Lecanographa grumulosa

Churchyard SYN: Lecanactis hemisphaerica J. R. Laundon (1976)

Status Nationally scarce UK BAP Priority Species Schedule 8 Wildlife & Countryside Act Lead Partner: Plantlife International Red Data Book – Near Threatened English Nature Species Recovery (1996) Programme 27/233 10km squares

UK Biodiversity Action Plan (BAP) These are the current BAP targets following the 2002 review:

T1 - Maintain populations at all extant sites. T2 - If biologically feasible and desirable, establish three new colonies of this species at suitable sites by 2005.

Progress on targets as reported in the UK BAP 2002 reporting round can be viewed online at: http://www.ukbap.org.uk/2002OnlineReport/mainframe.htm.

The full Action Plan for Lecanographa grumulosa can be viewed on the following web page: http://www.ukbap.org.uk/UKPlans.aspx?ID=404.

Contents 1 Morphology, Identification, & Genetics...... 2 1.1 Morphology & Identification ...... 2 1.2 Taxonomic Considerations ...... 3 2 Distribution & Current Status ...... 3 2.1 World ...... 3 2.2 Europe ...... 3 2.3 United Kingdom ...... 4 2.3.1 England ...... 8 2.3.2 Ireland...... 10 2.3.3 Scotland...... 10 2.3.4 Wales ...... 10 3 Ecology & Life Cycle...... 10 4 Habitat Requirements ...... 10 4.1 The Landscape Perspective...... 11 4.2 Communities & Vegetation ...... 12 5 Threats / Factors Leading to Loss or Decline or Limiting Recovery...... 13 5.1 Habitat Destruction ...... 13 6 Current Conservation Measures ...... 17 6.1 In Situ Measures...... 17 6.2 Monitoring ...... 17 6.3 Recommendations for Future Work ...... 17 7 References ...... 17 8 Acknowledgements ...... 18

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9 Contacts ...... 18 10 Links...... 18

1 Morphology, Identification, Taxonomy & Genetics

1.1 MORPHOLOGY & IDENTIFICATION DESCRIPTION When growing on buildings, Lecanographa grumulosa appears to be lichenicolous on Dirina masilliensis f. sorediata, a common and widespread grey, crustose of dry north-facing calcareous walls, though sometimes this is not always obvious. The host’s thallus is grey to white, usually sorediate although less so when parasitised by this species, and is characteristic of sheltered, calcareous wall surfaces (see Figure 1). The fruits, apothecia, (or pseudothecia according to continental authors) of Lecanographa are abundant, 0.4-1.2mm in diameter, sessile, crowded, black when abraded, but appearing grey to very dark-grey (in shade) to the naked eye due to a covering of calcium oxalate crystals, or pruina. A distinguishing feature of this species is the black, carbonaceous exciple at the base of the fruits.

Figure 1 - Thallus of Dirina massiliensis f. sorediata parasitised by Lecanographa grumulosa. (Photograph by Vince Giavarini).

CHEMISTRY The parasitised thallus contains a C+ red substance, which is believed to be due to a cocktail of lecanoric and gyrophoric acids with traces of erythrin. All other chemical reactions are negative, i.e. K-, Pd -, KC-, UV-. Egea et al (1993) found erythrin to be the major compound in non-parasitised Dirina. Chemical analysis of the various British populations is yet to be carried out.

MICROSCOPIC CHARACTERS Details of microscopic features are not always necessary to determine identity of this species but may be helpful in separating it from closely related species - the three (or

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four or five) septate, ellipsoid to fusiform spores within the range 12–17µm x 3-4µm will serve to distinguish it.

SIMILAR SPECIES Similar looking lichens growing in more or less identical habitats to Lecanographa grumulosa are few. The C+ rose red reaction separates it from Diplotomma alboatrum and species of have a C- reaction; Arthonia pruinata forms wafer-thin, peeling crusts and has ovoid spores. The host lichen, Dirina, is sterile and sorediate.

1.2 TAXONOMIC CONSIDERATIONS The hemispherical fruits characteristic of many colonies on man-made substrata led Laundon to describe this lichen as a separate species, Lecanactis hemisphaerica, in 1976. Subsequent investigations found the original species account to be flawed and that separation at the species level based on the characters given by Laundon was not justified.

2 Distribution & Current Status

2.1 WORLD The world distribution of Lecanographa grumulosa is centred in Mediterranean Europe. Outside Europe, the species is known to occur in Morocco, Senegal, the Canary Islands, the Cape Verde Islands, Antilles and the Baja California Peninsula in Mexico.

2.2 EUROPE The status of Lecanographa grumulosa in each country in Europe, where known, is shown in Table 1.

Table 1 – Country by country status of Lecanographa grumulosa across Europe. (*Country codes are taken from Flora Europaea as of 1964 with red data book listings where available [Definitions of the red list categories]).

