Report 404
Saxicolous lichen and bryophyte communities in upland Britain
(2009)
Orange, A.
The British uplands have two groups of lichen species of outstanding conservation interest: 1) species of western oceanic areas and 2) species of calcareous rock at high altitudes. The most characteristically oceanic of the communities delimited in the present study are SS E1 on siliceous rock and SL 15 on limestone. Samples from high altitude calcareous rocks were few in the present survey, but Community SS X1 from Eryri, the Ben Nevis range and Beinn Heasgarnich includes some examples. Most of the samples recorded were from treeless, grazed upland sites. A cessation of grazing in these areas would be a potential concern, likely to result in shading or engulfment of rocks by vascular plant vegetation or robust bryophytes. Recreational pressures are also known to be a potential threat in some upland habitats.

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Phytosociological data were collected to describe the terrestrial lichen and bryophyte vegetation of rock or saxicolous habitats within 14 Special Areas of Conservation (SAC) within upland Britain, with special reference to four saxicolous habitats listed in Annex I of the EU Habitats Directive. Additional data were available from other surveys within upland Britain, giving a total of 1539 relevés available for analysis.

 

Data were analysed using TWINSPAN, combined with manual sorting. A total of 83 communities were distinguished, including 56 on siliceous rock and 27 on limestone. A description and floristic table is provided for each community, along with a key for the placement of individual relevés is provided. As is commonly experienced in phytosociological work, delimitation of communities was not straightforward; this was attributed to the existence of variation in composition of vegetation in response to many independent environmental variables, precluding a simple system of classification. Despite these problems, the classification proposed is a major advance on earlier phytosociological knowledge of the lower plant communities of the British uplands.

 
 
 
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ISSN 0963 8091
 
Please cite as: Orange, A., (2009), Saxicolous lichen and bryophyte communities in upland Britain, JNCC Report 404, ISSN 0963 8091