A survey of the vegetation of Ben Nevis - Scottish Natural Heritage

Scottish Natural Heritage Commissioned Report No. 090 (ROAME No. F02LD01)
H21b Calluna vulgaris-Vaccinium myrtillus-Sphagnum capillifolium heath, Mastigophora woodsii-
Herbertus aduncus sub-community
This is the more western, oceanic form of the sub-montane damp heaths. It shares with the more widespread
Calluna-Pteridium sub-community H21a the dark, uneven sward of Calluna vulgaris and Vaccinium myrtillus,
tufted with with Deschampsia flexuosa and Carex binervis and dotted with Blechnum spicant, Potentilla
erecta, Galium saxatile, Succisa pratensis and Solidago virgaurea. Under the sward is a deep, damp layer
of Sphagnum capillifolium, growing with Hylocomium splendens, Hypnum jutlandicum, Rhytidiadelphus
loreus, Pleurozium schreberi and Racomitrium lanuginosum. In this sub-community there is also a colourful
and attractive array of oceanic, western liverworts including Herbertus aduncus, Pleurozia purpurea,
Bazzania tricrenata, B. pearsonii, Mastigophora woodsii, Mylia taylorii, Anastrepta orcadensis, Plagiochila
spinulosa, P. carringtonii, Scapania gracilis, Lepidozia pearsonii and the more lowland, woodland species
Saccogyna viticulosa. The filmy fern Hymenophyllum wilsonii is common, growing among the bryophytes
in green cascades of dark translucent fronds.
H21b is confined to rocky woods and heathery slopes in the far west of Britain and Ireland, but within
its range in the west Highlands it is far from uncommon. It was strange to find it so rare in the study area.
There is none at all in Coire Leis, nor in the glen between the Carn Dearg ridge and Aonach Mór. We found
it only in upper Glen Nevis, at the upper edge of the woods on the north-facing side and on the steep, rocky
slopes above.
H22a Vaccinium myrtillus-Rubus chamaemorus heath, Polytrichum commune-Galium saxatile
sub-community
This type of montane heath is widespread and common on steep slopes at moderate altitudes throughout the
study area. It marks out places where snow lies reasonably consistently through the winter, although it does
not linger sufficiently late in spring to suppress dwarf shrubs altogether. H22a has a vivid green sward of
Vaccinium myrtillus, V. vitis-idaea, V. uliginosum and Empetrum nigrum ssp. hermaphroditum, growing with
montane species such as Carex bigelowii, Diphasiastrum alpinum, Polytrichum alpinum and the lichen
Cetraria islandica as well as with an array of more widespread plants such as Deschampsia flexuosa,
Festuca vivipara, Potentilla erecta and Galium saxatile. Cornus suecica is an especially characteristic plant
of this type of heath. It does not occur in all stands, but where it does occur it can be really common, with
its small purple flowers enclosed by white petal-like bracts standing above its sturdy bright-green rosettes of
oval leaves. Rubus chamaemorus is another characteristic species of this type of vegetation, but it is less
common in H22a in the study area than it is in some of the bogs and damp snow-beds. Melampyrum
pratense is another, more widespread plant which can also be really plentiful in H22a. The bryophyte layer
is deep and dense, and gives a rich orange-green tinge to the vegetation. It is made up of mixed mats
of Sphagnum capillifolium, Rhytidiadelphus loreus, Hylocomium splendens, Pleurozium schreberi, Hypnum
jutlandicum, Plagiothecium undulatum, Polytrichum commune and Racomitrium lanuginosum. H22a resembles
the HX Vaccinium heath described below, but differs in containing northern upland species such as
R. chamaemorus, C. suecica, V. uliginosum, C. bigelowii and E. nigrum ssp. hermaphroditum.
H22b Vaccinium myrtillus-Rubus chamaemorus heath, Plagiothecium undulatum-Anastrepta
orcadensis sub-community
H22b is a moderately montane form of Calluna heath, intermediate between the tall sub-montane heaths
and the prostrate communities of exposed, high ground. It is a community of sheltered slopes at moderate
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