COUNTRY STATUS NOTES SOURCE(S) Bl ISLAS BALEARES Present but status unknown. MALLORCA Bu BULGARIA Present but status unknown. Br BRITAIN Regarded as Nationally Scarce. The Woods & Coppins ‘hemisphaerica’ form is known from 27 (2003). 10km squares compared with the natural form, which is in 17 10km squares. Ju JUGOSLAVIA Present but status unknown. CROATIA Ga FRANCE Woods & Coppins Regarded as Nationally Scarce. INCL. CHANNEL ISLANDS (2003). Gr GREECE Present but status unknown. It ITALY A fairly common species throughout Nimis (pers. Mediterranean Italy. comm.). Sa SARDEGNA Present but status unknown. Hs SPAIN Present but status unknown. Lu PORTUGAL Present but status unknown. Rm ROMANIA Present but status unknown.

The European distribution of the species is centred on Bulgaria, Croatia, France, Greece, Italy, Portugal, Romania, Spain, Corfu, Majorca, Sardinia and the Channel Islands. In southwest Morocco and southwest Spain, increased humidity through the frequency of

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coastal mists and moist onshore winds allow the species to grow as an epiphyte. The species reaches the northern limit of its range in Britain.

2.3 UNITED KINGDOM Lecanographa grumulosa occurs along the south and west sides of Great Britain (see Figure 2). In south and southeast England the species is mostly of the parasitic form Lecanographa grumulosa f. hemisphaerica. This form is almost wholly restricted to dry calcareous man-made habitats provided by the stonework of ancient churches and castles, whereas in the southwest and west of Britain Lecanographa grumulosa f. grumulosa dominates. Its natural habitat is in the sheltered niches of limestone ‘underhangs’ where it is known to grow as far north as the Hebridean island of Iona. This has produced two quite different distributions. The presence of the species in western Britain and especially in Scotland is probably further assisted by the effect of the North Atlantic Drift (Gulf Stream). This ensures that temperatures in coastal areas remain mild throughout the winter months, a key requirement of this frost-sensitive species.

Figure 2 - Distribution of confirmed populations of Lecanographa grumulosa f. hemisphaerica in Great Britain in 2003.

Key: ● Lecanographa grumulosa (forma hemisphaerica), extant populations. ■ Lecanographa grumulosa (forma hemisphaerica), old records. ● Lecanographa grumulosa (forma grumulosa), extant populations. ■ Lecanographa grumulosa (forma grumulosa), old records.

Following preliminary surveys in East Sussex, West Sussex and Kent, and more comprehensive searches of Dorset, Hampshire (where the species is absent), Norfolk

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and Suffolk, the species is now known on man-made structures from 28 hectads. In its natural habitat of sheltered limestone it is known from over 20 hectads. Three old records (East Cornwall, North Wales and Argyll) await modern confirmation. Altogether Lecanactis grumulosa is known to occur in a total of 52 hectads in the UK. Table 2 shows its present and former distribution by vice-county. Records of surveyed Lecanographa grumulosa sites in Britain are given in Table 3.

Following a detailed study by Woods & Coppins (2003), it has been recommended that the taxon formerly referred to as Lecanactis hemisphaerica be deleted from Schedule 8 of the Wildlife and Countryside Act following the next review. Therefore, it is unlikely that comprehensive searches of suitable habitat in East Sussex, West Sussex and Kent will be necessary in the near future. Under the synonym, Lecanactis hemisphaerica, this believed endemic was classified as Near Threatened in the (British) Red Data Book for Lichens (Church et al, 1996). [A taxon is considered to be Near Threatened when it has been evaluated against the threat categories and although close to qualifying, does not qualify as Critically Endangered, Endangered or Vulnerable].

Table 2 - Present and former distribution of Lecanographa grumulosa f. hemisphaerica by vice-county.

TOTAL NUMBER OF EXTANT V-C. MODERN ADMINISTRATIVE DATE OF SITES (POST- 1990)/ NO. COUNTY LAST RECORD EXTINCT SITES 6 North Somerset 1/ 0 2003 9 Dorset 9/ 0 2001 13 West Sussex 5/ 2 2002 14 East Sussex 6/ 0 1993 15 East Kent 7/ 0 2002 25 East Suffolk 11/ 1 2001 27 East Norfolk 8/ 0 2001

Table 3 – All records of surveyed Lecanographa grumulosa sites in Britain until the end of 2003.

V-C. 1ST COUNTY GRID REF RECORDER HERB. NO. RECORD 6 Somerset ST4421 1991 S S, G 9 Dorset SY8094 1982 G A, D 9 Dorset SY7088 2000 G G 9 Dorset SY9496 2000 G, BE G 9 Dorset SY9287 2001 G G 9 Dorset SY8595 2000 G G 9 Dorset SY7983 2000 G G 9 Dorset SY3795 2001 G G 9 Dorset SY5885 2000 G G 9 Dorset SY5785 2000 G G 13 West Sussex SZ8897 1990 J G 13 West Sussex SU7702 1992 R G 13 West Sussex TQ1911 1992 P G 13 West Sussex SU9108 1997 R, S G 13 West Sussex TQ0003 2002 Dy Dy 14 East Sussex TQ4112 1991 P G 14 East Sussex TQ4206 1991 P G 14 East Sussex TQ6505 1993 R, P G

