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  • Dr Julia Haywood

Biodiversity Net Gain: 5 Things to Consider Before Developing a Site

Updated: Jun 2, 2023

Biodiversity Net Gain (BNG) is arriving on developers' doorsteps in November 2023. Instead of seeing BNG as a legal requirement or restriction, it should be seen as a way for the development sector to become leaders in a nature-positive system, where development projects are leaving nature in a better state than before! If effectively done, this will benefit not only the site's residents or users but also the local communities and wider ecosystems. To help, here is a quick guide on BNG and a checklist of what to consider!


What is required for BNG?


The Environment Act includes a mandatory requirement for 10% BNG for development projects in England, that will come into effect in November 2023. BNG is a mandatory legal requirement for the development sector to deliver more for nature; setting a requirement for all new developments to increase biodiversity by a minimum of 10% compared to the baseline, and ensuring it is secured for at least 30 years.


BNG is relevant to developers from all sectors, including housing, energy, and transport and applies to any developments submitting planning applications after November 2023, and for small sites after April 2024.


5 things for developers to consider:


1. Avoid, Avoid, Avoid!


The easiest way to achieve BNG is to avoid impacts on biodiversity from the get-go! This means having biodiversity at the forefront of your decision-making, during site selection. Conducting a high-level assessment of BNG requirements determines if a site is viable and minimises the risks of proceeding with non-viable sites. This reinforces the mitigation hierarchy by helping developers avoid sites of high biodiversity value, e.g. with irreplaceable habitats, and in turn, preventing incurring high costs to achieve BNG.


2. Design for biodiversity


Once a development site is selected, design the site with biodiversity in mind. Following the mitigation hierarchy, it is important during the design to:

  • Avoid impacts by retaining areas of existing high biodiversity

  • Minimise impacts by altering the design around biodiversity

  • Mitigate impacts by enhancing or creating habitats on-site, e.g. via landscaping or green infrastructure.

Designing your site with these steps in mind will minimise your BNG requirements and improve the likelihood of achieving planning consent.


3. The last resort


If BNG cannot be achieved on-site, it is vital for the developer to identify a local off-site location where habitats can be enhanced or created to offset the impacts of the development. This location can be owned by the developer or through credits purchased from a land manager or habitat banker but these sites must be legally secured, registered, and approved. As a last resort, statutory biodiversity credits must be purchased from the government, however, evidence to confirm that on-site or off-site BNG is unattainable must be presented and these credits will likely be very costly. On-site and off-site BNG strategies need to be included in the BNG planning pre-application and submitted prior to project commencement.


4. Don’t do it alone


Consulting with a trained ecologist and/or landscape architect will enhance the success of a BNG strategy, by designing a site with best practice principles, local ecological expertise, and local priorities at the core. Collaborating with local stakeholders throughout the process will enhance the functionality of the site and create greenspaces that benefit the local community, as well as feed into regional and national biodiversity goals.


5. Think ahead


BNG must be secured for at least 30 years, requiring a long-term commitment by the developers to maintain and monitor the biodiversity on the site. This will require having ecologists and/or land managers provide maintenance and management to ensure the site delivers its targets and achieves the BNG as intended, as well as being resilient to external factors like climate change. Thinking ahead is vital to ensure you continue to meet your BNG requirements!

How can the BNG screening tool help?


The BNG screening tool is here to help! The tool allows for a rapid and efficient high-level assessment of development sites anywhere across England, identifying which development sites are viable or not for BNG. The tool uses highly trusted data sources, automates the process of conducting a desk-based review, and calculates the likely BNG implications using the Biodiversity Metric calculation, instantaneously. The BNG screening tool considers 55 habitats, and flags additional constraints such as designated sites and the presence of irreplaceable habitats. It allows non-viable sites to be avoided and informs site design, helping biodiversity to be placed at the forefront of decision-making.



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