Biodiversity Net Gain: Why Early Planning Matters
Biodiversity Net Gain (BNG) is now a key requirement for many planning applications across the UK. Yet one of the biggest challenges still affecting projects is timing.
At Encon Associates, our ecology team regularly sees BNG requirements being considered too late in the planning process, often leading to missed survey windows, project delays and unnecessary pressure on delivery timelines.
Understanding how BNG assessments work and when they should be carried out can make a significant difference to the success of a project.
What is a BNG Assessment?
At its core, a BNG assessment is about measuring and improving biodiversity on a site.
The process begins with a condition assessment survey carried out by an ecologist on site.
During the survey, habitats are identified, classified and assessed. The information gathered is then used to complete the BNG metric, allowing biodiversity to be quantified in measurable units.
This helps planners and developers understand the site’s ecological value and what measures may be needed to satisfy planning and legislative requirements.
Because when it comes to BNG, timing really does matter.
Why Timing Is So Important
Timing is one of the most important, and often overlooked, aspects of BNG. Most surveys are carried out between April and October.
However, this can vary depending on:
- Habitat types
- Species present
- Site conditions
This creates a limited seasonal window for collecting accurate ecological data. Missing that window can significantly delay projects, particularly if surveys cannot be completed until the following season.
Early engagement with an ecologist helps avoid this by ensuring surveys are completed at the right time and ecological constraints are identified before designs progress too far.
Every Site Is Different
The complexity of a BNG survey depends entirely on the site itself.
Smaller sites may only require a few hours of survey work, while larger or more complex habitats can take several days to assess fully.
Even areas of regularly mown grassland can still contain a variety of species that need to be recorded and assessed accurately to complete the BNG metric.
A Smarter Approach to BNG
BNG shouldn’t be treated as a last-minute compliance task.
When approached early, it becomes an opportunity to:
- Enhance site value
- Strengthen planning outcomes
- Deliver more sustainable developments
How Encon Associates Can Support
At Encon Associates, our ecology team supports projects from early feasibility through to planning and delivery. We help clients:
- Carry out BNG assessments and surveys
- Complete BNG metrics
- Develop practical enhancement strategies
- Navigate planning requirements confidently
As BNG continues to shape development across the UK, taking an early and proactive approach has never been more important.
Because when it comes to Biodiversity Net Gain, timing really does matter.
