Supplementary Planning Document: Biodiversity Net Gain

Figure 4 is a flow chart which sets out the end-to-end process for achieving biodiversity net gain. The stages in this flow chart are set out in more detail in this section.

At the very start of a development project there is often a stage called ‘project inception’.

During project inception several surveys and reports will be needed to inform how biodiversity is factored into the design.

Topographical surveying is an important starting point as it allows further accurate surveys to be undertaken and plans to be produced. Soil surveys are important for a range of disciplines but for biodiversity net gain it informs decisions on the types of habitat which can be (and would be most appropriate to be) created on site. Applicants should discuss this with council to determine what, if any, soil surveys should be undertaken.

Habitat and species surveys need to be undertaken to inform the ecological reports which will be produced for a site. It is typical for a ‘walk over’ survey to be undertaken initially; this might have included a ‘Phase 1 Habitat Survey’ to the Joint Nature Conservation Committee JNCC standard. However, the UKHab is now the default format for habitat surveying to work with the government’s metric.

During the walk over survey, signs which might mean that more detailed habitat or species surveys could be required, would be collected. The need for further surveys will also be informed by carrying out a search using the Buckinghamshire and Milton Keynes Environmental Records Centre database. Further surveys will need to be undertaken in accordance with industry best practice, these must be undertaken by a qualified and experienced ecologist - see CIEEM consultant ecologists.

Surveys to inform the completion of the metric will need to:

• be carried out by suitably qualified and experienced persons
• be carried out at the appropriate time of the year for the habitats in question (the botanical survey season (late March/Early April through to mid-October) although this can be longer or shorter in any given year)
• justify the categorisation of distinctiveness and condition of baseline habitats with the aid of descriptions, photographs and species lists
• if it is clear that habitats have been recently changed to their detriment, it will be necessary to make an informed assessment of what the best condition and distinctiveness of that habitat would have been, prior to the change. This will need to be justified to the Council and agreed by them

A Preliminary Ecological Appraisal is a consolidation of desk study work and initial survey works. It is to be produced in accordance with the CIEEM guidelines for a Preliminary Ecological Appraisal and will contain recommendations with regards to its findings. If further surveys are required, these will need to be undertaken to inform design.

A biodiversity net gain feasibility report is one of the reports listed in the CIEEM resource Biodiversity Net Gain Report and Audit Templates; the structure and guidance set out in this resource should be used.

A biodiversity net gain feasibility report is used at a pre-application planning stage. This will outline the feasibility of biodiversity net gain resulting from the potential development. This can be contained within or be separate to a Preliminary Ecological Appraisal Report. Within these reports there will be a Baseline Habitats Plan which will link to the biodiversity metric to show the baseline conditions and help in designing what is feasible for biodiversity net gain on-site. It is recognised that sufficient information may not be available at this stage for a final measure of biodiversity net gain to be provided.

It is vital that potential impacts upon irreplaceable, vulnerable, designated and priority habitats are highlighted at this stage as this could constrain the potential for delivering biodiversity net gain. Even where biodiversity net gain is not deliverable because of losses of irreplaceable habitats, a commitment to quantifiable compensation for impacts that can be mitigated is strongly recommended. Good practice would be to involve the council at this stage to help guide the design process. Clause 5.2 in British Standard 8686:2021 sets out important further guidance to be take into account when assessing biodiversity net gain feasibility.

The identification of biodiversity constraints and opportunities and an assessment of likely ecological impacts will be useful when considering the design of a site; the production of an Ecological Constraints and Opportunities Plan should be considered throughout the design and development process.

Through accurate surveying and assessment, and by following government guidance when completing the metric, a clear understanding of the baseline biodiversity value can be reached. This will be the foundation for the successful design of a site for biodiversity net gain. Applicants should contact the council or its website for guidance on the local nature priorities for the assessment of the land parcels and their strategic significance to biodiversity.

Following the collection of the above information it is advisable to seek planning advice from Buckinghamshire Council.

