Landscape Ecology and Biodiversity Net Gain

A future development site near Newbury in Berkshire 

landscape ecology UK/Chris Foster 2022

In February 2024 a minimum of 10% Biodiversity Net Gain (BNG) became mandatory for developers under Section 7A of the Town and Country Planning Act 1990 (as inserted by Schedule 14 of the Environment Act 2021) in England. In essence, wildlife value will be measurably greater after any development with the increase lasting for at least 30 years. 

The future success of BNG is fundamentally linked to the science of landscape ecology because it depends on biodiversity measured in units related to the size, quality, location and type of habitat parcels. The units are calculated using the Statutory Biodiversity Net Gain Metric (Statutory biodiversity metric tools and guides - GOV.UK (www.gov.uk).  

A biodiversity score must be calculated from a baseline survey of any area subject to development to which the 10% increase must be applied following a set of principles. The first and key principle of BNG is that the Mitigation Hierarchy must be followed. Damage to any Irreplaceable Habitat (Irreplaceable habitats - GOV.UK (www.gov.uk) must be avoided. If that is not possible damage must be minimised by altering development plans. If there are residual impacts after minimisation, onsite restoration must be attempted and finally if that is not possible offsetting may be required. 

A key strength of the BNG process in England is that it has made an incredibly complicated concept relatively simple by concentrating on habitats and this is also the main weakness. You would be right in thinking “but how do we protect species diversity?” In BNG it is assumed that habitat identity and condition act as a proxy for species diversity and this is only partly true. Fortunately, Ecological and Social Impacts Assessments must still be applied to planned developments and these cover rare and threatened species. 

There is a real opportunity for landscape ecologists to use their skills; for example, where onsite restoration goals can be virtually guaranteed over a set time period. Onsite delivery of BNG may be impossible for some projects and the most exciting part of the BNG process for landscape ecologists is the chance to create landscapes for wildlife in new areas that can act as a ‘bank’ of BNG units for developers to purchase. This may be through ‘wilding’ or ‘land sparing’ or complex ‘land sharing’ projects. Landowners are looking to provide biodiversity credits across the UK even though BNG is not yet in place legally in Northern Ireland, Scotland or Wales.  I would urge Landscape Ecology UK members to get involved in the numerous projects that are starting up to create BNG offsets on agricultural and forestry land for financial gain. Some of the projects maybe economically sensitive, so networking will be key if you wish to be included, perhaps using BNG social media groups as a source of contacts.  

Landscape Ecology UK members definitely have a role ensuring BNG projects can maximise biodiversity through sympathetic designs to protect, improve and restore functional landscapes. 

Peter carey