The principal of Biodiversity Net Gain (BNG) requires developments to provide or enhance habitats for wildlife such that the environment is left in a measurably better state than it was prior to the development taking place. Where a development has an impact on biodiversity, BNG requires developers to provide an increase in appropriate natural habitat over and above that being affected.

As a result of the Environment Act 2021, most planning applications will be required to provide a minimum of 10 per cent Biodiversity Net Gain, contributing towards reducing the current loss of biodiversity through development and enhancing the restoration of ecological networks.

BNG will be a mandatory requirement, currently anticipated to be sequentially introduced as follows:

• Major development: January 2024
• Small scale development: April 2024
• Nationally Significant Infrastructure Projects: November 2025.

Developers must assess the pre- and post- development habitat value of their proposals to establish that a 10% gain can be achieved prior to submitting a planning application. The delivery of BNG will be monitored and enforced over a 30 year period.

The council intends to produce a Supplementary Planning Document to provide guidance and confirm local policy requirements. In the meantime, additional information is outlined under specific questions below and any queries can be sent to nature.conservation@eastriding.gov.uk.

In the interim period, prior to the mandatory requirements, we will be requesting that all major applications demonstrate that they have sought to deliver no net loss in biodiversity. This can be achieved by use of Natural England’s current Biodiversity Metric (v4.0). The completed metric should be submitted along with a Biodiversity Statement explaining how no net loss is to be achieved, including pre and post-development habitat plans.

The interim requirement is to accord with sections 174 d) and 179 b) of the NPPF (2023) which refer to the provision of net gains for biodiversity; and section E of Policy ENV4 of the East Riding Local Plan Strategy Document (Adopted April 2016) which states that ‘proposals should seek to achieve a net gain in biodiversity where possible’.

Most planning applications will be required to demonstrate a 10% Biodiversity Net Gain under the Environment Act 2021.

This is currently expected to apply to major development submitted after January 2024 and to minor development from April 2024; with Nationally Significant Infrastructure Projects from November 2025.

Minor development means:

• For residential: where the number of dwellings to be provided is between one and nine inclusive on a site having an area of less than one hectare, OR where the number of dwellings to be provided is not known, on a site area of less than 0.5 hectares.
• For non-residential: where the floor space to be created is less than 1,000 m2 OR where the site area is less than one hectare.

Exemptions will be confirmed by secondary legislation, but it is understood that this is likely to include the following:

• Permitted development
• Development impacting habitat of an area below a ‘de minimis’ threshold of 25 m2, or 5m for linear habitats such as hedgerows
• Householder applications
• Small scale self-build and custom housebuilding
• Biodiversity gain sites (where habitats are being enhanced for wildlife).

In the interim period, prior to the mandatory requirements, we will be requesting that all major applications demonstrate that they have sought to deliver no net loss in biodiversity. This can be achieved by use of Natural England’s current Biodiversity Metric (v4.0). The completed metric should be submitted along with a Biodiversity Statement explaining how no net loss is to be achieved, including pre and post-development habitat plans.

The interim requirement is to accord with sections 174 d) and 179 b) of the NPPF (2023) which refer to the provision of net gains for biodiversity; and section E of Policy ENV4 of the East Riding Local Plan Strategy Document (Adopted April 2016) which states that ‘proposals should seek to achieve a net gain in biodiversity where possible’.

The Government’s Statutory Biodiversity Metric must be used to measure the biodiversity value pre- and post- development, once it has been published. Prior to the publication of the statutory metric, there will be a transitional period where Natural England’s existing Biodiversity Metric v4.0 will be accepted.

The Biodiversity Metric is a free biodiversity accounting tool published in Microsoft Excel format, which is used to calculate the change in biodiversity value caused by the change in land use and/or management included within a specific proposal. There are three types of biodiversity units, which are calculated in three separate ‘modules’ of the metric (area units, hedgerow units and watercourse units). A 10 per cent gain must be achieved for each unit type present on site pre-development.

Biodiversity Metric v4.0 (external website)

The Biodiversity Metric provides a measure of overall Biodiversity Value based on habitat type, area, distinctiveness, and condition, with an allowance to be made for strategic significance. The metric is a tool that allows the biodiversity value of a site to be measured pre- and post-development. The change in Biodiversity Units indicates either a net loss or net gain in biodiversity.

