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Useful updates on Biodiversity Net Gain



Useful updates on Biodiversity Net Gain

April 22, 2024

Dr Lynsey Robinson, Ecology Planning Lead, gives her latest lowdown on Biodiversity Net Gain and how to navigate the changes.

Biodiversity Net Gain (BNG) is a way of creating and improving biodiversity by requiring development to have a positive impact on biodiversity.

BNG is broadly trying to achieve four things:

  1. change how development happens
  2. change where development happens
  3. create a high integrity market for nature-based solutions
  4. contribute to nature recovery

The concept of development delivering a net gain for biodiversity has been part of national discussions for a long time and has been a SDNPA policy requirement since the adoption of our landscape-led Local Plan in 2019.

Following the Environment Act 2021 and subsequent secondary legislation, there is now a world-leading, national mandatory requirement for BNG which has applied to major developments since 12 February this year, and to small sites from 2 April.  You can read here the full definition of a small development but for residential development, it means a development with nine houses or fewer, on less than 1 hectare of land.

Extra guidance from South Downs National Park

There are very specific technical and procedural requirements associated with mandatory BNG.  To help developers, landowners and planning agents, the National Park has therefore produced a BNG Technical Advice Note to provide interim guidance for applicants and decision makers on how BNG is to be achieved in the South Downs National Park in accordance with existing South Downs Local Plan policy.

Importantly, the TAN sets out how BNG is expected to make a meaningful contribution to nature recovery.

The guidance covers five broad areas: scope of BNG requirements and exemptions; overarching principles; major applications; small sites; and securing and monitoring BNG.

The TAN will be subject to review over the coming months and will be updated as new national policy and guidance is available and through ongoing industry learning on key aspects of implementing BNG at national and local level.  The latest version of the TAN should always be used and this can be sourced from our website. 

We have also updated our local planning application requirements relating to BNG, and these are set out in our Local Validation List

The market for offsite biodiversity unit sites – which are locations for biodiversity gain outside of the development, if it’s not possible to deliver on-site – is developing. Sites are beginning to be made available on the Natural England register, meaning that they have all the necessary legal agreements in place to sell offsite units directly to developers or through online marketplaces. You can read more about SDNPA’s statutory planning role and our wider services in this area here

More government guidance about biodiversity net gain is available here and you can also learn how to calculate biodiversity value.