In a game-changing move towards environmental sustainability, the UK government has announced significant changes to the planning process, making biodiversity net gain mandatory for all planning applications starting from November 2023. These changes represent a fundamental shift in priorities, as the government aims to emphasise the protection and enhancement of biodiversity alongside economic development. In this blog post, we will explore the key elements of mandatory biodiversity net gain, its benefits, and the requirements of the Environment Act, highlighting the transformative impact on the UK’s sustainable development landscape.

Understanding Mandatory Biodiversity Net Gain
Mandatory biodiversity net gain refers to a new requirement where developers must demonstrate a measurable increase in biodiversity resulting from their projects. Starting in November 2023, all planning applications will need to include evidence-based calculations showing the net positive impact on biodiversity. However, it is worth noting that small site exemptions will exist, with specific criteria to be outlined in government guidelines to strike a balance between conservation efforts and the feasibility of smaller-scale developments.
Unravelling the Environment Act Requirements
The mandatory biodiversity net gain requirement stems from the Environment Act, which sets out several key objectives for developers:
- Calculating Net Gain: Developers must provide evidence-based calculations of the projected biodiversity net gain resulting from their projects. These calculations compare the pre-existing biodiversity value with the anticipated biodiversity value post-development, ensuring a measurable improvement.
- Long-term Maintenance and Monitoring: Developers will be required to submit plans for the long-term maintenance and monitoring of biodiversity enhancements resulting from their projects. This ensures the sustained success of ecological features, such as wildlife habitat creation and restoration.
- Conservation Covenants: The Environment Act introduces the concept of conservation covenants, which create legally binding agreements between landowners and relevant authorities. These covenants safeguard the enhanced biodiversity resulting from net gain initiatives, providing long-term protection for development sites.
Unlocking the Benefits of Mandatory Biodiversity Net Gain
The implementation of mandatory biodiversity net gain is expected to bring numerous benefits:
- Biodiversity Conservation: By requiring developers to actively contribute to biodiversity protection and enhancement, mandatory net gain secures the preservation of valuable habitats and supports species recovery. This approach promotes robust ecosystems and safeguards endangered or threatened species.
- Ecosystem Services: Biodiversity net gain initiatives enhance the delivery of essential ecosystem services, such as pollination, carbon sequestration, and water purification. These services directly benefit communities through improved air and water quality, flood prevention, and climate regulation.
- Urban Green Spaces: The incorporation of biodiversity enhancements within development projects will lead to the creation of more green spaces in urban areas. Access to nature promotes physical and mental well-being, fostering a stronger connection between people and their environment.
Embracing the Implementation Challenges
While the implementation of mandatory biodiversity net gain holds tremendous potential, it also poses certain challenges:
- Guidance and Support: Developers will benefit from clear guidelines and support to effectively implement biodiversity net gain measures. The provision of resources, training, and technological tools will help ensure accurate calculation and reporting of net gains.
- Small Site Exemptions: Defining clear and appropriate criteria for small site exemptions is crucial to avoid disproportionately burdening smaller-scale developments. Striking a balance between conservation and feasibility will be essential for achieving fair and sustainable development. While currently there is no official guidance as to what constitutes a small site, it is believed that ‘minor’ developments of 9 units or less will be exempt, at least until April 2024.
- Monitoring and Enforcement: Strong monitoring and transparent enforcement mechanisms are necessary to ensure compliance with biodiversity net gain requirements. Regular monitoring, audits, and transparent reporting will foster accountability and allow assessment of cumulative net gain achievements.
Conclusion
The upcoming changes to the UK planning process, implementing mandatory biodiversity net gain from November 2023, signal a significant milestone in prioritising environmental sustainability within development projects. These changes will foster a healthier and more resilient ecosystem, benefitting both nature and people. Despite the challenges, clear guidance, support, collaboration among stakeholders, and robust monitoring systems will pave the way for successful implementation. Together, there is no reason why we can’t shape a greener, more sustainable, and ecologically balanced future for housing and development the UK, while still strving to meet the constantly moving housing targets.
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