We have worked with Natural England and Defra to answer the questions we are most frequently asked by local authority officers and members about biodiversity net gain and those that have come up at events so far. We will be adding answers to more questions as we get them, including on the Biodiversity Metric as a follow-up to our October training event. We are keen to get your views and comments on these questions and answers, so please get in touch with Beccy Moberly to provide feedback: email@example.com.
Biodiversity net gain (BNG) is an approach to development, and/or land management, that aims to leave the natural environment in a measurably better state than it was beforehand.
The National Planning Policy Framework (NPPF) states [our emphasis]:
174: Planning policies and decisions should contribute to and enhance the natural and local environment by: [...]
d. minimising impacts on and providing net gains for biodiversity, including by establishing coherent ecological networks that are more resilient to current and future pressures
179: Plans should: [...]
b. promote the conservation, restoration and enhancement of priority habitats, ecological networks and the protection and recovery of priority species; and identify and pursue opportunities for securing measurable net gains for biodiversity and development whose primary objective is to conserve or enhance biodiversity should be supported; while opportunities to incorporate biodiversity improvements in and around developments should be encouraged, especially where this can secure measurable net gains for biodiversity.
180: When determining planning applications, local planning authorities should apply the following principles: [...]
d. development whose primary objective is to conserve or enhance biodiversity should be supported; while opportunities to improve biodiversity in and around developments should be integrated as part of their design, especially where this can secure measurable net gains for biodiversity or enhance public access to nature where this is appropriate.
The Environment Act sets out the following key components of mandatory biodiversity gain:
- Amends Town & Country Planning Act (TCPA);
- Minimum 10% gain required calculated using the Biodiversity Metric & approval of a biodiversity gain plan;
- Habitat secured for at least 30 years via planning obligations or conservation covenants;
- Delivered on-site, off-site or via a new statutory biodiversity credits scheme; and
- National register for net gain delivery sites.
It does not change existing legal protections for important habitats and wildlife species. It maintains the mitigation hierarchy of avoid impacts first, then mitigate and only compensate as a last resort. It will apply to Nationally Significant Infrastructure Projects (NSIPs) but not marine development.
We expect the mandatory requirement to come into place in Winter 2023. The Government's response to the 2018 consultation on net gain set out that there would be a 2 year implementation period for mandatory BNG once the Environment Bill received Royal Assent and became the Act (which happened on 9 November 2021). The Act includes provision for secondary legislation to set a date for the requirement to come into force.
Demonstrating BNG requires an approach to measuring biodiversity. The Biodiversity Metric is a habitat based approach to determining a proxy biodiversity value developed by Natural England. The Biodiversity Metric is designed to provide ecologists, developers, planners and other interested parties with a means of assessing changes in biodiversity value (losses or gains) brought about by development or changes in land management. Mandatory BNG as will require use of the latest version of the Biodiversity Metric. The current version is Biodiversity Metric 3.
The biodiversity gain plan is referred to in the Environment Act. Planning applications subject to mandatory BNG will be required to submit a biodiversity gain plan for planning authority approval. The Environment Act sets out that the biodiversity gain plan should cover:
- How adverse impacts on habitats have been minimised;
- The pre-development biodiversity value of the onsite habitat;
- The post-development biodiversity value of the onsite habitat;
- The biodiversity value of any offsite habitat provided in relation to the development;
- Any statutory biodiversity credits purchased; plus
- Any further requirements as set out in secondary legislation.
We expect more information on what biodiversity gain plans will entail to be included in the forthcoming Defra consultation on BNG secondary legislation.
The Environment Act makes provision for the Secretary of State to set up a system of statutory biodiversity credits that will be invested in habitat creation. The credits can be bought by developers as a last resort when onsite and local offsite provision of habitat cannot deliver the BNG required. The price of biodiversity credits will be set higher than prices for equivalent biodiversity gain on the market. The intention is that this system will be run by a national body, not at the local level. We expect more information on the national biodiversity credits scheme to be included in the forthcoming Defra consultation on BNG secondary legislation.
The Environment Act includes provision to exempt irreplaceable habitats from the mandatory BNG requirement. Natural England is currently developing new guidance which will set out the definition and a definitive list of irreplaceable habitats in England. This is being done in conjunction with key stakeholders and will also be informed by the forthcoming BNG consultation. It is intended for draft guidance to be produced by Summer 2022, and for this to form part of the forthcoming reform of national planning policy.
The Environment Act only applies to England. CIEEM have just published a briefing note for Scotland see: Biodiversity Net Gain in Scotland: Briefing Note for Local Planning Authorities.
The approach and metric for marine habitats and environments is not as developed as the terrestrial version, but we are expecting a Defra consultation on marine net gain in winter 2021.
Defra will be announcing the resourcing for new burdens soon. PAS will also be publishing a short guide on resourcing BNG to help local authorities consider what expertise they need to bring forward the requirements. PAS has been funded by Defra to provide guidance and training for LPAs to enable them to be 'day 1 ready for mandatory BNG'.