This part of the project covers the iterative process of design from initial concept design, through developed design towards technical design. The design process is informed by the collation of ecological information in the earlier stage and the bringing together of a multi- disciplinary approach to ensure the best outcomes can be achieved.

A Biodiversity Net Gain Design Stage Report, is one of the reports listed in the document Biodiversity Net Gain Report and Audit Templates (CIEEM). The structure and guidance set out in that document should be used. If a BNG feasibility report has not been provided, it may be necessary to adapt the structure to include key information from the feasibility stage.

A Biodiversity Net Gain Design Stage Report is produced to inform the planning application and its determination by the council. This will include a fully completed biodiversity metric and will be considered alongside an Ecological Impact Assessment.

A description of the current on-site baseline conditions must be provided, and it must directly relate to a Baseline Habitat Plan (this should reflect the biodiversity net gain feasibility report). Reference numbers for each habitat parcel must be given which cross reference with the metric.

Full details covering the retention, restoration and enhancement of existing habitats as well as the creation of new habitats must be provided clearly in a Proposed Habitats Plan showing the impact of development for the site. The existing and proposed site conditions (soil, aspect, intended use, proposed management regime, etcetera) must be taken into account when justifying the proposed distinctiveness and condition for habitats post-development.

Outline applications may not have the layout finalised. Here, a Proposed Habitats Plan and the biodiversity metric can be based upon a realistic scenario, taken from a parameters plan and/or an illustrative masterplan or landscape scheme. It is important that the requirements for allotments, sports pitches, play areas, natural green spaces, etc. are taken into account so that proposals are achievable.

Demonstrating the net biodiversity condition within the planning application enables the council to assess whether further net-gain could be achieved on-site. Where this is not possible, the council may require the applicant to secure off-set net gain with long-term management and monitoring through a legal agreement and, where relevant, secure further details and associated updated biodiversity metric calculations through reserved matters applications.

Where a development is to be phased, a biodiversity net gain strategy must be submitted at the outline stage, which shows how individual phases deliver a predetermined proportion of the biodiversity value. Reserved matters applications will then be required to demonstrate exactly how each phase will meet its biodiversity requirements.

An ecological impact assessment is a document which explains the effects that a development could have on ecology. This assessment is focused on specific impacts which will occur through a range of different identified actions and which affect different identified species or habitats of importance. Whereas, biodiversity net gain assessments provide a more generalised overview of aggregated biodiversity value as measured through habitats, hedgerows and watercourses.

The ecological impact assessment must be produced in accordance with CIEEM guidance. This assessment is a complementary document to be considered in the design process alongside the consideration of biodiversity net gain. The assessment will address impacts that have not been considered through biodiversity net gain assessment. This is important as it would be possible to address the needs of biodiversity net gain but fail to address the needs of this assessment and vice versa. When considered together the proposals should achieve additional ecological benefits.

An assessment of biodiversity net gain impact assessment using the 'biodiversity metric' must be submitted as a spreadsheet with the planning application so that it can be assessed. It is expected that the council’s guidance regarding strategic significance on biodiversity is used. Applicants should contact the council or its website for guidance on the local nature priorities for the assessment of the land parcels and their strategic significance to biodiversity.

The pre-application iterative design phase should follow the principles of the mitigation hierarchy set out below.

Example: woodland, grassland and hard standing.

Baseline equals 100%.

The baseline biodiversity value is worked out in the biodiversity metric. This sets the level from where a net gain is measured from. The baseline unit value for different sites will vary but it will always be 100%.

Example: new development, 1 tree and some grassland retained in garden in reduce condition/distinctiveness.

80% net loss.

An initial design with little consideration of biodiversity will likely result in a significant percentage loss in biodiversity. This design has only avoided the loss of 1 tree.

Example: avoidance of loss of some woodland and grassland; new development results in loss of some grassland and reduced condition/distinctiveness of that within garden.

40% net loss.

Iterating design with the mitigation hierarchy improves the situation for biodiversity. Avoidance is the first step on the mitigation hierarchy and in this case development in the woodland and some of the grassland has been avoided. Through the restriction of access to the retained habitat, mitigation has been achieved.

