Your Complete Guide to Biodiversity Net Gain
Now a part of UK legislation, biodiversity net gain (BNG) is a mandatory consideration for all major development projects in England, with only a few exceptions. It acts as a planning condition and policy requirement of planning consent, causing a significant impact on the decision-making process of local planning authorities as they determine whether planning permissions are granted or refused.
Based on this, delivering BNG has become an important part of many planning applications moving forward in the eyes of local authorities, and developers are required to show consideration of efforts to deliver measurable improvements as part of their pre-development plans. As soon as a biodiversity net gain approach has been approved by the local authority, the permitted development can continue.
What is Biodiversity Net Gain?
Biodiversity net gain (BNG) is a concept in planning that insists on developers improving the ecological value of the development site once the project is complete. Not all proposed developments apply, but for those that do, a biodiversity net gain consultant will ensure that the plot of land is preserved as much as possible, retaining various habitat types, avoiding biodiversity loss and protecting ecological features to encourage developers to continue their project in an environmentally considerate manner.
Created as a way of counteracting the potentially negative impact of a development on the natural environment, mandatory biodiversity net gain not only forces developers to replace any wildlife habitats that were removed due to the development but makes them required to deliver habitat creation, enhancement and rejuvenation as a method of improving the site area to a measurably better state.
BNG is an approach to development that often requests a minimum 10% BNG improvement from pre-development biodiversity value to post-development biodiversity value secured for a minimum of 30 years. Most commercial and residential development projects will be subject to the BNG policy – including nationally significant infrastructure projects – but biodiversity net gain exemptions are also in place at the validation stage, such as for plots on the biodiversity gain sites register, small-scale self-build and custom-build development, householder applications for householder development and de minimis exemptions.
On-Site Measures
Throughout the process of biodiversity net gain delivery, the ecological consultant will always favour seeing it provided on-site. It is possible to increase biodiversity by recommending existing habitat enhancement or restoration, or new habitat creation. That way, the on-site habitat can be altered or added to without the developer having to resort to alternative action, and the ecologist can make a measurably positive impact to achieve BNG.
A mitigation hierarchy will be used to choose the best course of action to achieve on-site gains, with avoidance of onsite habitat standing as the preferred option, followed by the mitigation of irreplaceable habitats or the compensation of any habitat lost with the planting of new high-quality natural habitat. Based on several options, it is hoped that the ecological consultant will be able to deliver biodiversity units and boost onsite biodiversity value using the biodiversity gain hierarchy.
Off-Site Measures
Whenever it isn’t feasible to see the biodiversity gain objective achieved on-site, the BNG consultant can instead generate off-site biodiversity gains. Often known as the process of biodiversity offsetting, a BNG register lists habitat banks of land owned specifically for land managers to create off-site gains on behalf of a developer in need of a set amount of off-site biodiversity units.
As BNG must remain effective for a minimum of 30 years after the applicable major or non-major development, a legal agreement known as a conservation covenant will be agreed between the landowner and the developer to ensure that the biodiversity enhancements are legally secured for the required period and at the 10% or higher percentage enforced by the local planning authorities.
If offsite gains on the other sites aren’t enough or if more biodiversity offsets are needed, the absolute last resort option would be to see the mandate delivered off-site by opting to buy statutory biodiversity credits from bodies approved prior to the process by the government. Off-site statutory credits reflect the number of on-site biodiversity units, but instead of funding off-site habitat on another site, the fee paid will contribute to off-site BNG somewhere else in the country.
Statutory Biodiversity Metric Calculations
A metric created by the Department for Environment, Food and Rural Affairs (DEFRA) enables ecological consultants to measure current biodiversity value and compare it to the predicted value of the development site once the project is completed based on the likely impact on priority habitats. The completed metric calculation tool has been updated several times by DEFRA over multiple versions, as well as the creation of a small-sites metric for smaller developments.