We expect LNRS to be prepared at the county or unitary authority level. The Environment Act contains a specific duty on all public authorities to "have regard" to relevant Local Nature Recovery Strategies (LNRS). The expectation is that they will be used to help inform how and where biodiversity net gain should be delivered, i.e. which habitats are appropriate in what locations. In particular, LNRS can be used to target offsite BNG so that it contributes to the Nature Recovery Network and the LNRS can be used as to determine the ‘strategic significance’ score that is part of the Biodiversity Metric scoring approach. The ‘strategic significance’ score is a landscape scale factor, which gives additional unit value to habitats that are located in preferred locations for biodiversity and other environmental objectives.
The expectation is that all local authorities will be involved in the development of LNRS, so it should reflect local priorities. Locally-specific plan policies could specify how the LNRS will be used to influence BNG delivery in a district, such as targeting of offsite BNG delivery and in Biodiversity Metric ‘strategic significance’ scoring.
Local authorities can use other local strategies to inform offsite targeting prior to implementation of LNRS, such Green Infrastructure strategies and biodiversity opportunity mapping. The availability and type of strategies available locally varies according to what activity and policy has been taken forward by local authorities, non-governmental organisations and other agencies. Where a Local Nature Partnership (LNP) is active, they are likely to have a mapping resource that can be used in advance of LNRS in locally-specific plan policies and to inform offsite targeting and determine ‘strategic significance’.
The Government has committed to funding all new burdens on local authorities arising from the Environment Act.
Defra have indicated to the Greater London Authority (GLA) that they anticipate there will be a single LNRS that covers the GLA area. The GLA is in discussion with Defra about this and awaits further details on how this will work in practice.
Essentially the 10% set out in legislation is mandatory and therefore there is no scope for LPAs to reduce the requirement based on viability or other issues.
Once the mandatory requirement for BNG is in place (expected to be Winter 2023), it will be a legislative requirement, so there is no need to repeat the legal requirements in local policy. However, we would encourage LPAs to develop a locally specific BNG policy for the following reasons:
- If the policy is in place before BNG becomes mandatory, it allows the authority to explore and test application of BNG prior to the legislative requirements. It also prevents the situation where applicants rush to get planning permission without any net gain before the requirement is mandatory.
- A locally-specific policy allows the local authority to set what strategies they require developers to take into account in delivering BNG, e.g. Green Infrastructure strategies, Local Nature Recovery Strategies (LNRS), for example in targeting offsite BNG delivery and to determine the ‘strategic significance’ score that is part of the Biodiversity Metric. This means that BNG can contribute to wider nature recovery plans in addition to local objectives. It can help ensure that the right habitats are provided in the right places.
- Including BNG in the Local Plan can link biodiversity to other strategic objectives and the overall place-making strategy for an authority, enabling a more holistic approach.
We will be sharing good examples of locally-specific policies and the evidence base used to develop policy as part of this PAS project. We will also share ways that you can start implementing BNG if your current Local Plan does not cover net gain. In the meantime, Section 4.2 of the CIEEM/IEMA/CIRIA Biodiversity net gain good practice principles for development covers evidence gathering and provides further detail on types of evidence and links to good practice, whilst Sections 4.6 and 4.7 cover policy development.
If this is set out in policy in the Local Plan and the Local Plan is deemed sound, i.e. viability has been tested and the BNG target checked against other policies in the plan, it will be difficult for a developer to challenge it. See answers under Viability for more information on assessing plan viability for BNG above 10%.
Mandatory net gain, informed by the Biodiversity Metric, will be a minimum requirement for applicable development types. Any local policy will need to achieve this minimum but can work alongside the mandatory requirement. The mandatory requirement will also be in addition to the London Plan policies. It will be necessary for applicants to provide a Biodiversity Metric score and a UGF (Urban Greening Factor) score when applicable.
Defra and Natural England (NE) are looking at a standardised template for the biodiversity gain plan that will also be in a digitised form. They are also looking at standardised reporting requirements over the 30 years for developers - again with a draft template and digital capability. NE are keen on a standardised management plan template too. All this would help with consistency and remove some of the need for specialist input to every application.
Monitoring is the responsibility of the developer and should be set out in the biodiversity gain plan. LPAs will have duties to report on BNG delivery. We expect further information on monitoring requirements to be set out in the forthcoming Defra consultation and secondary legislation.
Schedule 14 of the Environment Act sets out that a general condition will be applied to every planning permission (except those exempt from BNG requirements) that a biodiversity gain plan should be submitted and approved by the planning authority before commencement of development, specifically:
Every planning permission granted for the development of land in England shall be... subject to the [following] condition: ...the development may not be begun unless a biodiversity gain plan has been submitted to the planning authority... and the planning authority has approved the plan...
This means that a complete biodiversity gain plan will be required for all relevant development, but that this can be approved after the grant of planning permission, as long as this happens prior to commencement of development. We expect further information to be provided in the forthcoming consultation on BNG secondary legislation on what information on BNG will be required for planning permission to be granted, plus how the biodiversity gain plan approval process will be managed.
The metric does not take account of protected/priority species. A ‘low-value’ habitat could be inhabited, or valuable in other ways, to an important population.
BNG does not change existing protections, so current legal and policy provisions relating to development impacts on the natural environment, including protected sites and species, and priority species and habitats, all need to be considered in relation to habitat loss. A development cannot avoid this requirement by virtue of delivering a net gain. If there are protected species on-site then these should be approached and managed in the same way as they are currently. BNG and the Biodiversity Metric calculations would then be additional to this.
