National Biodiversity Network (NBN)
A project to collate and share the information about biodiversity and wildlife held in many separate sources. It aims to make records accessible and to spread knowledge, thus allowing decisions to be based on accurate, up-to-date information. The NBN forms one of the strands which aim to achieve the UK BAP objectives, laid out in the UK Biodiversity Steering Group Report.

NNR - National Nature Reserve
A reserve as declared under section 19 of the National Parks and Access to the Countryside Act 1949, or section 35 of the Wildlife and Countryside Act 1981, and managed by English Nature or by a body approved by English Nature. All NNRs are also SSSIs (see below).

NVC - National Vegetation Classification
A system providing a detailed phytosociological classification of Britain’s vegetation according to the presence/abundance of characteristic plants. They are described in five volumes entitled British Plant Communities, published by Cambridge University Press (Rodwell 1991 et seq.).

Nationally important numbers (of birds)
One per cent of the UK population of a species.

Nationally rare species
A terrestrial species of plant or animal which occurs in 15 or fewer 10km squares in Great Britain, or a marine species which occurs in eight or fewer 10km squares within the three mile territorial limit of seas for Great Britain.

Nationally scarce species
A terrestrial species of plant or animal which occurs in 16-100 10km squares in Great Britain, or a marine species which occurs in 9-15 10km squares within the three mile limit of territorial seas for Great Britain.

Natura 2000 sites
The Natura 2000 network of protected sites comprising Special Areas of Conservation (SACs) and Special Protection Areas (SPAs).

Natural Area
A biogeographic zone which reflects the geological foundation, the natural systems and processes, and the wildlife in different parts of England. They are used by English Nature to set objectives for nature conservation, and are increasingly being linked to Local Biodiversity Action Plans.

Natural Resource Accounts
Natural Resource Accounts attempt to monitor the stack of environmental resources over time, drawing their name from analogies with national accounting of economic and financial measures. As well as presenting indicators of environmental stocks, these accounts attempt generally to present indicators of changes in stock levels, known as ‘flows’.

Nature Conservation
The maintenance and enhancement of the Earth’s natural heritage. This includes its wildlife (habitats and species) and its landforms and geological heritage. Modern nature conservation is concerned more with active management rather than preservation, encapsulating sustainability.

Nature Conservation Review Site
One of more than 700 sites listed in A Nature Conservation Review (Ed. D.A. Ratcliffe, Cambridge University Press, 1977), and considered at the time to be of national or international importance.