Biodiversity Net Gain Sussex: Understanding BNG

To support the natural assets which Sussex has to offer, developers are encouraged to work with the Sussex Local Nature Recovery Strategy (LNRS) in mind. This ensures developments deliver measurable biodiversity improvements that align with regional priorities, such as enhancing the country’s hedgerows, reconnecting wildlife corridors that have been forgotten, and protecting habitats for key species like water voles, skylarks, and great crested newts.

In situations where on-site biodiversity enhancement is not feasible, whether this be because of space constraints or existing land use, both East and West Sussex County Councils alongside Mid Sussex District Council push the initiative of off-site BNG units. These can be purchased through recognised habitat banks or biodiversity offset providers, ensuring gains are delivered within ecologically relevant locations.

Popular off-site biodiversity credits include woodland creation, peatland and wetland restoration, and the rewilding of degraded farmland. All enhancements must be maintained and monitored for a minimum of 30 years, with encouragement to last into the future to continue to deliver the positive effects of Biodiversity units.

BNG applies to all types of developments, including:

• Residential developments with 10+ homes or sites larger than 0.5 hectares.
• Commercial or industrial building with over 1,000m² floorspace.
• Smaller scale projects, which may still need to meet BNG criteria depending on local authority guidance.

The goal of BNG is not simply to offset the harm caused by development, but to embed nature-positive outcomes into long-term planning. This involves site analysis, mitigation, and boosting habitats – to leave the natural environment better off rather than just minimising damage.

To meet BNG requirements, our ecological consultants work side by side with developers to use Natural England Biodiversity Metric tools, allowing them to quantify baseline habitat conditions and predict gains after the development is completed. Monitoring, habitat management plans, and ongoing stewardship are also required to ensure that promised gains are carried into the future.

There are ten guiding principles that underpin successful BNG development plans:

1. Follow the mitigation hierarchy to reduce biodiversity loss.
2. Avoid impacting irreplaceable habitats and protected species.
3. Work collaboratively and transparently with stakeholders.
4. Promote sustainability across ecological, social, and economic dimensions.
5. Engage with specialists and local communities throughout the project lifecycle.
6. Deliver measurable, long-term improvements to biodiversity.
7. Account for potential risks and changes over time.
8. Aim to exceed the 10% requirements when possible.
9. Use the latest biodiversity metric tools
10. Ensure projects provide lasting value for nature.

At Collington Winter Environmental, our team of ecologists and environmental consultants works with developers and land managers across Sussex to ensure BNG compliance. We assess habitats using the latest statutory biodiversity metrics and assemble detailed biodiversity net gain plans to guide developers through this sometimes tricky part of their development journey.

Our experts are familiar with local planning authorities’ policies and requirements, and we offer practical, tailored advice to support an application with the health and wellbeing of habitats in mind.

Whether you’re managing or planning a development project in Sussex, our consultants can offer vital insights into the national planning policy framework to help you meet your obligations and have a positive impact on biodiversity.

To learn more or speak to an ecological consultant about how we can help your development site achieve BNG, contact us at info@collingtonwinter.co.uk or fill out the contact form below.