BNG just ensures that habitat is ‘valued’ in a way that it may not have been and that is at least replaced with a 10% extra. Assuming the habitat lost is not irreplaceable and the project is otherwise permissible, a LPA could not refuse planning permission based solely on the lifespan of a replacement habitat. Ultimately it is the LPA’s decision whether the biodiversity net gain information accompanying an application is acceptable and whether to refuse or not on this basis, using the evidence submitted by the applicant, including on any locally distinctive habitats, to inform that decision. The Biodiversity Metric also takes into account the risk of delay to the creation/ enhancement of habitat; so where a habitat is being lost and new habitat being created to replace it, this is more costly in terms of biodiversity units (and harder to reach 10%) than enhancement. The LPA will need to be satisfied that the Biodiversity Metric has been used appropriately.
The Biodiversity Metric is a habitat-based approach, using habitat as a proxy for biodiversity. Species-based features such as bird and bat boxes are not included within the metric, instead it focuses on the habitats such species need to forage and complete their life cycles. The provision of such species features within developments should still be encouraged and LPAs can promote their usage through design guides and codes.
In relation to BNG, the Environment Act states that habitats should be secured for a minimum of 30 years: ‘habitat enhancement… will… be maintained for at least 30 years after the development is completed’. The 30 year term for biodiversity net gain isn’t meant to be regarded as in perpetuity – it was what was regarded as reasonable to ask for.
In some other cases, for example mitigation provided for sites or species protected under the Habitats Regulations, the requirement may be for management and maintenance of habitats ‘in perpetuity’. It will be up to the planning authority to determine the length of time that it is appropriate and reasonable to require ongoing management and maintenance of habitats as part of the grant of planning permission, taking into account the range of policy and legislative requirements, but the legal requirement for biodiversity gain habitats is 30 years as a minimum.
How does it work in terms of tiered onsite, offsite then buying statutory credits?
The biodiversity net gain approach embeds a fundamental principle for spatial hierarchy of habitat delivery, where there is a preference for onsite or local enhancements. The Environment Act requires that ‘information about the steps taken or to be taken to minimise the adverse effect of the development on the biodiversity of the onsite habitat and any other habitat’ is included in the biodiversity gain plan. More detail on the spatial hierarchy will be set out in the forthcoming BNG consultation and secondary legislation guidance.
In addition, the Biodiversity Metric 3 incentivises habitat delivery on or close to the development site through a ‘Spatial Risk Multiplier’, which reduces the biodiversity value of habitats delivered further away from the development. It is recommended that the onsite first, then local offsite hierarchy is also included in local plan policy.
Where a development cannot achieve BNG either wholly or partly onsite, then the developer can secure the unit shortfall by securing a bespoke site for net gain, or from appropriate sites on the local net gain habitat market from other landowners. These sites will need to meet the criteria of the biodiversity gain sites register (when available - see Delivery of BNG). If a shortfall in units required to achieve BNG remains, having explored the onsite and local offsite options, a developer can purchase statutory biodiversity credits from government as a last resort. The detail relating to this process will be set out in the forthcoming government consultation on BNG secondary legislation and regulations and in future guidance for developers and LPAs.
It is expected that a limited number of exemptions will be set out as a proposal in the forthcoming government BNG consultation. It is likely that householder applications will be one of these.
Permitted development will not be required to deliver BNG under the Environment Act. However, the metric can still be used to quantify the losses and gains of habitat associated with the development activity and this is already being done by a number of developers for permitted development.
There is expected to be a less onerous process for applying BNG to smaller developments, including use of the Small Sites Biodiversity Metric. We’ll find out more around the likely direction on this when the consultation on the statutory instruments comes out.
If an outline consent pre-dates the introduction of the Bill, can we still ask for BNG when reserved matters applications come in?
We expect the forthcoming Defra consultation on the statutory instruments to provide more detail on applying BNG to phased development. Reserved matters will not be required to fulfil mandatory BNG if the outline was approved prior to mandatory BNG; it will only apply to new applications submitted once BNG is mandated (from Winter 2023).
Within Schedule 14 of the Environment Act, which sets out the biodiversity gain condition for development, measures are included that allow planning authorities to recognise any habitat degradation since 30th January 2020 and to take the earlier habitat state as the baseline for the purposes of biodiversity net gain. In order to ascertain the habitats present and their condition on 30th January 2020, aerial imagery or data sets from that time could be used. 30th January 2020 is the relevant date as it was the day the Bill entered Parliament.
For example, if a grassland site were strimmed or ploughed in July, the planning authority would be able to seek compensation for the habitat as it was in June, rather than the degraded habitat present in July. This system will take effect when the biodiversity gain requirement in the Environment Act is commenced.
Natural England and Defra intend to produce guidance on how this will work and which data sources may be of assistance in demonstrating the former value of any degraded or destroyed habitats.
If a site has a baseline biodiversity unit value of zero, then it would be advisable to calculate any biodiversity unit gains as a numerical unit value as opposed to a percentage. It will be at the discretion of the LPA to agree an appropriate number of biodiversity units to be delivered for the site in question on a site-by-site basis. Where a local authority knows that a number of development sites are likely to have very little to no biodiversity value or of a major allocation that fits this bill, e.g. urban, recently-previously developed land, they could consider setting expected unit gain values for these sites in Local Plan policy.
