Understanding biodiversity net gain

What biodiversity net gain isis 

Biodiversity net gain (BNG) is a way toof contributecreating and improving natural habitats. BNG makes sure development has a measurably positive impact (‘net gain’) on biodiversity, compared to thewhat recoverywas ofthere naturebefore whiledevelopment.  

In developingEngland, land.biodiversity Itnet gain (BNG) is makingbecoming suremandatory under Schedule 7A of the habitatTown forand wildlifeCountry isPlanning inAct 1990 (as inserted by Schedule 14 of the Environment Act 2021).

Developers must deliver a biodiversity net gain of 10%. This means a development will result in more or better statequality natural habitat than itthere was before development.development. 

ThisFind willout applymore fromabout NovemberBNG 2023in:

• step by step guidance for developmentsdevelopers 

• step by step guidance for land managers

• guidance for local planning authorities (LPAs)

Measuring biodiversity  

For the purposes of BNG, biodiversity is measured in standardised biodiversity units. 

A habitat will contain a number of biodiversity units, depending on things like its:  

• size  
• quality  
• location   

Biodiversity units can be lost through development or generated through work to create and enhance habitats. 

Calculating the Townunits

There is a formula that calculates: 

• how many units a habitat contains before development  
• how many units are needed to replace the units of habitat lost and Countryto Planningachieve Act10% 1990,BNG

This unlessformula exempt.is Itcalled willthe applystatutory biodiversity metric.

Using the statutory biodiversity metric tool

To prove you have accurately calculated the number of biodiversity units for existing habitat, or habitat enhancements to smallachieve sitesBNG, fromyou Aprilmust 2024.use the calculator called the statutory biodiversity metric tool.

Who

This ittool willapplies affect

Read guidance on the standard biodiversity metric.

Who BNG rules will applyaffect 

You need to youknow about the new rules if you’re a:a: 

• landdeveloper managerof: 

  • major developments when BNG becomes mandatory  
  • small sites from April 2024    
  • nationally significant infrastructure projects from late November 2025   

  developer

• land manager wanting to sell in the BNG market 

• local planning authority (LPA)
  ) 

IfExempt you’redevelopments 

Some adevelopments landare managerexempt from BNG regulations. 

YouFind canout getwhat paidtypes of development are exempt.

Ways to achieve BNG: on-site units, off-site units and statutory biodiversity credits 

Through site selection and layout, developers should avoid or reduce any negative impact on biodiversity. They must deliver 10% BNG, as measured by sellingthe statutory biodiversity units.metric.

YouThere mustare be3 ways a landdeveloper managercan with:achieve 10% BNG: 

1. landThey incan England

   enhance and restore biodiversity on-site (within the red line boundary of a development site). 

2. consentIf todevelopers registercan only achieve part of their BNG on-site, they can deliver through a mixture of on-site and off-site. Developers can either make off-site biodiversity gains on their own land ifoutside you’rethe notdevelopment site, or buy off-site biodiversity units on the landowner

   market.

3. If developers cannot achieve on-site or off-site BNG, they must buy statutory biodiversity credits from the government. This must be a legallast agreementresort. forThe government will use the landrevenue you’reto registering

   invest in habitat creation in England.  

If

Developers you’recan acombine developerall 3 options, but must follow the steps in order. This order of steps is called the biodiversity gain hierarchy. 

Example

YouA developer cuts down some trees on the site. They must trymake up for this impact on the habitat, as well as delivering a 10% BNG uplift.

They must do a survey of habitat before development and use the statutory biodiversity metric to avoidexplore options. This tells them how to make up for the loss of habitatthe trees and what more they need to do to achieve 10% BNG.

If they cannot achieve the 10% BNG by creating and enhancing on-site habitats, they must buy off-site units.

If that is not enough to achieve BNG, they must buy statutory biodiversity credits.  

Creating, enhancing and maintaining habitats to dodeliver developmentBNG 

The workland on.manager is legally responsible for creating or enhancing habitat, and managing that habitat for at least 30 years to achieve the target condition. 

If you cannotmake doon-site this,gains or sell off-site gains on a site you own, you are the land manager. If you buy off-site units, you are paying the land manager to manage the land for 30 years to achieve the target condition. 

What developers have to do 

There is step by step guidance for developers. 

Unless exempt, developers of major developments in England are required to provide 10% BNG once it becomes mandatory. 

You must createtry to avoid loss of biodiverse habitat when doing development work. Developers must deliver 10% biodiversity net gain, either on-site or off-site.off-site, or as a last resort by buying statutory biodiversity credits.  

