FAQs
Whether you’re a developer, ecologist, local planning authority (LPA), or landowner, navigating BNG compliance, habitat assessments, and biodiversity unit calculations can be complex.
These FAQs break down the key information you need, answering the most common questions for each stakeholder group. Explore how BNG affects your work, what tools and metrics to use, and how to turn compliance into an opportunity for sustainability and growth.
1. What is Biodiversity Net Gain (BNG), and why does it matter for developers?
BNG is a legal requirement under the Environment Act 2021, mandating that most developments deliver a minimum 10% biodiversity net gain compared to pre-development conditions. This means developers must assess, mitigate, and enhance biodiversity as part of planning applications. Non-compliance can lead to project delays, increased costs, or refusal of planning permission.
2. How do I calculate BNG for my development project?
BNG is calculated using the Statutory Biodiversity Metric 4.0, which assesses habitat size, distinctiveness, condition, and connectivity to determine biodiversity units. Developers must compare pre-development (baseline) units with post-development (enhanced) units to ensure at least 10% net gain.
3. What is the BNG Small Sites Metric, and does my project qualify?
The BNG Small Sites Metric is a simplified version of the Statutory Biodiversity Metric, designed for smaller developments:
- Residential: Fewer than 10 dwellings on a site under 1 hectare.
- Non-residential: A footprint of less than 0.5 hectares.
This metric makes compliance easier for small-scale developers.
4. What are my options if I can’t achieve BNG on-site?
If on-site biodiversity enhancement isn’t possible, developers can:
- Partner with landowners to create off-site biodiversity units.
- Purchase statutory biodiversity credits from the government.
- Work with conservation organisations to fund habitat restoration projects.
Planning authorities will require proof of these commitments in the BNG Plan submitted with your application.
5. How does BNG affect project costs and timelines?
BNG adds upfront costs for surveys, habitat creation, and long-term management but can enhance project value by improving green space and community appeal. Early engagement with ecologists ensures compliance without unexpected delays.
6. What happens if I don’t comply with BNG requirements?
Ecologists provide 30-year monitoring and reporting, ensuring habitats are maintained to deliver the promised net gains. This includes conducting condition assessments, reviewing management plans, and adapting strategies based on ecological changes.
7. What should be included in a Biodiversity Net Gain (BNG) plan?
A BNG plan must demonstrate how a development achieves the 10% biodiversity net gain requirement and typically includes:
- Baseline habitat assessment using the Statutory Biodiversity Metric 4.0.
- On-site and/or off-site biodiversity enhancements with detailed habitat creation or restoration plans.
- Long-term management and monitoring commitments (minimum 30 years).
- Legal agreements (e.g., Section 106 or conservation covenants) securing BNG delivery.
8. When should BNG be considered in the development process?
BNG should be integrated as early as possible—ideally during site selection and planning stages—to:
- Avoid costly redesigns if BNG cannot be met on-site.
- Identify opportunities for habitat enhancement from the outset.
- Ensure smooth planning approval and regulatory compliance.
9. As a developer, am I qualified to undertake a Biodiversity Net Gain (BNG) assessment?
As a developer, you must ensure your project meets BNG requirements, but conducting a BNG Assessment requires specialised ecological expertise in:
- Habitat classification (e.g., UKHab, Phase 1)
- Biodiversity unit calculations using the Statutory BNG Metric
- 30-year habitat management planning for compliance
BNGAI™ simplifies the process, enabling developers like you to:
- Automatically map and classify habitats using AI-powered remote sensing
- Instantly calculate biodiversity units, ensuring compliance with DEFRA’s BNG metrics
- Identify on-site and off-site BNG options early in planning
- Generate fully compliant BNG reports for LPAs.
While ecologists are still essential for detailed assessments, BNGAI™ helps developers streamline workflows, reduce costs, and ensure BNG compliance with greater speed and accuracy.
1. What is the role of an ecologist in delivering BNG?
Ecologists play a critical role in baseline habitat assessments, BNG metric calculations, habitat creation planning, and long-term monitoring. They ensure compliance with statutory metrics and help developers integrate BNG effectively.
2. What tools and technologies can ecologists use to assess BNG?
In short, ecologists rely on:
- Statutory BNG Metric 4.0 – Calculates biodiversity units
- BNG Small Sites Metric – Simplifies assessments for smaller projects
- UKHab & Phase 1 Surveys – Standardised habitat assessments
- GIS Tools – Software like ArcGIS for spatial analysis
- Remote Sensing & AI – Satellite and drone imagery for habitat mapping
These tools enhance accuracy, efficiency, and compliance in BNG assessments.
