Seven things we learned about Biodiversity Net Gain with Sam Bower, Balfour Beatty

14.05.2026

As part of the Green Finance Topic Advisory Group, we spoke with Sam Bower, Head of Sustainability – Natural Environment at Balfour Beatty, to explore how Biodiversity Net Gain (BNG) is playing out in practice.

England’s BNG programme is an ambitious attempt to create a regulated market for nature, linking development directly to measurable biodiversity improvement. Understanding how this policy works on the ground is essential to reveal whether BNG is not only creating biodiversity assets but also delivering a functioning and investable market.

Our conversation with Sam offered a candid view from the contractor’s side. How BNG is interpreted, where it adds value, and where the system still needs to evolve. Read below for the key insights.

1. BNG is a contractual obligation, not automatically “Nature Positive”

For contractors, BNG is a contractual requirement which must be delivered to specification. Nature‑positive outcomes only emerge when teams go beyond what the contract requires. For example, protecting more habitat, creating additional areas, or increased mitigation of impact during construction (outside the boundaries of what is expected).

2. BNG marks a major shift from species‑based compliance to whole‑habitat thinking

Instead of focusing narrowly on individual protected species, BNG treats habitats as a whole ecosystem. This legal framework means all aspects of habitat creation become critical components of maintaining the ecosystem e.g. soil, water, ecological function. This has made it easier to secure buy-in from non-specialists, who now recognise these elements as fundamental to project success rather than just an add-on.

3. Adaptive management is essential for long term value

BNG’s 30-year commitment means habitats must be designed to mature and function over decades. However, nature is dynamic, and climate uncertainty makes long‑term planning inherently challenging. The most successful habitat designs are those that can adapt in response to a changing environment.

Balancing flexibility with high accountability is a challenge, but with the necessary expertise, practitioners can be trusted to make decisions that don’t always fit neatly into the metric.

4. The success of BNG will depend on monitoring quality and enforcement

BNG has the potential to drive genuine ecological improvement, but only if monitoring is rigorous, consistent and backed by meaningful consequences when commitments are not met.
Without this, the system risks drifting into a box‑ticking exercise that measures compliance rather than ecological outcomes.

5. Resilience is becoming the defining concept in habitat design

Resilience, rather than instant visual impact, is now the priority. Unlike ornamental landscaping which aims to look impressive from day one, habitat creation requires long term planning to create habitats that mature and evolve over time. Designs must account for climate uncertainty, pests, pathogens and human pressures over decades.

6. The system already contains mechanisms for flexibility

Two features stood out:

The ability to override the metric with strong ecological justification
The protection of irreplaceable habitats

These mechanisms allow for innovation while preventing ecological harm, but they rely on practitioners having the confidence, expertise and professional courage to use them.

7. The future of BNG

There is a clear desire for a more holistic system – one that includes soil health, water quality, air quality, cultural value and human use. Biodiversity is only one part of the wider environmental picture, and future frameworks should reflect that.

At the same time, emerging technologies such as remote sensing, eDNA and acoustic monitoring will expand what is measurable and make monitoring more accurate, frequent and cost‑effective. These tools could help BNG evolve into a more robust, evidence‑rich system.