Biodiversity Net Gain (BNG) Case Studies
Biodiversity Net Gain (BNG) case studies are real-world project examples showing how developments can achieve measurable net gains for nature. On this page, we present a portfolio of BNG case studies, anonymised but based on actual assessments, to demonstrate our expertise in delivering positive biodiversity outcomes across various sectors. Each case study includes before/ after biodiversity metrics, key interventions, sector context, and the percentage uplift in habitat value achieved.
These studies serve as proof of our capability to meet and exceed the 10% net gain target now expected by UK planning authorities. Whether you are a planning officer ensuring compliance or a developer seeking inspiration, our BNG case studies provide clear, evidence-based examples of best practice in action. By sharing these results (with visual before/after metric charts and data), we illustrate how following professional guidelines and innovative design can lead to meaningful biodiversity improvements.
You can also drop us an email at hello@acp-consultants.com and we’ll get back to you within 24 hours to help with your inquiry!
We follow a simple, transparent process to ensure your project runs smoothly from the very first contact to the final report. Our approach is designed to provide you with clarity at every step, so you’re fully informed and confident in moving forward.
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Step 1: Request a Quote
Fill out our quick quote form or call us, and our team will provide a free, no-obligation quote, outlining the services tailored to your needs.
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Step 2: Confirm Your Booking
Once you approve the quote, simply return the booking form. We’ll schedule your survey and ensure all the details are taken care of.
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Step 3: Receive Your Report
After your survey is completed and payment is received, we’ll promptly issue your survey report, ensuring you get the results as quickly as possible.
CIEEM BNG Guidance in Practice
Implementing Biodiversity Net Gain requires adherence to industry best practices. We follow the recognised BNG principles developed by CIEEM, CIRIA and IEMA to ensure each project “leaves biodiversity in a better state than before.”
These principles include applying the mitigation hierarchy (avoid, mitigate, compensate), measuring gains with the Defra biodiversity metric, and aiming for sustainable, long-term enhancements. In practice, this means our ecologists design habitat creation and enhancement measures that not only meet the numeric 10% net gain requirement but also align with local conservation priorities.
For example, we ensure no significant habitat is lost without equivalent or greater biodiversity uplift provided, either on-site or via approved off-site offsets. We also integrate BNG guidance by engaging stakeholders and securing management plans so that net gains are maintained for decades, not just at project completion.
By embedding these guidelines into our workflow, each case study in our portfolio reflects a rigorous, science-led approach. Our team stays updated with the latest resources, including new national guidance and handbooks, ensuring that our methods remain cutting-edge and fully compliant with emerging policy.
For professionals seeking to upskill, we also offer training and CPD opportunities.
BNG Case Studies Across Sectors
Our BNG case studies span a variety of project types, including education, leisure, residential, housing regeneration and commercial developments. Below is a selection of anonymised case study summaries (with composite data drawn from real projects) illustrating how we delivered net gains in different settings. Each example highlights the baseline before/after conditions, key interventions, and the achieved gains in biodiversity value.
BNG Case Study 1 – Primary School Redevelopment (Education Sector)
Site & Baseline: The redevelopment involved upgrading a primary school site, including new classrooms, hardstanding, and improved facilities for pupils. The baseline ecological survey showed the land was dominated by short-mown amenity grassland with very limited biodiversity value. A handful of scattered young trees were present, but there were no significant semi-natural habitats, and the overall biodiversity unit score was low.
Challenge: The initial design placed new buildings and playground areas over much of the grassland. Metric calculations predicted a significant reduction in biodiversity value, with an estimated –57% habitat unit change. This not only failed to meet the 10% net gain requirement but also breached trading rules by reducing the overall distinctiveness of the site. Without changes, the scheme risked planning refusal.