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V-C. 1ST COUNTY GRID REF RECORDER HERB. NO. RECORD 14 East Sussex TQ9218 1993 R, P G 14 East Sussex TQ60 2003 Dy 14 East Sussex TQ60 2003 Dy 15 East Kent TR0328 1967 Ld A 15 East Kent TR2757 1997 P G 15 East Kent TR2460 1999 P G 15 East Kent TR2457 2001 G G 15 East Kent TR2555 2001 G G 15 East Kent TR0627 2001 G G 15 East Kent TR0130 2002 G G 25 East Suffolk TM5282 1975 L A, E, H 25 East Suffolk TM466 1976 L E, C, H 25 East Suffolk TM4999 1983 H H 25 East Suffolk TM4983 1990 H H 25 East Suffolk TM4975 1992 H H 25 East Suffolk TM3852 1997 H H 25 East Suffolk TM5386 2001 G G 25 East Suffolk TM5081 2001 G G 25 East Suffolk TM4575 2001 G G 25 East Suffolk TM4469 2001 G G 25 East Suffolk TM3959 2001 G G 27 East Norfolk TG4611 1980 L G 27 East Norfolk TG4913 1981 L G 27 East Norfolk TG4919 1999 H H 27 East Norfolk TG4812 2001 G G 27 East Norfolk TG4411 2001 G G 27 East Norfolk TG3926 2001 G G 27 East Norfolk TG4305 2001 G G 27 East Norfolk TG4207 2001 G G

KEY TO SOURCES OF RECORDS AND HERBARIA: A Natural History Museum, London B B. Benfield BE B. Edwards C National Museum and Gallery of Wales, Cardiff D Dorset County Museum, Dorchester Dy Simon Davey E Royal Botanic Garden, Edinburgh G Vince Giavarini H Chris Hitch J Peter James L Peter Lambley Ld Jack Laundon P Keith Palmer S Ken Sandell

PLANTLIFE SURVEY FOR NEW LOCALITIES OF LECANOGRAPHA GRUMULOSA 2000-2002 The churches listed in Table 4 were selected for survey on the grounds of location, age and suitability of habitat for Churchyard lecanactis. The search was concentrated mainly in Somerset, Hampshire, Dorset, Kent (Romney Marsh), Norfolk and Suffolk. The main reason for visiting so many churches was that previous workers had overlooked window tracery, a major habitat for the taxon. Sites where it was confirmed as present are tabulated. Those searched unsuccessfully are listed separately. The table reflects genuine differences in the shape of the apothecia by referring to mainly convex fruited

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material as belonging to the ‘hemisphaerica’ or ‘H’ form, while broader, sessile apothecia are best described as ‘grumulosa’ or ‘G’ forms. The morphological complexity of this taxon is illustrated by its vast synonymy (see ITALIC, taxon query interface: http://dbiodbs.univ.trieste.it/).

Table 4 - Results of Plantlife survey for new Churchyard lecanactis sites in 2000-2001.

V-C. 10 KM DATE OF COUNTY OUTCOME NO. SQ. SURVEY 9 Several colonies of the ‘grumulosa’ (G) Dorset SY78 2000 form. 9 Dorset SY89 2000 Several colonies of the ‘G’ form found. 9 Several colonies of the ‘G’ form in north- Dorset SY58 2001 facing bays. 15 Several small colonies of the East Kent TR25 2001 ‘hemisphaerica’ (H) form. 15 A number of small ‘H’ colonies on west & East Kent TR25 2001 southwest-facing walls. 15 Colonies of the ‘H’ form on plaster of a East Kent TR02 2001 northwest-facing wall. 25 Large population of the ‘H’ form on a East Suffolk TM58 2001 south-facing side. 25 Colonies of ‘H’ form on north-facing East Suffolk TM58 2001 windows. 25 East Suffolk TM47 2001 ‘H’ form north-facing colonies. 25 North-facing side with some ‘H’ form East Suffolk TM46 2001 colonies. 25 East Suffolk TM35 2001 ‘H’ form colonies on window tracery. 27 East Norfolk TG41 2001 ‘H’ form colonies on one window. 27 East Norfolk TG41 2001 ‘H’ form colonies on window tracery. 27 East Norfolk TG32 2001 Sparingly, on a north-facing side. 27 East Norfolk TG40 2001 ‘H’ form, on north-facing windows. 27 East Norfolk TG40 2001 ‘H’ form, on a north-facing blocked door.

CHURCHES SEARCHED UNSUCCESSFULLY FOR THE SPECIES (IN ORDER OF SURVEY):

SOMERSET Curry Rival (ST32), Huish Episcopy (ST42), Martock (ST41), South Petherton (ST41), Muchelney (ST42), Muchelney Abbey (ST42). All in 2000.

DORSET Athelhampton Hall (ST79). In 2000.