• Habitat type: A habitat classification derived from multiple sources, principally the UK Habitat Classification System (external website).
• Area: The size of the habitat parcel to be retained, enhanced, created, or lost. Size is measured in hectares for area features, or in kilometres for linear features.
• Distinctiveness: A value for each habitat type which is pre-set within the metric. It is based on species richness, rarity, the extent to which the habitat is protected by designations and the degree to which a habitat supports species rarely found in other habitats.
• Condition: Condition is used as a measure of the quality of a habitat, since this can vary between areas of the same habitat type. Condition assessment can be undertaken by a suitably qualified ecologist in accordance with the methodology included within the Metric Guidance.
• Strategic significance: Describes the local significance of the habitat based on its location and the habitat type.

Please note: the strategic significance of a habitat type will ultimately be defined on a local basis through Local Nature Recovery Strategies (LNRSs). The East Riding LNRS is currently being developed:

East Riding Local Nature Recovery Strategies (LNRSs)

Interim guidance is to be produced and will be included on this website once complete. In the meantime, the following documents should be consulted in accordance with section 5.4 of the Biodiversity Metric User Guide to assist in allocating strategic significance on a site-specific basis, with justification provided by the assessor completing the Metric.

• National Habitat Network (external website)
• East Riding Local Plan (adopted April 2016) – habitat network/green infrastructure plans
• The East Riding of Yorkshire Landscape Character Assessment
• The Humberhead Levels Nature Improvement Plan
• Lower Derwent SPD.

The Biodiversity Metric has been designed to follow the mitigation hierarchy and support the retention of valuable habitats. It disincentivises the loss of better-quality habitats by awarding them a higher unit value making them significantly more expensive to provide net gain for, compared to habitats of lower biodiversity value. The replacement of specific habitats of particularly high value, termed ‘irreplaceable’ habitats, is not to be incorporated within the metric and may require that parts of the site are safeguarded from development. More information and a list of ‘irreplaceable’ habitats is awaited from Natural England.

Consequently, it is important to establish the baseline value of a site at as early a stage as possible when considering its development potential, as the loss of higher value habitats or presence of ‘irreplaceable’ habitats may make a scheme unviable.

This work should be undertaken by a suitably qualified Ecologist (relevant institute websites provide directories to identify suitably qualified ecologists including The Chartered Institute of Ecology and Environmental Management (external website) and The Institute of Environmental Management and Assessment (external website).

Schedule 14 of the Environment Act includes measures that allow the Local Planning Authority to take account of any habitat degradation or destruction undertaken on a site since January 2020. If a site has been cleared or degraded the baseline for the purposes of Biodiversity Net Gain is taken to be that before the clearance or degradation has taken place.

Aerial or other photographs may be used to evidence the habitat types formerly present on site and, in the absence of any other information, the habitat should be allocated a condition score of ‘good’ on a precautionary basis.

This is to deter intentional degradation/destruction prior to planning applications being submitted, by ensuring that there is no advantage to be gained by the deliberate clearance of land to achieve a lower baseline value for BNG with potential penalties where a higher value habitat or condition has to be assumed in the absence of evidence to the contrary.

The Environment Act requires proposals to provide a minimum 10% gain compared with the pre-development biodiversity value of the site. Achieving 10% net gain means fully compensating for losses of habitat on a development site, but then going further so that overall, there is a gain in biodiversity value of at least 10% as a result of the development process. The gain can be provided on site, off site or through a combination of the two. As a last resort Statutory Biodiversity Credits, a national credits purchase system will be available for purchase from Natural England.

The 10% net gain in biodiversity value should, where possible, be provided on the development site itself. However, where space and circumstances do not allow this, provision of biodiversity gain on land off-site, or a combination of on- and off-site provision, would be considered. Off-site habitat creation can be undertaken on land owned by the developer, or on third party land where the landowner is willing to undertake such work and maintain it for at least 30 years in return for a payment from the developer.

As an Authority East Riding of Yorkshire Council will encourage the provision of habitat on-site as a priority with off-site habitat creation/enhancement as a secondary option once appropriate on-site measures have been provided. The Statutory Biodiversity Credit scheme is seen as a last resort option, use of which must be justified by the applicant, and has been priced accordingly to deter use and encourage the development of a local off-site BNG markets.

The ultimate BNG will be secured by a pre-commencement condition. However, at the point of application, sufficient information will need to be submitted to allow the Authority to be satisfied that an appropriate level of net gain can be provided by the development either utilising on-site land, a combination of on-site and off-site (either developer owned or third party land) or as a last resort, where on-site and off-site provision is unable to provide a 10% net gain, the purchase of Statutory Biodiversity Credits, is being proposed to deliver the outstanding units.

Further guidance from Government and secondary legislation are anticipated shortly to confirm, however, validation requirements are anticipated to be as follow:

• the metric calculations (Excel spreadsheet format)
• a Biodiversity Net Gain Statement outlining how the development will achieve a minimum 10% net gain, including details of the existing baseline on site habitats, and the anticipated post development habitats retained, created or enhanced to achieve net gain.