It cannot be assumed that just because a site is small it has no baseline value. The baseline value reflects the ecological value of the pre-development site, not its size.
Yes. Private gardens can make positive contributions to biodiversity, but appropriate planting and ongoing management can not be secured in the long-term. The Biodiversity Metric recognises this in its scoring of the value of gardens. See the Biodiversity Metric section for more information on this aspect.
Yes. See https://www.london.gov.uk/what-we-do/urban-greening-biodiversity-net-gain-design-guide for further information on how this can work. Both scores will need to be submitted where applicable. One cannot be used as a proxy for the other policy.
Delivery of BNG
Natural England are currently developing the digital Biodiversity Gain Sites Register. Natural England's Biodiversity Net Gain digital services blog provides updates on this work and the digital credit sales service. Further information on how the register will operate will be available in the forthcoming Defra consultation on secondary legislation.
The ambition is to include onsite as well as offsite BNG delivery on the national biodiversity gain sites register, but there is no mandate for this under the Environment Act. Any offsite land used for the purposes of achieving BNG will need to be registered. Discussions are continuing as to how to include relevant information about onsite delivery on that same national register.
It is expected that land used for off-site BNG delivery will be secured for the length of the net gain agreement, either via Section 106 agreements, or a conservation covenant. A conservation covenant is a private voluntary legal agreement, made in writing, between a Responsible Body and a landowner which establishes that land will be used for a conservation purpose. See Conservation Covenants below for more information.
We do not expect offsetting on SINCs to be excluded, though it is unlikely that it will be allowed on nationally designated sites like Sites of Special Scientific Interest (SSSIs).
This is not correct. Defra’s view is that LAs using their own land for offsite BNG does not interfere with their obligations under the NERC (Natural Environment and Rural Communities Act) biodiversity duty, subject to the usual caveat that what they do is compliant with their policies and other legislative requirements. The cleared line below provides the full picture.
“The enhanced duty in the Environment Act requires each public authority to consider the actions it can take to conserve and enhance biodiversity, consistent with the proper exercise of its functions, and then take those actions. Our purpose in strengthening the duty was to encourage wider and more consistent action from public authorities and clearly actions taken to enhance biodiversity through net gain, assuming this is compliant with net gain policy or legislative requirements, are exactly the kind of actions a local planning authority may consider taking. In fact, local planning authorities will be required to report on the actions they have taken to deliver net gain and the results of that action as part of the reporting requirement in the strengthened biodiversity duty.”
LPAs that have their own land and who wish to enter into the market for providing offsite biodiversity units to developers will also need to familiarise themselves with the Biodiversity Metric as it will be the basis on which they calculate the baseline value of such sites and the potential for any biodiversity unit uplift that they could sell to developers.
The policy and processes for implementing mandatory biodiversity net gain are still under development. Natural England's proposed approach is that:
- Local authorities will be able to use their own land to offer offsite biodiversity units to developers or act as a broker for third party units.
- When the mandatory BNG requirement comes into effect, this will need to be subject to the same confirmed rules and requirements for BNG as for other biodiversity unit providers, including registration on the Biodiversity Gain Sites Register and allocation to development.
- Local authorities will not be able to direct developers to purchase biodiversity units from them in preference to other ecologically equivalent suppliers, and will be expected to manage any associated conflicts of interest.
- Local authorities will not be able to operate a tariff system (ie a general fee) for delivery of offsite gains which are not registered and clearly allocated to developments under mandatory BNG.
- Local authorities will need to calculate appropriate biodiversity unit prices for offsite gains delivered on their land, or sold by them on behalf of a third party. Any enhancements for which payment is taken will need to be registered and allocated to developments. The prices will need to be sufficient to cover the costs of creating or enhancing the habitat and maintaining it for a minimum of 30 years.
The forthcoming 2021 BNG consultation covers the subject of offsite biodiversity gains and the market for biodiversity units and this is a useful opportunity for local authorities to engage and offer views on this aspect. Following the consultation, the government response will set out further detail.
No. When mandatory BNG comes into force (estimated late 2023), any approach to the delivery of BNG will need to meet the minimum requirements as set out in the legislation (primary and secondary). This means that LPAs will not be able to levy a local BNG tariff to then pool money for investment in nature elsewhere at some future point. Offsite lands used for BNG must be registered on the biodiversity gain register and their usage linked back to a specific planning permission, measured using a standardised biodiversity metric and legally secured for at least 30 years.
There is, however, scope to encourage the development of a local habitat bank (on LPA or other third party land) from which multiple developments could secure BNG through a single site through the sale of smaller parcels of biodiversity unit uplift (see above re schemes for local offsite delivery).
Yes. This is where having a Local Plan policy that links BNG to delivery of local strategic priorities is really helpful. Natural England's Biodiversity Net Gain digital services blog provides updates on the Statutory Biodiversity Credit Sales Service they are developing.
The national credit scheme will not allow for funds to be earmarked for a particular region, but local schemes could be set up to receive the national credits, which would then contribute to the LNRS.
No, this is not currently under consideration by Natural England or Defra.