Measuring biodiversity using the latest version of the DEFRA metric works by turning the information submitted from the assessment into a numerical figure. The value of important habitats will vary depending on species and condition, and once the pre- and post-development readings are created, the ecological consultant can enhance biodiversity and create biodiversity gains by removing any deficit between the two numbers and increasing by at least 10%.
Biodiversity Net Gain Assessments and Plans
To meet the biodiversity net gain requirements, a BNG assessment, plan and report will need to be carried out and put together, with the possibility of other surveys such as a biodiversity habitat management and monitoring plan (HMMP) and other such things as a river condition assessment (RCA), any number of protected species surveys, and the purchase of nutrient neutrality credits.
Biodiversity Net Gain Survey
In new developments that apply to the BNG target, a biodiversity net gain assessment will be needed for ecologists to inspect all important habitats within the red-line boundary of a site. Protected species of animals and invasive species of plants will be noted down, as well as other habitats such as natural or man-made linear habitats of hedgerows, rivers and streams.
With the development subject to biodiversity net gain, the pre-development biodiversity value will be based on the available supporting evidence. A secondary post-development biodiversity value will be based on the predicted outcome of adverse effects on irreplaceable habitats, taking account of the project’s development and site plans.
Biodiversity Net Gain Plan and Report
Both a BNG plan and a BNG report will usually be included within the same document. Although the two are similar and equally important at the planning application stage, each of them has a different purpose.
Plan
A biodiversity net gain plan explains the proposed approach to support biodiversity and work within the biodiversity gain condition. All of the steps that need to be taken to avoid a net loss of biodiversity, retain at the current standard and enhance by at least 10% will be included.
It includes mitigation and compensation measures decided using the biodiversity gain hierarchy, landscaping plans where applicable, sustainable development and green infrastructure concepts, off-site land unit purchases or any proposed habitats with a strategic significance in ensuring the proposals meet the new guidance.
Other cases that could overlap with the produced guidance will also be considered, such as simplified planning zones or protected sites like sites of special scientific interest (SSSI), special areas of conservation (SAC), special protection areas (SPAs) and Ramsar sites.
Report
A biodiversity net gain report explains the results of the assessment process and lists the minimum information that will be key to the planning application stage. It will provide evidence of crucial observations about the site and metric readings reflecting the value of the site before and after the development.
An important part of the planning process to achieve BNG, the report will make it clear what the outcome of the survey was to help with planning decisions. The person submitting the BNG report to the local planning authority should then be able to see planning permission granted, as that and the BNG plan will demonstrate the application of the policy.
Biodiversity Gain Plan
While sounding similar to a biodiversity net gain plan, a biodiversity gain plan is actually different and refers to a potentially important asset in the planning system. Local planning authorities may or may not ask for a planning application setting out the method to achieve BNG, but if they do, you will need to work with your ecological consultant to fill out and submit a subsequent biodiversity gain plan.
The biodiversity gain plan itself is a document provided by the gov.uk website. It requires all additional information from the development site and planning project, including further guidance provided by the biodiversity consultant who conducted the assessment and created the plan. Now that BNG is mandatory, more local authorities are likely to insist on the completion of an overall biodiversity gain plan.
Habitat Management and Monitoring Plan (HMMP)
Enough habitat enhancements to hit the BNG target are expected to last for at least 30 years. With this, a habitat management and monitoring plan (HMMP) ensures that ongoing management and monitoring reports are undertaken and created as part of guaranteeing that the habitat enhancement steps are suitable and sustainable.
Apart from wildlife habitats that don’t need to be frequently analysed such as sealed surfaces and vegetated gardens, an HMMP would apply to most major applications that BNG apply to. The habitat and land management process would then continue for a 30-year term. After this point, however, the developer would no longer be under a legal obligation to local nature recovery.
Other Assessments that Support Planning Applicants with BNG
The wide scope of BNG makes many other types of surveys and processes relevant to meeting the needs of the national planning policy.