Interventions: Working with the design team, our ecologists identified opportunities to enhance biodiversity without compromising educational objectives. On-site, we introduced a more diverse landscaping plan, incorporating seven new native trees, seasonal wildflower borders, and pollinator-friendly planting across green spaces. Recognising space was still constrained, we worked with the client to set aside a nearby underused parcel of land. This area was designed as a small meadow and community orchard, managed to improve species diversity and deliver measurable habitat units. These measures followed good practice principles, ensuring both on-site and off-site interventions contributed to long-term ecological improvements.
Outcome (Achieved Gains): When the revised proposals were run through the statutory biodiversity metric, the outcome shifted from a significant loss to a clear net gain. The final calculation demonstrated an overall increase of approximately +15% in habitat units, comfortably meeting the 10% requirement and satisfying all trading rules. The project not only secured planning consent but also delivered educational value by creating outdoor learning spaces and biodiversity features for pupils.
BNG Case Study 2 – Rural Tourism Lodges (Leisure Sector)
Site & Baseline: This project involved the transformation of a former equestrian and agricultural site into a sustainable holiday lodge destination. The baseline ecological survey recorded modified grassland, areas of bare ground associated with stables, and patches of scattered scrub. While the site had some ecological features, overall distinctiveness and condition were modest, and the initial biodiversity unit score was relatively low.
Interventions: The design team was keen to integrate biodiversity into the leisure development from the outset. A key intervention was to upgrade large areas of modified grassland into species-rich neutral grassland. This was achieved through re-seeding with a native wildflower mix, altering mowing regimes, and setting out a long-term maintenance plan to encourage diverse flowering species. New native hedgerows were introduced along boundaries and internal pathways to provide structure, shelter, and foraging opportunities for birds, bats, and invertebrates. Over 30 native trees – including oak, field maple, and hawthorn – were planted across the site to enhance connectivity and provide future canopy cover. Importantly, where scrub removal was necessary to accommodate access routes, it was replaced like-for-like in carefully chosen areas to ensure no net habitat loss. The interventions were designed to deliver measurable biodiversity uplift while complementing the aesthetic and recreational value of the lodge park.
Outcome (Achieved Gains): When reassessed using the statutory biodiversity metric, the site demonstrated a clear ecological improvement, achieving a net gain of +25.8% in habitat units. Trading rules were satisfied, and the project significantly exceeded the 10% benchmark required for compliance. The outcome illustrates how leisure and tourism developments can deliver strong biodiversity enhancements by embedding habitat creation into landscaping schemes. Guests now benefit from natural surroundings that support wildlife, while the client can showcase the development as both environmentally responsible and commercially attractive.
BNG Case Study 3 – Urban Infill Housing (Residential Sector)
Site & Baseline: This scheme focused on redeveloping a small urban plot by replacing a single dwelling with three modern residential units. The baseline survey revealed that the majority of the site comprised sealed surfaces, including hardstanding and the existing building footprint. A small, low-quality rear garden was the only green space, offering limited ecological value. As a result, the baseline biodiversity unit score was extremely low, reflecting the restricted habitats typical of dense urban environments.
Interventions: Recognising the space constraints, the design team worked closely with ecologists to identify opportunities for creative biodiversity enhancement. The scheme incorporated vegetated private gardens for each new dwelling, adding permeable green areas where none had previously existed. To increase canopy cover, two native courtyard trees were introduced, selected for their suitability to urban conditions and ability to support pollinators and birds. In addition, wildflower green roofs were installed on ancillary structures such as bin and cycle stores. These were designed using low-maintenance seed mixes adapted for shallow substrates, providing valuable nectar sources in spring and summer while requiring minimal intervention. Together, these measures diversified the habitat offer on-site, creating a mosaic of small but high-value features embedded within the new development.
Outcome (Achieved Gains): Despite the limited footprint, the project demonstrated a significant ecological uplift. When run through the statutory biodiversity metric, the redevelopment achieved approximately +26.5% net gain in habitat units. While the absolute number of units gained was modest, the percentage improvement was magnified because the baseline value was so low. This result was sufficient to meet all policy requirements and provide confidence to the planning authority that the project delivered a meaningful ecological benefit. Beyond compliance, the enhancements also contributed to placemaking, with residents benefiting from greener, more attractive surroundings.
