Since mandatory biodiversity net gain (BNG) came into force in England, developers have had to think differently about the planning process. Biodiversity is no longer a consideration that can be addressed once a scheme has been designed. Instead, it is now a legal requirement that influences site design, planning approval and long-term land management from the outset.
For major developments, mandatory biodiversity net gain has applied since 12 February 2024, with small sites following on 2 April 2024. Most developments must now demonstrate at least a 10% increase in biodiversity value, supported by a Biodiversity Gain Plan that is approved before development starts.
A biodiversity net gain planning consultant helps developers navigate these requirements, ensuring projects remain compliant while reducing planning risk and avoiding unnecessary delays. From ecological surveys and biodiversity net gain assessments through to habitat creation strategies and off-site biodiversity units, the right technical expertise can make the difference between a smooth planning process and an expensive redesign.
Why Biodiversity Net Gain Matters
The Environment Act 2021 introduced mandatory biodiversity net gain to ensure new development leaves the natural environment in a measurably better state than before.
Rather than simply mitigating environmental impacts, developers must now demonstrate measurable net gains by increasing biodiversity value using the statutory biodiversity metric published by Natural England.
This legislation applies to most residential developments, commercial schemes and many other development proposals. While certain applications, such as some householder developments, may be exempt, biodiversity net gain has become a central part of planning for the majority of development sites.
For developers, this means biodiversity net gain is no longer simply an ecological exercise. It has become an important part of securing planning permission and meeting local planning authority expectations.
What Does a Biodiversity Net Gain Planning Consultant Do?
A biodiversity net gain planning consultant supports developers throughout the planning process by providing ecological advice, technical assessments and practical solutions that help achieve biodiversity net gain.
Their role begins long before planning applications are submitted. Consultants assess the site’s baseline biodiversity, identify ecological constraints and advise how biodiversity can be incorporated into development plans without compromising project viability.
As projects progress, they prepare biodiversity net gain assessments, complete biodiversity metric calculations, produce biodiversity gain plans and advise on habitat creation, habitat enhancement and long-term habitat management.
They also work closely with architects, planning consultants, engineers and local planning authorities to ensure biodiversity requirements are fully integrated into site plans from the earliest design stages.
Understanding Your Site's Baseline Biodiversity
Every successful biodiversity net gain assessment starts with understanding the existing ecological value of the development site.
A consultant will usually begin with ecological surveys and, where appropriate, an ecological impact assessment to establish the pre-development biodiversity value. Habitat surveys identify existing habitats, ecological features and any constraints that could affect development proposals.
The statutory biodiversity metric uses habitat information to generate biodiversity units based on habitat size, habitat quality and habitat type. These biodiversity units form the basis for calculating biodiversity value before and after development.
Accurate baseline data is essential because every future biodiversity gain is measured against this starting point. Incorrect biodiversity metric calculations or incomplete habitat surveys can delay planning approval and require additional ecological work later in the planning process.
Calculating Biodiversity Net Gain
One of the most valuable services a biodiversity net gain consultant provides is accurately calculating biodiversity net gain.
Using the statutory biodiversity metric, consultants compare the pre-development biodiversity value with the anticipated post-development biodiversity value after habitat creation and biodiversity enhancements have been completed.
These biodiversity metric calculations determine whether a proposed development will achieve the required biodiversity gain objective or whether further measures will be needed.
Because biodiversity metrics must be completed by a competent ecologist, involving experienced consultants ensures calculations comply with current legislation and Natural England guidance.
Where biodiversity gain cannot be fully achieved on site, consultants can identify appropriate alternatives before planning applications are submitted, helping developers avoid delays during the decision-making process.
Integrating Biodiversity Into Development Plans
One of the biggest advantages of appointing a biodiversity net gain consultant early is that biodiversity can be designed into a scheme rather than added afterwards.
Consultants advise how habitat creation and habitat enhancement can be incorporated into development plans while maintaining commercial viability.
On-site biodiversity enhancements may include wildlife ponds, species-rich grassland, native planting, green roofs, sustainable drainage features and enhanced habitats that improve biodiversity while creating attractive developments.