Studland (SZ08), Worth Matravers (SY97), Church Knowle (SY98), East Lulworth (SY88), Owermoigne (SY78), Warmwell (SY78), Bincombe (SY68), Upwey (SY68), Portesham (SY68), Long Bredy (SY59). All in 2001.

Hampshire Christchurch Priory (SZ19), Porchester Castle (SU60), Wickham (SU51), Southwick (SU06), Titchfield (SU50), Warblington with Emsworth (SU70), Northney Church, Hayling (SU70).

West Sussex Steyning Church (TQ11), Upwaltham (SU91), Albourne (TQ21). In 2000.

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East Sussex Offham Church (TQ41). In 2000. Kent Chislet (TR26), Stodmarsh (TR03), Wickhambreaux (TR25), Littlebourne (TR25), Godmersham (TR05), Brook (TR04), Smeeth (TR03). All in 2001.

Suffolk Blundeston (TM59), Carlton Colville (TM59), Gisleham (TM58), Barnby (TM48), Mutford (TM48), Benacre (TM58), Wangford (TM47), Reydon (TM47), Dunwich (TM47), Middleton (TM46), Leiston (TM46), Knodishall (TM46), Aldringham (TM46). All in 2001.

Norfolk Ormesby (St. Margaret) (TG41), Hemsby (TG41), Horsey (TG42), Hickling (TG42), Thrigby (TG41), Rollesby (TG41), East Somerton (TG41), Sea Palling (TG42), Hempstead (TG42), Lessingham (TG32), Happisburgh (TG32), Walcott (TG33), Ridlington (TG33), Knapton (TG33), Trunch (TG23), Southrepps (TG23), Witton (TG33), Bacton (TG33), Paston (TG33), Roughton (TG23), Freethorpe (TG40), South Burlingham (TG30), Beighton (TG30), Hassingham (TG30), Cantley (TG30), Limpenhoe (TG30). All in 2001.

2.3.1 ENGLAND Jack Laundon, working in the lichen section of the Department of Botany at the Natural History Museum in London, first described Lecanactis hemisphaerica (‘Churchyard lecanactis’) as new to Britain in 1976. He based his description of the species on material he collected from plaster render at a church in Kent on May 7, 1967 and on a second collection from a church in Suffolk, provided by Peter Lambley in 1975. It was regarded as a British endemic for almost 15 years. Early on, it was regarded as a southeastern, possibly continental species and not until P.W. James confirmed material from Dorset in 1982 did its distribution appear disjunct. Then, between 1990 and 2000, a spate of recording in churchyards stimulated by Tom Chester and the British Lichen Society churchyard recording group, yielded several additional records of the plant from East Kent, East Suffolk, Somerset, East & West Sussex and Norfolk. Its distribution extended in an almost unbroken line around the coastline from North Norfolk to West Dorset suggesting that it might be frost sensitive. In spite of this, the most pressing questions were in relation to its origin as all known records were from old, artificial calcareous habitats such as church or castle walls (see Figure 3). The paradox of a rare endemic living only on man-made substrata called for an immediate re-evaluation of the original species account.

The question of its endemic status was soon settled. Material of Churchyard lecanactis, collected from Puglia in southeast Italy by M.R.D Seaward, was examined in 2000 and found to be this species. With the assistance of Peter James and Alan Orange, flaws in the original diagnosis and in the ‘Flora’ account were identified. Churchyard lecanactis (Lecanactis hemisphaerica) was actually the closely related species, Lecanactis grumulosa, a morphologically variable taxon with its distribution centred in Mediterranean Europe. The British distribution of this taxon, now referred to as Lecanographa grumulosa f. grumulosa, is revealing. It too hugs the coastline but is more regularly discontinuous around the southwest peninsula, west of Dorset, missing out most of Wales, before terminating in the Inner Hebrides of Scotland. This distribution mainly picks out areas of natural limestone but also accounts for its presence on the limestone associated with old church buildings and barns (Barbara Benfield, pers. comm.) situated near the western seaboard. The rounded to hemispherical apothecia in Lecanographa grumulosa forma hemisphaerica is the only distinguishing feature separating it from forma grumulosa, and is most typical of apothecia on plaster render or decaying limestone where calcium is readily available.

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Figure 3 – Lecanographa grumulosa growing on the tower of a church in Somerset. (Photograph by Vince Giavarini).

Egea et al (1993) working in Spain during 1992 revealed a further twist to the story that only came to light during the interrogation process. Observations of Lecanographa grumulosa in the Mediterranean region showed it to be a mainly parasitic life form, targeting various species of Dirina and Roccella as host plants. Observations of British populations and their association with Dirina masilliensis f. sorediata appear to confirm this finding.

What was formerly believed to be the cretaceous thallus of Lecanographa grumulosa is, in reality, the hijacked thallus of Dirina. The effect of the parasite on the host is best seen when the thallus is moist:

the plant gradually ceases to produce soredia, which are usually plentiful in the normal state.

necrosis of the thallus is visible as a dark shadow.

the original ‘live’ thallus slowly begins to degenerate, leaving behind a fragile network of veins and ridges resting on a chalky base of calcium oxalate residue.

