Distribution of Bryophytes

Much of our knowledge of the distribution of bryophytes in the British Isles comes from work done over many years by members of the BBS. This information is recorded in a number of ways:

1. Vice-County recording.

   The vice-counties of Great Britain were originally defined by H C Watson in 1852, and those of Ireland by R L Praeger in 1901. They approximate to administrative county boundaries, but whereas these shift according to political whim, the vice-county boundaries remain fixed to ensure consistency of botanical recording. More information can be obtained from the Biological Records Centre, and from the latest Census Catalogue .
   
   Distributional data is recorded in the BBS Census Catalogues which are updated periodically. Annual additions and deletions are published in the Bulletin. The BBS Recorders for Mosses and Hepatics maintain an up to date database for vice-county distributions. New records are submitted to them with a voucher specimen, which once verified is incorporated into the BBS herbarium.

2. BBS 10-km square recording.

   In 1960 the BBS set up a mapping scheme to record the distribution of bryophytes at a 10-km grid square scale. After 30 years of recording, the three volumes of the Atlas of the Bryophytes of Britain and Ireland were published, displaying this data on distribution maps. Records were obtained mainly through field recording, but also through other sources such as herbarium specimens and published species list.
   
   Recording in this format continued following the publication of the Atlas, and still continues. Records are usually made on special recording cards, and then passed on to the Recording Secretary. The information is now held as an electronic database by the Biological Records Centre, and distribution maps can be viewed on line via the National Biodiversity Network Gateway at www.SearchNBN.net. A useful pdf document entitled "Desk instructions of the NBN Gareway" can be downloaded from their site here.

3. Local recording.

   Distributions at a local level are often recorded in local floras and check-lists. These may be purely bryophyte floras in their own right, or may be incorporated into vascular plant floras. The floras are usually written for a particular vice-county, and give valuable information about the local distribution and frequency of occurrence of individual species. There is usually information about the soil, topography, geology and climate.
   
   Check-lists are simply lists of species known to occur in the particular area. Some vice-counties have a Bryophyte Red Data Book which give details about uncommon species and those of conservation importance.

   
   Information about available local floras can be found on the appropriate page for each vice-county, which are listed on the vice-county map page.