Examples include a river condition assessment (RCA) for evaluating the condition, value and effectiveness of the ecosystem within rivers and streams, the ability to buy nutrient neutrality credits as a way of compensating for pollution in watercourses, and protected species surveys if the applicant believes that listed species protected by law are somewhere on the site.
Biodiversity Net Gain Principles
According to the Chartered Institute of Ecology and Environmental Management (CIEEM), there are ten key good practice principles of biodiversity net gain that lead to the developer delivering biodiversity net gain.
CIEEM is a responsible body that provides further information and expert advice on implementing BNG correctly. Even with the new planning condition in place to combat the climate and ecological emergency, it is made clear that navigating through the planning process is still perfectly realistic and possible.
Mandatory BNG Principles
- Utilise the mitigation hierarchy to minimise the impact on biodiversity
- Eliminate negative impacts on biodiversity that cannot be offset elsewhere
- Involve all pre-development and post-development stakeholders in forming mandatory net gain solutions
- Understand the potential risks and variable factors to achieve biodiversity net gain
- Determine a suitable method to secure a better state of biodiversity
- Ensure the best possible outcomes from biodiversity net gain
- Offer nature conservation that exceeds the BNG requirements
- Focus on generating long-term environmental benefits from biodiversity net gain
- Cover all areas of sustainability, incorporating economic and societal factors
- Communicate all biodiversity net gain outcomes with complete transparency
Check out CIEEM’s biodiversity net gain principles for a more thorough explanation of these factors.
Why is Biodiversity Important?
The concept of biodiversity is important for a number of reasons, and it applies globally regardless of country.
Key benefits that biodiversity offers include:
- Enabling the production of raw materials
- Enhancing the Earth’s visual appearance
- Facilitating a scientific understanding of the natural world
- Offering recreational activities such as birdwatching, camping, fishing and hiking
- Providing jobs for farmers and other agricultural vocations
- Supplying oxygen and water to the ecosystem
Biodiversity is vital, and as such, the concept of the BNG regulations provides a defined, structured and regulated method of ensuring that all of the above factors are encouraged and supported over future years.
Improving natural habitats and creating habitats makes sure that the development meets the BNG condition, letting developers continue with achieving the goals of their projects without harming the environment and in fact leaving it in a better condition than before.
Why was Biodiversity Net Gain Brought In?
Since the new rules came into effect, architects, developers, landowners and planning consultants have had to consider biodiversity net gain as part of the planning application process. The national planning policy to accomplish BNG delivery, however, is only one small part of the Environment Act. After being raised multiple times since December 2018, there are multiple reasons why BNG was introduced.
One of the primary purposes of biodiversity net gain is as a consequence of the UK’s decision to leave the European Union. Without association to the EU and as an independent country, the UK is no longer obliged to follow European environmental regulations. Due to that, the introduction of mandatory biodiversity net gain presented a new legal framework to seek the bigger picture of nature recovery.
The strategic planning from making a positive impact net gain on biodiversity value contributes to the environment in a number of ways. For instance, through understanding BNG and creating or enhancing the natural world correctly, outcomes can include better water and air quality, well-tended green spaces, heightened economy, and more desirable locations to live and work in.
Various regulators, organisations and local communities endorse the continued progress of aims to leave the environment in an improved condition, such as Natural England, CIEEM, DEFRA and any relevant wildlife trust associations. In addition to this, it is illegal to ignore the application of biodiversity net gain, as it is weaved into UK legislation, such as:
BNG Legislation
- The Conservation of Habitats and Species Regulations 2017
- The Natural Environment and Rural Communities (NERC) Act 2006
- The Town and Country Planning Act 1990
- The Wildlife and Countryside Act 1981
Other factors relating to the legal requirements include local development orders, planning obligations and whenever any existing local policies apply, as well as local nature recovery strategies or other policies relating to developer guidance or government guidance.