BNG Case Study 4 – Estate Regeneration (Housing Sector, Phased)
Site & Baseline: This case involved the phased regeneration of a large housing estate. The baseline survey identified areas of short-mown amenity grassland, scattered ornamental and semi-mature trees, and large expanses of hardstanding. While the site offered some ecological value, the habitat distinctiveness was generally low to medium, producing a mid-range biodiversity unit score.
Interventions: The original landscape design focused mainly on amenity and visual improvements, but metric testing revealed it would deliver only a negligible gain of around +0.26%. To address this, we worked closely with the project’s architects and landscape designers to integrate biodiversity measures into the masterplan. Large tracts of amenity grass were replaced with wildflower lawns, increasing structural diversity and pollinator habitat. New rain gardens with native wetland planting were incorporated along pathways to manage surface water sustainably while boosting biodiversity. Ancillary structures such as bin stores and bike sheds were topped with wildflower green roofs, turning under-used surfaces into functional habitat. In addition, a programme of diverse native tree planting was introduced to increase canopy cover, improve microclimate, and support local species.
Outcome (Achieved Gains): With these revisions, the overall biodiversity uplift rose to approximately +12% net gain, meeting the mandatory 10% requirement without relying on off-site measures. The results showed how a carefully targeted redesign could turn a marginal gain into a compliant, policy-supporting outcome. Beyond metrics, residents also benefit from greener surroundings, enhanced drainage resilience, and improved wellbeing spaces.
BNG Case Study 5 – Commercial Development (Warehouse)
Site & Baseline: The project comprised the development of a new commercial warehouse on previously farmed land. The baseline survey recorded low-diversity arable fields and edge grassland of moderate ecological value. While open in character, the habitats offered limited species richness, resulting in a moderate starting biodiversity score.
Interventions: To achieve compliance and deliver ecological benefits, the design strategy prioritised converting intensively managed areas into semi-natural habitats. Margins surrounding the warehouse were sown with native wildflower meadow strips, providing nectar resources and visual interest. Mixed native woodland blocks were planted on embankments to stabilise soil and enhance habitat connectivity. Additionally, a wildlife-friendly SuDS pond was installed, designed with gradual margins and aquatic vegetation to support invertebrates, amphibians, and bird species. Together, these interventions created a varied habitat mosaic around the built form, turning a functional site into an asset for local biodiversity.
Outcome (Achieved Gains): The completed design produced an estimated +20% net gain in habitat units. This uplift strongly exceeded the 10% benchmark and demonstrated how commercial projects can integrate biodiversity measures alongside operational requirements. Converting low-value agricultural land into semi-natural grassland, woodland, and wetland features ensured trading rules were met and provided long-term ecological resilience. The scheme also supported the client’s sustainability objectives, strengthening the development’s planning case and corporate environmental credentials.
How We Evidence Results
Delivering Biodiversity Net Gain is about more than achieving a number on a metric, it’s about demonstrating outcomes in a clear, transparent, and credible way. We use consistent reporting structures, recognised guidance, and publicly available planning documentation to evidence the gains achieved. This ensures our work can be trusted by planning officers, developers, and communities alike.
Sharing outcomes responsibly
We are often asked to provide examples of our Biodiversity Net Gain assessments. While we cannot share client project details directly due to confidentiality, many of our completed reports are submitted alongside planning applications. These documents are available through local authority planning portals, where they become part of the public record. This allows planning officers, developers, and the wider community to see our methodology and outcomes in a transparent way.
