Biodiversity Net Gain

Biodiversity Net Gain (BNG) is a land management approach designed to achieve measurable improvements for nature by creating or enhancing habitats such as wildlife areas, rivers, streams, and hedgerows, often in connection with new developments. These biodiversity improvements must be "additional," meaning that new projects should leave nature in a better condition than before.

The Wildlife Trusts have played a key role in shaping BNG for over a decade, starting from early efforts in 2012 to measure and offset biodiversity loss due to development. They have been instrumental in testing and refining the Defra metric and advocating for strong BNG commitments in legislation. At a local level, Wildlife Trusts have influenced the inclusion of BNG policies in local plans and promoted voluntary adoption of BNG. Recently, many Wildlife Trusts have also positioned themselves as providers of high-quality habitats to support BNG initiatives.

If done well, BNG offers a positive step forward in the way we think about development and nature in a more integrated way. It also offers new ways to fund and implement nature’s recovery, raising money from the sales of biodiversity units to reinvest in nature’s recovery and making sure biodiversity is at the heart of the planning process.  

Avon Wildlife Trust is currently exploring the feasibility of providing high integrity environmental credits to the local nature market. We will update this page as our work progresses. If you have questions, please contact us using the form at the foot of the page.

There are three ways in which BNG can be delivered:  

1. Firstly, through on-site enhancement and restoration of biodiversity (within the red line boundary of a development site).  

2. Secondly, if all of the BNG cannot be delivered on site , off-site biodiversity gains can be considered. This can either be on land owned by the developer, outside of the development site, or through buying off-site biodiversity units.  

3. Finally, if developers cannot achieve on-site or off-site  BNG, they must buy statutory biodiversity credits from the government. This should be considered a last resort. 

All three methods can be used, however they must be considered in order  

All habitats created for BNG must be managed and monitored for 30 years to achieve and demonstrate the planned uplift. When delivering BNG on-site developers must carefully consider how the BNG gains can be managed, monitored and protected (e.g. ensuring these areas will not be needed for future development) over the 30 years. When considering on-site gains it is also very important to consider how additional on-site pressures, for example from increased footfall, dog walkers and other human usage, can be balanced and accounted for within the planned uplift.  

The delivery of off-site Biodiversity Net-Gain must be secured with a comprehensive Habitat Management and Monitoring Plan (HMMP) and legal agreement. The legal agreement can either be in the form of a Section 106 (S106) with the Local Planning Authority or through a Conservation Covenant with a Responsible Body. Once the HMMP and legal agreement are in place, the off-site BNG must then be registered on Natural England’s BNG register, that opened in February 2024. Once the site is registered BNG units can be sold and included within planning permissions.