Biodiversity Net Gain Timescale
The process of passing the Environment Act 2021 into law and initiating biodiversity net gain required several steps over a lengthy period of time.
Below, we outline a clear timescale of the introduction of biodiversity net gain into UK law:
| December 2018 | Environment Secretary Michael Gove announces the concept of biodiversity net gain, citing it as a “commitment to protecting and enhancing our natural world [that] can go hand in hand with our ambition to build more high-quality homes.” |
| December 2018 – February 2019 | DEFRA holds a consultation on biodiversity net gain to allow affected parties to have their say. |
| March 2019 | Chancellor of the Exchequer Phillip Hammond presents the spring statement to parliament, with biodiversity net gain included as one of several policies and draft statutory instruments. |
| July 2019 | DEFRA publishes a report on the results of the consultation, detailing the feedback they had and responses to individual comments. |
| October 2019 | The government announces the Environment Bill, replacing environmental protection policies that would no longer apply as a result of Brexit. Biodiversity net gain was included as one of several core components of the bill. |
| January 2020 | The Bill undergoes the first reading in the House of Commons. |
| February 2020 | The Bill undergoes the second reading in the House of Commons, as well as passing a programme motion, money resolution, and ways and means resolution. |
| March 2020 | The Bill passes the committee stage in the House of Commons. |
| June 2020 – January 2021 | The Bill passes multiple programme motions, as well as a carry-over motion. |
| January 2021 – May 2021 | The Bill passes the report stage in the House of Commons. |
| May 2021 | The Bill undergoes the third reading in the House of Commons before undergoing the first reading in the House of Lords. |
| June 2021 | The Bill undergoes both the second reading and the committee stage in the House of Lords. |
| September 2021 | The Bill passes the report stage in the House of Lords. |
| October 2021 | The Bill undergoes the third reading and consideration for Commons amendments in the House of Lords before undergoing the consideration of Lords amends and programme motion in the House of Commons. |
| November 2021 | The Bill undergoes the consideration of the Lords’ message in the House of Commons and a second consideration of Commons amendments in the House of Lords. It then achieves royal assent, earning the title of the Environment Act 2021 and passing into UK law. |
| November 2021 – November 2023 | The planned two-year transition period takes place. |
| November 2023 | Mandatory roll-out is delayed until January 2024. |
| January 2024 | Mandatory roll-out is delayed until February 2024. |
| February 2024 | On 12 February 2024, biodiversity net gain becomes mandatory in applicable major development projects across England. |
| April 2024 | On 2 April 2024, biodiversity net gain becomes mandatory in applicable minor development projects across England. |
In England today, any current or future development where BNG applies must be arranged with consideration to the planning policy and developers are expected to provide reasons for how their development plans will be successful in delivering biodiversity net gain.
It would also be beneficial to generally outline planning permissions with an eye on the natural environment.
Contact Arbtech for Biodiversity Net Gain Advice
If you need help with succeeding in meeting the biodiversity net gain requirements, Arbtech can help.
Our team has been involved in the BNG mandate ever since it was first announced, and from then onwards, we’ve been supporting developers up and down the country with guidance and biodiversity net gain plans. Situating ecological consultants throughout England means we can cover clients everywhere regardless of location. And if any arboricultural surveys, other ecology surveys or different types of assessment affecting development are needed, we’re qualified to help with them too.
Whether you can satisfy the biodiversity gain objective on your development site, you need to buy off-site biodiversity units from land managers or you need to buy statutory biodiversity credits from the government – or even if you don’t know where to start and are currently stuck at step one – get in touch with Arbtech today and we can find a relevant date to help you out.
Call us, email us, message us via social media or complete the quote form at the top of this page and we can send you a free quote based on your site and project. We can then set a date immediately before you start your development or at an even earlier date as necessary to attend your site, conduct a BNG assessment, create a BNG plan and report, undertake any other required surveys, and get viable planning applications submitted to your local planning authority using all this information.
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