DM Policy 38: Biodiversity Net Gain
Biodiversity Net Gain
Historically, planning policy has focused primarily on protecting important designated habitats and species. However, it is increasingly apparent that the UK’s biodiversity decline is so severe that increased efforts to bring about recovery, as opposed to merely arresting loss, are essential. Since 2012 the NPPF has incorporated the principle of Biodiversity Net Gain (BNG) achieved through development, meaning that developments must fully mitigate any loss of biodiversity but then go further to provide a gain, leaving the environment in a better state than before the development. The requirement for the delivery of BNG will become mandatory once the Environment Bill currently progressing through final readings in the House of Commons is signed into law, and all developments that come forward during the Plan period, with some limited exemptions, will have to achieve BNG.
The draft Environment Bill mandates a 10% biodiversity net gain above the ecological baseline for development sites. It also requires the creation of nature recovery networks, which will operate at district level and will guide the delivery of biodiversity net gain projects. The objective is for new development to contribute towards the delivery of net gains for biodiversity, so that the environment, across the district as a whole, is improved by the end of the plan period.
The requirements of the Environment Bill are expected to be provided with a two-year transition period to enable local planning authorities, developers and others to prepare for the proposed requirement. Minor residential sites of fewer than 10 units are likely to be subject to longer transition arrangements or a lower BNG requirement, as well as a simplified process for calculating BNG, to be set out at a future date. As the specific requirements of the Environment Bill and associated guidance are still being produced, this policy will be subject to further revision to take account of emerging legislation and guidance and recommendations of ongoing work with partner organisations.
It is expected that some types of development are likely to be exempt from the policy requirements. The exceptions currently under consideration in ongoing work on the Environment Bill are national infrastructure projects, sites with no biodiversity value (e.g. site covered wholly by sealed surfaces), previously developed (brownfield) sites that don’t contain protected or priority habitats or face genuine viability difficulties, and permitted development and extensions. Where sites are exempt from the minimum BNG requirement, this will not mean that those sites should not still aim to maximise biodiversity enhancements to provide as much gain as possible, or at the very least avoid a net biodiversity loss.
Planning applications will be required to include the relevant information needed to demonstrate that the proposals will meet the requirements for a minimum of 10% net gain, informed by appropriate surveys and assessments carried out by suitably qualified persons. This should include a Biodiversity Net Gain Plan and supporting reports which should provide an assessment of the likely effects of the development and changes to the ecological baseline, whether they are positive or negative.
Net Gain will be measured using Defra’s Biodiversity Metric 2.0. This metric works by placing a value on different habitats based on their distinctiveness, area, condition and contribution to an ecological network, and in doing so, allows the biodiversity value (expressed as ‘biodiversity units’) before and after a development takes place to be measured. In this way, the level of biodiversity gain or loss can be clearly seen by comparing the two values. At the time of writing, Defra is consulting on the metric methodology. DEFRA is, at the time of writing, producing a simplified metric for minor development proposals, as set out above, which are likely to be subject to a simplified process.
Proposals for BNG must be acceptable to the Council in terms of design and location and should take into account local priorities set out in the Local Nature Recovery Strategy, Dover District Green Infrastructure Strategy and the Kent Environment Plan. Proposals should have appropriate delivery and funding mechanisms that are capable of being secured by condition and/or legal agreement. Monitoring of biodiversity net gain projects will be funded by the developer, with reports provided to the Council for inclusion in the Authority Monitoring report.
The delivery of Biodiversity net gain reinforces and supports adherence to the mitigation hierarchy of avoidance, mitigation and, as a last resort, compensation, which is already well established in planning policy. Proposals for BNG will therefore be expected to demonstrate the application of the mitigation hierarchy. Loss or damage to irreplaceable habitats cannot be offset to achieve a net gain.
It is expected that the requirement for BNG should be met on-site, within the application site boundary. If it can be clearly demonstrated that ecologically meaningful biodiversity net gain cannot be achieved within the development site boundary, the Council will consider off-site provision or a financial contribution to a biodiversity offsetting scheme.
