What is BNG? And what do all these BNG terms actually mean?

Whether you're new to BNG or just need a quick refresher, this glossary breaks down the key terms in a way that’s easy to understand. From habitats to habitat banks (and everything in between), here’s your go-to guide for getting to grips with Biodiversity Net Gain.

A

• Application stage – where BNG requirements must be evidenced to secure planning
  
  

• Arden National Character Area (NCA) – landscape designation relevant to site location and spatial risk
  
  

B

• Biodiversity Net Gain (BNG) – mandatory planning policy requiring a 10% uplift in biodiversity

• Baseline assessment – an ecological survey to determine the biodiversity value of a site before development

• Biodiversity Metric – Natural England’s tool used to calculate losses and gains in biodiversity

• BNG Plan – A BNG Plan sets out how a development will deliver Biodiversity Net Gain (BNG). It explains the site's current biodiversity, how the project will affect it, and the steps being taken to create a measurable net gain. BNG Plans are now a key part of the planning process, and for most major developments, they’re legally required. Developers must show exactly how they’ll leave biodiversity in a better state than before
  
  

C

• Connectivity – linking habitats to improve ecological networks and species movement
  

• Conservation Covenant – a legally binding agreement ensuring long-term management of biodiversity units
  
  

D

• Defra Biodiversity Gain Site Register – official register for approved off-site biodiversity units
  

• Development footprint – the physical area impacted by a proposed scheme
  
  

E

• Ecological uplift – measurable improvement in habitat condition and biodiversity value
  

• Ecosystem context – the local environmental and policy framework surrounding a development or offset site

• Ecosystems – Ecosystems are communities of living things – like plants, animals, and microorganisms, interacting with each other and their environment. They can be anything from a tiny pond to a huge forest, and every part of an ecosystem plays a role in keeping it healthy and balanced.
  
  

H

• Habitat Bank – a site managed to deliver biodiversity units in advance of development
  

• Habitat types – the specific ecological features (e.g. grassland, woodland, wetland) scored in BNG calculations
  
  

L

• Local Planning Authority (LPA) – the authority responsible for assessing planning and BNG submissions
  

• Legal agreement – formalised contract for the delivery, monitoring and enforcement of biodiversity units
  
  

M

• Monitoring – the long-term observation and reporting of habitat success, often required for 30+ years
  

• Metric 4.0 – the current version of the BNG calculator tool
  
  

N

• National Character Area (NCA) – an area of defined landscape identity that informs spatial risk and ecological planning
  
  

O

• Onsite vs. Offsite – whether biodiversity uplift is delivered within the red line boundary of a site or externally
  
  

P

• Planning permission – official approval required to begin development, now linked to BNG compliance
  

• Pre-approved units – biodiversity units created in advance, often banked and ready to sell
  

• Policy context – the regulatory and local plan framework that shapes how BNG is applied
  
  

R

• Risk multiplier – a weighting factor applied based on how far offset units are from the impacted site
  
  

S

• Spatial Risk Multiplier (SRM) – increases the number of biodiversity units required when sourced further from the development
  

• Scrub, meadow, neutral grassland – examples of habitat types frequently restored in Dragonfly banks
  

• Statutory biodiversity credits – government-issued units where no other option is viable (last resort)
  
  

T

• Timeline for delivery – the critical period for establishing biodiversity units in line with planning requirements