Mandatory Biodiversity Net Gain is soon to be required for all planning applications with the implementation of the forthcoming Environment Bill. Many planning authorities have already included it in planning policies and it is quickly becoming the norm. But what does it mean for your development?

What is Biodiversity Net Gain?

Biodiversity Net Gain (BNG) is “an approach to development that leaves biodiversity in a better state than before”. To deliver BNG, an increase in natural habitat and ecological features, over and above that being affected by the development, is required. The over-arching aim is to reverse the continuing loss of biodiversity.

What are the Legislative Requirements for BNG?

The forthcoming Environment Bill dictates that most future development schemes in England must deliver a mandatory 10% BNG, and that this should be maintained for at least 30 years. In reality BNG has been part of the National Planning Policy Framework for a few years (NPPF, Para 170(d) and Para 175(d)), but it was not previously quantified.  Furthermore, many Local Planning Authorities (LPAs) have already incorporated BNG into their local plans.

Some types of development will be exempt from providing BNG for the time being, including nationally significant infrastructure projects (NSIPs), marine development, urban brownfield sites which do not contain protected or priority habitats and face genuine viability issues, and permitted development and householder extensions. The government also proposes that some developments, for example brownfield and small sites, could be subject to a simplified assessment process.

How will BNG be Delivered?

BNG will be delivered through the planning system and all new projects (with the exceptions outlined above) that have any kind of land take will be required to deliver 10% BNG on pre-development levels. The 10% gain may be achieved through the provision of on-site measures, such as creation of diverse public open space or the enhancement of existing ecological features which are to be retained. However, for many projects design or spatial restrictions will prevent this 10% gain from being delivered on-site. This is when off-site gains, also known as biodiversity offsetting, will need to be secured elsewhere (usually in the same District). This may be on land owned by the developer, a third party or, where there is no suitable land in the locality, through a statutory credit scheme. The principles for biodiversity offsetting are the same as for on-site measures. Any measures will need to be secured through appropriate legal agreements to ensure both delivery and long-term management of BNG areas and the Environment Bill sets out new legal supporting structures.

How is BNG Calculated?

The mechanism for measuring biodiversity is known as the ‘DEFRA Metric’. This is a spread-sheet based tool which allows the quantification of the baseline value of a development site, and for BNG calculations of the compensation measures. There are multiple factors affecting the calculations including the area and condition of the habitat, its relationship with other habitats (i.e. ecological connectivity) and also its functionality or strategic significance within the landscape. The overall value for each habitat is expressed in ‘Biodiversity Units’ (BU). Using the Defra Metric it is therefore possible to calculate the losses and gains for any development and ensure that the overall outcome achieves the required 10% improvement.

What are the Financial Impacts of BNG?

The Impact Assessment that accompanied the Environment Bill presents an analysis of likely cost of creating a biodiversity unit in the region of £11,000; to put this into context on one hectare of land it would be possible to create approximately ten biodiversity units by creating species rich grassland. However, this cost can vary with different habitat types costing anywhere between £9,000 to £15,000 per biodiversity unit, depending upon the route taken to achieve net gain.

How Can Avian Ecology Help?

Avian Ecology has successfully delivered multiple BNG projects and, as such, has practical experience of when and how BNG should be considered and – importantly – both the commercial and planning implications. , We have provided BNG calculations for many of our existing clients and projects in the residential, commercial and solar array sectors.

Given there can be substantial cost implications, we strongly recommend that developers start considering BNG at the project inception. The project ecologist and landscape designer should be brought into the project team early, so that the possible BNG requirements can be incorporated into the scheme design and the overall costs understood and managed.

As well as practical experience, the Avian Ecology team has received comprehensive training in BNG, including the use of the Defra Metric.

We are well placed to assist with the delivery of ecology elements for the majority of projects so please get in touch for further advice and information.