This may answer many questions relating to the variable appearance of the species at different sites. However, many questions still remain unanswered. Are the natural populations in Britain also parasitised? What factors are responsible for producing the significant differences in the appearance of the ‘hemisphaerica’ and ‘grumulosa’ forms of

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Lecanographa grumulosa? Answers to these and other questions may only be found through further research.

2.3.2 IRELAND Not recorded.

2.3.3 SCOTLAND Lecanographa grumulosa f. grumulosa has been recorded from Dumfries, Galloway, Kintyre and Iona. There is also a further old record from Argyll.

2.3.4 WALES There is one old Welsh record of Lecanographa f. grumulosa from near Colwyn Bay.

3 Ecology & Life Cycle The ecological requirements of both forms of this species have been assessed from field observations and from accounts in the literature.

Dispersal is by ejection of ascospores. Apothecia, which are usually abundant, are the principal distinguishing feature of Lecanographa grumulosa. It is almost impossible to recognize when sterile.

At a magnification of x 400 the spores can be seen to be moderately large in size (12- 17µm (-19µm) x 3-4µm), 3 septate, (to 4 or 5 septate when mature), ellipsoid to fusiform in shape and bound by a thin gelatinous sheath. Usually, the spores have a slight waist at the mid-septum, the upper cells being wider than the lower ones.

Vegetative dispersal by lichen propagules is unknown since the thallus does not produce isidia, soredia or undergo fragmentation. Pycnidia, however, can be found with careful searching. These produce conidia that are straight, to slightly curved in shape and c. 4- 6µm x 1µm in size.

Little is known about the exact mode by which the spores are dispersed but various agents are believed to be responsible such as water droplets, air currents and invertebrate activity. The mechanisms involving evaporation and transpiration of water vapour and subsequent condensation under conditions of falling temperatures may assist the release and circulation of spores.

The photobiont alga, , is fairly abundant in moist, sheltered, slow-drying habitats. Access to the photobiont (Trentepohlia) in Dirina could be through the soredia on the surface of the cortex. This could then provide easy entry to the medulla and subsequent parasitism of the thallus described by Egea et al in 1993 as ‘more or less necrotic’. The parasitic form appears to do best where Dirina is thickly developed and the underlying medulla is well differentiated. Young colonies of Dirina characterised by thin crusts bearing pink, efflorescent blooms of soredia are not usually parasitised. Where these blooms may appear to be parasitised, careful searching will usually reveal that Lecanographa grumulosa f. hemisphaerica apothecia are associated with an older, partly obscured, overgrown thallus.

4 Habitat Requirements The habitat requirements of Lecanographa grumulosa f. hemisphaerica, based on British populations, are summarized in Table 5.

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Table 5 - Habitat requirements of Churchyard lecanactis in Britain.

TYPE DESCRIPTION Physical and Very low altitude, predominantly coastal fringe – below 50m. topographical High humidity – seasonal mists frequent near marshes and watercourses. Dry surfaces unaffected by direct rain – vertical north-facing church walls. Aspect – north or west-facing most favoured. Substratum - bare and weathered limestone, mortar, lime plaster or render. Substratum age - surfaces mostly exposed since medieval times. Habitat disturbance – very minimal usually for essential repair work. Host species - Dirina masilliensis f. sorediata in various stages of development. Orientation of substratum - mainly vertical unless in recessed mouldings. Height above the ground - never on the ground but occasionally just above it on suitable habitat, often extending upwards on church towers. Biological Tolerant of partial to heavy shade - caused by high tree canopy, shrub encroachment, re-positioning of porch or adding of shelters. Competition from other species - generally unfavourable for higher plants and ferns, except on castle walls, mainly bryophytes and alga. Lichen competitors - mostly slow-growing species. Chemical Toxicity from lead roofing. Churches situated in areas with low SO2. On castle walls not directly sprayed by weedkiller.

Lecanographa grumulosa f. grumulosa occurs on dry, vertical or sometimes overhanging, calcareous rocks especially near the coast or among large boulders that have originated from cliff falls. The species is very rare inland. Dirina masilliensis f. sorediata has a near identical habitat but will also colonize coastal siliceous rocks. It is not known whether Dirina colonies on siliceous rock support Lecanographa grumulosa.

Lecanographa grumulosa f. hemisphaerica, or Churchyard lecanactis, can grow either independently or on its host Dirina masilliensis f. sorediata on the calcareous walls of man-made structures, especially those of ancient buildings, such as medieval churches and castles (see Figure 4). Because of its low light and low moisture requirements, this lime-loving species prefers shaded vertical habitats where competition from other species is limited and associated lichens are few. Principal habitats include plaster and mortar rendering of north-facing, medieval church walls where bays are largely absent; window tracery; stone window mullions; blocked-in north-door arches; grooves between the arch chamfering surrounding west-facing doors, and in the niches provided by recessed mouldings.

