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

Scottish Natural Heritage Commissioned Report No. 090 (ROAME No. F02LD01)
W9b Fraxinus excelsior-Sorbus aucuparia-Mercurialis perennis woodland, Crepis paludosa
sub-community
There are small, mostly linear patches of W9b in the gullies which cut down the western slope of Meall
Cumhann, and which are flushed with base-rich water from the limestone above. There are also patches
along the banks of the Allt Coire a’ Mhadaidh in the north-east of the study area. It is a woodland of damp,
basic soils and has a canopy of ash Fraxinus excelsior, hazel Corylus avellana, birch Betula pubescens, elm
Ulmus glabra, goat willow Salix caprea and rowan Sorbus aucuparia. Under the trees is a rich tangle of
tall herbs and grasses: a colourful spread of flowers in summer. The species here include Agrostis capillaris,
Deschampsia cespitosa, Anthoxanthum odoratum, Geum urbanum, Geranium robertianum, G. sylvaticum,
Filipendula ulmaria, Stachys sylvatica, Ranunculus acris, Prunella vulgaris, Sanicula europaea, Primula vulgaris,
Fragaria vesca, Viola riviniana, Angelica sylvestris, Cardamine pratensis and the ferns Athyrium filix-femina,
Dryopteris affinis, D. filix-mas and Blechnum spicant. The uncommon grass Melica nutans grows here in this
type of vegetation. There is a deep carpet of bryophytes on the ground, over rocks and on the bases
of trees, mostly made up of Thuidium tamariscinum, T. delicatulum, Isothecium alopecuroides, I. myosuroides,
Hylocomium splendens, H. brevirostre, Hypnum cupressiforme, Rhytidiadelphus loreus, R. triquetrus,
Brachythecium plumosum, Racomitrium aciculare, Atrichum undulatum, Plagiomnium undulatum and
Eurhynchium praelongum. Some of the herb-rich grassland above the woodland on the slopes of
Meall Cumhann and Coire Choimhlidh might develop into this kind of woodland if grazing were less intense.
W11a Quercus petraea-Betula pubescens-Oxalis acetosella woodland, Dryopteris dilatata
sub-community
This type of grassy, acid woodland has a canopy of birch Betula pubescens, rowan Sorbus aucuparia and
hazel Corylus avellana. The ground layer is lightly grazed. The sward of species such as Holcus mollis,
Agrostis capillaris, Potentilla erecta, Viola riviniana and Conopodium majus is punctuated by tall clumps of
Dryopteris filix-mas and D. dilatata. In some patches there is also much Rubus fruticosus or R. idaeus, or trails
of Lonicera periclymenum. The bryophyte layer is made up of species such as Hylocomium brevirostre,
Thuidium tamariscinum, Hylocomium splendens, Pleurozium schreberi and Polytrichum commune. Large ferns
and scrambling shrubs are rare in upland woods unless grazing is light. They are also a much more common
component of the vegetation from the south-west Highlands southwards, where summers are warmer than
they are further north. So W11a is quite a notable type of vegetation in the study area. It occurs in Glen Nevis
on islands in the river and on the very steep slopes of the gorge.
W11b Quercus petraea-Betula pubescens-Oxalis acetosella woodland, Blechnum spicant
sub-community
This is the most extensive type of woodland on the steep slopes in Glen Nevis. It is also a common
component of the mixed woodlands on steep, rocky slopes along the northern edge of the study area. It is
a grassy woodland of well-drained acid soils. It is so common in the uplands that people seldom realise that
it is far from natural, and that the ground layer would be more heathy or more herb-rich were it less grazed.
The canopy is of birch Betula pubescens, with smaller amounts of oak Quercus petraea, rowan Sorbus
aucuparia, holly Ilex aquifolium, hazel Corylus avellana and even alder Alnus glutinosa and ash Fraxinus
excelsior. Underneath the trees, the field layer is green and grassy and made up of Anthoxanthum odoratum,
Agrostis capillaris, A. canina, Holcus mollis and H. lanatus. This is speckled with small herbs such as
Potentilla erecta, Galium saxatile, Viola riviniana, Primula vulgaris, Blechnum spicant, Oxalis acetosella,
Conopodium majus and Anemone nemorosa. Hyacinthoides non-scripta can be common, stippling the
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