Policy BG/BG: Biodiversity and geodiversity

DRAFT version for various committee meetings.

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Figure 53: Map of existing nature sites and undesignated green infrastructure
Figure 53: Map of existing nature sites and undesignated green infrastructure

What will this policy do?

This policy will control the biodiversity impacts from development, including the approach to Biodiversity Net Gain (which requires developers to ensure habitats for wildlife are enhanced and left in a measurably better state than they were in before development, and is expressed as a percentage). It will also control development affecting sites of biodiversity and geodiversity importance.

Proposed policy direction

The policy will require development to achieve a minimum 20% biodiversity net gain (BNG), noting that: 

  • BNG calculations should be submitted using the Defra Biodiversity Metric 32.0 or its successor 

  • BNG should be delivered on-site where possible, recognising that for smaller developments in particular, more significant and long-lasting biodiversity enhancements may be achieved via contributions towards off-site, larger scale projects. 

  • Where it is agreed that off-site habitat measures would bring greater biodiversity benefits than on-site measures, these must be consistent with the strategic aims of the Greater Cambridge green infrastructure network strategic initiatives (see BG/GI

  • The Councils will seek to use planning conditions to secure on site habitat creation and its long-term management, and obligations where BNG is on land outside the applicant’s control 

The policy will also seek wider environmental net gains. Ways of measuring this are currently being developed at a national level, and at the draft plan stage we will review whether and how to implement this policy requirement.

The policy will state that development proposals adversely affecting sites of biodiversity or geological importance will not normally be permitted. Exceptions will only be made where the public benefits significantly outweigh any adverse impacts. In such cases where development is permitted, we will require that the intrinsic natural features of particular interest are safeguarded or enhanced.

The policy will require development to mitigate evidenced recreational impacts on designated biodiversity and geodiversity sites, including applying Natural England’s Impact Risk Zones for Sites of Special Scientific importance.

Why is this policy needed?

National policy requires development to achieve a net gain for biodiversity. Biodiversity net gain requires developers to ensure habitats for wildlife are enhanced and left in a measurably better state than they were in before development.

The emerging Environment Bill is likely to introduce a mandatory 10% minimum biodiversity net gain across the country. At an OxCam Arc level we and our partner authorities have agreed a set of Arc Environmental Principles which include the aims of doubling the area of land managed primarily for nature, and also to deliver a minimum 20% biodiversity net gain on development sites. These ambitions, together with the relatively low level of designated sites and priority habitats that Greater Cambridge has compared with other English areas, highlight the need for development to bring further net gains beyond the 10% proposed nationally.

The focus for biodiversity enhancements is intended to be within the boundary of a site, and could include providing wildlife areas, trees, or smaller measures such as including bat or swift boxes.  However, If the required level of net gain cannot be provided on site there is the potential for applicants to contribute to biodiversity enhancements elsewhere – a range of strategic initiatives have been identified to support biodiversity enhancement across Greater Cambridge (see BG/GI), meeting national policy requirements to take a strategic approach to promoting the restoration and enhancement of the green infrastructure network. Ahead of the draft plan we will work with partners to explore the best way to collect and distribute funds from development for this purpose.

Beyond biodiversity net gain, national policy encourages Local Plans to seek wider environmental gain from development. Approaches for measuring this are emerging nationally, and we will review this topic ahead of the draft plan.

National planning policy requires us to protect and enhance sites of biodiversity and geodiversity importance, with the level of protection being appropriate to its international, national or local significance. We have a range of important biodiversity and geodiversity sites within Greater Cambridge, most being of local significance. This policy approach sets out that development adversely impacting on our biodiversity and geodiversity sites is in principle not supported. Where in exceptional cases development impacting on such sites is justified for the public benefits it could bring, the policy will set out how impacts will be assessed, how protection will be measured and enhancements secured.

Designated biodiversity sites within and close to Greater Cambridge are being impacted by increasing numbers of visitors – an issue that needs to be addressed to protect these vulnerable habitats and the species they support. For nationally designated sites, Natural England have identified Impact Recreation Zones and recommend the application of Suitable Alternative Natural Greenspace standards to inform the quantity of green space provision required for people, to lessen the impacts on these nature sites. Greater Cambridge has relatively few nationally designated nature sites, but many locally designated sites. Ahead of the draft plan we will explore how we can best measure and mitigate the impact of development on these local sites.

What consultation have we done on this issue?

Feedback to the First Conversation consultation regarding biodiversity and geodiversity included support for the protection of existing nature sites, and very strong support for biodiversity net gain including use of off-site contributions. A large number of responses also suggested that the plan should identify and support a nature recovery network for Greater Cambridge, to help address the biodiversity emergency at a more strategic level. A number of comments highlighted the importance for biodiversity of tackling decreasing water resources and the associated pressure on the natural environment, with suggestions for solutions including through strategic projects and on a smaller scale, via different design requirements for new development.

What alternatives did we consider?

  • 1. Rely on emerging national legislation, likely to state a 10% mandatory biodiversity net gain - This alternative is not the preferred approach, as it would not bring such great benefits for biodiversity.

    2. Require biodiversity net gain higher than 20% - This alternative is not the preferred approach as it would be likely in most instances to require significant off-site measures, whereas the national approach to net gain prioritises on-site measures. Requiring high net gain might also negatively affect development viability.

    3. Rely on national policy for protection of sites of biodiversity importance - This alternative is not the preferred approach as we consider that additional clarity is required to set out how the principles set out in national policy should be applied at a local level.

Supporting evidence studies and topic papers

  • Greater Cambridge Local Plan: Topic paper 3: Biodiversity and Green Spaces  

Existing policies in adopted 2018 Local Plans

South Cambridgeshire Local Plan 2018 

  • Policy NH/4: Biodiversity 

  • Policy NH/5: Sites of Biodiversity or Geological Importance 

Cambridge Local Plan 2018 

  • Policy 69: Protection of sites of biodiversity and geodiversity importance 

  • Policy 70: Protection of priority species and habitats 

Tell us what you think

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