Retaining valuable ecological features wherever possible often reduces the need for offsite biodiversity units later in the project.
This approach also follows the biodiversity gain hierarchy and mitigation hierarchy, which require developers to first avoid biodiversity loss, minimise impacts, enhance existing habitats and only then consider off-site biodiversity units or statutory biodiversity credits where necessary.
Integrating biodiversity into site plans at an early stage not only helps improve biodiversity but can also simplify planning approval and reduce project costs.
Preparing a Biodiversity Gain Plan
A Biodiversity Gain Plan has become one of the most important planning documents for developments subject to mandatory biodiversity net gain.
Developers must submit a Biodiversity Gain Plan before development starts, following the grant of planning permission. The plan must be approved by the relevant local planning authority before the biodiversity gain condition can be discharged.
A biodiversity net gain planning consultant prepares the documentation needed to demonstrate compliance with biodiversity net gain requirements.
This includes the statutory biodiversity metric calculations, baseline biodiversity information, habitat creation proposals, biodiversity enhancements, biodiversity units to be delivered, post-development plans and the proposed Habitat Management and Monitoring Plan.
The Biodiversity Gain Plan should also explain how biodiversity gains will be maintained over the required 30-year period and identify any legal mechanisms needed to secure those gains.
Many local planning authorities may request additional biodiversity information where complex development sites or sensitive ecological features are involved, making early preparation particularly valuable.
Working With Local Planning Authorities
Every planning authority has its own priorities, although all operate within the same statutory biodiversity framework.
A biodiversity net gain consultant understands how local planning authorities assess development proposals and can help developers respond to planning queries efficiently.
This often includes considering local nature recovery strategies, local plans and biodiversity priorities that influence planning decisions.
Many local planning authorities also expect developments to contribute towards wider nature conservation objectives by protecting biodiversity, enhancing habitats and strengthening ecological networks.
By engaging with planning authorities early, consultants help reduce uncertainty, identify local requirements and improve the quality of planning submissions before formal determination begins.
When are off-site biodiversity units required?
Not every development can achieve the required biodiversity gain through onsite habitat creation alone. Where biodiversity metric calculations show that the proposed development cannot deliver the minimum 10% biodiversity increase within the development site, a biodiversity net gain planning consultant can identify suitable off-site biodiversity units.
Before recommending offsite biodiversity units, consultants ensure the biodiversity gain hierarchy has been followed. This means opportunities to avoid impacts, protect existing habitats, enhance biodiversity on site and maximise habitat creation have already been explored.
Where further biodiversity gain is still required, consultants help developers source off-site units from registered biodiversity gain sites that meet planning requirements. These sites must be recorded on the Biodiversity Gain Site Register maintained by Natural England and secured through the appropriate legal agreements.
Using off-site biodiversity units strategically allows developers to achieve biodiversity net gain while ensuring biodiversity improvements are delivered in locations where they provide the greatest long-term environmental benefit.
Understanding Statutory Biodiversity Credits
If suitable offsite biodiversity units cannot be secured, statutory biodiversity credits may be available.
These credits are provided by the government and are intended as a last resort rather than a preferred solution. Before purchasing statutory biodiversity credits, developers must demonstrate that reasonable opportunities for on-site habitat creation and off-site biodiversity units have been fully explored.
A biodiversity net gain consultant can advise whether statutory biodiversity credits are appropriate and help ensure developers remain compliant with biodiversity net gain requirements while avoiding unnecessary expenditure.
Supporting Planning Permission From Start to Finish
Ecology consultancies play an important role throughout the planning process rather than simply producing reports.
They prepare ecological reports required for planning applications, complete biodiversity net gain assessments, undertake biodiversity metric calculations and advise on habitat creation, habitat enhancement and environmental management strategies.
Consultants also work alongside architects, planning consultants and engineers to ensure biodiversity is integrated into site plans from the earliest design stages.
This collaborative approach helps developers secure planning permission while delivering measurable net gains that satisfy local planning authorities and comply with biodiversity net gain guidance.
