Biodiversity Net Gain – the Basics from the Landowner’s Perspective

Jun 21, 2024

Recent legislation means that most planning permissions are now granted subject to a condition that the development will deliver at least a 10% increase in biodiversity value compared to the pre-development biodiversity value of the onsite habitat. Some local plan policies may require gains over and above 10%. These gains can be achieved on the development site, through registered offsite biodiversity gains or through statutory biodiversity credits. The gains must last for at least 30 years (i.e. 30 years maintenance from when the habitat enhancement work is completed).

As developers can meet their BNG requirements through offsite gains there are exciting opportunities for landowners who are able to create or enhance habitats on their land in such a way as to generate biodiversity units which can be sold to developers.

Closeup shot of a finch perched on a rock with a blurred background

Biodiversity units are established through use of a statutory biodiversity metric which measures the baseline biodiversity of the land and then calculates how many units habitat creation or enhancement could generate. This exercise should be undertaken by a qualified ecologist. It is worth consulting any relevant Local Nature Recovery Strategy which are being produced in order to assist the better targeting of BNG.

Biodiversity units must be registered with Natural England and can be sold and therefore allocated to developers who need them to meet their BNG requirements. Allocations must also be registered.

The biodiversity units are secured by a planning obligation under section 106 of the Town and Country Planning Act 1990 (with the local planning authority) or through a conservation covenant (with a body designated by DEFRA, these include Natural England). Each of these is a written legal agreement which is executed as a deed.  Those agreements will make the landowner legally responsible for creating or enhancing the habitat and maintaining it for at least 30 years most likely in accordance with a habitat management and monitoring plan. It is therefore essential that when a landowner sets the price for their units they should take into account all of the likely costs over that thirty year period.

Further useful information can be found in the DEFRA guidance ‘Sell biodiversity units as a land manager’ and the ‘Step by Step Flowcharts

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Marc Garfield
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