Biodiversity Net Gain For Developers: What You Need To Know

February 7, 2025

Biodiversity Net Gain (BNG) is now a crucial consideration for developers, having been a legal requirement for most developments since February 2024. 

But what does biodiversity net gain mean, and how does it affect developers?

Essentially, the biodiversity net gain regulations require projects to leave the natural environment in a measurably better state than before. 

Under the Environment Act 2021, developers must ensure that their projects deliver a minimum of 10% net gain in biodiversity, compared to the predevelopment baseline to secure planning permission.  

Major developments, including large residential and commercial projects, had to comply from 12th February 2024, with smaller sites following in April 2024 and Nationally Significant Infrastructure Projects (NSIPs) expected to comply by 2025.

This shift presents challenges, but also opportunities for developers, landowners, and conservation professionals. Understanding how BNG works, available compliance options, and the long-term commitments involved is crucial for anyone in the development sector. 

In this guide on biodiversity net gain for developers, we’ll break down everything developers need to know about BNG, including how tools like Landstack’s BNG layer can help simplify the process. 

Pre-Development BNG Requirements For Developers

Before any construction work can begin, developers must adhere to strict Biodiversity Net Gain regulations, ensuring their projects enhance biodiversity rather than diminish it.

For sites where BNG applies, planning permission will only be granted if the developer commits to a Biodiversity Gain Plan.

This document prepared by the developer, outlines how the project will achieve at least a 10% net gain in biodiversity compared to the site’s pre-development ecological value. 

Approval Process and Compliance

The first step is to assess the site’s existing biodiversity by calculating a pre-development biodiversity score

This is then compared to a predicted post-development score, which must demonstrate a minimum 10% improvement, even after construction.

The Biodiversity Gain Plan must be approved by the Local Planning Authority (LPA) before any building work begins. However, it does not need to be submitted at the same time as the initial planning application. It can be provided after permission has been granted. 

If a developer fails to adhere to their approved BNG plan, the Local Planning Authority has the power to enforce compliance, even if BNG conditions were not explicitly stated in the planning approval. 

Additionally, once a development achieves its BNG commitments, the site’s biodiversity must be maintained for at least 30 years. This obligation is legally tied to the land itself, meaning that if ownership changes, the responsibility remains with the property. 

The LPA retains the power to enforce compliance with this long-term commitment, ensuring biodiversity gains are preserved for future generations. 

Pre Development BNG Requirements For Developers
If a developer fails to adhere to their approved BNG plan, the Local Planning Authority has the power to enforce compliance, even if BNG conditions were not explicitly stated in the planning approval. 

Measuring Biodiversity Net Gain For Developers

Biodiversity Net Gain is assessed using a standardised biodiversity metric, which quantifies habitat value in measurable biodiversity units. These units take into account factors such as quality, location, and habitat size, to determine their ecological worth. 

Developers can generate biodiversity units by creating new habitats or enhancing existing ones, to increase their environmental value.

To gain approval for a Biodiversity Gain Plan, developers must use the statutory biodiversity metric tool

This tool calculates the baseline biodiversity value of the site before development and the projected post-development value. It determines the total number of biodiversity units required to: 

  1. Offset any biodiversity losses caused by development
  2. Achieve the mandatory 10% net gain to meet legal requirements

By converting these calculations into an overall BNG score, the metric maintains a transparent approach to assessing biodiversity across all developments. 

Measuring Biodiversity Net Gain For Developers
Developers can generate biodiversity units by creating new habitats or enhancing existing ones, to increase their environmental value.

How To Achieve Biodiversity Net Gain

Developers have three primary options to meet mandatory biodiversity net gain requirements which all have different implications: on-site improvements, off-site habitat creation, or purchasing statutory biodiversity credits. 

On-Site Biodiversity Gains

Where possible, developers should prioritise enhancing biodiversity within the development site itself.

This involves incorporating nature-friendly design elements such as native plantings, green roofs, wildlife corridors, and ponds within the site boundary (often referred to as the ‘red line’ area).

On-site biodiversity improvements provide immediate ecological benefits, helping to maintain local habitats and promote biodiversity resilience directly within the development.

Off-Site Biodiversity Gains

If achieving the required BNG uplift within the development area is not practical, developers can invest in off-site biodiversity projects. This involves collaborating with landowners or conservation organisations to improve habitats in other locations. 

All off-site biodiversity enhancements must be registered in the public Biodiversity Gain Sites Register and require landowner consent. This approach allows developers to support broader ecological restoration efforts, while still fulfilling their BNG obligations.

Statutory Biodiversity Credits

If neither on-site nor off-site biodiversity improvements are possible, developers can purchase statutory biodiversity credits as a last resort.

These credits are used to fund conservation initiatives elsewhere, helping to offset biodiversity losses. However, this is considered the least desirable option, as it does not contribute directly to the local environment or the development site’s ecological value.

On-Site Biodiversity Gains
Developers should prioritise on-site biodiversity gains with nature-friendly design elements, resorting to statutory biodiversity credits only as a last resort.

How Landstack’s BNG Layer Helps Developers

Understanding Biodiversity Net Gain and maintaining compliance can be complex, but Landstack’s BNG layer provides an innovative solution to simplify the process. 

Our new BNG layer offers an interactive mapping tool which covers the entire country, allowing developers to instantly assess habitat types on any piece of land. 

This feature combines satellite imagery with verified environmental data sets, creating a detailed habitat map that helps developers understand the existing ecological value of a site before development begins. 

Landstack’s BNG Layer: Key Features

  • Comprehensive Habitat Data: Displays various habitat types, including wetlands, hedgerows, watercourses, and grasslands.
  • Interactive Site Analysis: Developers can click on a specific location to instantly view habitat details, such as biodiversity score and distinctiveness value.
  • Automated BNG Appraisal: Using a mapping tool, users can outline a site to generate an initial BNG assessment report, estimating the biodiversity units needed for compliance.
  • Quick and Free Access: Available to all Landstack subscribers, allowing unlimited assessments without additional cost.

Landstack’s BNG layer helps developers proactively evaluate their sites, estimate potential biodiversity requirements, and make informed decisions on habitat enhancements or offset strategies. 

Our tool streamlines the planning process, helping developers comply with BNG regulations more efficiently, reducing the risk of planning delays. 

Call us on 01285 706708 for more information.