What’s included in our assessments
Every BNG assessment we produce follows a consistent structure. Reports typically include:
- Baseline vs. post-development metric snapshot (before/after units and % change)
- Trading rules summary and how they were satisfied
- Interventions (habitats created, enhanced, or retained)
- Management notes (how net gains will be secured and maintained long-term)
Accessing examples
If you would like to understand what a BNG assessment looks like, many of our reports are submitted alongside planning applications and become publicly available through local authority planning portals. While not every project is published in this way, a large number are accessible and can be found by searching planning portals. This provides a transparent view of how our Biodiversity Net Gain assessments are structured and presented in real applications, while ensuring client details remain fully protected.
How to Increase Biodiversity Net Gain: What Our Projects Show
Our projects provide experience-led insights into the most effective ways to boost biodiversity on development sites. The lessons below are drawn directly from case study evidence and highlight practical steps for achieving Biodiversity Net Gain (BNG) while balancing design and budget constraints.
Integrate BNG Early in Design
Projects that considered biodiversity from the outset consistently achieved higher net gains. Early involvement of ecologists allows space for habitats such as ponds, hedgerows, and wildflower areas to be built into the masterplan. This avoids costly retrofits and ensures biodiversity is part of the development vision rather than an afterthought.
Enhance Existing Habitats
Not all gains require starting from scratch. Improving current habitats often delivers substantial benefits with relatively little land take. For example, enhancing low-value grassland into species-rich meadow or upgrading hedgerows improves ecological function while maximising existing space.
Use Native Planting and Create Diverse Habitats
A varied approach yields stronger ecological outcomes. Using native species supports local wildlife and improves resilience. Mixing habitat types such as trees, shrub borders, wildflower areas, and green roofs creates niches for different species and increases overall biodiversity unit scores.
Consider Off-Site Solutions Where Necessary
When on-site space is limited, off-site habitat creation, habitat banks, or statutory credits can help developments reach the required 10% gain. These measures ensure trading rules are met while aligning with local ecological priorities.
Follow the Metrics and Best Practice Guidance
The Defra biodiversity metric provides a clear framework for measuring before-and-after values. Understanding how distinctiveness, condition, and trading rules affect calculations ensures interventions deliver measurable, policy-compliant gains. Aligning with professional good practice principles adds credibility to assessments.
Commit to Long-Term Management
Gains only count if they are maintained. Each of our case studies included long-term management plans to secure outcomes—such as tailored mowing regimes, invasive species control, and tree care. This ensures biodiversity improvements not only persist but often strengthen over time.
Turning Strategy into Approvals
By applying these principles, developers and planners can approach biodiversity positively rather than as a hurdle. Our portfolio demonstrates that with the right planning, exceeding the 10% net gain threshold is achievable. Embedding biodiversity into design helps projects secure planning consent while leaving a lasting ecological legacy.
In the past year, we’ve delivered over 750 audit-ready reports supporting 400+ projects for developers, planners, and architects nationwide. We put quality over quantity and build lasting relationships based on trust, ensuring your planning applications are backed by robust evidence and delivered on time.
You can also drop us an email at hello@acp-consultants.com and we’ll get back to you within 24 hours to help with your inquiry!
Frequently Asked Questions (FAQs) on Biodiversity Net Gain (BNG) Case Studies and Delivery
Biodiversity Net Gain is a relatively new requirement in UK planning. Many developers, planners, and landowners still have questions about how it works in practice. To support you, we have compiled answers to the most common queries we receive about BNG case studies, assessments, reporting, and implementation. These FAQs explain what case studies are, why they matter and how the rules are applied across the UK. They also explain what steps can be taken to achieve and maintain measurable biodiversity improvements.
What is a Biodiversity Net Gain (BNG) case study?
A case study is a worked example that demonstrates how Biodiversity Net Gain has been assessed and delivered on a project. It sets out the baseline ecological conditions, the predicted impacts of development, and the interventions that were designed to avoid, mitigate, or compensate for those impacts. A good case study also includes the calculated before/after biodiversity unit values and the percentage change achieved. For planners, developers, and consultants, these examples provide tangible proof that the principles of BNG can be applied successfully.
Why are BNG case studies important?
