain?

Biodiversity Net Gain (BNG) is an approach to development that aims to leave the environment in a better state than it was before the development project took place. Previously, planning policy has encouraged UK construction and developments to achieve “no net loss” for biodiversity.

However, over the years, biodiversity has declined in the UK, and as such, the BNG initiative was launched to leave nature in a measurably better state. Overall, there has been a positive response to the consultation from ecological consultants, developers, and landscape professionals.

Biodiversity Net Gain (BNG) is being requested more frequently by Local planning authorities to inform planning applications. The aim is to show how the proposed development impacts biodiversity in the area.

Biodiversity net gain also acts as a planning condition as well as a policy requirement for planning consent. It can have a significant impact during the decision making process of local planning authorities when they are debating whether to grant or refuse a planning application.

What is a biodiversity net gain survey?

Biodiversity net gain surveys can be used to compare baseline conditions on a site to post development plans. Securing measurable net gains for biodiversity is achieved when the post development plans provide a net improvement to the biodiversity of a site. A biodiversity net gain survey will use some sort of metric to assess each habitat type.

Natural England’s Biodiversity metric 4.0 is currently the most widely used metric, which is used to calculate biodiversity unit scores and translate them into the standards of the local authority.

The following steps are carried out to calculate biodiversity net gain or loss through a biodiversity net gain survey:

  • An initial field survey is undertaken to collect all necessary pre development habitat information
  • Post development habitat data is determined using landscaping plans
  • Both pre and post development habitat data is then converted into ‘biodiversity units’ using biodiversity metrics.
  • Biodiversity net gain or loss is then calculated using the difference between the pre and post development habitat data. This information is then typically presented as a percentage

The government website provides a biodiversity metric 4.0 calculation tool that can help developers to determine their biodiversity unit score under the standards of their local planning authority.

Biodiversity net gain plans

In order to gain planning permission for a development, developers must now be able to prove that they are taking all of the correct measures necessary to increase biodiversity net gain. For these plans to be considered valid, BNG must be guaranteed and maintained for at least 30 years. One of the first steps in this process is to contact an experienced biodiversity net gain consultant who will be able to create and develop a biodiversity net gain plan.

Upon the consultant’s findings from a biodiversity net gain survey, a biodiversity plan will help to determine any habitats or natural elements that could be at risk as a result of the development. A biodiversity net gain plan can also help to identify any mitigation methods that may need to be undertaken on site and off site in order to prevent biodiversity loss.

Application of the mitigation hierarchy must be followed and demonstrated to minimise, avoid or compensate for any biodiversity losses. It is not possible to avoid or compensate on site; offsetting will be required in post development through conservation covenants or by purchasing biodiversity credits.

How can we assist with biodiversity net gain?

Our team of biodiversity consultants have helped a wide range of clients over the years to meet the biodiversity requirements of local planning authorities to obtain planning permission. We have conducted biodiversity net gain surveys on development sites across the UK and can assist clients during the early stages of development and planning.

Delivering biodiversity net gain is now essential for all future development projects. Therefore, it is important to contact an experienced biodiversity net gain consultant for the guidance needed.

Please feel free to get in touch if you would like further information about biodiversity net gain assessments or BNG plans. We are happy to offer free CPD sessions on the Biodiversity Net Gain Principles and how we can help your schemes achieve this.

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01204 939 608


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