Yes, it will be the developer’s responsibility to find a suitable location for off-site BNG delivery. This land will need to be legally secured and managed for the duration of the BNG period. Further information on the planning application process is expected to be set out in the forthcoming BNG consultation. PAS is currently exploring how offsite BNG will be secured, monitored and enforced and the role of LPAs and the planning decision process, including conditions and S106, with Defra and Natural England to provide further information and guidance on this for LPAs.
The DEFRA evidence base and impact assessment considers that the 10% requirement is unlikely to significantly affect viability issues for development. DLUHC and Defra are not aware of any evidence to the contrary. Essentially the 10% set out in legislation is mandatory and therefore there is no scope for LPAs to allow a reduction on viability grounds. If developers submit above 10% this is voluntary and anything above 10% would be subject to negotiation (and possibly would include viability justification) as part of planning application discussions with the LPA. If LPAs set the requirement higher than 10% in local policy, they would have to justify the level set in policy as part of their Local Plan process.
The following text extracted from the impact assessment highlights likely differences between impacts on developers:
We expect there will be a wide distribution of impacts, given that the costs and benefits will be highly dependent on the location and design of individual developments. In our analysis we assume that developers either: (1) already deliver net gain (entirely as we have proposed) or (2) do not deliver net gain (or even ‘no net loss’) and do little to mitigate or compensate habitat damage caused by their developments.
Given this, those currently doing the most to benefit the environment should find that this provides certainty. Since these developers already incur all or most of the costs of net gain, the most significant change for them (within our analysis) will be benefits associated with greater consistency in net gain within the planning process and greater consistency in expectations. The developers who currently cause high levels of environmental damage and do little to compensate for this will face the highest additional costs. This means, in practice, it is likely that the costs will fall unevenly across developers.
Biodiversity net gain should, therefore, steer development towards the least environmentally damaging areas and design practices. A significant proportion of costs imposed on developers are likely, in the medium to long term, to be ‘passed through’ to developable land prices, thereby affecting landowners.
In terms of costs to developers, the following conclusion is reached in the impact assessment:
Overall, the analysis indicates that net gain delivery costs are likely to be low as a proportion of key variables such as build costs and land prices. In addition, it is unlikely to lead to a significant increase on existing average developers contributions. While the analysis identifies regions where potential residential and non-residential viability issues may arise (e.g. Midlands, the North), this analysis is not a prediction of where site specific viability issues may arise in reality.
For residential development costs to developers:
Our analysis demonstrates that, while there is a range of expected cost from delivery of net gain, relative to build costs they are relatively small for brownfield (between 0.1% and 0.8%) and greenfield (between 0.1% and 3.9%) developments. However, regions in the Midlands and the North have the highest potential costs as a percentage of build costs, but also have lower developable land prices which indicates potential for site specific housing viability issues.
And for non-residential:
The analysis shows that the majority of the costs across scenarios are expected to be less than 5% of land value, and that regions with higher costs (i.e. implying a potential site specific viability issue) tend to be in the North.
Local Plans, viability and percentage level of net gain
Warwickshire County Council undertook a feasibility assessment of introducing biodiversity accounting in Buckinghamshire and Milton Keynes in 2019. The study covered viability, but the conclusion was that viability impacts can only be assessed on a case-by-case basis and then factored in at the concept/design stage for an individual proposal. A developer can then consider BNG in combination with other contributions and factor it in to land purchase.
Salford Borough Council assessed the impacts of BNG on viability for their Local Plan and a background paper sets out the conclusions of this, alongside other issues raised with their Local Plan policy for 10% BNG. The conclusion was that 'net gain delivery costs are low as a proportion of overall costs'.
In terms of the percentage of net gain, a sensitivity analysis was carried out as part of the Defra impact assessment to look at impacts of 5% BNG, 10% BNG and 20% BNG, the conclusion being:
While this suggests that varying the level of net gain between 5% and 20% has very limited impact on the outcome, there is a trade-off between cost implications for developers and the likelihood of net gain being delivered at a national level (e.g. less costly/likely at 5% net gain compared to 10%, and vice versa for 20%). Our chosen policy approach, which sets out that 10% is the right level to demonstrate net gain, considers this trade-off among other issues.
The Kent Nature Partnership net gain group is gathering information and evidence to understand the implications of a 20% BNG approach for Kent, and have recently commissioned a county-wide viability assessment.
Swale Borough Council used the Defra impact assessment ‘central estimate cost per dwelling for the South East’ for their draft Local Plan Viability Study. This looked at the difference between provision of 10% and 20% BNG and put costs at £948 per dwelling for 10% BNG with an additional £180 per dwelling for 20% BNG. Swale BC recently consulted on their pre-submission Local Plan Review which included a policy for 20% net gain.
We will share further examples of Local Plan evidence and viability assessments for BNG as part of this project.
BNG alongside other mitigation and benefits - 'additionality', 'stacking' and 'bundling', natural capital
Natural England and Defra are currently looking at 'additionality' or 'stacking' to understand how you can work out whether enough habitat has been provided for different mitigation/compensation aspects, like district level licensing for great crested newts (GCN), plus SANG (Suitable Alternative Natural Greenspace) and other sites provided as Natura 2000 site mitigation, alongside BNG. We expect a position to be set out in the forthcoming Defra consultation on BNG secondary legislation, so the following may be subject to future change depending on the responses to that.