Example: avoidance of loss of woodland and restoration of some grassland. New development results in loss of some grassland and reduced condition/distinctiveness of that within garden.

10% net loss.

The second iteration shows greater avoidance and some restoration of the grassland and woodland (in compensation) as well as mitigation measures.

Example: avoidance of loss of woodland and restoration of more grassland. New development results in reduced condition/distinctiveness of grassland within garden.

No net loss.

The third iteration shows even greater avoidance and restoration of the grassland and woodland (in compensation) as well as mitigation measures. Some of the grassland will be turned into garden lawn which a lower biodiversity value but this is compensated through the restoration of areas to give ‘no net loss’ overall.

Example: avoidance of loss of woodland and restoration of more grassland. New development results in reduced condition/distinctiveness of grassland within garden, plus a green roof enhancement.

10% net gain.

The fourth iteration builds upon the third iteration but it includes a green roof as an enhancement.

This scenario achieves an onsite biodiversity net gain. Achieving the biodiversity net gain on site is preferable over resorting to offsetting.

Example: avoidance of loss of woodland and restoration of some grassland. New development results in loss of some grassland and reduced condition/distinctiveness of that within garden.

10% net loss.

In some situations, where the mitigation hierarchy has been followed, it might still not be possible or appropriate to achieve a biodiversity net gain on site. In this situation it might be appropriate to allow the required net gain to be achieved through biodiversity offsetting.

Example: taking agricultural grassland and turning it into meadow and woodland through 30 years of management.

Gain equivalent to 20% of development site baseline.

Offsetting can be arranged in several different ways, but the end result must always mean that enhancements which are created and maintained off site will not only compensate for onsite losses but also achieve the required biodiversity net gain.

It is necessary for the council to be confident that biodiversity net gain requirements will be achieved as a result of the development. The way this will be achieved is examined and then secured during this stage.

As set out in figure 2, biodiversity net gain on-site is the primary goal for any development. However, if this is not possible, after the designs have been iterated within the mitigation hierarchy, it is highly likely that at least some of the biodiversity units can be provided on-site. Providing biodiversity on-site enables the benefits of biodiversity to be experienced by those occupying the development and the local community.

Planning conditions attached to a planning application can secure the implementation of on- site mitigation, compensation and enhancement measures.

The format in which details are provided can vary depending upon the scale of the development. Documents may include a Construction Environmental Management Plan and a Landscape and Ecology Management Plan.

Where there is a need for full details of the management and monitoring required to achieve and maintain the suggested distinctiveness and condition for habitats, over a period of at least 30 years (as set out in a metric), this must be provided in a Biodiversity Net Gain Management and Monitoring Plan which follows good practice guidance. Details contained within this plan may overlap with those contained in a landscape maintenance plan or a Landscape and Ecology Management Plan; these documents can be combined to ensure consistency.

More details of what might be expected in the biodiversity net gain management and monitoring plan can be found at the bottom of Table 2 of the CIEEM resource biodiversity net gain report and audit templates, more details are included in section 8 of British Standard 8693:2021, extracts are included in Appendix 3.

The delivery of biodiversity net gain takes time, and it is reliant on a biodiversity net gain management and monitoring plan being implemented successfully. It will therefore be necessary to include the source of funding for its management and maintenance and to identify who will be responsible for achieving the target condition and who will carry out the work.

To ensure progress is reported, it is essential that future audit reporting is secured through planning conditions. It will be important to secure who is responsible for the production of the reports and what details they will contain. Details of what should be included in an audit report are contained in Table 3 of the biodiversity net gain report and audit templates.

The frequency of audit reporting will depend upon the scale of the project, but in all cases they will be needed:

• following any changes to project design post-consent - significant changes may require a full review of earlier stages of the process
• immediately following project implementation, for example, the completion of construction or at the end of a landscape establishment phase
• when the majority of created habitats are expected to have reached their target condition

Where there are large gaps in time between different habitats reaching their target condition, it may be necessary to timetable additional audit reports. To ensure biodiversity net gain is being achieved in line with the Biodiversity Net Gain Management and Monitoring Plan, the council needs to monitor and record the progress towards reaching biodiversity net gain wherever and however this is secured.

