THE LICHEN VEGETATION OF CHALK AND LIMESTONE STREAMS IN BRITAIN

Authors
Citation
Ol. Gilbert, THE LICHEN VEGETATION OF CHALK AND LIMESTONE STREAMS IN BRITAIN, Lichenologist, 28, 1996, pp. 145-159
Citations number
13
Categorie Soggetti
Plant Sciences
Journal title
ISSN journal
00242829
Volume
28
Year of publication
1996
Part
2
Pages
145 - 159
Database
ISI
SICI code
0024-2829(1996)28:<145:TLVOCA>2.0.ZU;2-7
Abstract
The results of a nationwide survey of lichens associated with streams on chalk and limestone are reported. The lichen communities are presen t as a series of overlapping bands related to length of submergence. T hese have been named the submerged, fluvial mesic, fluvial xeric and f luvial terrestrial zones. The flora involves around 50 lichens, many o f which are rarely recorded specialists restricted to this habitat. Th e richest sites for submerged species are headwaters, especially aroun d springs. Active tufa deposition and disturbance of the stream bed by farm stock are detrimental to aquatic lichens. Diversity further down stream is related to the amount of exposed limestone available for col onization, with topographical complexity also important. An investigat ion of the influence of water quality suggests that suspended solids ( silting) is a significant determinant of lichen distribution together with eutrophication. (C) 1996 The British Lichen Society