Lichen: Kelvin LawrenceLichen: Kelvin Lawrence

Derbyshire has areas of major lichen interest, with some colonies potentially thousands of years old. Steve Price reports.

Lichens are not a single organism. They are the result of a symbiotic relationship between a fungus and a photosynthesising partner, usually an alga. The two form such a close partnership they appear to be a single individual; the fungal part of the organism cannot survive without its algal partner. Some colonies of lichen may be thousands of years old. Many lichens are susceptible to pollution and have suffered during two centuries of industrialisation. With the reduction in sulphur dioxide deposits, lichens have improved dramatically over the past three decades. Some previously rare species are now occurring regularly. But the increase in atmospheric nitrogen from agriculture and motor vehicles has led to a 'yellowing of the countryside' as nitrophilous species of lichen become dominant.

Derbyshire has areas of major lichen interest. The limestone dales support communities of lichens typical of basic rocks. The disused lead mines of the limestone plateau support a distinctive range of metalliferous lichens. The gritstone boulders and block scree of the Dark Peak support a range of upland lichens with a preference for siliceous rocks (containing silica). The gritstone edges and outcrops which are more exposed than the boulders seem to be much poorer, probably having been denuded of lichens by 200 years of industrial pollution. The woodlands are interesting but not particularly noteworthy; by contrast the trees of parklands like Chatsworth Old Park hold a good number and range of notable species.
The east and south of the county is generally not as rich as the Peak District, but a recent survey in the Moss Valley found a wide range of species in very low abundance. The positive interpretation of this situation is these lichens are returning and in another ten years will be found in some abundance. Churchyards in many areas of the south and east of the county are the only source of exposed rock, and this usually in variety, so it is not surprising churchyards support a significant number and range of species.

Recording in Derbyshire
In addition to true lichens, non-lichenized fungi with the characteristics of a lichen are also studied and recorded. In addition there are a number of lichenicolous fungi (fungi having lichens as their specific hosts) and these are commonly only studied by lichenologists and are included in lichen lists.
At the time of writing, 691 taxa are recorded in the county, about one third of the number of lichens on the British list. This total figure of 691 includes 31 species of lichenicolous fungi and 23 species which have been recorded in the past but are now considered to be extinct in the county.
Over the past six years there has been a resurgence of interest in lichens and recording in the county. The Sorby Natural History Society holds regular field recording meetings in the Peak District. The county has hosted the British Lichen Society on two field meetings; these together with consultancy surveys have added significantly to the knowledge of our lichens and their status.
Every churchyard in the county has been surveyed for lichens, most of the work being done by Ivan Pedley in the 1990s. Oliver Gilbert (died 2005) and Brian Fox (died 1999) did significant recording through the 1980s and 1990s. Prior to that there was much work by David Hawksworth in the late 1960s and 1970s.
Records of lichens in the county have been published in summary form in The Lichenologist, The Naturalist and The Sorby Record starting with David Hawksworth's The Lichen Flora of Derbyshire in 1969.
A distribution mapping scheme, to a 10km resolution, is maintained by the British Lichen Society (BLS) and until recently this was the most accessible source of record data. The BLS now maintains a national database of records and this includes over 22,000 records of lichens from Derbyshire. This database information is supplied to the National Biodiversity Network and through this is accessible by the public.

Records from Woodside Nature Reserve
Woodside having not yet been studied by lichenologists has just two species recorded. Both species like nutrification and are to be found in abundance across the county. There are other species that would be expected to be found alongside them. 

Species Recorded During the Woodside BioBlitz
Physcia adscendens 
Xanthoria parietina