Last updated February 2007

The importance of Churchyard Lichen Habitats

The term ‘churchyard’ includes cemeteries, burial grounds, ruined abbeys and cathedral precincts

The British churchyard is a major habitat for lichens. They are important because they have changed little over decades or even centuries, and this allows slow growing lichen species the time and stable conditions that they need to become established and flourish. A few lichens are rare and only found in churchyards.

In lowland Britain there are few natural stone outcrops. However, the diversity of stone used in church buildings and memorials maintains lichen diversity.

Lichens are links in an ecological chain. A number of minute invertebrates depend upon lichens for food and shelter.

Factors Affecting Lichen Diversity in Churchyards

Lichen colonisation: the stone chemistry, surface texture and water-holding capacity, pH, and aspect determine establishment.

Generally, the oldest stones [church walls and old memorials] have the greatest lichen interest.

Historical management factors such as past repairs to stonework, application (or removal) of rendering and the growth (or removal) of vegetation, particularly ivy, can also have a significant effect on the number of lichen species found on a church building.

Lichens can also grow on mosses, pebbles, chippings, bare wood and trees, and amongst short grasses.

The Management of Churchyards for Lichen Conservation

In General, threats to lichens occur through:

• Disturbance by cleaning or repair work
• Heavy shading out from other plants
• Removal or repositioning of memorials

Church Buildings and Churchyard Boundary Walls

Repair work to the Church Fabric

Repair only where necessary. If repairing a wall, for example, try to do small areas at a time with a 5-year interval between repairs. This allows for lichen re-colonisation from the original stonework.

Replace worn stone with a stone similar to that used in the building

Re-point with lime-based mortar

Take particular care of areas of intact medieval stonework where significant lichen communities are often present. Those on the south and west walls of the church flourish in the unshaded conditions usually found there, whereas those on the north wall are adapted to damper and shadier conditions. Try not to alter these conditions.

Roofs

Reuse original materials as far as possible and do not brush or clean tiles before re-positioning.

Boundary Walls

Reuse as much of the original material as possible.

When rebuilding, place stones with lichen cover on the outside.

Shading out

Ivy and other plants climbing over the church and boundary walls smother the existing lichen flora and inhibit lichen establishment. They should be actively discouraged.

Check regularly (at least once a year) for self-setting bramble, elder, ivy etc. Hand weed or, when necessary, spot treat with a herbicide.

Gravestones

Lichens enhance the appearance of a stone.

Variety in design and geology encourages species diversity. Kerb memorials and ledgers provide an important microhabitat for many species.

Specific lichens prefer different niches. The aspect of a memorial is very important. If this is altered some lichen species will die. Removing or relocating a tombstone is to be avoided; where removal is unavoidable a lichenological survey should be undertaken first.

Relocate stones to replicate the original light conditions and alignment.

Leaning stones against a church or boundary wall kills the lichens on the memorial as well as those on the wall covered by the tombstone.

Ancient chest tombs often have significant lichen communities particularly on the flat tops. Ivy and other vegetation should not be permitted to grow upon them.

The oldest stones often have the greatest lichen diversity.

Grassland

Grass cuttings thrown onto horizontal slabs, low ledges and kerbstones should be brushed off. If allowed to remain the cuttings will smother the lichens.

Fertilisers and weed killers alter the grassland composition and will adversely affect mosses, lichens and fungi that are only found in unimproved grasslands.

Weedkillers should not be used around the base of a tombstone. They are ‘wicked up’ by the sedimentary stones, damage the lichen flora and leave an unsightly stain.

Trees

If trees have to be planted, indigenous broad-leaved varieties are preferable.

Select the planting site carefully, remembering that the root system and canopies of mature trees are extensive.

Try to avoid shading the south-facing church wall – even the shade from rose bushes can have a detrimental effect.

Lignum (fences, seats etc)

Where lichen-rich fences have to be replaced, try to retain some old sections from which colonisation can progress to the new wood.

Do not paint seats.