The rules in plain English
- Very High distinctiveness loss: replace with the same broad habitat at Very High; no downgrading permitted.
- High distinctiveness loss: replace with the same broad habitat at the same or higher distinctiveness.
- Medium and below: replace with the same or higher distinctiveness; broad habitat alignment encouraged but not strict.
The rules are encoded in the JP039 trading-rules matrix.[S1]
Compliant worked example
0.5 ha of high-distinctiveness lowland meadow lost; replaced by 0.6 ha of lowland calcareous grassland created on-site with management plan and 30-year monitoring. Same broad habitat (semi-natural grassland), same distinctiveness band (high); trading-rule compliant. After temporal and difficulty multipliers the post-development unit yield must still reach baseline x 1.10.
Non-compliant example
0.5 ha lowland meadow lost; proposed replacement is 1.0 ha modified grassland on a separate parcel. Broad habitat aligned but distinctiveness downgraded from High to Low; trading-rule breach. The developer must either redesign on-site delivery, source off-site high-distinctiveness units, or default to statutory credits at the punitive tier price.[S3]
Watercourse and hedgerow modules
Watercourses and hedgerows trade in separate modules under the metric; a hedgerow loss cannot be compensated by area habitat creation and vice versa. Each module has its own trading rules and statutory credit tier.