Biodiversity Net Gain Toolkit — Parcel Accounting

Paint parcels on a land-use grid the way an ecologist scopes a UK planning application: red cells are the development footprint that destroys existing habitat, green cells are the offset or on-site creation that must replace it. Every parcel carries a habitat type (grassland through wetland, each with its own distinctiveness score), and the offset side is discounted for how long it takes to mature and whether it sits on-site or off-site — exactly the risk stack the real Biodiversity Net Gain metric applies before it accepts a scheme as meeting the statutory +10% net-gain requirement. Move the sliders and watch the required and delivered unit totals chase each other in real time.