HE3D Calluna vulgaris – Racomitrium lanuginosum heath
Vegetation
Calluna vulgaris and Racomitrium lanuginosum dominate in this low-growing, wind-clipped heath, together forming a carpet of springy vegetation. Erica cinerea and Vaccinium myrtillus are also constants and Empetrum nigrum frequently adds to the dwarf shrub component. Potentilla erecta and some thin tufts of Deschampsia flexuosa are likely to be found. The bryophyte layer is scarcely lower than the other plants and here Hypnum jutlandicum and Rhytidiadelphus loreus join the hoary mounds of Racomitrium. Lichens are a regular feature of this community, with the forking shoots of Cladonia uncialis a constant presence and Cladonia portentosa frequent. These heaths are dotted with occasional, clustered shoots of Huperzia selago.
Ecology
This is a montane heath community of exposed upper mountain slopes, ridges and plateaux (mean altitude = 535 m, n = 205; mean slope = 16.3°, n = 163). The soil is shallow, acidic and infertile. These heaths are typically strewn with rock fragments (mean extent of bare rock = 10.2%, n = 163).
Sub-communities
Two sub-communities have been described. The Arctostaphylos uva-ursi – Juniperus communis sub-community (HE3Di) is easily identified as Arctostaphylos is invariably present and Juniperus communis is frequent. These species are not found in the typical sub-community (HE3Dii).
Similar communities
The abundance of Racomitrium lanuginosum makes this a striking community. It could be confused with HE3E Racomitrium lanuginosum – Festuca vivipara heath, but in that assemblage Calluna vulgaris is less abundant and there is a greater grass component. In community HE3B Calluna vulgaris – Scapania gracilis heath, pleurocarpous mosses and Sphagnum capillifolium tend to be more prominent. The present community lacks the Nardus stricta patches of community HE3C.
Conservation value
Almost all of the examples of this vegetation qualify as EU HD Annex I habitat 4060 Alpine and subalpine heath. This is on average a heath community of middling diversity (species/4 m2 = 18.7, n = 209).
Management
These heaths, which often form parts of commonages, may be used as rough grazing land (typically for sheep) and overgrazing can be a problem. Climate change threatens arctic-alpine species which are restricted to montane communities such as this.