RH1B Teucrium scorodonia – Mycelis muralis pavement community
Vegetation
This is usually a sparsely vegetated community. The constant species in the field layer are Asplenium ruta-muraria, Teucrium scorodonia, Sesleria caerulea, Geranium robertianum and the non-native Mycelis muralis. These are frequently joined by Ceterach officinarum, Hedera helix, Thymus polytrichus, Phyllitis scolopendrium and Senecio jacobaea. There is often also a scrub element to the flora with some patchy growth of Prunus spinosa, Corylus avellana, Rosa spinosissima or Rubus fruticosus agg.
Ecology
This is a community of karstic limestone pavement (mean extent of bare rock = 83.0%, n = 154) occurring in the lowlands (mean altitude = 61 m, n = 126; mean slope = 1.0°, n = 28). Soils are skeletal and can be largely confined to the shady grykes, which thus support much of the vegetation. Conditions are base-rich, fairly infertile and fairly dry.
Sub-communities
No sub-communities are described.
Similar communities
The RH1A Asplenium trichomanes – Ctenidium molluscum community may also occur on limestone pavement, but there Asplenium ruta-muraria, Teucrium scorodonia and Mycelis muralis are less frequent. That community is also somewhat more open with lower frequencies of woody species. The RH1B community often occurs in mosaic with patches of limestone grassland belonging to the GL3A Briza media – Thymus polytrichus grassland community, which has a greater overall vegetation cover, lower fern cover and greater graminoid cover.
Conservation value
Almost all examples of this community qualify as EU HD Annex I priority habitat 8240 Limestone pavement*. Species/25 m2 = 17.8, n = 154.
Management
Limestone pavement sites are traditionally winter grazed by cattle and the main threats there are scrub encroachment, quarrying and destruction for purposes of agricultural improvement. The non-native Mycelis muralis is not regarded as a problematic species and no management actions have been taken to control the species.