Below are the definitions of some common terms used in the concept of biodiversity net gain. More detailed glossaries can be found in the resources linked to the main Biodiversity net gain page.

Biodiversity unit

A unit which represents a combined measure of habitat distinctiveness, area and condition.

Ecosystem services

The benefits people obtain from ecosystems. These include provisioning services such as food and water; regulating services such as flood and disease control; cultural services such as spiritual, recreational, and cultural benefits; and supporting services such as nutrient cycling that maintain the conditions for life on Earth.

Environmental net gains

Net improvement of all aspects of environmental quality through a scheme or project. It means going further than biodiversity net gain to achieve net increases in the capacity of affected natural capital to deliver ecosystem services.

International, national and locally designated sites of importance for biodiversity

All international sites (Special Areas of Conservation, Special Protection Areas, and Ramsar sites), national sites (Sites of Special Scientific Interest) and locally designated sites including Local Wildlife Sites.

Irreplaceable habitats

Habitats which would be technically very difficult (or take a very significant time) to restore, recreate or replace once destroyed, taking into account their age, uniqueness, species diversity or rarity. They include ancient woodland, ancient and veteran trees, blanket bog, limestone pavement, sand dunes, salt marsh and lowland fen.

Local planning authority or LPA

A local planning authority is responsible for deciding whether a development should go ahead. This includes borough, district and county councils, unitary authorities, national park authorities and development corporations where relevant.

Local sites

These are locally designated sites which do not typically receive statutory protection but are recognised in planning policy for their importance. These include Local Wildlife Sites.

Mitigation hierarchy

The principle that environmental harm resulting from a development should be avoided, adequately mitigated, or, as a last resort, compensated for.

Nature Recovery Network

An expanding and increasingly connected network of wildlife rich habitat. It will be designed to stimulate the recovery of wildlife and will support the delivery of other economic and social benefits, such as water quality improvement or flood attenuation.

Biodiversity net gain

Delivering more or better habitats for biodiversity and demonstrating this measurable gain through use of the Defra biodiversity metric. Development that adopts a biodiversity net gain approach seeks to make its impact on the environment positive, delivering improvements through habitat creation or enhancement after avoiding or mitigating harm.


The creation or enhancement of wildlife habitat to compensate for loss or degradation elsewhere.

Priority habitats

Priority habitats, or habitats of principal importance, are all the habitats in England that were identified as requiring action in the UK Biodiversity Action Plan (UK BAP) and continue to be regarded as conservation priorities in the subsequent UK Post2010 Biodiversity Framework. They include terrestrial habitats such as upland hay meadows to lowland mixed deciduous woodland, and freshwater and marine habitats such as ponds and subtidal sands and gravels.


Government's net gain consultation included proposals for a tariff mechanism to implement a financial charge on development for nature conservation when net gain could not be achieved.

Not what you were looking for?