Biodiversity Net Gain – What Does This Mean for Your Projects?

Biodiversity net gain (BNG) is an approach that means changes brought about by development result in biodiversity faring better than it did before works took place. This replaces the previous policy of ‘no net loss’. 

BNG is already required by the National Planning Policy Framework (NPPF) and the current planning decision-making process. At present, the NPPF does not state a specific measurement for this gain, however many local planning authorities (LPA) have started to request a 10% requirement, which is in line with the Environment Bill (currently under consultation) which will require all future schemes to deliver a mandatory 10% net gain, which will then require to be managed for a minimum of 30 years. ​​​​​​​

​​​​​​​BNG still relies on the mitigation hierarchy of avoidance, mitigation or compensation (as a last resort) being applied and should be used in addition rather than as a replacement. BNG also encourages developers to provide an increase in natural habitats and ecological features over and above that being impacted on during development and aims to restore ecological networks.

So, What Does This Mean for Your Projects?

Simply put, the BNG assessment will compare the current baseline (i.e., what is there already? What is the ecological importance of this baseline?) to what the future development will be (i.e., what will be retained or lost during the construction process? What new habitats will be created?).

This baseline data will be gathered by the Ecology Team during the Preliminary Ecological Appraisal and should be considered as early on in the project as possible. The ecology team will then use this data, as well as the project landscape plans to calculate the post-development habitats. This is converted into Biodiversity Units using a biodiversity metric.

What is a Biodiversity Metric?

The standard is currently the Defra Biodiversity Metric which was first released in 2019 and then updated and replaced by the Natural England Biodiversity Metric 2.0 (Beta Version). While this is the most widely used metric, there are some LPA’s who have developed and use their own, such as Warwickshire and Dorset.

The metric is simply a tool to make the process of BNG transparent and quantitative. It allows the Ecology Team to compare the site baseline to the post-development as each habitat is assigned a unit depending on its value to biodiversity, size, condition, connectivity and local importance. For instance, the loss of woodland would be of greater value, and ‘cost’ more to replace, than a similar area of amenity grassland or lawn. By engaging the BNG process early on in the project, it enables the team to ensure that biodiversity within the site can be maximised. For example, on a 2020 residential development in Bishop’s Stortford, we were able to demonstrate a 10% BNG and therefore helped to gain planning permission for our client.​​​​​​​

So, What Next?

The Ecology Team are here to help de-risk your projects from an early stage and will assist by advising on the appropriate metric to use and liaise with the LPA about the level of BNG they require as this can vary. For instance, Lichfield require a 20% biodiversity net gain which is a deviation from the ‘norm’.

Early engagement will help to avoid problems at a later date. Even if you think that your scheme does not require BNG, the Ecology Team will be able to advise on this and guide the project forward. It is much easier for us to do this early in the project than 2 weeks before the planning application is due in!

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