The current position is that it is possible to use sites delivering nutrient neutrality/SANG/GCN habitat to also deliver biodiversity net gain, on the basis that:
- Delivery of the non-BNG outcomes via habitat creation/enhancement could contribute up to a point equivalent to no net loss of BNG (as calculated by the Biodiversity Metric) but not beyond – assuming they meet any other BNG requirements e.g. agreement type/duration etc.
- Additional habitat features created or enhanced on that same land beyond those delivered for the purpose of non-BNG outcomes could take you into positive BNG territory (again if measured and demonstrated using the metric) – assuming they meet any other BNG requirements e.g. agreement type/duration etc
- Good practice would be to illustrate BNG contributions derived from the above using a separate accounting line for transparency reasons. It is intended for this to be required in the biodiversity gain plan. Further details on this will be provided in the forthcoming BNG consultation.
So, habitats. The contribution to BNG through measures required as part of DLL is capped at a point equivalent to no net loss irrespective of the actual delivery outcome, as measured by the Biodiversity Metric 3.
Biodiversity Metric 3 has been designed to work alongside the Environmental Benefits from Nature Tool (EBNT). EBNT provides developers, planners and other interested parties with a means of enabling wider benefits for people and nature from biodiversity net gain. The tool uses a habitat-based approach to provide a common and consistent means of considering the direct impact of land use change across 18 ecosystem service services.
For example, a user can run habitat data through the Biodiversity Metric 3 in order to quantify any losses or gains in biodiversity unit value. They could then use that same data in the EBNT to calculate the wider ecosystem service benefits associated with the habitats (such as, carbon sequestration, recreational value and air quality benefits).
You can access the recording and slides from the Natural England training session we hosted in October 2021 for more information on the Biodiversity Metric. The following questions and answers are taken from that session.
Currently, and for the immediate future, the Biodiversity Metric is a Microsoft Excel-based tool and therefore requires Excel to operate. It is expected that the full metric spreadsheet should be submitted by developers to LPAs for consideration, with a planning application. Natural England will be exploring options to digitise the metric in the future.
The metric calculations/spreadsheets are technical and beyond the capability or time resources of existing planning officers to scrutinise, who will do this?
The value of a site's habitat can be a subjective view. Does the metric recognise if a site has been under or overvalued?
Responsibility for completing the Biodiversity Metric assessment and calculations
For habitat condition assessments in association with development, it is the developer's responsibility to provide the Biodiversity Metric calculations to include in the Biodiversity Gain Plan. The Biodiversity Gain Plan will require a statement of competency for a named person who has carried out the assessment and metric calculation. So, developers will need to employ a ‘competent person’ to conduct the habitat survey and assessments and complete the metric tool. The developer will then share the full spreadsheet with the LPA, alongside other required documents for the application. LPAs will not be responsible for completing the metric.
‘Competency’ to use the metric
A 'competent person' is defined as: being able to confidently identify the positive and negative indicator species for the range of habitats likely to occur in a given geographic location at the time of year the survey is undertaken. For a full metric application, the competent person should be an ecologist. However, in circumstances where the development fits with the criteria to use the Small Sites Metric it is not necessary for the metric to be completed by an ecologist but by someone who is competent to use that metric. LPAs should verify that the person who has completed the metric fulfils this criteria and is suitably competent to be able to do so, as described in the metric User Guide. Natural England is looking at accreditation for BNG and we will add more information on this as it becomes available.
LPA responsibilities and how to meet these
It is expected that LPAs will review and check the metric spreadsheets. In order to verify the habitat surveys, LPAs could refer back to aerial photos, Local Environmental Record Centres or other data sources and seek the advice of local ecologists (where available).
Natural England and Defra recognise that resources within LPAs are stretched and we hope that there will be more information on new burdens funding for LPAs soon. PAS is producing a short guide on resourcing BNG for local authorities to help identify what skills and expertise are needed to meet the new requirements.
The Natural England session we hosted on the metric in October was intended to assist planners in getting to grips with the metric and how to interpret its results. We expect to run further sessions in the future. Natural England would welcome feedback on how they can further assist planners with interpreting and understanding the metric’s outputs. You can email them at: Biodiversitymetric3@naturalengland.org.uk
Assessing the values ascribed by the metric
The values ascribed to individual habitat types within the metric are based on the ‘distinctiveness’, condition and spatial location of those habitat features. The metric cannot recognise whether a habitat type has been correctly identified or the condition and strategic significance assessed accurately. This is reliant upon the competence and integrity of the individuals entering the data. Detailed guidance has been provided to assist in assigning the correct habitat type and condition to a habitat.
The habitat distinctiveness scores are set within the metric and are based on ecological evidence that will be kept under regular review. Fixing the distinctiveness scores in the metric ensures greater consistency and reduces the scope for subjectivity and dispute.
Habitat condition is established by undertaking a habitat survey and ascribing a condition score to a habitat, based on the judgement of a suitably competent person (usually an ecologist). Condition sheets have been published with the metric to allow for greater consistency of assessment. In the case of rivers and riverine habitats, the person undertaking the condition assessment must be accredited in the use of the condition assessment methodology. For a small number of habitats, the condition is fixed and prepopulated in the metric and a condition assessment is not required.
