117) Developers should use the latest DEFRA statutory metric29 to show their development's percentage biodiversity net gain. When delivering net gain the mitigation hierarchy set out in the NPPF should be followed. The mitigation hierarchy is also one of the overarching principles for achieving net gain as set out under the Biodiversity Net Gain: Good Practice Principles for Development. (CIEEM, CIRIA and IEMA, 2016).
Figure 4 - Biodiversity net gain mitigation hierarchy (source: DEFRA Metric 3 guidance)
| Avoid | Minimise | Remediate | Compensate |
|---|
| Where possible habitat damage should be avoided. | Where possible habitat damage and loss should be minimised. | Where possible any damaged or lost habitat should be restored. | As a last resort, damaged or lost habitat should be compensated for. |
Measurable net gains should ideally be achieved on site. Where the required gains are to be achieved off-site they should be provided as locally as possible, as encouraged by the DEFRA statutory metric (and Small Site Metric where applicable) and as required by the Biodiversity Gain Hierarchy. Any required biodiversity offsetting should be delivered within Stockport unless it is clearly evidenced and justified why this is not possible or not appropriate. This will help ensure biodiversity units needed for offsetting stay within Stockport to accord with the wider approach of BNG delivery, which embeds a fundamental principle for a spatial hierarchy of habitat delivery, where there is a preference for onsite or local enhancements.
Natural England’s Green Infrastructure Framework30 is a tool to support the creation of good quality green infrastructure and help create more green and blue spaces in urban areas, linking them to local and national nature recovery goals. The Green Infrastructure Framework is structured around five standards, and our policy on the Urban Greening Factor reflects the recommendations in Natural England’s standard. For more information on the use of the Urban Greening factor, please see the user guide and calculator spreadsheet prepared by Natural England31.
The use of the Urban Greening Factor is an important tool to support our approach to increasing climate resilience within Stockport, by protecting communities from flooding and overheating. Urban greening should be designed to ecologically enhance and, where possible, physically connect to our ecological network. Urbanised areas with significant proportions of artificial surface cover can lock in heat far more than in more rural surroundings; this is sometimes known as the