Published on 07/02/25 & Updated on 30/05/25
Biodiversity Net Gain (BNG) has become a key consideration for every developer, now a legal requirement for most developments since February 2024.
But what does it actually mean? In simple terms, BNG requires that every project leave the natural environment in a measurably better state than before development.
Under the Environment Act 2021, Under the Environment Act 2021, all qualifying projects must deliver at least a 10% net gain in biodiversity compared with the site’s pre-development baseline to gain planning approval.
- Major developments (large residential or commercial) have been required to comply since 12 February 2024.
- Small sites followed in April 2024.
- Nationally Significant Infrastructure Projects (NSIPs) will follow by 2025.
This shift brings both challenges and opportunities for developers, landowners, and planners. Understanding how BNG works and how to stay compliant is now essential.
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
- Baseline assessment: Calculate the site’s existing biodiversity value before development.
- Projected improvement: Estimate the biodiversity score after construction – it must show at least a 10% net gain.
- Gain Plan submission: The plan must be approved by your Local Planning Authority (LPA) before any works start. It can be submitted after planning permission is granted.
If a developer fails to meet their approved plan, the LPA can enforce compliance, even if BNG conditions weren’t listed in the original approval.
Once biodiversity improvements are achieved, they must be maintained for at least 30 years. This obligation is tied to the land, meaning future owners inherit the responsibility.
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:
- Offset any biodiversity losses caused by development
- 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.
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.
1. 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.
2. 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.
3. 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.
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.