Spatial location can also affect a habitat's value, in particular whether or not the habitat is of, or in a location that is of, ‘strategic significance’. This is determined by published local plans and strategies and can be specified by the LPA. It is expected that Local Nature Recovery Strategies (LNRS) will standardise strategic significance by mapping and describing those habitats of particular local importance (for creation and/or enhancement). See also above under Strategic for further information on ‘strategic significance’ and LNRS, as well as under Local Plans for advice on applying this in policy.
Yes, we recommend that Local Plan policy should specify use of the metric and the percentage of BNG required. Under mandatory BNG, there will be a requirement to use the latest version of the Biodiversity Metric. Prior to mandatory BNG, there is no requirement to use the Biodiversity Metric and projects can continue to use an alternative metric (unless the LPA has specified which metric to use). If the LPA does not specify the use of another metric, then we would recommend using the most recent version of the Biodiversity Metric.
It would be helpful if potential site allocations could be assessed for their biodiversity value as this will help ensure application of the mitigation hierarchy by flagging up any high value (for biodiversity) sites before these get allocated. It will also help to give an indication of how easy (or otherwise) developers will subsequently find it to deliver BNG solely within the allocated site baseline, or whether they will likely need to go off-site to meet the local BNG % requirement i.e. if the allocated site has a low biodiversity unit baseline score it is likely that BNG could be delivered entirely within the site. If it has a high score, then it will be very difficult and the developers will likely need to look for off-site opportunities. LPAs could then think about how to encourage strategic habitat banks to provide the supply of offset units developers will need – the baseline assessment will have provided sufficient intel to be able, with some confidence, to anticipate what types of habitats and unit types will be required.
In addition to such uses the metric can also be used to track changes in the biodiversity value of land overtime and, as such, can be used for performance monitoring and reporting purposes.
We are in discussion with Natural England to better understand how the metric might be applied during the Local Plan process and will provide more guidance on this in due course.
It is not expected that LPAs will need to produce their own metric guidance. There is currently a simple user guide for the metric embedded within the tool (click the “Instructions” tab on the opening page). This is also available on the Biodiversity Metric web page, along with 2 substantial guidance documents: the ‘User Guide’ and ‘Technical Supplement’. Natural England is also producing a suite of case studies to assist in the interpretation of this guidance and intends to publish these in 2022.
It is strongly recommended that a plan is supplied, and that information provided in the plan enables habitat parcels shown to be clearly identified in the associated metric calculation. There is a facility to attach a plan to the metric on the start page. It is expected that there will be more information relating to Biodiversity Gain Plan requirements for mandatory net gain in the upcoming Defra consultation. LPAs should encourage developers to submit as much information as possible within the “assessor comments” section of the metric to justify their decision-making regarding each habitat parcel.
The metric is intended to be used early in the design process, in order to quantify and evaluate the impacts of different design options when there is more scope to influence design changes and achieve better ecological outcomes. The metric can be applied on an indicative basis and by adopting a precautionary approach when ascribing habitat condition and distinctiveness values.
The metric accounts for a variety of risk factors within it which can influence whether or not a particular habitat will be successfully established. These risk factors are standardised, evidence based and will be kept under review.
The minimum percentage requirement (e.g. 10%) should be applied to all area and/or linear unit types found within the development site red line boundary and should be applied irrespective of whether the habitat in question was directly or indirectly impacted by the development. Area, hedgerow and river habitat units are all considered separately and are not interchangeable; you cannot address a loss of one type by providing another. The metric trading rules should always be followed, for example there should be no trading down in habitat distinctiveness. All high distinctiveness habitats require re-creation on a like-for-like basis should they be lost, whereas there is more flexibility for lower distinctiveness habitat types in terms of what habitat can be delivered if they are lost. (See Table 6-1 in the User Guide)
Urban tree canopy cover should be considered separately to the habitat that it stands on. For example, if there was a one-hectare area of grassland with five trees, then you would record both the one-hectare of grassland and the five trees separately.
Less biodiversity units will be generated where higher distinctiveness woodland is being proposed, compared to a lower distinctiveness woodland type (e.g. ‘other woodland; broadleaved’). This is due to the difficulty of successfully creating a new woodland from scratch and the associated inbuilt risk multipliers within the metric, such as the time taken for high distinctiveness woodland to reach good condition. Providing the trading rules are adhered to, aiming for a lower condition, or a lower distinctiveness woodland, is more realistic and therefore will generate more biodiversity units within the Biodiversity Metric. As a rule of thumb, when creating new woodland from scratch, unless required to do otherwise to compensate for the loss of an existing area of high distinctiveness woodland, use the ‘other woodland; broadleaved’ category and ascribe a target condition of no greater than ‘moderate’. This is explained further in the metric guidance.
All habitats inputted into the Biodiversity Metric need to be measured in hectares, unless they are part of the two linear tabs for either rivers and streams, or hedgerows and lines of trees, which need to be measured in kilometres. The exception to the above is sites that meet the requirements that allow them to use the small sites metric, in which case area and length is measured in square metres and metres respectively.