4.1 THE LANDSCAPE PERSPECTIVE SUBSTRATUM All known records of both forms of Lecanographa grumulosa have originated from soft calcareous rock. This may explain its absence from hard Carboniferous limestone found in localities such as the Mendips in Somerset and Gower in south Wales.

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Figure 4 – Lecanographa grumulosa at a church in West Sussex. (Photograph by Vince Giavarini).

HUMIDITY Most sites are close to the sea at altitudes of less than 50m. Many back on to saltings, estuaries or former estuaries, or overlook flood plains that provide higher than normal levels of water vapour owing to frequency of sea mists and onshore winds.

ATMOSPHERIC POLLUTION Populations occur mainly on churches and castles in areas with low atmospheric pollution levels.

ASPECT The host colonies grow best on sheltered walls and in niches away from direct sunlight, and so favour north and west-facing aspects. Where colonies have developed in recesses on south-facing walls, they are maintained by a favourable microclimate. The thallus however, bleaches to a white colouring that is distinctive even from a distance.

4.2 COMMUNITIES & VEGETATION The lichen community to which Lecanographa grumulosa f. hemisphaerica belongs - a modified form of the Dirinetum - is unique in Britain and is the nearest saxicolous equivalent to the Lecanactidetum, the community of long-generation species known to inhabit ancient tree bark. In its early stages it is often composed of unparasitised crusts

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of Dirina masilliensis f. sorediata along with Belonia nidarosiensis, Caloplaca citrina s. lat, Caloplaca flavescens, Caloplaca ruderum (in East England), Diploicia canescens, Diplotomma alboatrum, Lecania erysibe and the morphologically variable taxon Opegrapha calcarea. Succession is slow, the advanced stage involving only a handful of species (q.v.).

HOST SPECIES Lecanographa grumulosa f. hemisphaerica appears to be widely parasitic on Dirina masilliensis f. sorediata (Egea et al, 1993). It is suspected that spores from Lecanographa produce apothecia shortly after the host thallus has been penetrated since there is no obvious thallus structure produced initially. The host is considered to be the most characteristic species of dry, north-facing, calcareous church walls in Britain.

ASSOCIATED SPECIES Once the lichen community of dry, vertical limestone walls has had time to become established, the presence of Arthonia pruinata, Opegrapha areniseda or the fungal hyphomycete Spiloma auratum often indicates a transition to a later, more advanced phase of colonization, one which has never before been observed on naturally occurring limestone outcrops. The lichen community may be said to have reached this stage on the appearance of one additional species with Lecanographa, a mixture of two additional species present, or in some cases with all four together. Fortunately, walls supporting these species do not invite attention. Only on close inspection do the various grey-white layers reveal details of their structure and extent.

5 Threats / Factors Leading to Loss or Decline or Limiting Recovery

5.1 HABITAT DESTRUCTION CLIMATE CHANGE The effects of climate on this predominantly coastal, Mediterranean species would suggest that climate change might enable Lecanographa grumulosa to spread further inland. One of the key restrictions imposed on its current dispersal is not the availability of suitable habitat but temperature, and particularly its sensitivity to extreme frost. Even in the Mediterranean, the species is restricted to recesses and sheltered niches in calcareous rock at altitudes above 100m. In southern England, village churches a short way inland from the coast may lie in frost-hollows, especially in deep coombs on the chalk in Dorset, Sussex and Kent. In East Anglia, cold arctic air combined with wind-chill on the open plains may be too extreme in winter for a species that favours northerly aspects. A church in Somerset appears to be the exception (see Figure 5), but it lies on flat ground just above the marshes of a river at an altitude of only 15m.

LOCALIZED HABITAT CHANGE Quite small changes in the degree of shade and shelter can influence air temperature and humidity sufficiently to promote spread of Lecanographa grumulosa. The construction of a porch on the north-facing side of a church in West Sussex appears not to have affected the development of colonies within (see Figure 6). At a church near Lowestoft in northeast Suffolk, a small, open-fronted, slate-tiled shed, fastened onto the wall on the south side of the church may even have encouraged the spread of the species.

The close proximity of some trees and shrubs to walls supporting Churchyard lecanactis can be beneficial by creating shelter and moderate shade. Trees and bushes also act as a buffer between the masonry and ammonia-rich compounds that cause hypertrophication. Sheltered walls decorated with galleted flints provide ideal microhabitats. The cold flints act as condensing surfaces and this appears to keep the plaster damp and receptive to colonization by lichens over a long period.

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Figure 5 – Lecanographa grumulosa growing on the tower of a church in Somerset. (Photograph by Vince Giavarini).

Tree cover only becomes problematical when canopy shade reaches a critical point beyond which lichens will not grow. This is when intervention and management may be necessary to help prolong populations. Tree branches should be kept from contact with the walls of the church anyway, since fine detail such as tracery is easily damaged and can be very expensive to replace (see DAC regulations in Diocesan Handbook).

