Biodiversity net gain
Practical support to help developers achieve 10% biodiversity net gain
Development that leaves nature in a better state than before
Biodiversity net gain (BNG) measures the impact a development will have on biodiversity. To achieve BNG, a development must include a measurable increase in habitat over and above what is lost.
The National Biodiversity Network’s State of Nature 2019 report noted that from 1970 and 2016, there has been a 13% decrease in the abundance of species. To tackle this continuing decline, mandatory BNG was introduced with the Environment Act 2021.
BNG can be done on-site, off-site or through a combination of measures. If off-site is the only way, the local planning authority will want any improvements secured through a planning obligation or conservation covenant for 30 years.
The mitigation hierarchy
The first step developers can take to avoid further habitat loss is to follow the mitigation hierarchy.
1. Avoidance
1. Avoidance
The ideal option is to avoid any negative impacts. Examples include finding an alternative site for the development, retaining habitat features or changing work timings to fit around species activity.
2. Mitigate
2. Mitigate
The second most desirable option is to apply mitigation measures to reduce impacts to the point where works will have no adverse effects.
3. Compensate
3. Compensate
If avoidance and mitigation is not achievable, the project should then look to compensate on site for biodiversity losses.
4. Offset
4. Offset
If none of the above is possible, developers can pay for improvements elsewhere to offset the impact. This should be only a last resort.
Calculating your BNG
Because biodiversity is not measurable, we use biodiversity units to calculate a site’s biodiversity value. The size, location and quality of on-site habitats are entered into a biodiversity metric to calculate biodiversity units. The calculation helps us to understand the impact a development will have. It also enables us to determine the required offset action.
At ADAS, our ecologists use the most recent industry standard. Defra announced that Natural England’s Biodiversity Metric 4.0 has replaced Biodiversity Metric 3.0. This became the mandatory standard in 2023.
How ADAS can support you in achieving BNG
To reduce any risk of a net loss, we will want to consider net gain as early as possible in the development design process to avoid substantial offset costs later. At ADAS, we have a diverse team of experts to help you meet any biodiversity planning conditions at every stage.
Initial site surveying
Our CIEEM-accredited ecologists conduct a baseline survey and habitat assessment. They will also undertake desk-based studies of the local area to gather relevant information. This can be done as part of a preliminary ecological appraisal for the proposed development.
Calculating BNG requirements of your development
Using that survey information, our geographic information system (GIS) team will create accurate habitat measurements. We will enter this data into the latest biodiversity metric to produce the site’s current biodiversity value. Details about the proposed development will also be inputted to predict the biodiversity value for the finished project.
Designing the scheme to maximise biodiversity gain
Our landscape architects will work with you to design a scheme for net gain. By involving ADAS at the initial design stage, our landscape architects will spot any potential net losses before plans are finalised. We can then offer recommendations on what habitats could complement the project and where to locate them as part of the design.
Speak to the teamProducing a BNG plan
After completion of the design process and finalisation of BNG calculations, we will produce a concise and robust biodiversity net gain report for your planning application. The report will:
- detail each stage of the assessment for transparency
- provide evidence of our processes and our decision making
- describe how the proposal followed the mitigation hierarchy
- describe how the measures will meet each of the ten biodiversity design principles
- safeguarding details of how biodiversity net gain will be sustained long term
- details of any offsetting requirements
If it’s not possible to achieve net gain on site
We can assist with finding a suitable off-site location. The agriculture side of our business has very close ties with rural business. These relationships mean we may be able to connect you with a land manager to carry out habitat improvements on your behalf.
By working closely with both the local authorities and landowners, we can help ensure the project meets long term requirements.
Implementation and long-term management
Habitat creation and site management
Habitats created for biodiversity need to be protected and managed for at least 30 years. Our team of experts will produce a long term management plan that will provide all the information and data needed to help achieve a successful programme.