Net Gain

Biodiversity Net Gain (BNG) is an ecological principle which is achieved when a development or project leaves biodiversity in a better state than before. It is also an approach where developers work with local governments, wildlife groups, landowners, and other stakeholders to support their priorities for nature conservation (CIEEM, CIRIA, IEMA, 2016).

Biodiversity Net Gain

Biodiversity Net Gain (BNG) is the ecological principle whereby a development site that has been granted planning permission leaves the natural environment in a measurably improved state than it started. This is generally accepted through the Environment Act 2021 to be a 10% net gain through habitat creation and enhancement.

The approach of BNG relies on developers, land owners and individuals developing land to work with local governments, wildlife groups, landowners, and other stakeholders to support their priorities for nature conservation (CIEEM, CIRIA, IEMA, 2016).

At Wharton, we work with our clients to ensure you not only comply with the legislation but also to ensure your project is commercially viable in relation to BNG from the outset. Our dedicated team of ecologists and landscape architects will enable you to deliver the balance between the built and natural environments. This not only enables you to achieve planning permission but also ensures you are making measurable improvements to the environment. This generally means creating better communities, increased speed of sale, high sale values and a legacy to your project.

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Illustration of an ecosystem featuring birds and woodland


Biodiversity Net Gain provides an invaluable opportunity to ensure that developments and construction projects enhance wildlife and people’s ability to experience nature where they live and work for years ahead. BNG also provides a unique opportunity to put nature back at the heart of planning and development, working in line with a developer’s green targets.

With around 180,000 homes being built in England each year and thousands more commercial developments underway, it’s crucial that Biodiversity Net Gain is a key focus of every project. Landowners, developers and local councils must consider the potential impact of a development or project on people, wildlife and the environment as a whole. 

The benefits of Biodiversity Net Gain can be far-reaching. As well as having greener places to live, BNG can also provide more wildlife habitats and natural flood protection. In contrast, developing without factoring in these elements will create both short and long-term negative effects. With prevention always being favoured over a cure, now is the time to put the best practices into place based on what we already know about threats to our environment. 

Therefore, BNG is important because it seeks to create the best outcomes. It ensures that any new developments or construction projects do not come at a cost to the local environment or all those who live and work in it. 

Biodiversity Net Gain is a team effort which also highlights its importance, in that it requires all applicable parties to comply. Working together is how we can solve the climate crisis and any future environmental challenges we face. It is without a doubt that BNG underpins all of this essential work.


The environmental bill is also known as the Environment Act 2021.

The UK Government brought in the Environment Act 2021 with the intention of outlining targets, plans and policies for various environmental causes. It is hoped the bill will encourage better conversation and biodiversity by tackling all of the threats to our environment.

Some of the issues the environmental bill covers include: 

  • Air pollution
  • Biodiversity 
  • Farming
  • Pesticides
  • Plastic consumption
  • Waste management
  • Wildlife conservation 

Having such a framework in place is important for two reasons. Firstly, it outlines tangible steps that businesses and organisations need to take, especially since the UK has now left the EU. 

Also, having the Environment Act 2021 in place means that it becomes easier to identify breaches of the required standards that could threaten biodiversity. As well as making it easier to inform and educate all applicable parties, this means that planning permission and even potential prosecutions will be subject to a consistent, rigorous process. All of which means potentially harmful actions or decisions can be best avoided.

Biodiversity Net Gain
Biodiversity Net Gain


Anyone undertaking land development, or who owns land needs to consider biodiversity net gain. In short, the considerations must focus on how any work can be undertaken without compromising the environment. In addition, other projects may need to be facilitated to offset any potential disruption to the local ecosystem. 

Traditionally, land development has caused biodiversity to decline. This can be easily seen in urban environments whereby very little green space or other natural habits exist, where once they thrived. Beyond the impact on wildlife, towns and cities can also suffer from poor air quality and flood threats due to planning without biodiversity in mind. 

Owning or developing land with biodiversity in mind looks to limit such poor outcomes for people, nature and the land itself. 

A simple (and by no means exhaustive) example of what a project could entail would be planting trees around a new housing development. These trees would provide natural habits for wildlife while helping to capture carbon from nearby traffic pollution.


The value of a development site is calculated by considering four major factors:


The area/length of the habitats.


The habitat types present at a development site and their ‘distinctiveness’ (loosely translated to their ecological importance).


The condition those habitats are in, compared to the reference Habitats based on published condition criteria.


Whether any of those habitats are strategically significant or in an ecologically desirable location (such as in green infrastructure plans, local biodiversity action plans etc.)

Man and woman looking at house plan illustration

To calculate Biodiversity Net Gain, your ecologist will go through the following process during the baseline assessment:


Undertake a site visit to classify, map, and assess the condition of the habitats at your development site.


Measure the size of the habitats in an appropriately geo-referenced digital mapping system.


Check local policies to determine the strategic significance of habitats (if any).


Input the data into the relevant biodiversity metric.

Once the baseline assessment is complete, your ecologist can inform you how many ‘biodiversity units’ your site contains and how many units need to be provided in line with local policy.


