NBN Atlas
What it is
The NBN Atlas is the UK's largest aggregator of species occurrence records — "this species was recorded here, on this date" — pooled from wildlife recording schemes, local record centres, conservation bodies, and citizen scientists. It is a species resource, not a habitat one: it tells you what has been seen, not what habitat is present.
How it's produced
Aggregated from many independent data providers, each with its own methods, standards, and coverage. Records range from expert survey to opportunistic citizen sightings, with varying spatial precision (some blurred/gridded for sensitive species).
Update frequency & currency
Continuously updated as providers contribute, but coverage and recency vary wildly by taxon, region, and recording effort.
Spatial resolution / precision
Highly variable — from precise grid references to deliberately coarse blurring for sensitive species. Never assume uniform precision.
Known limitations
- Recorder-effort bias — the defining caveat. Records cluster where people recorded, not where species necessarily are. Well-visited sites look biodiverse; under-recorded areas look empty. Absence of records is emphatically not evidence of absence.
- Presence-only. The data says where something was seen, not where it wasn't.
- Heterogeneous quality. Aggregated from many sources with different rigour.
- Temporal spread. A record may be decades old.
Role in BNG assessment
Contextual / advisory — NBN records help build a species-context picture for a site (e.g. protected or notable species recorded nearby), informing what field survey might need to target. It is not a habitat-parcel source and cannot, on its own, confirm presence or absence for a planning decision.
The NBN Atlas is indispensable and constantly misused, and both facts stem from the same thing: recorder-effort bias. A blank map around a site usually means "nobody looked", not "nothing there" — yet absence of records gets quietly treated as reassurance all the time. Conversely, a dense cluster of records often just marks a popular nature reserve or an active local recorder, not a uniquely rich site. We use NBN to raise questions for survey — "there are historic GCN records within 500 m, check this" — never to answer them. Treating presence-only citizen data as a complete species inventory is one of the most common and most confidently-made errors in desk-based ecology.
Official source
Last reviewed
5 July 2026. A stable resource; revisit mainly if the NBN Atlas changes its data model, access terms, or major data-provider coverage.