Case studies bridge the gap between policy and practice. They show that the mandatory 10% uplift is not just a theoretical requirement but something that can be achieved in a range of sectors, from residential schemes to commercial developments. For planning authorities, they provide reassurance that applicants understand the process. Also, for developers, they offer practical insight into design solutions that deliver measurable ecological improvements. Finally, for consultants, they serve as a reference point when advising on new projects.
Is Biodiversity Net Gain mandatory everywhere in the UK?
In England, BNG has become mandatory for most planning applications, requiring at least a +10% increase in biodiversity value compared with baseline. This must be secured for a minimum of 30 years through planning conditions or legal agreements. In Wales and Northern Ireland, similar principles are encouraged. However, the policy framework differs and does not yet mandate the 10% requirement. In Scotland, BNG is not yet a legal requirement, though many developers are voluntarily adopting the approach to demonstrate sustainability and anticipate future policy. Always check the latest local planning policy, as approaches continue to evolve.
What does “before/after” mean in BNG?
“Before/after” is shorthand for the comparison between baseline conditions and proposed outcomes. The “before” score comes from ecological surveys that map and classify habitats on-site, assess their condition, and calculate biodiversity units. The “after” score is based on the proposed landscape or habitat management plan, factoring in new planting, enhancements, or off-site measures. The difference between these two scores shows whether the project results in a net loss or net gain, with a +10% uplift being the policy target.
What are some effective ways to increase biodiversity net gain?
There are several proven strategies:
- Design with ecology early so habitats can be retained or enhanced rather than removed.
- Upgrade low-value habitats, such as converting amenity grass into species-rich meadow.
- Plant native and diverse species to improve ecological resilience and support local wildlife.
- Integrate green infrastructure such as hedgerows, rain gardens, green roofs, and SuDS ponds.
- Use off-site measures or credits where on-site land is limited.
- Secure long-term management, as biodiversity gains only count if they are maintained for decades.
Our case studies show that using a combination of these strategies consistently leads to positive outcomes.
What is CIEEM BNG guidance?
The Chartered Institute of Ecology and Environmental Management (CIEEM), working with CIRIA and IEMA, has published Good Practice Principles for Biodiversity Net Gain. This guidance sets out ten principles covering the mitigation hierarchy, stakeholder engagement, measurable outcomes, and long-term management. It ensures that projects don’t just hit a numerical target but deliver genuine ecological benefits. Following this guidance gives credibility to assessments. It reassures planning authorities that BNG has been applied in line with industry standards.
Do you offer training or CPD on BNG?
Yes. We deliver training sessions and Continuing Professional Development (CPD) workshops tailored for planners, architects, and developers. These cover how to use the biodiversity metric, how to interpret results, how to integrate BNG into project design, and how to comply with policy requirements. Training can be delivered in-house, online, or as part of wider industry events. Many participants use these sessions to build internal knowledge so their organisations can handle BNG requirements more confidently.
How can I see more detailed examples?
Because of client confidentiality, we cannot share reports directly. However, many of our assessments are submitted as part of planning applications and are therefore publicly accessible through local authority planning portals. By searching these systems, you can often find examples of our Biodiversity Net Gain assessments. This allows you to see the structure of our reports, how the metric is applied, and how gains are evidenced in real applications.
How long must biodiversity gains be maintained?
Under current requirements in England, biodiversity gains must be secured for a minimum of 30 years. This is typically achieved through planning conditions, Section 106 agreements, or conservation covenants. Long-term monitoring and management are therefore essential parts of any BNG plan.
What if a project cannot achieve 10% net gain on site?
In some cases, site constraints mean that the full 10% cannot be delivered within the red-line boundary. In these situations, developers can use off-site habitat creation, often through habitat banks, or purchase statutory biodiversity credits from the government. These routes ensure that projects remain compliant, although the preference is always for on-site or local measures wherever possible.
References
- Common Standards Monitoring Guidance for Ditches. JNCC.
- BNG Condition Assessment Report. Defra.
