HE3F Calluna vulgaris – Eriophorum vaginatum bog
Vegetation
In this community Calluna vulgaris dominates, forming a fairly dense shrub layer interspersed by tussocks of Eriophorum vaginatum, spreading tufts of Eriophorum angustifolium and patches of Vaccinium myrtillus. Juncus squarrosus is frequent, often indicating some disturbance, and in some variants Empetrum nigrum occurs. In the bryophyte layer, the heathland quartet of Rhytidiadelphus loreus, Hypnum jutlandicum, Hylocomium splendens and Pleurozium schreberi will usually be found, together with hummocks of Sphagnum capillifolium, but other sphagna are occasional or scarce. Racomitrium lanuginosum is occasional and not abundant. The pale green threads of Plagiothecium undulatum are commonly found beneath the heather.
Ecology
This is a high-altitude bog community of upper mountain slopes, ridges and plateaux (mean altitude = 468 m, n = 99; mean slope = 8.8°, n = 74). It occurs on fairly deep, rather wet, acidic, ombrogenous peat soils of low fertility (mean extent of bare rock = 0.0%, n = 74).
Sub-communities
Two sub-communities have been described for this community, the slightly degraded Juncus squarrosus – Luzula sylvatica sub-community (HE3Fi) and the typical sub-community (HE3Fii). These are differentiated chiefly on the abundance of Juncus squarrosus, which is invariably present in HE3Fi and only occasional in HE3Fii.
Similar communities
This bog community is placed alongside the high-altitude heaths of the HE3 Vaccinium myrtillus – Racomitrium lanuginosum group due to the abundance of Calluna vulgaris, the high frequency of Vaccinium myrtillus and the pleurocarpous nature of the bryophyte layer. However, community HE3F differs significantly in the abundance of Eriophorum spp. Indeed, the most similar community is the BG2E Calluna vulgaris – Eriophorum spp. bog. That community is rather wetter in nature with a greater cover of Erica tetralix, Molinia caerulea and Trichophorum cespitosum/germanicum but less Vaccinium myrtillus. BG2E also supports a greater range of Sphagnum species whilst pleurocarpous mosses are less prominent. Juncus squarrosus is typically more abundant in HE3G than in HE3Fi.
Conservation value
Most of the examples of this vegetation qualify as EU HD Annex I habitat 7130 Blanket bogs (active)*. This is on average a fairly species-rich community (species/4 m2 = 19.5, n = 104).
Management
These bogs, which often form parts of commonages, may be used as rough grazing land (typically for sheep) and overgrazing can be a problem. Erosion is commonplace within such bogs, producing gullies and haggs.