How Habitat Banks Generate Verified Biodiversity Units (and Why Verification Matters)
Since mandatory Biodiversity Net Gain came into force in February 2024*, the demand for verified off-site biodiversity units has grown sharply. Applicable to major developments from February 2024 and extended to small sites from April 2024, the requirement for a 10% net gain above pre-development baseline is now a standard feature of the planning landscape.
For developers who cannot achieve that gain on-site, habitat banks are a critical part of the compliance toolkit.
But not all units are equal, and understanding how verified units are generated, and what verification actually means in practice, is essential before committing to a purchase.
The habitat bank is where that process begins.
*introduced through Schedule 14 of the Environment Act 2021, which inserted Schedule 7A into the Town and Country Planning Act 1990
What Is a Habitat Bank and How Does It Function?
A habitat bank is a site – typically farmland, degraded grassland, or riparian land – that is deliberately managed and enhanced over a long period to generate measurable ecological value. That value is quantified and verified, before being sold as biodiversity units to developers who need to demonstrate a net gain above their pre-development baseline.
The mechanics are more involved than they may appear. A habitat bank is not simply a parcel of land set aside for nature, instead a legally bound system of habitat creation and long-term management, underpinned by a conservation covenant , or Section 106 agreement, that commits current and future landowners to delivering specific ecological outcomes for a minimum of 30 years.
Key distinction: Biodiversity units from a habitat bank are a compliance instrument. They must be generated from genuine ecological uplift: land that demonstrably improves in condition and is held accountable for doing so.
The parties involved typically include the landowner, a specialist BNG provider such as BioGains, and the Local Planning Authority or a Responsible Body who holds the legal agreement governing the site’s long-term obligations. Responsible Bodies may be conservation charities, certain public bodies, local authorities, or (where conservation is among their main activities) private sector organisations, such as BioGains who achieved Responsible Body status in 2025. Natural England oversees the national framework within which all of this operates.
The Process of Generating Biodiversity Units
Biodiversity units generation follows a defined sequence that begins well before any units are sold, and continues for decades after:
Baseline Assessment
Before anything else, ecologists must establish what is already present on the site. A thorough baseline survey documents existing habitats, their condition, and their current unit value according to the DEFRA Biodiversity Metric. This is the fixed departure point from which all gains are measured. The baseline cannot be altered: if a site already carries significant ecological value, the potential uplift (and therefore the number of units available for sale) is correspondingly lower.
Habitat Design and Management Planning
With the baseline confirmed, ecologists determine the most appropriate and achievable habitats. Habitat type, spatial arrangement, connectivity to surrounding land, and the management interventions required to reach target conditions all feed into both the ecological outcome and the unit yield. A habitat management and monitoring plan sets out, in contractual detail, the actions required across the 30-year period: grazing regimes, scrub control, water management, monitoring frequencies, and the standards against which conditions will be assessed.
Legal Securing
No valid units can be generated until the habitat management and monitoring plan is legally secured. This is typically achieved through a conservation covenant under the Environment Act 2021 or a Section 106 planning obligation. The legal instrument binds current and future landowners alike, protecting both unit buyers and the long-term ecological integrity of the site.
Metric Calculation and Unit Quantification
The DEFRA Biodiversity Metric is then applied to calculate the number of units the site will generate once the target condition is achieved. For area-based habitats, the calculation accounts for habitat type, condition, area, local distinctiveness, strategic significance, connectivity, and temporal discounting. Where linear habitats such as hedgerows or watercourses are involved, these are assessed separately under the relevant components of the metric. Temporal discounting reflects how long it will take for the habitat to reach its target state – habitats that take longer to mature, such as woodland, carry heavier discounts than faster-establishing habitats like grassland. The metric is designed to be conservative, and for good reason.
The Role of Natural England and Responsible Bodies in Verification
The credibility of any biodiversity unit rests on independent verification. Two bodies sit at the heart of this in England.
Natural England is the government’s statutory nature conservation body and the authority responsible for the national BNG framework. It maintains the statutory biodiversity metric, issues guidance to local planning authorities, and oversees the register of off-site biodiversity gains. Any unit used in a planning application must be traceable to a registered, verified site on that register – the primary safeguard against double-counting, to prevent the same unit being sold to more than one buyer.
Responsible Bodies are organisations approved to hold conservation covenants on behalf of landowners. They act as the long-term custodians of the legal agreement, with a duty to monitor compliance and take action if management obligations are not met. Their involvement is a substantive accountability mechanism, not an administrative formality.
Why this matters for developers: A unit sold without proper legal securing and Natural England registration is not compliant. If it cannot be independently verified and traced by the Local Planning Authority, it will fail to satisfy the mandatory BNGplanning condition – an exposure that can be difficult and costly to remedy.
Verification also involves independent ecological assessment of the site’s current condition and proposed management, confirming that the stated uplift is genuinely achievable. This is not a desk-based sign-off.
Why Verification Ensures Credibility and Long-Term Ecological Outcomes
It is worth being direct about what verification is actually protecting against.
Without a robust verification framework, the biodiversity unit market would face the same structural weaknesses that have undermined voluntary carbon markets: vague accounting, poor additionality, and units that represent intentions rather than outcomes. The mandatory BNG regime has been designed with that risk in mind. The requirement for units to be registered, legally secured, and independently assessed is the mechanism by which the system maintains integrity over time — not just at the point of sale.
For developers, the practical stakes are clear:
A verified unit is bankable. It satisfies planning conditions, holds up under scrutiny from local planning authorities, and increasingly meets the expectations of lenders and ESG-conscious investors reviewing the quality of nature-related commitments.
Verified units from well-managed habitat banks also tend to deliver stronger ecological outcomes over time: relevant as corporate biodiversity reporting continue to expand under frameworks such as TNFD.
Habitats are not static, and verification accounts for that. A site that reaches target condition in year five can deteriorate by year fifteen without sustained management. Legal securing, Responsible Body oversight, and structured monitoring create accountability across the full 30-year term – not a one-time assurance at the point of transaction.
How BioGains Delivers Verified, High-Quality Biodiversity Units after Habitat Creation
At BioGains, we work with landowners across England to identify, design, and deliver habitat banks that generate verified biodiversity units for the off-site compliance market. Site selection, ecological baseline surveys, habitat management planning, and legal securing are all carried out to the standards required by the national framework, before any units are offered for sale.
Every BioGains habitat bank is registered with Natural England and legally secured through appropriate conservation mechanisms. Units are calculated transparently using the statutory DEFRA Biodiversity Metric (covering area-based and linear habitats in full) and subject to independent verification at each stage.
For developers, that means units with the documentation, traceability, and legal underpinning needed to satisfy planning conditions, and the confidence that what is purchased will hold up over the long term. As BNG compliance faces increasing scrutiny from planning authorities, lenders, and regulators, the provenance of the units underpinning it matters more than ever.