IMIS

The point data were generated using nomenclature supplied from the AlgaeBase database (www.algaebase.org), developed by Prof. M.D. Guiry, Martin Ryan Institute, National University of Ireland. A small number of records are derived from the NCC River Macrophyte Database but the major divisions in the dataset are as follows:

• 71000 records from the 1985 provisional atlas dataset held at BRC
• 28500 records provided in electronic format from Prof Michael Guiry
• 7600 records input from assorted record cards deposited at BRC since the publication of the 1985 atlas
• 4000 records from the herbarium at the Royal Botanic Garden, Edinburgh.

Purpose of data capture: To provide phycologists and scientists with a distribution map of algal species and encourage future mapping. Also to enable the monitoring of the spread of non-native species like Sargassum muticum and Undaria pinnatifida. Methods of data capture: Records were submitted by a variety of volunteers and professionals. The validity of submitted records was checked with the help of two panels of referees. Members of one panel were species experts and members of the other had local geographical knowledge and could consider the likelihood of a species being found in a particular place. Doubtful data were not included. Geographical coverage: The dataset contains coastal and estuarine records for many parts of the British Isles. Coverage of certain groups relied on very few experienced recorders and because of this, the entire coastline is not covered for all species groups. This may affect the interpretation of data for some species. Temporal coverage: Records span 1750-2003 with peaks at 1950, 1960 and 1999. There is sustained recording effort between 1966 and 1988. Data quality: The data were validated and verified by members of the Recording Scheme, although according to the atlas, few records are supported by herbarium specimens. Records may not exist for some species while others may be under-recorded. This dataset is held by the Biological Records Centre and was used in the publication of: Hardy, F.D. & Guiry, M.D (2003) A Check-list and Atlas of the Seaweeds of Britain and Ireland. London: British Phycological Society The full tekst can be viewed on the BPS website as a PDF document. This atlas also contains related data that can be found in the following NBN Gateway datasets:

• Marine Nature Conservation Review (MNCR) and associated benthic marine data held and managed by JNCC
• Marine Data from DUCHAS as part of MNCR
• Marine Data from Northern Ireland as part of MNCR
• Marine Nature Conservation Review (MNCR) and associated benthic marine data held and managed by CCW
• Marine Nature Conservation Review (MNCR) and associated benthic marine data held and managed by English Nature
• Marine Nature Conservation Review (MNCR) and associated benthic marine data held and managed by Scottish Natural Heritage