Vegetation
This heathy upland community is dominated by a combination of Calluna vulgaris and the tough, wiry leaves of Juncus squarrosus, attended by some low growth of Vaccinium myrtillus. Frequently, there is some sparse cover of Galium saxatile with its diminutive white flowers or a grassy element provided by Agrostis capillaris, Agrostis canina/vinealis or Nardus stricta. Empetrum nigrum is occasional here as also are Eriophorum vaginatum and Eriophorum angustifolium which occur on deeper peats. The bryophyte layer is quite diverse. The pleurocarps Rhytidiadelphus loreus, Hypnum jutlandicum and Hylocomium splendens are constants as are the whitish-grey patches of Racomitrium lanuginosum and the scarlet hummocks of Sphagnum capillifolium. Liverworts tend to be a feature, the most common being Scapania gracilis, but Diplophyllum albicans, Lophozia ventricosa, Calypogeia muelleriana and Anastrepta orcadensis may also be found.
Ecology
This is a community of acidic, infertile, wet upland peaty soils, prominent in areas where sheep grazing has favoured the rhizomatous expansion of Juncus squarrosus. It usually represents a variant of montane heath and may occur on shallow soils where upland bog has eroded away. It also occurs on deeper soils where it forms a rather poor version of upland blanket bog itself. Mean altitude = 641 m, n = 63; mean slope = 9.2°, n = 63; mean extent of bare rock = 0.8%, n = 63.
Sub-communities
No sub-communities have been described for this community.
Similar communities
From other heath types, the abundance of Juncus squarrosus helps distinguish this community. In HE3C Calluna vulgaris – Nardus stricta heath, this rush can also be plentiful but there Nardus tends be a dominant. Juncus squarrosus also occurs in HE3A Calluna vulgaris – Hylocomium splendens heath, but there Racomitrium lanuginosum is seldom found.
Conservation value
Most examples of this community correspond with EU HD Annex I habitat 4060 Alpine and subalpine heath. On deeper soils, however, it may correspond to a rather degraded form of habitat 7130 Blanket bogs (active)*. It is a species-rich community (species/4 m2 = 21.2, n = 75).
Management
These heaths and bogs, which often form parts of commonages, may be used as rough grazing land (typically for sheep). Indeed, the presence of this community may be an indicator of overgrazing. Climate change threatens arctic-alpine species which are restricted to montane communities such as this.