Monitoring which the site manager undertakes is to enable adaptive management to keep delivery of biodiversity units on track and to provide evidence for audit reporting of the progress towards reaching target conditions. The council will charge a fee for biodiversity net gain monitoring of on-site habitats in line with the council’s schedule of fees and charges. This will be used to review audit reports, make occasional site progress checks, keep track of cumulative gains and losses and report information internally and to government.

Where biodiversity net gain cannot be achieved on-site, despite iterative design and when on- site opportunities have been exhausted, biodiversity off-setting is required to make up any shortfall. There are 3 main ways in which biodiversity off-setting can be delivered. Option 1 involves the developer paying the council an amount of money the “Financial Contribution”, determined by the council’s Biodiversity Accounting Financial Calculator, in exchange for the council taking on the responsibility for securing the delivery of the biodiversity net gain off site.

This option has several advantages for both the developer and the council. The developer can make a payment which covers the cost of off-setting and council project delivery costs, and it discharges the developer’s responsibility to provide net gain at that point. The council can manage the creation, restoration and enhancement of habitats in a strategic way in line with the current NEP Biodiversity Action Plan and Local Nature Recovery Strategy.

A planning obligation secured through a Section 106 agreement would be the usual legal method to secure a financial contribution to the council. This will cover both the biodiversity offsetting costs to achieve biodiversity net gain and the council project delivery costs. The Section 106 will be based upon the Buckinghamshire Council biodiversity offsetting Section 106 template. There will be a separate charge to cover legal fees for the drafting of a legal agreement.

If biodiversity net gain cannot be achieved on-site and a developer has land within their control which is suitable to act as a biodiversity offset site, option 2 might be preferred. However, for a site to be considered suitable it will need to meet several requirements:

• security - it must be possible to secure the land for at least 30 years
• quantity - it must be possible to achieve the required number of biodiversity units
• equivalence - it must be possible to secure the biodiversity units in right type of habitats to ensure there is no ‘trading down’
• proximity – this is determined by the spatial risk categories which are set by the government in their guidance relating to the metric. In reference to how spatial risk is determined in the guidance, the whole of Buckinghamshire Council is the Local Planning Authority

To ensure that the offset site can provide suitable biodiversity units, surveys will need to be undertaken. Surveys will need to be undertaken in the same manner as those for a development site. It will also be necessary to produce details in a report format which cover the same issues as the Preliminary Ecological Appraisal, Biodiversity Net Gain Feasibility Report and Baseline Habitat Plan, Ecological Constraints and Opportunities Plan and also details which would otherwise be found in the biodiversity net gain Design Stage Report including a Proposed Habitat Plan. The Biodiversity Impact Assessment Metric produced would need to show how the required biodiversity net gain will be achieved.

Details similar to those in paragraph 3.4.2. will be secured through planning conditions.

A monitoring fee will need to be secured to ensure biodiversity net gain is being achieved in line with the Biodiversity Net Gain Management and Monitoring Plan. The council needs to track and record the progress towards reaching biodiversity net gain wherever and however this is secured. The Biodiversity Net Gain Management and Monitoring Plan will set out the frequency for the council to be sent audit reports.

The council will secure a fee to cover the costs of reviewing audit reports, make occasional site progress checks and keep track of cumulative gains and losses as well as report information internally and to government. The council’s Biodiversity Accounting Financial Calculator will be used to calculate the council’s monitoring cost; this will be secured as a fee to the council through legal agreement with the developer. This is additional to any fees which are paid to the council to determine planning application and legal fees for the drafting of legal agreements.

A legal agreement will need to be completed between the council and the developer which secures the delivery of the biodiversity units to achieve biodiversity net gain and to maintain the land in the long term (for at least 30 years).