Offsetting must follow the principle of ecological equivalence. There must be no trading down of habitat types. Habitat types, (particularly priority habitats listed under Section 41 of the Natural Environment & Rural Communities Act, 2006), will be required to be replaced on a like for like or like for better basis.
Offsetting schemes should be discussed and agreed in the first instance with the Council and will be expected to be strategically located for nature conservation, and be informed by local and national guidance and data sets, including The Kent Habitat Survey, the Kent Biodiversity Strategy and the Biodiversity Opportunity Area (BOA) in which the site is located, the Dover Green Infrastructure Strategy, and the Dover Nature Recovery Network. The Council will pursue net gains for biodiversity in and around BOAs and the emerging Nature Recovery Network. Projects which seek to connect fragmented habitats and improve the ability of species to move through the environment in response to predicted climate change will be supported.
As with on-site provision, proposals for offsetting schemes will be required use the appropriate DEFRA metric to demonstrate compliance with the policy, and should comprise the full calculations of the DEFRA metric results for both development site and offset location, combined with a qualitative assessment of their ecological baselines. The evidence will show how the offset is strategically located to offer the best opportunities for habitat creation, restoration and connectivity to other areas of habitat.
For development schemes, which are unable to provide ecologically meaningful net gains on site, the Council intends to provide an alternative mechanism for developers to achieve biodiversity net gain. This could include setting up one or more habitat banks within the district. They are areas of land, secured and managed appropriately for nature conservation, to offset the impacts of multiple developments. The developer fulfills their duty by making a financial contribution to the habitat bank.
Local Nature Recovery Strategies will be made available and a Dover District Biodiversity Net Gain Strategy will be produced as SPD to the Local Plan. In advance of this being produced, reference should be made to the latest guidance, Biodiversity Net Gain – Good Practice principles for development, a practical guide (CIEEM, CIRIA, IEMA, 2019) and and British Standard BS42020 Biodiversity - Code of Practice for Planning and Development, or subsequent revisions.
DM Policy 38: Biodiversity Net Gain
Development proposals must provide a minimum of 10% biodiversity net gain. Proposals for biodiversity net gain must:
a) be provided as part of the development within the development site boundary. Only if it can be demonstrated that ecologically meaningful biodiversity net gain cannot be achieved within the site boundary will the Council consider off-site alternatives or financial contributions towards a biodiversity off-setting scheme within the District;
b) be provided above the agreed pre-development ecological baseline of the site, for both area and linear habitats;
c) focus on local priorities and be informed by the Local Nature Recovery Strategy, Dover District Green Infrastructure Strategy and the Kent Biodiversity Strategy;
d) be secured for a minimum of 30 years,
e) be informed by a comprehensive understanding of habitats and species associated with the site, to include survey and assessment work carried out by suitably qualified professionals and relevant information from the Kent and Medway Biological Records Centre; and
f) follow the mitigation hierarchy and demonstrate by appropriate project design, evidence of adequate avoidance and mitigation measures. Where harm to wildlife habitats cannot be avoided or adequately mitigated, appropriate compensation measures will be sought. Biodiversity net gain must be in addition to any form of compensation.
Planning applications must be supported by a Biodiversity Net Gain Plan and supporting reports with information to demonstrate how 10% biodiversity net gain will be achieved, including:
g) Use of the most up-to-date DEFRA metric calculation, including breakdown of stages;
h) an assessment of the likely effects of the development and changes to the ecological baseline;
i) details of the ecological assessments to include both qualitative and quantitative evidence;
j) details of the design and location of the proposals; and
k) details of how the net gain proposals will be implemented, managed and maintained.
Biodiversity net gain proposals will be secured by condition and/or legal agreement. This will include a requirement to cover the Council’s costs associated with the long-term monitoring of the biodiversity net gain proposals.
Applications for change of use in order to create biodiversity sites in appropriate locations, including biodiversity off-setting sites and sites within Local Nature Recovery Strategies will be supported.