On paper, Biodiversity Net Gain is assessed by undertaking an initial habitat survey and habitat condition assessment, then comparing the pre-development habitats to the post-development habitats (usually as detailed in a landscaping plan).

There are then several options for the physical delivery of BNG, including habitat creation and enhancement on-site, habitat creation and enhancement off-site, and/or the purchase of habitat ‘credits’ from local schemes or via the central Government’s credit bank.


The principle of Biodiversity Net Gain has been enshrined in the Environment Act 2021, which stipulates that all development under the Town and Country Planning Act 1990 (as amended) must deliver a minimum of 10% BNG by the end of 2023.

There is currently a two-year transition period for a range of secondary supporting legislation to be produced, as well as Habitat Banks, the Credits System and Local Nature Recovery Strategies to be implemented before 10% can be mandated. After this period, all relevant development under the TCPA will have to deliver a minimum of 10% BNG.


The key to understanding your Biodiversity Net Gain requirements is to engage an ecologist as early in the design and planning process as possible; this enables detailed guidance right from the start of the development or project. Liaison with the local planning authority to understand policy requirements and local delivery methods is also critical, as it ensures that the process of delivering BNG is clearly understood from day one.

Why Trust

Hire a Professional Ecological Consultant

Since 2008, we have established a team with extensive experience with all types of surveys, including BS5837 Tree Surveys for planning, Tree Surveys and Reports for risk management, Ecological Surveys including Preliminary Ecological Appraisals, Preliminary Roost Assessments, Protected Species Surveys, and Biodiversity Net Gain.

Our highly qualified and experienced team of ecological consultants and specialists has a proven track record of assisting our clients in identifying successful natural-infrastructure solutions and nature conservation for even the most complex projects. We strive to consistently deliver high-quality, practical and innovative ecological consultancy services on a consistent basis while adhering to environmental laws, wildlife legislation, industry legislation, policy, and best practices.

Our ecological consultant listens to our clients; collaboration is one of our four core values, and it shows in the success we’ve shared with them in maximising development opportunities, managing trees and woodlands or enhancing biodiversity and landscapes while delivering the best environmental solutions. Our certified and professional ecology consultants have solid experience in helping with environmental conservation problems like air quality, water quality, waste management and reclaiming contaminated land.

Simply put – we understand natural infrastructure. Trust us that our ecological consultants have the expertise and key skills to help you design and plan a successful development, mitigate and compensate for impacts, manage risks and keep your project moving forward.

Get your Biodiversity Net Gain Quote

Our in-house experts will be able to provide you with a cost for undertaking a BNG assessment on your site if this is required by the Local Planning Authority. We’re also happy to discuss any questions you may have over the phone to put your mind at ease and talk you through our approach and the process.

For a no-obligation quotation please fill in the form to the right and one of our consultants will be in touch.

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Personal Support

Now more than ever time is money. We guarantee our turnaround times to ensure you receive the right information at the right time to unlock the true value of your site.

We believe good communication lies at the heart of any successful ecological consultancy work. That’s why our recommendations whether on the phone in person or in a report are always easy to understand and use.

A Unique Approach

Whether you’re looking to plan, develop or manage your site, our ecologists provide the natural advice you need to successfully balance commercial, environmental and human needs, naturally increasing the true value of your land or property. By combining detailed research and data analysis of the existing trees and ecology, our arboricultural consultant will help turn any constraints into exciting opportunities to achieve planning success, improve quality of life, and allow nature to thrive.

After taking the time to research and understand your needs, our expert ecological consultants use the latest techniques to record and assess the trees and ecology on your site. Then, drawing on our in-depth experience, we help find the best way forward for you, your customers and the nature of your land and property. Ultimately, our ecological consultancy services will help increase the value of your site.

Quality Advice

Our commitment to providing honest advice that considers the wider context of your scheme enables us to secure a successful planning process and applications the first time and every time.

After a decade of success, we have developed strong relationships with planners and councils so that when a scheme does prove more challenging we can bring the right people together to find the best way forward.

Expert Analysis

Our highly qualified team of ecology consultants constantly review and update their knowledge and skills to ensure we are at the forefront of industry knowledge, environmental studies and best practice, especially in terms of environmental issues or ecological issues.

This forward-thinking approach enables Wharton environmental consultant to provide thought leadership across the whole natural-infrastructure sector driving innovation and excellence.

Commercially Minded

We understand the need to find a balance for each site between commercial environment and community requirements. So we focus on trees, ecology and habitats as assets rather than commercial development constraints.

Our approach to the environmental management of ecological constraints allows us to deliver practical and innovative services that ensure owners retain viable natural infrastructure and developers optimise their investment.

Time Conscious

For anyone in the planning sector, professional advice provided quickly and in an easily digestible format is vital to allow you to make decisions. We pride ourselves on delivering the highest and quickest level of ecological consultancy service to all clients from homeowners to those managing strategic land. 

Our team will ensure you know all critical dates either for planning matters, seasonal constraints or protected animal species activity seasons. Connect now with the right ecology consultant, we will ensure you don’t miss a thing.