The SPBM will provide applicants of national and major developments, as well as those requiring an Environmental Impact Assessment (EIA), with a mechanism for demonstrating biodiversity enhancement in line with Policy 3b of National Planning Framework 4 (NPF4). As NatureScot has been signalling for some time, while the SPBM’s functionality closely mirrors that of England’s Biodiversity Net Gain (BNG) Metric, this is not intended to create a credit-based off-site market.

Using a metric to assess the impacts of development on habitats will be familiar to many, particularly those involved in the English planning system, where delivering a 10% increase in biodiversity has been law since early 2024. Unlike in England, however, the overarching planning policy for Scotland (NPF4) does not mandate the use of a metric nor does it prescribe a minimum percentage uplift.

Instead, it promotes a holistic approach that considers a broad range of environmental, social and economic outcomes. In our experience of supporting planning applications and site promotions across Scotland, the freedom afforded by NPF4 to assess and evidence impacts through quantitative and qualitative methods, rather than pursuing a set percentage, often leads to better outcomes for people, places and the planet.

For those of us who have been navigating Policy 3b, the publication of the long-awaited Scotland-specific tool is expected to bring much needed clarity and uniformity of approach across local planning authorities. By providing a more consistent assessment framework, the tool can help shift conversation away from perceived changes and towards a clearer and shared understanding of the relationship between development and biodiversity enhancement. This will be particularly valuable for the developers who engage early to understand a site’s ecological baseline, seek to respond to local priorities and requirements for nature-based solutions, and embed environmental enhancements within the scheme from the outset. 

How will the SPBM measure biodiversity?

As with the Defra metric, the SPBM will utilise habitat data gathered by ecologists and assign each habitat type/parcel a numerical ‘value’, which is calculated on:

Habitat Area x Condition x Distinctiveness x Strategic Significance

Where does it differ from the Defra metric?

Our in-house team of natural capital consultants and ecologists have been heavily involved in all versions of the Defra metric and have been able to use these insights to compare it to the initial version of the SPBM. Distinctive features of the SPBM include:

• A broader range of habitats, particularly across grassland habitats. This will allow grassland habitats to be more accurately recorded to site-specifics, reflecting the ecology of Scotland.
• In some instances, a greater emphasis placed on professional judgement when assessing habitat conditions, which may unintentionally introduce more subjectivity into a mechanism which is intended to be objective and ‘quantifiable’. Our experiences with the Defra metric continue to highlight that such subjectivity is often the cause of variations and dispute in the application and determination of BNG calculations.
• A single-tier off-site option. Within the Defra metric, off-site habitat creation is considered in three categories: within the same local planning authority (LPA) or National Character Area (NCA), within a neighbouring LPA or NCA, or further afield. In the SPBM consultation, off-site habitat creation is assigned one tier, with a 0.9 x multiplier. It will be at a given council’s discretion as to the appropriateness of an off-site strategy, regardless of the biodiversity units calculated from a given off-site intervention.

What does this mean for biodiversity markets in Scotland?

While there are similarities between the English and Scottish biodiversity metrics, a key distinction between the two approaches is the absence of a statutory biodiversity unit market in Scotland. NatureScot’s biodiversity metric development programme does not include a public off-site register comparable to that supporting BNG in England.

Furthermore, Scottish planning authorities that have published biodiversity enhancement guidance generally favour a flexible approach, with off-site measures delivered locally to address local priorities. Collectively, these factors suggest that a market for trading biodiversity units to meet a planning requirement, as exists in England, will not exist in Scotland under current Scottish Government plans. Where off-site biodiversity enhancement is required, bespoke agreements, similar to those used for compensatory planting and peatland restoration, are expected to remain the primary mechanism for securing delivery and long-term management.

Our experience working with developers and project teams indicates that NPF4 encourages a more proactive assessment of impact, including on biodiversity, from the earliest stages of project development. This allows impacts to be avoided, managed and mitigated more effectively, alongside embedding biodiversity enhancement into the design process. As a result, the need for off-site enhancement is often reduced, which may limit the scale of any future off-site market. In addition, we have observed that location is a key factor influencing reliance on off-site provision and therefore opportunities for landowners to enter off-site biodiversity enhancement deals. Location influences a site’s ecological baseline, competing priorities (such as natural flood management and community open space), housing delivery pressures, and the opportunity cost of allocating land for biodiversity enhancement.

Separately, the Scottish Government is supporting private, voluntary biodiversity markets through the development of an Ecosystem Restoration Code. This is to facilitate a developing market in which businesses can fund biodiversity improvements across Scotland through a voluntary mechanism, more akin to the voluntary carbon markets than BNG (which is a compliance-driven market). The SPBM remains a mechanism for developers to understand and mitigate against biodiversity loss, rather than a framework to create a biodiversity market.

Further information

Contact Francesca Fowler-Walsh or Debbie Mackay