National Vegetation Classification (NVC)

Correspondences with other classifications

Correspondences have been identified between the communities and sub-communities of the NVC and types in other mainstream vegetation/habitat classification systems. These include:

• UK BAP Broad & Priority habitat types (based on the list of habitats produced prior to the Species and Habitats Review in 2008) 
• Phase 1 Habitat Classification
• EU Habitats Directive Annex I
• EUNIS (European Union Nature Information System) Classification
• Vegetation communities of British lakes

A spreadsheet outlining these correspondences was produced in 2008. 

NVC volumes – British Plant Communities

The NVC was published by Cambridge University Press in a five-volume series entitled British Plant Communities, edited by John Rodwell. The final volume includes a phytosociological conspectus of British Plant Communities, placing the NVC in a European framework.

• Rodwell, J.S. (ed.) 1991. British Plant Communities. Volume 1. Woodlands and scrub. Cambridge University Press.
• Rodwell, J.S. (ed.) 1991. British Plant Communities. Volume 2. Mires and heaths. Cambridge University Press.
• Rodwell, J. S. (ed.) 1992. British Plant Communities. Volume 3. Grassland and montane communities. Cambridge University Press.
• Rodwell, J.S. (ed.) 1995. British Plant Communities. Volume 4. Aquatic communities, swamps and tall-herb fens. Cambridge University Press.
• Rodwell, J.S. (ed.) 2000. British plant communities. Volume 5. Maritime communities and vegetation of open habitats. Cambridge University Press.

NVC Handbook, field guides and summary descriptions

In addition to the main volumes, a series of other publications and reports are available:

• The NVC Users' Handbook (2006). An introduction to the NVC, its application, and advice on carrying out and analysing an NVC site survey.
• An Illustrated Guide to British Upland Vegetation (2004).  A major work that brings together and describes all NVC communities found in the uplands. It includes updated distribution maps for the communities involved.
• The NVC Field Guide to Woodland (revised 2004) (includes updated distribution maps for woodland communities). The NVC woodland classification is based on 2,648 samples from ancient and recent woods throughout Britain (Rodwell 1991). This is the biggest dataset yet analysed for the production of a woodland classification in Britain (the Stand Type system, for example, was based on about 800 samples (Peterken 1981)). Apart from the sheet numbers of samples, the geographic and ecological spread of sampling makes it the classification most representative of the range of British woodland. The relationships between the NVC and other woodland classifications are shown in Appendix 1.
• Summary of NVC Woodland Descriptions (1992) (largely superseded by the NVC Field Guide to Woodland).  This provides straightforward descriptions of the 18 woodland types identified by the NVC, and keys to their sub-communities. A valuable complement to the NVC, especially for use in the field.
• NVC Field Guide to Mires and Heaths (2002). This volume gives a detailed account of 38 mire communities and 22 heath communities in the UK, providing information on their composition, structure and distribution. From these descriptions, it also relates their similarity and environmental status to other types of vegetation categories, both in Britain and on the continent.
• Summary descriptions of NVC Grassland and Montane Communities (1998) (note a downloadable version of this document is not available). An aide-memoir for field workers and others that combines a series of keys and summary descriptions covering all mesotrophic, calcicolous and calcifugous grassland types within Volume 3 of the National Vegetation Classification.

NVC types

The NVC comprises 286 community types subdivided amongst 12 major types of vegetation. These are arranged in the published NVC volumes as shown (codes for types are given in brackets)

NVC floristic tables

Each community/sub-community within the NVC is uniquely defined by a particular combination of frequency and abundance values for the species found in the samples grouped within it. This information is summarised in a standardised tabular format (i.e. a 'floristic table').

Each floristic table includes all of the vascular plants, bryophytes and macro-lichens that occur within the type with a frequency of 5% or more in any one of the sub-communities (or for vegetation types with no sub-communities within the community as a whole). The species are arranged in blocks to indicate their pattern of occurrence through the community, as explained in the NVC Users' Handbook and main NVC Volumes.

A spreadsheet containing much of the information in the NVC floristic tables accompanies the Users' Handbook.

NVC survey data

The published volumes of the NVC are based on a total of about 35,000 samples or relevés. In most cases these comprise a list of species and their abundances from a single square quadrat, together with information on the locality, soil, etc. For woodland stands, however, a sample summarises data from three nested quadrats, each covering a separate layer (i.e. field layer, tall field layer, canopy and shrub layer).

Since the time of original publication, many thousands more NVC samples have been made. Some have associated site maps that show the extent of particular NVC communities/sub-communities. The country nature conservation bodies and others have significant data holdings coded using the NVC. Some of the more extensive NVC surveys have been collated or summarised, for example:

• Sand Dune Vegetation Survey of Great Britain (see Dargie 1993, Dargie 1995, Dargie 2000, Radley 1994);
• Coastal Vegetated Shingle Structures of Great Britain (see Sneddon and Randall 1993);
• NVC Review of Scottish Grassland Surveys (see Cooper and MacKintosh 1996);
• Review/experience of woodland NVC data (see Hall 1997, Goldberg 2003);
• Lowland Grassland Survey of Wales (see Stevens et al. 2007);
• Lowland Heathland in Wales (see Sherry 2007).

Although some of this data has been encoded in various types of database or spreadsheet software, much has not, and NVC information remains widely dispersed in numerous locations that are not linked electronically. There is no centralised database of all NVC samples or surveys undertaken.

Distribution maps of NVC types

A collection of Excel-based mapping tools is available on JNCC's Resource Hub, which show the distribution of NVC types in Britain, dating back to around 2008 or earlier. There are four resources, covering the following NVC types:

• Upland (as published in An Illustrated Guide to British Upland Vegetation)
• Lowland Grassland
• Woodland
• Lowland Heathland (in Wales).