#50 Cartilage Lichens by Peter Cook
Meet Peter Cook, Recorder Emeritus in the BSBI and Naturalist in the County’s Far East!
Armed with Observer’s books, Peter learned the names of some common lichens, mosses, ferns and flowering plants in the 1950’s thus starting his life-long interest in the natural world. He went on to read chemistry, zoology and botany, graduating in 1970. Later in life he settled for study of flowering plants as a hobby, specialising in grasses. On returning to his native East Yorkshire in 1988 he started to record plants first for the South Holderness Countryside Society (SHCS) and later for the YNU and the Botanical Society of Britain and Ireland (BSBI) in vc61. He is now Recorder Emeritus in the BSBI and has held the offices of Divisional Secretary for the YNU and Conservation Projects Officer, Chairman, Treasurer and Executive Committee member for the SHCS. He has retired as a Fellow of the Linnean Society.
After retiring from a professional career in veterinary medical research and scientific, technical, and medical writing he worked freelance conducting botanical surveys for ecology consultancies. For 14 years he also surveyed and evaluated candidate Local Wildlife Sites for the East Riding of Yorkshire Council. Now in poor health, Peter has reverted to his childhood, dabbling with interest in lichens, stoneworts, mosses, leaf miners and plant galls.
He can be contacted on the e-mail address: botanical748@gmail.com.
Peter has chosen ‘cartilage lichens’ selecting 3 from the 13 UK species in the genus Ramalina. These are highly sensitive to atmospheric sulfur dioxide concentrations and are increasing in the Holderness area of the East Riding as a result of decreasing sulfur dioxide pollution. Ramalina farinacea has been recorded in the area whereas R. fastigiata and R. lacera are rare though are becoming more common. These lichen species are seemingly effective in monitoring improvement of air quality as a result of reducing fossil fuel usage.
Ramalina fastigiata
Discovery in 2016 of Ramalina lacera, R. farinacea and R. fastigiata occurring in Holderness alerted Peter to a developing phenomenon. In more than 25 years of observing botanical interest in the region, he had seen only a few single occurrences of R. farinacea. In further study, with expert confirmation, 11 records for R. fastigiata, 8 for R. farinacea and 5 for R. lacera were found in 5 hectads across SE Holderness (1). These species are of Least Concern in conservation status but have been hitherto rare this far East in Yorkshire.
The plain of Holderness and the City of Hull lay in the wake of former coal-fired power stations of which Drax has been converted to use a biomass feedstock and both Ferrybridge and Eggborough plants have closed down. Reduction in these sources of atmospheric pollution by compounds of sulfur favours an upsurge in the occurrence of lichen species such as those in the genus Ramalina. The plain of Holderness also lay to the East of Hull. A study of the lichen flora of Hull by Professor Mark Seaward (2) in 2002-2004 showed three air quality zones delimited on the basis of lichen surveys. Substrates in the sub-urban/rural zones radiating out from Hull were richer in lichen diversity with the exception of the easterly direction into Holderness. The random ‘snapshot’ of Ramalina species occurring 20-30 km East of Hull suggests that there may by now be, 20 years after Professor Seaward’s surveys, many other sulfur dioxide intolerant species to be recorded.
There are a few other species within the genus Ramalina with verified records in fewer than five hectads across VC61 for example R. subfarinacea, R. calicaris, R. fraxinea and R. siliquosa. Any new records for these would be significant, indicating sulfur dioxide levels below 30-40 micrograms/m3 (3). There are possibly other sulfur-sensitive species on the increase or recorded for the first time in the area. This presents increased recording interest with value in air quality assessment at a time when there are revolutionary changes in the quest to halt climate change.
“These species are not photogenic or charismatic” admits Peter “but they stand out with their erect or pendulous, fruticose thalli and therefore direct me to examine a substrate more closely. They can be mistaken with Evernia prunastri and they are challenging to identify to species, especially when they are not fully developed or atypical. Spotting Ramalinas has become a purpose while pausing for a rest and letting the dog fertilize the ‘canine zone’. They are an indicator to me for monitoring the trend in spread of these 3 taxa, for searching for ‘new’ Ramalina species and finding lichens new to my experience.”
Recording and monitoring
There are no known recording schemes specifically for cartilage lichens, however, verified records for individual species included in NBN and British Lichen Society databases are accessible online. Some of the Ramalina spp. are difficult to identify with certainty. They are generally not reliably ‘do-able’ from even good close-up photographs, and they still need to be checked by microscopy and comparison with confirmed reference material. Together with seeking expert confirmation this prolongs the period between finding and recording so that databases may not be up to date.
Ramalina farinacea
Further information and acknowledgements
NEYEDC would like to thank Peter for his time and expertise in helping to create this blog.
References
1. Cook, P.J. (2019). A recent increase in observations of species of the lichen genus Ramalina in southern Holderness. Naturalist. Vol. 144, p. 151.
2. Seaward, M.R.D. (2004). The lichen flora of Hull, with particular reference to zonal distribution and environmental monitoring. Naturalist. Vol. 129, pp. 61-66.
3. Hawkesworth and Rose Zone scale for the estimation of mean winter sulphur dioxide levels in England and Wales in: Dobson, F.S. (2000). Lichens. An Illustrated Guide to the British and Irish Species. ISBN 0 885546 094.