Gardens are included in Biodiversity Metric 3 for use in biodiversity net gain calculations. Their pre-defined distinctiveness is set at 'low' or 'very low' (depending on whether the garden is vegetated or un-vegetated), and the condition for gardens is set at no greater than 'poor'. The metric also assumes that a significant amount of any gardens established will be ‘lost’ over time i.e. due to decking, etc. Therefore, although gardens can be included within calculations, their low biodiversity unit value accounts for the assumption that a large proportion will potentially be lost, reflecting the fact that these are largely private spaces and so they cannot be legally secured in the same way. That said, gardens can and do provide locally important spaces for biodiversity and their retention and incorporation into design is to be encouraged, hence their inclusion in the metric.
Guidance is provided on how suburban housing should be accounted for in the metric using a precautionary assumption that a housing development would be in the proportion 70:30 developed land/sealed surface to vegetated garden. This can be negotiated up or down by the consenting body or if sufficient justification can be provided by the applicant to deviate from this. (See 6.20 and Box 6-2 in Metric 3.0 User Guide.)
Yes, Green Infrastructure (GI) features can contribute to a project’s BNG calculations and there are a range of GI features included within the tool, including green roofs, green walls and Sustainable Drainage Systems (SuDS). All such features, whether found on the baseline or included in the post-intervention proposal, should be included in the metric calculations.
The metric as it currently stands is not a 'final product' and it will be updated periodically to incorporate feedback. Natural England have been working closely with the minerals industry to ensure that the metric is applicable and suitable for mineral sites and projects. Natural England will also be publishing specific case studies, developed in conjunction with the sector, to illustrate how best to approach metric calculations on minerals sites and how this will work in practice. Further information on the application of the BNG policy requirement to minerals sites. e.g. s73 and ROMPs, is expected in the forthcoming Defra consultation.
Monitoring is the responsibility of the developer and should be set out in the biodiversity gain plan, secured through the grant of planning permission. LPAs will have duties to report on BNG delivery. We expect further information on monitoring requirements to be set out in the forthcoming Defra consultation and secondary legislation. PAS is currently exploring how BNG will be secured, monitored and enforced and the role of LPAs and the planning decision process, including conditions and S106, with Defra and Natural England to provide further information and guidance on this for LPAs.
The Small Sites Metric (SSM) is a simplified version of the Biodiversity Metric which has been specifically designed for use on small development sites where the project chooses to do so, providing there is no priority habitat present on-site. The SSM is not suitable to calculate losses and gains off-site.
It is proposed that a development may use the SSM where it fulfils both of the following criteria (which were the subject of a recent Natural England consultation – now closed):
1. Development sites where:
- For residential developments, the number of dwellings to be provided is between one and nine inclusive on a site having an area of less than one hectare.
- The number of dwellings to be provided is not known, the site area is less than 0.5 hectares.
- For all other development types where the site area is less than 0.5hectares or less than 5,000sqm.
2. There is no priority habitat present within the development area (excluding hedgerows and arable margins).
Natural England will not be a statutory consultee on BNG, and so will not be commenting or responding to Biodiversity Metric calculations on a regular basis unless it is a development that triggered Natural England’s involvement as a statutory consultee on other grounds. Dependent on resource, there may be specific cases such as high-risk or high-opportunity case work, where NE may examine metric calculations, likely via their Discretionary Advice Service.
It is an agreement between a landowner and a designated “responsible body” such as a conservation charity, public body or for-profit body which conserves (protects, restores or enhances) the natural or heritage features of the land. It is a private, voluntary agreement made for the public good, which can continue to be effective even after the land changes hands.
Defra intends to commence the conservation covenant provisions (Part 7 and Schedules 18-20) of the Environment Act 2021 in the autumn of 2022. This will allow time for important secondary legislation to be put in place so that conservation covenants can function correctly.
Defra will publish full guidance on gov.uk before the provisions come into force which will include the criteria and process for becoming a responsible body.
Once the conservation covenants provisions have been commenced, and when the criteria against which applicants will be assessed have been published, organisations will be able to apply to be responsible bodies. This includes local planning authorities that wish to take on the role. Once organisations have been designated, they will then be able to start agreeing covenants with landowners.
Conservation covenants are a possible tool to secure biodiversity gains – and are specifically referred to in the net gain clauses in the Bill. We expect this will make them a valuable tool for local authorities and developers to ensure that compensatory habitats are maintained in the long term, even if the relevant land is sold.
The use of conservation covenants under mandatory net gain will be subject to certain conditions such as land under agreement being maintained for at least 30 years to help ensure delivery of net gain outcomes. Defra will consider what is required in regulations and accompanying guidance to maximise the benefit of conservation covenants to deliver biodiversity net gain objectives.
In the meantime if you have questions about conservation covenants please contact Defra via this mailbox firstname.lastname@example.org.
Environment Act beyond BNG
The Environment Act introduces a ‘Duty to Consult’ for local highway authorities which will give the public the opportunity to understand why a street tree is being felled and express any concerns regarding this. The Act also introduces Forestry Enforcement Measures which strengthens the Forestry Commission’s power to clamp down on illegal tree felling across England, ensuring the Commission has the powers to continue to protect and maintain our forests. The relevant section of the Act is: House of Commons: Environment Bill (parliament.uk)
The Office for Environmental Protection is a new independent environmental watchdog set up under the Environment Act. Further information is available on their website: Office for Environmental Protection | oep (theoep.org.uk).
At present, we do not have enough information on the planning reforms to know how this will work, but we are told that Defra and DLUHC are working together closely to make sure the Environment Act and Planning Bill work together effectively.