For future developments, establishing biodiversity considerations early also provides greater certainty around costs, programme timescales and planning approval.
Habitat Management and Monitoring
Achieving biodiversity net gain is only one part of the process. Maintaining biodiversity improvements over the long term is equally important.
The biodiversity gain plan must include a habitat management and monitoring plan explaining how habitats will be managed for a minimum of 30 years. This document sets out maintenance responsibilities, monitoring requirements and management actions that will ensure biodiversity value is retained throughout the life of the agreement.
Whether biodiversity gains are achieved on-site or through off-site biodiversity units, local planning authorities will expect long-term management arrangements that demonstrate biodiversity improvements can be sustained.
Monitoring also provides confidence that biodiversity gain objectives continue to be achieved after development has been completed.
Conservation Covenants and Legal Agreements
Long-term biodiversity gain cannot rely solely on good intentions. Legal mechanisms are required to secure biodiversity gains for future generations.
Where biodiversity units are delivered off site, conservation covenants or planning obligations are commonly used to ensure habitat management commitments remain legally enforceable.
These agreements protect biodiversity enhancements for at least 30 years and provide certainty for developers, landowners, local planning authorities and responsible bodies.
A biodiversity net gain consultant can advise on the most appropriate legal mechanism for each project while working alongside legal teams, planning consultants and local authorities throughout the planning process.
Avoiding Common Planning Delays
Many planning delays occur because biodiversity requirements are addressed too late.
Waiting until planning applications have been submitted before commissioning ecological surveys or biodiversity metric calculations often results in additional work, revised site plans and extended planning timescales.
Common issues include incomplete biodiversity net gain assessments, inaccurate biodiversity metric calculations, insufficient habitat creation proposals and failing to consider local nature recovery strategies during the design process.
Developers also encounter delays where off-site biodiversity units are sourced too late or where habitat management and monitoring plans lack sufficient detail.
By appointing a biodiversity net gain planning consultant at the earliest opportunity, these issues can usually be identified and resolved before they become planning obstacles.
Supporting Residential and Commercial Developments
The principles of biodiversity net gain apply across a wide range of developments.
Whether preparing residential developments, commercial schemes, mixed-use projects or future developments on brownfield sites, ecology and biodiversity considerations must now form part of the overall development strategy.
An experienced consultant understands how biodiversity net gain requirements interact with planning policy, environmental legislation and local authority expectations, helping developers deliver compliant schemes while maintaining commercial viability.
This integrated approach supports planning approval, improves biodiversity outcomes and creates developments that contribute positively to the natural environment.
How Civity Supports Your Development
At Civity, we provide specialist biodiversity net gain consultancy for developers, planners and landowners across England.
Our team supports developers once biodiversity metric calculations are sufficiently advanced to identify any off-site biodiversity requirements. We review completed metric assessments, provide accurate quotations for off-site biodiversity units, advise on unit availability and help secure suitable units from registered gain sites. As project layouts and biodiversity requirements evolve, we work closely with developers and their ecologists to ensure off-site unit allocations remain aligned with the latest metric calculations and planning requirements.
Where biodiversity gain cannot be fully achieved on-site, we help clients identify suitable off-site biodiversity units from registered biodiversity gain sites and provide guidance on conservation covenants, planning obligations and long-term compliance.
By working closely with project teams and local planning authorities, we help developers achieve biodiversity net gain while reducing planning risk and avoiding costly delays.
Conclusion
Mandatory biodiversity net gain has fundamentally changed the planning process, making biodiversity an essential consideration from the earliest stages of development.
A biodiversity net gain planning consultant provides the technical expertise needed to calculate biodiversity value, prepare biodiversity gain plans, coordinate ecological surveys and identify practical solutions that satisfy local planning authorities.
Rather than treating biodiversity as a planning hurdle, early ecological input allows developers to improve biodiversity, integrate habitat creation into development plans and achieve measurable net gains that benefit both development and the natural environment.
By partnering with Civity, developers can navigate biodiversity net gain requirements with confidence, secure planning permission more efficiently and deliver sustainable developments that remain compliant with current legislation.
