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Biodiversity Net Gain: Expert Team to Help You Achieve BNG

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What is Biodiversity Net Gain?


The concept of biodiversity net gain (BNG) involves leaving an area in a better state that it was before, following the completion of any development project. The concept was developed as a way of counteracting the negative impacts a development project.

Although BNG is currently part of UK legislation, it will become mandatory at the end of 2023 due to the passing of the Environment Bill and the subsequent Environment Act gaining Royal Assent in November 2021.

Biodiversity Net Gain will soon become a requirement for obtaining planning permission; however some local planning authorities are already enforcing the new National Planning Policy Framework in line with guidance from Natural England and DEFRA and are already applying the 10% BNG requirement for development proposals.

The purpose of biodiversity net gain is to encourage developers to consider the impact of development on the natural environment within their pre development and post development plans.

What does biodiversity net gain involve?

The concept of BNG should be considered by anyone involved in a development project, including:

  • Developers
  • The relevant local planning authority
  • Architects
  • Land owners
  • Anyone carrying out a project

Biodiversity net gain involves preserving the land as much as possible, retaining habitat types and avoiding the loss of biodiversity. It also involves replacing any elements of an area that were removed due to a development by 10% through habitat creation, as well as enhancing the habitats on the land.

The 10% mandatory increase to enhance a site can be achieved in a number of ways; but whatever route is taken, the net gain must be maintained for at least 30 years.

Biodiversity net gain should be done on-site if possible; however, in some cases, it is just not possible to significantly enhance the biodiversity on the site. In these circumstances, off-site biodiversity net gain may be achievable through off-site habitat enhancement.

BNG will become an integral element of the planning process for all development projects as local planning authorities will new expect developers and those in charge of a planning project to factor in mandatory BNG.

Developers will need to understand the need for delivering biodiversity net gain as well as biodiversity net gain requirements. The should have an understanding on biodiversity units, credits and DEFRA biodiversity metric.

Biodiversity net gain principles


The Chartered Institute of Ecology and Environmental Management (CIEEM) have outlined ten good practice principles of biodiversity net gain. A brief overview of these principles can be found below:

  • Utilise the mitigation hierarchy to minimise the impact on biodiversity
  • Eliminate any negative impacts on biodiversity
  • Communicate each BNG outcome with complete transparency
  • Cover all areas of sustainability, including societal and economic factors
  • Involve any pre-development and post-development stakeholders in creating mandatory net gain solutions
  • Focus on producing long-term environmental benefits from BNG
  • Understand the variable factors and potential risks in order to achieve biodiversity and deliver net gain
  • Offer nature conservation that exceeds the stated BNG requirements
  • Determine a suitable method in order to secure measurable biodiversity net gains
  • Ensure the best possible results from biodiversity net gain.

Calculating biodiversity net gain

Comparisons can be made between the existing value of a site and what will be delivered through development or management and post development. This may include an increase in natural habitats and ecological features through retention and enhancement and/or creation, which goes over and above the environmental habitat originally on site.

Net gains for biodiversity can be calculated through the DEFRA biodiversity metric 4.0, which requires a limited number of factors. These factors include:

 The type of habitat (both on and off site)

  • Any locations (if they are local environment priorities)
  • The size of habitat parcels in kilometres or hectares
  • The condition of any habitat parcels

The government website also provides a biodiversity metric 4.0 calculation tool, which can help to calculate biodiversity net gain and determine your biodiversity unit score that translates into the standards of a local authority.

How can a biodiversity net gain expert assist on your project?


When planning your development, it would be prudent to consider obtaining the assistance of a biodiversity net gain consultant to ensure BNG is achieved and planning permission is achieved.

Our biodiversity net gain experts have helped numerous clients over the years, including policy guidance for biodiversity gain. Achieving BNG and avoiding biodiversity loss through development is something that we are experienced and qualified in, and we can offer advice on planning projects and landscape management plan requirements.

Some of the services a biodiversity net gain expert from our team can offer include:

There are three stages of BNG assessments, and we assist our clients during the very early stages of development, including promotions and land purchases. We can complete an informal initial assessment for sites of interest. This helps our clients understand the probable implications and costings of Biodiversity Net Gain from the offset.

Please get in touch if you would like further information about biodiversity net gain, or biodiversity net gain plans. We are happy to offer free CPD sessions on the biodiversity good practice principles and how we can help your schemes achieve this.



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