If biodiversity net gain cannot be achieved on-site, a developer might choose to use a third- party off-set provider, broker (or a government scheme). An offset provider or broker will take money from a developer to provide an offset in a similar way to how the council would in Option 1. However, details of how the biodiversity units will be delivered must be provided to the council, and additional conditions and/or legal agreements may need to be put in place.

Details will need to be provided of the proposed offset provider, the proposed site for the offset, surveys which the baseline condition and proposals which will ensure the anticipated net gain will be provided. A Biodiversity Metric will need to be completed for the offset site using the same version as that used for onsite calculations.

Securing the long term delivery of the offset site will be through planning conditions similar to those set out in 3.4.2. The offset provider will need to certify that they have received the funds to enable the offsetting to take place.

A monitoring fee may need to be secured as per 3.4.7. Where this is with the developer it may likely be through a Section 106 agreement. Where it is with an offset provider it may be through a Section 39 agreement of the Wildlife and Countryside Act, or a Conservation Covenant. If it is with a broker a different type of legal contract may be required.

The decision to grant planning permission is dependent upon a range of considerations. The granting of permission may be withheld for several reasons including:

• inadequate information is submitted with regards to demonstrating biodiversity net gain
• if better outcomes are achievable for biodiversity but a developer will not engage in iterating the design following the mitigation hierarchy
• if (even after iterating the design following the mitigation hierarchy) biodiversity net gain is not achievable through the proposals on site and the applicant is unwilling to accept necessary pre-commencement conditions relating to biodiversity or sign a legal agreement for Biodiversity Offsetting

Planning conditions may need to be applied to planning decisions to secure the submission of information and the carrying out of particular actions. There is often also a need to use legal agreements as well as or instead of planning conditions because planning conditions:

• are not appropriate for securing financial contributions
• may not be able to be applied outside of the development site
• may be limited in their scope in other ways

Legal agreements may include section 106 agreements, unilateral undertakings, or conservation covenants.

Long term management and monitoring of habitats is essential to ensure that biodiversity net gain is achieved. The 4 options for achieving biodiversity net gain differ in terms of who will carry out the management of the habitats as set out in a Biodiversity Net Gain Management and Monitoring Plan, but their progress will be tracked by Buckinghamshire Council.

A developer will often employ a management company to manage habitats, however, given the special requirements for managing habitats for biodiversity it may be the case that specialist contractors are required. Auditing should be undertaken by an ecological consultant as they will have greater surveying knowledge and should be independent from the contractor.

Buckinghamshire Council Biodiversity Offsetting (option 1 in figure 5) is not available at the point of adoption of this SPD.

Buckinghamshire Council could deliver offset sites in several ways:

• through management of areas of existing council-owned land
• through purchasing land specifically for the purpose of achieving biodiversity net gain
• through working with partner organisations, securing legal agreements for the management of their land
• through working with other landowners to secure legal agreements for the management of their land

In all instances a biodiversity net gain management and monitoring plan will either be produced by the council or its partners. The carrying out of the land management to provide the offset units will vary in different circumstances.

Where a developer provides an offsetting site this will need to have been secured prior to planning application determination, and the means by which it will be managed, monitored and reported on, including arrangements for providing information on progress to the Council, should be set out and agreed with the Council. In most cases this will be as per paragraph 3.4.2.

Where developer sources an offsetting site through an offset provider or broker, the details will have been secured prior to determination along with the means by which it will be managed, monitored and reported on, which should be agreed with the Council, including arrangements for providing information on progress to the Council. The way in which this is arranged will be dependent upon the type of offset provider or broker.

Monitoring or tracking of the progress towards achieving the anticipated biodiversity units for both on and off-site habitats will be carried out by the council. This will include the scrutiny of biodiversity net gain auditing reports submitted to the council as well as carrying out occasional site checks. Monitoring details will be used to inform the councils own planning monitoring reports as well as feeding back to government where necessary.

There is an important distinction to be made between this monitoring undertaken by the council and that which forms part of the Biodiversity Net Gain Management and Monitoring Plan which is carried out by the offset provider as part of adaptive management of the habitat.