3. How does BNG affect the demand for ecological surveys?
With BNG now mandatory, demand for ecological surveys has surged, requiring ecologists to complete more habitat assessments, metric calculations, and long-term monitoring reports.
BNGAI™ can help ecologists streamline their biodiversity net gain work and get more work. Reduce admin, focus on the field, and let AI handle the rest.
4. What challenges do ecologists face in implementing BNG?
- Balancing speed and accuracy in BNG calculations
- Ensuring GIS and remote sensing data align with field surveys
- Educating developers and LPAs on realistic biodiversity outcomes
- Navigating evolving DEFRA guidelines and updates to BNG metrics
5. How can ecologists support Local Planning Authorities in reviewing BNG Plans?
Ecologists can assist LPAs by validating biodiversity unit calculations, assessing habitat enhancement feasibility, and ensuring BNG Plans align with local conservation priorities.
6. What long-term role do ecologists play in BNG compliance?
Ecologists provide 30-year monitoring and reporting, ensuring habitats are maintained to deliver the promised net gains. This includes conducting condition assessments, reviewing management plans, and adapting strategies based on ecological changes.
7. Can ecologists partner with BNGAI™?
Managing biodiversity net gain can be time-consuming, requiring significant operational work, data analysis, mapping, and more. BNGAI™ by AiDash is a cutting-edge platform that uses satellite imagery and AI to streamline biodiversity net gain workflow for ecologists. From conducting rapid habitat classifications and simplifying condition assessments to creating robust BNG plans with full compliance, BNGAI™ is an end-to-end compliance platform designed to deliver accurate results, saving you time and resources.
An exclusive Ecologist Partner Program opens doors to numerous exclusive resources and opportunities.
1. What is the LPA’s role in enforcing Biodiversity Net Gain?
LPAs are responsible for:
- Reviewing and approving BNG Plans in planning applications.
- Ensuring developments meet the 10% net gain requirement.
- Monitoring long-term compliance through Section 106 agreements or conservation covenants.
2. How do LPAs verify BNG calculations submitted by developers?
LPAs assess BNG Plans using the Statutory Biodiversity Metric and require:
- Baseline habitat surveys from qualified ecologists
- Evidence of on-site or off-site biodiversity gains
- Detailed 30-year habitat management commitments
3. What happens if a developer fails to meet BNG requirements?
Non-compliant projects may face:
- Planning application refusals
- Enforcement notices requiring biodiversity improvements
- Legal agreements (S106) mandating off-site compensation
4. How can LPAs streamline BNG implementation?
- Training planning officers on biodiversity metrics
- Standardising BNG assessment criteria in local plans
- Encouraging partnerships with landowners for off-site BNG delivery
5. What challenges do LPAs face in managing BNG compliance?
LPAs face several challenges in enforcing Biodiversity Net Gain (BNG), including:
- Limited ecological expertise to assess BNG Plans accurately
- High workloads and resource constraints slowing reviews
- Ensuring 30-year monitoring with limited enforcement tools
- Balancing development with biodiversity commitments
- Navigating complex BNG metrics and evolving regulations
6. Can LPAs require higher BNG percentages than 10%?
Yes, some authorities set higher local BNG targets (e.g., 20%) to align with regional biodiversity strategies, but this must be supported by local policies.
1. How can landowners benefit from Biodiversity Net Gain?
Landowners can generate income by selling biodiversity units to developers needing off-site compensation. This supports habitat restoration while creating new revenue streams.
2. What types of land are suitable for BNG projects?
- Degraded farmland suitable for rewilding or habitat enhancement
- Woodlands, wetlands, and grasslands that can be restored for biodiversity credits
- Marginal or underused land with potential for long-term ecological value
3. How do I register my land for BNG offsetting?
Landowners can register through:
- Private biodiversity unit marketplaces
- Direct agreements with developers needing off-site BNG solutions
- Local Nature Recovery Strategies (LNRS)
4. What legal agreements secure off-site BNG projects?
BNG commitments require 30-year legal agreements, such as:
- Conservation covenants with responsible bodies
- Section 106 agreements tied to planning approvals
5. What are the financial benefits of hosting BNG projects?
Landowners can earn revenue through biodiversity credit sales, government grants, or conservation funding while enhancing their estate’s environmental value.
6. Do landowners need to maintain habitats long-term?
Yes, BNG agreements require 30-year habitat management, often with regular monitoring and reporting to ensure compliance.