Impact Type: Deposition of pollutant
Key Concerns:
Ramalinas belong to the family Usneaceae, having a fruticose strap shaped thallus. The many species of Ramalinas show a preference for either rock or bark, the chemistry of which may buffer acid deposition. Few if any studies have investigated the effects of wet acid deposition on Ramalinas
Most Ramalina spp. are very sensitive to dry acid deposition which may have resulted in their disappearance from much of their former range. R. farinacea which can stand up to 60 µg m-3, but it has disappeared from some parts of its former range in north-central England, London and Central Scotland due to air pollution (Seaward & Hitch 1982). R. fastigiata which can stand mean winter levels of SO2 up to 35 µg m-3, has disappeared from central and northern England (Seaward & Hitch 1982). R. fraxinea which can also stand mean winter levels of SO2 up to 35 µg m-3, is now very rare or extinct in most of central and SE England where it was once common (Seaward & Hitch 1982).
Additional Comments:
The critical level for Ramalina spp. may need to revised downwards (Bates 2001).
| Critical Load/ Level |
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No estimate available |