Likewise, ivy can do tremendous damage to established lichen communities when rooted into the base of walls. The worst cases of ivy obliterating Churchyard lecanactis are on the Norfolk Broads. There are many examples of buildings with good north-facing wall habitat that seem to be ideally suited to Lecanographa colonization, yet it is not present. This poses the question, why? Is it due to neglect, perhaps harking back to a period when money, resources, grazing animals and labour for upkeep of the churchyard were hard to come by? In lean times ivy thrives and, although initially it is decorative in appearance, in time it will bring down masonry, guttering and even penetrate cavities in stained-glass windows. This may have been the case at a church in Sussex where, inexplicably, there are very few Lecanographa grumulosa f. hemisphaerica colonies although Dirina is plentiful.

HYPERTROPHICATION An increase in the nitrogen content of airborne particulate matter in the form of dust or fumes, coupled with elevated levels of ammonia, will contribute to the total of nutrients available to lichen-forming organisms. The localized effect of heavy concentrations of nutrients from farms adjacent to churches is well documented, for example. Despite the all-pervasiveness of hypertrophication, it does not appear to impact directly on the

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Figure 6 – Lecanographa grumulosa at a church in West Sussex. (Photograph by Vince Giavarini).

Dirinetum (the lichen community involving Lecanographa). Assemblages generated by high nutrient availability belong to the Xanthorion. Components are essentially easily identified, fast-growing species which require sunny, well-drained, fast-drying environments to thrive. In the Dirinetum, calcium carbonate dominates the vertical environment, species are slow-growing, shade and low-light demanding, very slow- drying and averse to fluctuations in temperature.

DAMAGE FROM BIOCIDES The main threat to lichens from pesticides is from drifting spray applied in windy conditions. Herbicides and weedkillers are applied to eliminate unwanted plants growing at the base of tall defensive walls or on wall tops, where woody root systems can cause structural damage. This is generally more a problem with castle defences than churches because of their more extensive wall surface. Chemical contamination of lichen communities can set back the process of succession by decades.

PHYSICAL DAMAGE Abrasion of wall surfaces can easily occur when sub-contractors working on a replacement boiler, toilet installation or church extension, lean items against a solid external wall or decide to store building materials nearby. In these cases it is appropriate for the senior churchwarden to brief workmen on potential damage to wall surfaces in advance. By contrast, stonemasons employ a strict disciplinary code regarding such matters. Where major works are planned the presiding body such as English Heritage usually insists on seeing plans of the building showing areas of nature conservation

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importance. Where Lecanographa colonies occur, scaffolding can usually be erected to avoid unnecessary contact.

Weathering of limestone stonework is unavoidable. In Dorset, weathered stonework supports the same form of Churchyard lecanactis that in southeast England grows on plastered walls. The species thrives on neglected wall surfaces that have not required remedial attention for decades. In this case weathering can be seen as beneficial. In the churchyard, however, weathering can be far more damaging to graveyard monuments such as headstones and tombs. Weathering can often enhance the appearance of church buildings by preparing fresh surfaces for colonization by lichens and other cryptogams. On newly constructed church walls it may be many years before the stone is sufficiently weathered for lichens with Trentepohlia, such as Dirina, to become properly established.

Although shade may be regarded as beneficial for the uninterrupted development of Lecanographa, excessive shading can adversely affect photosynthesis. Positioning a flowerbed against the wall of a church building is an unnecessary intrusion. Winds can easily generate frictional rubbing that can soon remove lichens and leave unsightly stains.

Inappropriate grass management can also cause damage to these communities. The use of a collecting bag to catch cuttings is essential. Today, management using strimmers for edging is commonplace. In damp weather these machines may throw clods of grass several metres. Lecanographa is known to occur at ground level on churches at several sites, occasionally separated by a retaining wall and drainage channel. If wet grass that impacts onto stone is not removed it can spoil lichen colonies through acidification and staining. Irresponsible grass management is often blamed for damaging centuries old lichen mosaics on tombs and headstones by causing deterioration in both their appearance and aesthetic value. This is yet another task undertaken by external contractors who may need to be shown the areas where extreme care in using grass cutting machinery is warranted.

UNSYMPATHETIC RESTORATION Today, unsympathetic restoration is rare. Generally, patch repair is the preferred option where plaster or stonework is frail or in need of some re-pointing or re-surfacing work. This helps to create a lichen community comprising a mosaic of age structures rather than even aged populations. Only at sites where the plaster has ‘blown’ due to frost or ice is more extensive repair work desirable.

The threats to Churchyard lecanactis (Lecanographa grumulosa f. hemisphaerica) are summarised in Table 6.

Table 6 - Threats to Churchyard lecanactis.

TYPE THREAT Habitat destruction Climate change. Localised habitat change – tree cover, ivy growth. Hypertrophication. Damage Biocides. Physical damage - abrasion of walls, excessive shading, grass mowing, weathering. Unsympathetic restoration.