On-siteFor meanssignificant on-site gains, and all off-site gains, the BNG must be maintained for at least 30 years. Responsibilities will be set out in a legal agreement. 

The following guides will help you: 

• when you buy off-site units, record the allocation of off-site biodiversity gains on the public biodiversity gain sites register, with the land manager’s permission  
• estimate the cost of and buy statutory biodiversity credits if you’re unable to use on-site or off-site units 

Exploring options and using the biodiversity metric 

Read guidance on your developmentoptions workand ishow on.to Off-sitefind isregistered eitheroff-site units to buy. 

You should discuss your ownplans landwith awayan fromecologist, who will measure the developmentbiodiversity site,value orof youyour haveexisting boughthabitat unitsand fromexplore aways landto manager.achieve BNG using the statutory biodiversity metric tool.

Read guidance on the statutory biodiversity metric. 

If you cannothave a small site, you don’t need an ecologist. You can either use on-sitethe simpler small sites biodiversity metric tool yourself, or off-sitesomeone land,familiar with the site can do a survey and make a calculation. This could be the project manager, a gardener or a landscape architect.  

Planning permission and biodiversity gain plans  

When you mustapply buyto statutorythe creditsLPA for planning permission, you will need to confirm whether your development is exempt from BNG.

If it is not exempt, you will need to attach a baseline metric calculation showing the government.site’s biodiversity value before development. You mustshould also provide evidenceinformation forabout usinghow thisyou option.intend Thisto mustmeet bethe BNG objective, including details of proposed significant on-site enhancements.  

You may need a lastlegal resort.agreement. You may also need a habitat management and monitoring plan (HMMP). The governmentterms of these will investset inout habitatresponsibilities for creation elsewhereand inenhancement, England.and monitoring and reporting. 

YouIf maythe beLPA ablegrants toplanning combinepermission, allyou 3will optionsneed to makecreate upa yourbiodiversity gain plan. This is a document that shows how you will achieve BNG. In your biodiversity gain plan you must provide evidence for your BNG decisions.  

You must discusssubmit thisyour withbiodiversity angain ecologist,plan, asincluding a biodiversity metric calculation that shows how you will needmeet your mandatory BNG, to provethe whyLPA. (See youthe cannotguidance useon onethe option.statutory Youbiodiversity metric.) The LPA must getapprove approvalor fromrefuse your localbiodiversity planninggain authorityplan within 8 weeks.  

The LPA must approve your biodiversity gain plan before you start building.development. 

If you’reapplicable, athe local30 years of BNG management and maintenance starts from the time the agreed initial habitat creation or enhancement is completed (for example, after one year of tree planting, pond digging or seeding).  

If you do not meet your BNG requirements, you might be in breach of planning conditions, planning obligations or legal agreement, and the LPA could take enforcement action against you.   

What land managers have to do

Read step by step guidance for land managers. 

‘Land manager’ refers to these different roles across BNG guidance: 

• landowner 
• farmer 
• estate owner 
• habitat bank operator 
• facilities, property or estate manager 
• land agent 
• land advisor  
• planning authority using land they own 
• developer using land they own 

LPAsSelling on the BNG willmarket haveis a choice for land managers. It is a potential source of revenue and could fund nature recovery work on your land. You can sell off-site biodiversity units on your land to approvedevelopers, who may need to buy these under mandatory BNG requirements. 

Registering a site and recording units

When you sell your units, you (or the developer, with your permission) need to record the allocation of off-site biodiversity netgains to a development.

Before you record the allocation of units, you need to register a biodiversity gain plansite onto the government’s publicly searchable register of all off-site biodiversity projects.

Measuring biodiversity value

As part of registering, you need to consult an ecologist who will measure the biodiversity value of your existing habitat and advise on suitable habitat creation or enhancement for developmentthe workland.

Read beforeguidance iton using the statutory biodiversity metric tool.  

You will sign a legal agreement with a responsible body or local authority which will set out how you will create, enhance, maintain and monitor the biodiversity of your registered units over a minimum of 30 years, to deliver off-site biodiversity net gain.  

What LPAs have to do

Read guidance for LPAs. 

Further information  

You can start.get support from:

• Future Homes Hub
• Local Government Association’s Planning Advisory Service

Draft statutory instruments

Draft legislation is available.

The Biodiversity Gain (Town and Country Planning) (Modifications and Amendments) (England) Regulations 2024

The Biodiversity Gain Requirements (Exemptions) Regulations 2024

The Biodiversity Gain Requirements (Irreplaceable Habitat) Regulations 2024

The Biodiversity Gain Site Register Regulations 2024

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