BSG Ecology has experience of biodiversity gain (previously referred to as biodiversity net gain) on a wide range of projects throughout England, including brownfield reclamation, residential, minerals and waste and commercial/retail developments.

What is Biodiversity Gain?

Government guidance describes Biodiversity Gain as “an approach which aims to leave the natural environment in a measurably better state than beforehand” (

In practice, biodiversity gain refers to development that gives rise to a positive impact through avoiding or mitigating harm to biodiversity, specifically in relation to habitat features, and then delivering improvements through habitat creation or enhancement.

National Planning Policy Framework (NPPF), Paragraph 170, refers to biodiversity gain: “Planning policies and decisions should contribute to and enhance the natural and local environment by … minimising impacts on and providing net gains for biodiversity, including by establishing coherent ecological networks that are more resilient to current and future pressures”. This is current national policy in England.

The Environment Bill, which is expected to become law in England with Royal Assent due in Autumn 2021, will make biodiversity gain mandatory. The Government’s expectations for delivery of biodiversity gain are set out in the forthcoming legislation which will include amended biodiversity duties for local planning authorities:

  • Developers must deliver 10 per cent biodiversity gain through their schemes; this will be measured through a metric.
  • Local Planning Authorities must produce “local nature recovery strategies” and administer the system; this will encourage habitat creation and enhancement in the right places.
  • If they cannot deliver biodiversity locally, developers will have to buy “biodiversity units”.
  • Developers have to guarantee the biodiversity gain for 30 years. This provides the security of biodiversity gain delivery.

Some local planning authorities in England already have biodiversity gain policies within their Local Plans, although the approach taken by different planning authorities currently varies.

Biodiversity Gain Capability

We have helped our clients deliver biodiversity gain assessments since 2013, when Defra ran its first series of trials. We have a thorough understanding of the policy basis for biodiversity gain in England, how this currently varies across the country, the application of the Biodiversity Metric 2.0, and options for delivering biodiversity gain.

For clients with significant landholdings, we can undertake an audit of the biodiversity gain potential to help plan future developments strategically to optimise biodiversity gain return and identify opportunities to sell back biodiversity credits to the emerging local and national site register.

All of our senior staff are experienced in biodiversity gain assessments. We can provide advice and support at all stages of a project:

Project Feasibility

  • Identifying implications for potential development projects.
  • Audits of land for biodiversity gain capacity at land acquisition stage, akin to risk assessment or due diligence.
  • Providing advice on options for delivery of biodiversity gain on and off-site.

Assessment and design

  • Baseline survey and habitat condition assessment – to provide data for the biodiversity metric.
  • Design-phase input: advising on the retention of ecological features, scope for habitat creation and enhancement.
  • Combining green infrastructure, SANG and habitat provision.
  • GIS expertise: managing metric data and supporting calculations.

Planning consent and delivery

  • Planning conditions/obligations: working with a project team to ensure that the proposed requirements are reasonable, proportionate and practical.
  • Preparing long-term site management plans and advising on future management commitments.
  • Site-based advice and expertise in working with contractors to deliver habitat creation, restoration and enhancement.
  • Liaison and negotiation with local authorities, conservation organisations, and other third parties for agreeing the delivery of biodiversity gain.