- Guidance: Statutory biodiversity credit prices.
- Guidance: Estimate the cost of statutory biodiversity credits.
- Biodiversity Net Gain Monitoring Fees. Torridge District Council.
- Biodiversity net gain legislation 2024. UK Statutory Instruments.
- Guidance: Understanding biodiversity net gain.
- Creating a habitat management and monitoring plan for BNG. Defra.
- Biodiversity Net Gain (BNG) – Habitat banks, monitoring, and fees. East Devon District Council.
- Register your interest in a legal agreement to regulate an off-site biodiversity net gain site. Buckinghamshire Council.
- The Biodiversity Net Gain Statutory Instruments – explained. Defra.
- Statutory Biodiversity Metric User Guide. Defra.
- CIEEM Case Studies. CIEEM.
- Good Practice Principles for Development Case Studies. CIEEM.
- River Condition Assessment for Baseline Appraisals. Modular River Survey.
- Condition Sheet: DITCH Habitat Type. Somerset Council.
- The Biodiversity Gain Requirements (Exemptions) Regulations 2024. UK Statutory Instruments.
- Get ready for new Biodiversity Net Gain legislation. Natural England.
- Exemptions & de minimis thresholds. Householder, small self-build, and very small impacts where no priority habitat is affected. Exemptions Guidance (GOV.UK) and Defra Environment Blog.
- Statutory biodiversity metric – How units are calculated, modules, factors, and guidance on early use. Statutory Metric and User Guide (GOV.UK).
- The Biodiversity Gain Site Register Regulations 2024. UK Statutory Instruments.
- Securing off-site Biodiversity Net Gain: Expert legal perspectives. Natural England.
- BNG in Practice Report (2025) – Case studies showing how BNG is being delivered in real projects. Institute of Environmental Sciences.
- Biodiversity Net Gain – Principles and Guidance for UK Construction and Developments. Chartered Institute of Ecology and Environmental Management.
- BNG Research Briefing – This post note outlines the mandatory biodiversity net gain policy introduced in England. UK Parliament.
- Biodiversity net gain: where to start. Natural England.
- Biodiversity Net Gain Report and Audit Templates- CIEEM.
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Next Steps
Delivering Biodiversity Net Gain requires careful planning, evidence, and long-term commitment. Whether you are at the early design stage, revising a scheme, or preparing a planning submission, expert input can make the difference between falling short and achieving a clear net gain.
Explore More Biodiversity Net Gain Resources
Interested in how Biodiversity Net Gain (BNG) principles are applied across different projects? Explore ACP’s technical guides and resources to understand the process behind each of our case studies. Begin with the Biodiversity Net Gain Overview and BNG Assessment Guide to learn how ecological baselines and post-development habitats are assessed.
Understand the calculation process through the Statutory Biodiversity Metric 4.0 or Small Sites Metric (SSM), and prepare compliant documentation using our Biodiversity Gain Plan (BGP) and Habitat Management and Monitoring Plan (HMMP).
To explore how results are monitored and secured, visit our BNG Monitoring Fee Calculator and learn how Off-Site Biodiversity Units and Conservation Covenants vs Section 106 Agreements are used to safeguard habitat delivery. You can also download supporting materials from our BNG Templates & Downloads and review relevant BNG Legislation & Guidance for compliance with the Environment Act 2021.
You can also drop us an email at hello@acp-consultants.com and we’ll get back to you within 24 hours to help with your inquiry!
- Last Updated:
- October 2025
Disclaimer: Our content is prepared by ACP Consultants’ in-house specialists and is based on current guidance, standards, and best practice in environmental consultancy. While we make every effort to keep information accurate and up to date, it is provided for general guidance only and should not be relied upon as a substitute for professional advice on specific projects. Planning authorities retain final decision-making powers, and requirements may vary between local authorities and over time. ACP Consultants accepts no liability for any loss arising from reliance on this content without obtaining tailored advice for your project.