About Habitat Banks West Midlands
Habitat Banks West Midlands supports biodiversity net gain delivery by connecting development projects with off-site habitat creation across England. It works with developers, landowners and planning professionals on habitat banking, biodiversity unit provision and long-term ecological management, and publishes resources explaining how BNG and habitat banking work. Learn more at habitatbankswestmidlands.co.uk.
How GIS Is Transforming Biodiversity Net Gain Site Selection Across the UK
Every planning application in England now carries a spatial data problem. Since the mandatory requirements of biodiversity net gain (BNG) for developers, they can no longer simply win permission and start building. They have to show, square metre by square metre, that a site will hold more measurable biodiversity after construction than it did before, then keep demonstrating it for thirty years. That is a mapping question long before it becomes an ecology one.
For GIS professionals, this is one of the most significant new applications of spatial technology to reach UK planning in years. Habitat boundaries, condition scores, protected-site buffers, land ownership and thirty-year projections all have to line up in the same coordinate space.
Get the geography wrong, and the biodiversity calculation falls over with it. This article looks at how GIS has moved from a supporting tool to the backbone of BNG site selection, assessment and long-term monitoring.
Why biodiversity net gain became a GIS problem
The rule is easy to state. Most developments in England must now leave a site measurably better for wildlife than they found it, by at least 10%. That has applied to major schemes since February 2024, to smaller ones since April, and it will reach major infrastructure projects from November 2026. The gain is counted in biodiversity units using Defra and Natural England’s statutory metric, and it has to hold for thirty years.
The hard part is everything behind that number. A biodiversity unit depends on the habitat’s type, area, condition, distinctiveness and where it sits. Developers have to work down the mitigation hierarchy, avoiding harm first, reducing it next, and compensating only as a last resort. When a site can’t deliver enough on its own, the shortfall is bought in from off-site habitat banks that have created or restored habitat elsewhere. Every one of those calls comes back to a question of where things are.
Screening and Surveying
Before BNG, an early look at a site meant a desk study, some planning history and maybe a walkover. Habitat data, if it existed at all, was scattered across PDFs and spreadsheets; boundaries were drawn by hand, and two ecologists might label the same field two different ways.
A 10% legal test shows the weakness in that. If the first proper read on a site’s ecology arrives with a survey booked after the land is chosen, any bad news lands late, when the only options left are an expensive redesign or walking away from the deal. Surveys cost money and take time, and there simply aren’t enough ecologists to walk every field a developer might fancy.
Working from spatial data flips the order. You screen a long list of sites from the desk, drop the ones with obvious problems, and send an ecologist out only to the few that look worth it. The survey then confirms what the maps already suggested, and scarce ecology time goes where it counts.
How GIS is changing site selection
The real shift is that BNG feasibility can be judged before anyone sets foot on site.
Multi-layer screening: A single GIS project can stack priority habitats, designated sites such as SSSIs and SACs, flood zones, topography, land ownership, utilities and planning constraints in one view. Instead of cross-referencing five reports, a planner sees how the constraints overlap and where they cancel each other out.
Rapid multi-site comparison: Rather than backing one plot, developers can run the same screen across dozens and rank them by likely BNG cost and delivery risk. The National Planning Policy Framework now nudges applicants to weigh net gain early and build it into site selection and design.
Better design decisions: With habitats mapped up front, a layout can steer around the high-distinctiveness parcels and keep patches connected, instead of bolting mitigation on once the master plan is fixed. That is the mitigation hierarchy doing its job.
Standardised habitat mapping: The statutory metric is built on the UK Habitat Classification, and Natural England has published a GIS data standard and QGIS template so habitat polygons feed the metric the same way every time. Ordnance Survey’s Enhanced Land Cover (Beta) takes it further, blending its national topographic database, aerial imagery and OS Terrain 5 with open habitat sources such as Natural England’s Living England and the UKHab classification. Practitioners get a shared national baseline rather than each firm redrawing one from scratch.
Faster, targeted surveys: Wessex Water manages biodiversity across roughly 3,000 hectares in Wiltshire, Dorset and Somerset, viewing hundreds of sites in one spatial picture and modelling thirty-year projections, using Linckia’s Habitat Fabric on the Esri platform inside the GIS it already ran.
Finding off-site units that fit
Plenty of schemes can’t fit their full 10% inside their own boundary. When that happens, the developer buys units from land elsewhere that’s been improved to produce them, and the task turns into finding the right match on a map.
This is where GIS earns its place. A developer can filter the available off-site units by the things that determine whether they’ll actually work for a scheme:
- How close is the land to the development
- Whether the habitats on offer match what’s being lost
- The ecological condition and distinctiveness of that habitat
- The price and how many units are genuinely available
Authorities are building this into their own systems. Hertfordshire County Council uses ArcGIS Survey123 to gather landowner details, likely unit counts and the species present, which helps line supply up with demand. Natural England’s public Biodiversity Gain Sites Register adds another view, recording where registered gain sites sit and how their units have been allocated.
Dedicated habitat bank providers, such as Habitat Banks West Midlands, create and manage habitat ahead of demand, then sell the verified units on to schemes that need them. To a GIS professional, each bank is one more spatial dataset to find, weigh up and fold into a site’s wider picture of BNG for landowners and developers.
Monitoring that has to last 30 years
A 10% gain that must survive thirty years isn’t something you check once. It becomes a record someone has to keep, update and defend for three decades, which is squarely GIS territory.
East Riding of Yorkshire Council is building an environmental digital twin for exactly this, a living map where planning officers log which habitats are being created or restored, check new applications against it, and report on what’s been gained or lost. Because the layers are time-aware, the same map can show a new woodland as saplings today and model it as a mature habitat later.
The monitoring gets lighter too. Satellite and aerial imagery can catch encroachment or damage between visits, so not every check needs someone on site. When a visit does happen, mobile GIS records GPS-located, photographed condition surveys that feed straight back into the master map, and that is what builds the audit trail a regulator will eventually ask to see.
GIS is now a core planning infrastructure
BNG has done something quietly important for the profession. It has made GIS the thing a legal process depends on, rather than the software that tidies up a map at the end. Spatial data now decides which sites get screened in, keeps habitat records consistent, feeds the metric, points developers towards off-site units and carries the monitoring record across thirty years.
There are two things here worth following if you work in GIS. One is the spatial workflow itself. The other is the market it feeds, the trade in biodiversity units and the habitat banking behind it. The teams treating BNG as a data problem as much as an ecological one are the ones getting it right.