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6 Current Conservation Measures

6.1 IN SITU MEASURES Successful management is non-interventionist. One of the key reasons for the presence of Lecanographa grumulosa on ecclesiastical buildings and castle walls is because the host species and its associates have been able to grow undisturbed, sometimes for centuries. However, it is important that objects are not propped up against old masonry by contractors when building restoration work is in progress. Portacabins and similar structures should be situated well away from the walls of the church and not just clear of scaffolding.

6.2 MONITORING Because populations of Lecanographa grumulosa are restricted to church buildings rather than churchyards, colonies are generally stable and require little management other than vigilance in assessing potential threats. The size and extent of some colonies, especially at core sites, show that growth can sometimes be prolific. However, since Lecanographa grumulosa f. hemisphaerica does not appear to generate an independent thallus until apothecia are produced, growth is not easily assessed. A targeted search of core sites in Dorset, Somerset and West Sussex has identified patches of Dirina that may have been recently parasitised. Growth can by measured by recording the location and extent of colonies and by estimating the number of mature and developing apothecia present, observable through a x10 hand lens.

6.3 RECOMMENDATIONS FOR FUTURE WORK LIAISON Liaison may be regarded as ongoing with parishes and the Diocesan Advisory Committee (DAC), and the list of contacts, especially of churchwardens, needs to be constantly updated.

RESEARCH Future work on this taxon other than growth monitoring could include the chemical analysis of the two forms of this taxon, namely forma hemisphaerica and forma grumulosa. This should help to identify trends in dominance of the two accessory substances lecanoric and gyrophoric acid. Erythrin is the major component.

Further research is needed to determine whether the natural populations in Britain are also parasitised, and what factors are responsible for producing the significant differences in the appearance of the ‘hemisphaerica’ and ‘grumulosa’ forms of Lecanographa grumulosa.

7 References Church, J.M., Coppins, B.J., Gilbert, O.L., James, P.W. & Stewart N.F. (1997) [‘1996’]. Red Data books of Britain & Ireland: Lichens. Volume 1: Britain. Peterborough, Joint Nature Conservation Committee. Coppins, B.J. (2002). Checklist of Lichens of Great Britain and Ireland. British Lichen Society. Egea, J.M., Torrente, P. & Manrique, E. (1993). The Lecanactis grumulosa group (Opegraphacea) in the Mediterranean region. Plant Systematics and Evolution, 187: 103-114. Giavarini, V.J. (2001). The current status of Churchyard lecanactis Lecanactis hemisphaerica in Britain. Plantlife Report no. 168. Plantlife, London.

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Giavarini, V.J. (2002). The current status of Churchyard lecanactis Lecanactis hemisphaerica in Britain. Plantlife Report no. 191. Plantlife, London. Giavarini, V.J. (2003). The current status of Churchyard lecanactis Lecanographa grumulosa in Britain. Plantlife Report no. 219. Plantlife, London. James, P.W., Hawksworth, D.L. & Rose, F. (1977). Lichen communities in the British Isles, a preliminary conspectus. In: Lichen Ecology (M. R. D. Seaward, ed.): 295- 413. London, Academic Press. Laundon, J. (1976). Lichens New to the British Flora: 5. Lichenologist, 8: 142-145. National Trust (2001). Wildlife and Buildings: Technical Guidance for Architects, Builders, Building Managers and Others. Cirencester, Estates Department. Plantlife (2001). Churchyard Lecanactis: old walls can harbour secrets. Back from the Brink Management Series. Plantlife, London. Purvis, O.W., Coppins, B.J., Hawksworth, D.L., James, P.W. & Moore, D.M. (1992). Lichen Flora of Great Britain and Ireland. London, Natural History Museum Publications. Torrente, P. & Egea, J.M. (1989). The identity of Opegrapha diaphoroides Nyl.. Lichenologist, 21: 386-387. Woods, R. & Coppins, B.J. (2003). Conservation Evaluation of British Lichens. British Lichen Society.

8 Acknowledgements André Aptroot (Utrecht), Brian Coppins, Bryan Edwards, Oliver Gilbert, Chris Hitch, Peter Lambley, P. Luigi Nimis (Trieste), Alan Orange, Peter James, Jack Laundon and Mark Seaward. New lichen records during 2003 were provided by Barbara Benfield (Devon), Simon Davey (East Sussex) and Bob Hodgson (Cornwall).

9 Contacts Plantlife International The Wild Plant Conservation Charity 14 Rollestone Street Jenny Duckworth – Salisbury Jenny. [email protected] Wiltshire SP1 1DX Tel: 01722 342730 Vince Giavarini [email protected] British Lichen Society [email protected]

10 Links ARKive species web page for Churchyard lecanactis: http://www.arkive.org/species/ARK/fungi/Lecanactis_hemisphaerica/

Plantlife International wishes to acknowledge the financial support of English Nature, Scottish Natural Heritage & the Countryside Council for Wales for the Back from the Brink (species recovery) programme.

Work on Lecanographa grumulosa is supported by:

Original draft by Vince Giavarini Edited by Plantlife International First draft dated 8 July 2004 Last revised 14 October 2004

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