Biodiversity Net Gain

What is Biodiversity Net Gain?

Mandated by law from January 2024, Biodiversity Net Gain (BNG) is a piece of development legislation which ensures that any land use changes (for example development, urbanisation, and infrastructure projects) produce a net increase in biodiversity. Developers must either offset biodiversity loss on-site or as close-to the development project as possible.

Crucially, this net increase must be measured and validated by industry professionals to ensure authentic uplift against pre-development baselines. Regulated Assessments calculate the number of BNG units required for demonstrating 10% uplift, and these units are created and maintained using Habitat Management and Monitoring Plans.

Where net gain cannot be produced on-site, developers can purchase BNG units from local planning authorities.

The ultimate aim of new BNG legislation is to provide a framework for planning, implementing, and monitoring projects in a way that not only mitigates the adverse impacts of biodiversity loss, but also to promote environmental sustainability and ecosystem restoration through the offsetting of any loss caused during development with equal or greater gains elsewhere.

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How is biodiversity net gain measured?

Developers must calculate the number of units required to offset the impact to these ecosystems of the development project, which is done using standardised biodiversity metrics.

Natural England’s Biodiversity Metric 4.0 measures the number of biodiversity units available within a surveyed space. The metric uses plant species surveys to assess vegetation quality and diversity, and the presence of water. The number of units calculated is used as a baseline for measuring the required minimum uplift (net gain). Metric 4.0 also identifies the type of habitats that will achieve the necessary number of BNG units to offset development.

Ongoing Habitat Management and Monitoring Plans are then used to ensure that the mandated 10% (in some cases higher) net increase in biodiversity is sustained post-development.

Nature-friendly Farming

What’s the difference between BNG units and biodiversity credits?

Units used to demonstrate biodiversity net gain differ from other biodiversity credits, and it’s important to distinguish between the two.

Read our helpful article on the difference between BNG units and biodiversity credits here.

Woodland and Peatland Carbon Codes

What are the benefits of biodiversity net gain?

Biodiversity Net Gain provides a range of benefits, both local and global. On a local level, it can provide more attractive and varied green spaces in urban areas, providing improved places for people to enjoy.

On a global level, it has been shown that increases in human development can be balanced by restoring natural areas around the world , helping to fight climate change and preserve biodiversity.

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We calculate BNG offerings using our bespoke WILDnCAT financial modelling tool

BNG represents one of the many alternative natural capital income streams that Real Wild Estates provide indicative forecasting for. As a green finance product it leverages the natural capital income potential of land and makes strategised and managed nature recovery financially viable for landowners.

Speak to us about modelling natural capital income opportunities available on your land.

7 key components and principles to biodiversity net gain

No Net Loss

BNG aims for a net gain with legislation requiring at least a 10% upliift, and some local authorities asking for higher. This means that any biodiversity loss resulting from a development project must be compensated for by enhancing similar habitats or creating new habitats elsewhere to ensure that the overall biodiversity of the region meets this uplift criterion.

Baseline Assessment

Before development begins, all of the existing biodiversity and ecosystems in the area affected by the proposed development must be assessed. Depending on land use plans, these can vary but will always be verifiable by industry standards and regulation.

Biodiversity Metrics

BNG relies on specific metrics and indicators to quantify how it might be affected, including species richness, habitat condition, type and number of ecosystem services,and species genetic diversity. But it’s not all about quantity as the quality and resilience against ongoing, long-term shifts such as climate change is also key.

Monitoring and Reporting

The aforementioned metrics are key to creating the monitoring and reporting mechanisms which underpin the ongoing progress tracking which characterises successful BNG initiatives. Beyond baseline data collection, ongoing assessments of the health and diversity of ecosystems and species in the impacted and offset areas must be carried out.

Offset Mechanisms

Habitat restoration, reforestation, or conservation easements are examples of the measures that developers and landowners are required to enact to show how they have compensated for any biodiversity loss resulting from their project. When designing offset mechanisms, the locality, and framework must be closely aligned with local requirements so that their benefits are maximised and the outputs support biodiversity enhancement.

Adaptive Management

Another key component of successful BNG is the ability for any offset plans to be adaptable and responsive to shifting conditions within climate and ecosystems, based on relevant scientific knowledge. This flexibility allows for adjustments to be made to strategies as required for achieving the originally intended outcomes.


Central to Real Wild Estates’ approach to BNG is our collaboration with developers, credit brokers, local authorities and planning agents, Government agencies and communities. The partnerships we build are centred around stakeholder engagement plans aiming to meet both biodiversity offset requirements and client and wider stakeholder group needs.

Balancing nature recovery with business viability ensures returns for nature and for you.

Aim Wilder
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