Biodiversity Net Gain (BNG) is a pioneering environmental planning approach that requires development projects in the UK to leave biodiversity in a measurably better state than before development commenced. Introduced in 2021, BNG requires most developments to deliver a minimum 10% increase in biodiversity value, calculated using Natural England’s Statutory Biodiversity Metric.

The legislation represents a significant shift in how ecological impacts are assessed and mitigated within the planning process, moving beyond traditional impact avoidance towards measurable ecological enhancement. The biodiversity metric is gaining attention worldwide, and is helping countries around the globe adopt a measurable, transparent approach to biodiversity restoration.

To conduct a BNG assessment ecologists must undertake detailed habitat surveys, assess current habitat condition, map proposed (post-development) habitats from (landscape) architect CAD plans, and calculate change in biodiversity ‘units’. The process requires robust GIS workflows.

This presentation will provide a practical case study of how QGIS can support efficient, accurate, standardised, and scalable workflows for delivering BNG analysis. It will explore some of the principal technical challenges involved in conducting BNG analyses. It will also explore the suite of tools (including QGIS forms and models), video training courses, and QGIS workflows developed by Maplango/Spatialsesh to support ecologists. Attention will be given to the role of Qfield/Mergin Maps in streamlining ecological survey workflows, reducing duplication, and improving data quality between field and office environments.

By demonstrating how open-source GIS technologies can be configured to deliver complex regulatory ecological workflows, this session will highlight the growing role of QGIS as a professional platform for biodiversity assessment and environmental planning in both national and international contexts.