Please note: that it is accepted that post development habitat plans may be indicative at this stage, particularly with respect to outline applications. However, sufficient detail must be provided to enable the Authority to have confidence that the level of BNG proposed is realistically achievable.

This work should be undertaken by a suitably qualified Ecologist (relevant institute websites provide directories to identify suitably qualified ecologists including The Chartered Institute of Ecology and Environmental Management (external website) and The Institute of Environmental Management and Assessment (external website).

A new statutory pre-commencement planning condition will be used to secure BNG.

Anticipated condition wording: No commencement of development until a Biodiversity Gain Plan has been submitted to and approved by the LPA.

The condition will require the submission of a Biodiversity Net Gain Plan, a template for which is due to be published by Natural England. It is anticipated that the plan will be based upon the BNG Statement and Biodiversity Management and Monitoring Plan submitted with the planning application, confirming how the 10% net gain anticipated will be provided, including details of the habitat management to be undertaken to ensure achievement, monitoring and measures to be implemented if the BNG anticipated is not being achieved. Regular monitoring of the habitats will be required, anticipated at years 1, 2 ,3 ,4 ,5, 10, 15, 20, 25 and 30, at which points the developer will be required to submit Monitoring Reports to the LPA which identify whether the intended habitat types and conditions are being achieved and outlining the actions to be undertaken in the next management period in order to rectify any failings. This is to ensure that the Biodiversity Gains proposed with the development are achieved in the long term.

This must then be secured by legal agreement for a minimum period of 30 years. Section 106 agreements are anticipated to be the primary method for securing BNG. However, conservation covenants, a new form of agreement specifically designed for BNG, is being proposed by Natural England between a landowner and a ‘responsible body’ and this may become more widely used as the system develops.

Once the Local Authority has approved the Biodiversity Gain Plan any off-site biodiversity units being used must be registered on a National Register which will be run by Natural England.

No, the metric does not change existing biodiversity protections, statutory obligations, or policy requirements; BNG is in addition to existing wildlife legislation and policy.

BNG introduces a quantitative measure to demonstrate a net gain in biodiversity and a framework to secure its implementation. It does not replace the requirement to carry out other assessments of impacts on biodiversity including protected species (e.g. bat and great crested newt surveys) or protected habitats (e.g Habitat Regulations Assessments in respect to European Sites). Appropriate licences in respect to derogation of the legal protection given to specific species or sites will still be required where unavoidable impacts are identified.

Compliance with other environmental planning policies will still need to be demonstrated by the developer; these include requirements relating to:

• protected or important nature conservation sites
• protected or important species
• irreplaceable habitats.

BNG maintains the mitigation hierarchy with the principles having been built into the technical guidance that accompanies the Metric. In this process adverse impacts on biodiversity should in the first instance be avoided, then minimised or mitigated and, only as a last resort, compensated as follows:

• Avoidance - actions taken to avoid causing impacts to the environment prior to beginning development (for example, moving the development to a different location, retaining habitats of importance within the design)
• Minimisation - measures taken to reduce the duration, intensity, extent and/or likelihood of the unavoidable environmental impacts caused by development (for example, adapting the development design to minimise impacts via timing, utilising precautionary working methods)
• Mitigation/remediation - actions taken to repair environmental degradation or damage following unavoidable impacts caused by development; and
• Compensation - measures taken to compensate for any adverse environmental impacts caused by development which cannot be avoided, minimised and/or mitigated (e.g. including habitat creation to offset losses).

Where developers are unable to provide a 10 per cent Biodiversity Net Gain on-site they can purchase off-site units from third parties either through brokers, habitat bank operators or direct from land owners or land managers.

Information on selling biodiversity units as a landowner or land manager can be found on government websites.

The council is currently considering its potential role in the off-site BNG Market. Current plans include the compilation of a list of landowners and land managers with a potential interest in providing off-site BNG. This list would be made available to applicants in need of securing off-site BNG for their proposed developments. If you are a landowner or land manager with a potential interest in providing off-site BNG and would like to be included on this list please contact nature.conservation@eastriding.gov.uk.

Further resources, information and guidance can be found at the external links below:

Natural England Biodiversity Net Gain Brochure (external pdf)

BS 8683 Process for Designing and Implementing Biodiversity Net Gain

Biodiversity Net Gain: Good Practice Principles for Development – a Practical Guide (CIEEM, IEMA and CIRIA)

Future Homes Hub: Biodiversity Net Gain Project

Biodiversity Net Gain Metric and User Guide

Current Government guidance

GOV.UK - Understanding Biodiversity Net Gain

GOV.UK - Collections: Biodiversity Net Gain