A data-driven, science-backed approach to Biodiversity Net Gain (BNG) is helping housebuilders manage regulatory risk and align with long-term sustainability goals, explains Neill Hogg at Fera Science Ltd.
As the housing sector adapts to the realities of BNG regulation in its first full year of implementation, uncertainty persists.
Concerns remain around the accuracy of biodiversity measurements, the complexity of long-term tracking, and the financial pressures involved in navigating an evolving compliance landscape.
With most new developments currently required to demonstrate at least a 10% improvement in biodiversity, there is growing recognition that scalable, evidence based approaches offer clarity and confidence.
While conceptually aligned with broader sustainability goals, the practical realities of achieving BNG are far from simple.
There’s still uncertainty around whether current BNG delivery models will deliver the intended outcomes, especially over a 30-year period.
That uncertainty stems in part from how the Biodiversity Metric is interpreted, the capacity of local planning authorities to enforce requirements, and decisions around whether to pursue onsite or offsite delivery.
Offsite vs onsite
While many developers adopt an onsite first strategy, offsite delivery, such as sourcing biodiversity units externally, offers another route to compliance.
There’s a logic to using external providers. These organisations often have more formalised governance and ongoing management practices in place. In areas where planning teams are under-resourced, this external overview may offer greater assurance that BNG obligations will be upheld over time.
That said, onsite schemes remain a core part of many developments, but may face challenges if long-term ecological management is not adequately planned for.
The importance of baseline data
For both delivery approaches, the foundation of any successful BNG plan is an accurate habitat baseline.
Baseline habitat mapping is the first building block in any BNG strategy. Every subsequent decision, from uplift and monitoring to compliance, is derived from that initial assessment.
While traditional field surveys remain essential for ecological due diligence, spatial tools using remote sensing and GIS (geographic information systems) are increasingly being applied at the early land acquisition stage.
These approaches enable developers to conduct rapid, desk-based habitat assessments, often across large or multiple sites, ahead of detailed planning.
One such tool, Fera’s LAND360, supports digital habitat mapping that can be integrated into developers’ GIS platforms. This doesn’t replace traditional methods, but it gives early insight that can reduce risk, streamline feasibility work, and highlight where further ecological input is needed.
Early planning benefits design outcomes
For design teams, the implications of BNG extend beyond compliance.
Incorporating biodiversity data into early design workflows enables a more holistic approach to placemaking, helping identify where natural features should be retained, enhanced, or supported through offsite measures.
This supports not just BNG requirements but wider goals, such as community wellbeing, access to nature, and integration with green infrastructure.
These conversations need to happen early in the process. Environmental planning should not be an afterthought; it should be embedded from the outset.
Future-proofing with science
With the policy environment still evolving, developers and their architectural partners need confidence that their strategies will stand up to future scrutiny.
Using structured baselines and spatial data gives decision makers more certainty. It enables informed trade-offs, supports transparency, and helps demonstrate that biodiversity is being taken seriously.
As tools and metrics develop, the underlying principle remains: BNG must be meaningful and measurable, not just procedural.
We’re helping the sector take a practical, scientifically sound approach to delivering environmental value.
Long-term assurance through Responsible Bodies
A central pillar of BNG compliance is the requirement to secure biodiversity gains for at least 30 years.
Traditionally achieved through Section 106 agreements, a newer option – conservation covenants – provides a different route. Overseen by designated Responsible Bodies, meaning they can hold and manage legally binding covenants, working with landowners, developers, or conservation groups, to verify and monitor long-term biodiversity outcomes.
This accreditation is about independent oversight, meaning they can sign off management plans, carry out monitoring, and report on compliance. It’s an added layer of accountability, and one that helps developers show they are doing things properly.
In practice, this model can help reduce the burden on under-resourced planning authorities while giving developers greater confidence in their compliance strategy.
Strategic land mapping at scale
In 2022, Fera and other partners worked with a leading UK housing developer to pilot a science-led approach to assessing BNG potential across multiple strategic land sites.
The organisation conducted remote, desk-based habitat mapping using GIS and ecological expertise to produce accurate baseline assessments, removing the need for initial onsite surveys at that stage.
These baselines were integrated into the developer’s GIS systems, enabling early insight into biodiversity uplift potential across the land portfolio. It helped streamline planning and prioritisation ahead of more detailed site assessments.
The pilot has since informed a wider roll-out across the developer’s estate, establishing a scalable model for identifying and managing ecological opportunities.
It’s a good example of how early, spatially informed planning can support BNG delivery and reduce uncertainty from the outset.
Neill Hogg is business development manager and natural capital specialist at Fera Science Ltd