Phase 1 Habitat Classification



The Phase 1 Habitat Classification and associated field survey technique provide a standardised system to record semi-natural vegetation and other wildlife habitats. The approach is designed to cover large areas of countryside relatively rapidly. It presents the user with a basic assessment of habitat type and potential importance for nature conservation. Each habitat type/feature is identified by way of a brief description of its defining features. It is then allocated a specific name, an alpha-numeric code, and unique mapping colour.


Brief history

Early work on the Phase 1 survey technique dates back to the 1970s. This was developed further in the 1980s and in 1990 an A4 Phase 1 Handbook and supporting A5 Phase 1 Field Manual were published by the Nature Conservancy Council (NCC). Later versions of these publications (with limited additions) have been produced by JNCC (see below).


Since its creation, the Phase 1 technique has been used widely. Many county-wide surveys have been completed, along with many other more localised mapping projects (see Wyatt 1991). The Phase 1 Habitat Survey of Wales, which was completed in 1997 by the Countryside Council of Wales, provides coverage of the whole of Wales (Howe et al. 2005). The approach is a commonly used standard in the preparation of environmental impact statements and other ecological baseline surveys. It is also useful in identifying Open Country under the The Countryside and Rights of Way Act 2000.


Details of the Phase 1 habitat types

The Phase 1 classification comprises ten (A-J) broad high level categories:

        A: Woodland and scrub

        B: Grassland and marsh

        C: Tall herb and fen

        D: Heathland

        E: Mire

        F: Swamp, marginal and inundation

        G: Open water

        H: Coastland

        I: Exposure and waste

        J: Miscellaneous


Amongst these, 155 specific habitat types are recognised, each having its own name, alpha-numeric code, description and mapping colour. A spreadsheet containing all the Phase 1 habitat names and codes is available via the following download: Phase 1 codes for habitats & dominant species. This spreadsheet also contains the Phase 1 codes for dominant species and shows the additional habitat categories created for the Phase 1 Habitat Survey of Wales (NB: the latter have NOT been formally incorporated into the JNCC Phase 1 classification).


Descriptions of each of the Phase 1 habitats are available in the JNCC A4 Phase 1 Handbook or A5 Phase 1 Field Manual.


Correspondence with other classifications

An interactive spreadsheet containing the correspondences between Phase 1 types and those identified in other mainstream vegetation/habitat classification systems is available via the following download: NBN dictionary habitat correspondances.


GIS (including Phase 1 colour mapping palette)

An ArcGIS 'style file' containing the Phase 1 colour mapping palette is available via the following download:

Phase 1 mapping palette.


This file can be extracted and applied to ArcGIS shapefiles (polygons, lines and points), using ArcGIS version 8.x or later. The download includes:


(i) a README.doc file (explaining how to extract and install the palette);

(ii) the Phase 1 ArcGIS palette style file;

(iii) a PDF legend showing the whole palette on a single page;

(iv) an Excel spreadsheet containing the RGB (Red-Green-Blue) values for each colour used in the palette (this should allow users to create the same palette in other software).



For MapInfo GIS users, a Phase1 habitat survey 'keysheet package' is available from the RSK website. This includes examples of its application and a key in PDF format. The website has instructions on its use and a contact for feedback.


BosqMap Ltd have also produced a MapInfo add-on tool for producing Phase 1 habitat maps. MapInfo fill pallet, line styles and symbols have been customised to match the styles in the Phase 1 Handbook. The software works on all MapInfo versions from 8.0 onwards. Click here for further details and to request a trial download.



SNH Information and Advisory Note Number 62 provides advice on handling Phase 1 habitat survey data within a GIS environment.


JNCC Phase 1 publications

There are two JNCC Phase 1 publications, which have been reprinted several times with limited revisions and additions (see below). There has, however, been no change made to the Phase 1 habitat types or the colour palette since its publication in 1990.



A4 Phase 1 Handbook: this was published first in 1990, reprinted in 1993, reprinted again in 2003 with limited revisions & additions, reprinted again in 2004, reprinted agian in 2007 with minor additions, and reprinted last in 2010 with minor revisions.


Note that no changes have been made to the Phase 1 classification itself, including the alpha-numeric coding scheme, habitat descriptions, and colour mapping scheme, since it was published in 1990 



A5 Phase 1 Field Manual: this was published first in 1990, reprinted in 1993, reprinted again in 2003 with limited revisions and additions, and reprinted last in 2005.


It is now available only as Part 2 of the A4 Phase 1 Handbook.





List of other Phase 1 related publications

Blackstock, T.H., Burrows, C.R., Howe, E.A., Stevens, D.P. and Stevens, J.P. 2007. Habitat inventory at a regional scale: a comparison of estimates of terrestrial Broad Habitat cover from stratified sample field survey and full census field survey for Wales, U.K. Journal of Environmental Management Volume 85, pages 224-231.


Blackstock, T.H., Stevens, J.P., Howe, E.A. and Stevens, D.P. 1995. Changes in the extent and fragmentation of heathland and other semi-natural habitats between 1920-22 and 1987-88 in the Llŷn Peninsula, Wales, UK. Biological Conservation Volume 72, pages 33-44.


Cherrill, A.J. and McClean, C. 1999. Between observer variation in the application of a standard method of habitat mapping by environmental consultants in the UK. Journal of Applied Ecology Volume 36, pages 989-1008


Cherrill, A.J. and McClean, C. 1999. The reliability of Phase 1 habitat mapping in the UK: the extent and types of observer bias. Landscape and Urban Planning Volume 45, pages 131-143.


Dargie, T. 1993. Repeat Phase 1 habitat survey and detection of vegetation change. English Nature Research Reports 51. English Nature, Peterborough.


Howe, L., Blackstock, T., Burrows, C. and Stevens, J. 2005. The Habitat Survey of Wales. British Wildlife Volume 16, pages 153-162.


Stevens, J.P., Blackstock, T.H., Howe, E.A. and Stevens, D.P. 2004. Repeatability of Phase 1 habitat survey. Journal of Environmental Management, Volume 73, pages 53-59.


Wyatt, G. 1991. A Review of Phase 1 Habitat Survey in England. England Field Unit, Nature Conservancy Council.


Yeo, M.J.M. and Blackstock, T.H. 2002. A vegetation analysis of the pastoral landscapes of upland Wales, UK. Journal of Vegetation Science Volume 13, pages 803-816.


Return to Graphics version

| JNCC - Adviser to Government on Nature Conservation | Site Map | Search | Legal | Feedback | List Access Keys |