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

Scottish Natural Heritage Commissioned Report No. 090 (ROAME No. F02LD01)
U4d Festuca ovina-Agrostis capillaris-Galium saxatile
Rhytidiadelphus loreus sub-community
grassland, Luzula multiflora-
U4d is the more upland, montane counterpart of the Typical U4a and tends to occur on damper soils and
on shaded slopes. It is typical of gullies on a steep slope where the soil is damper and deeper than it is on
the intervening rocky ribs. U4d is widespread but rarely extensive throughout the study area. This type of
grassland has a deep-green sward made up of Festuca vivipara, Anthoxanthum odoratum, Agrostis canina,
Deschampsia flexuosa, D. cespitosa, Carex binervis and Luzula multiflora. Within the turf are clumps of
Blechnum spicant, trailing shoots of Potentilla erecta and Galium saxatile, and a scatter of species such
as Succisa pratensis, Viola palustris and Campanula rotundifolia. There is a deep, richly-coloured underlay
of bryophytes made up of Rhytidiadelphus loreus, Hylocomium splendens, Hypnum jutlandicum, Pleurozium
schreberi, Thuidium tamariscinum and Polytrichum commune. In some examples there are clumps of Sphagnum
capillifolium, suggesting that this type of vegetation may be derived by grazing from damp heath vegetation.
U4e Festuca ovina-Agrostis capillaris-Galium saxatile grassland, Vaccinium myrtillus-
Deschampsia flexuosa sub-community
U4e is the most montane form of Festuca-Agrostis-Galium grassland. It is most common on stony soils at high
altitudes, although it also occurs at lower altitudes on suitable substrates. In the study area it is most extensive
above about 700m on the south-facing slopes of Ben Nevis, Sgurr a’ Bhuic and Sgurr Chòinnich Beag, and
on the western slopes of Meall an t-Suidhe and Carn Dearg, where the soils are thin, stony and well-drained.
On the east-facing side of Coire a’ Bhuic, U4e forms distinctive mosaics with the damper Luzula-
Rhytidiadelphus sub-community U4d, covering the rocky ribs in between the gullies with U4d. U4e is also
extensive on the summit slopes of Sgurr Chòinnich Beag. Here it looks as if it is taking the place of the more
natural Carex-Racomitrium heath U10 as a result of heavy grazing. U4e is a grassland with a short, silverygreen
sward of Festuca vivipara, Agrostis capillaris, A. canina, A. vinealis, Nardus stricta and Deschampsia
flexuosa growing through a carpet of Racomitrium lanuginosum. It is a species-poor community, sprigged with
a little Vaccinium myrtillus and with Potentilla erecta, Galium saxatile and Euphrasia officinalis agg. At higher
altitudes there may be a few montane species such as Diphasiastrum alpinum or Polytrichum alpinum.
There are few bryophytes under the sward apart from Racomitrium lanuginosum – just small wefts and patches
of R. ericoides, Hypnum jutlandicum, Pleurozium schreberi, Rhytidiadelphus loreus and Hylocomium splendens.
U4eA Festuca ovina-Agrostis capillaris-Galium saxatile grassland, Vaccinium myrtillus-
Deschampsia flexuosa sub-community, Alchemilla alpina variant
This form of grassland is not represented in the NVC, although it is reasonably common in the hills of the
west Highlands. It is much like the ordinary U4e, with a thin sward of Festuca vivipara, Agrostis capillaris,
A. canina, A. vinealis, Nardus stricta and Deschampsia flexuosa growing in a thin, grey-green mat of
Racomitrium lanuginosum. However, here there is also much Alchemilla alpina, giving a distinctive look to
the vegetation with its neat dark-green leaves and heads of lemon-yellow flowers. Locally there can be a
few montane species, such as Carex bigelowii, Luzula spicata, Diphasiastrum alpinum, Gnaphalium supinum
and the mosses Kiaeria starkei and K. blyttii, together with less exacting plants such as Galium saxatile,
Potentilla erecta, Blechnum spicant, Veronica officinalis, Campanula rotundifolia, Carex pilulifera, C. caryophyllea,
Luzula multiflora, Hypnum cupressiforme, Breutelia chrysocoma, Polytrichum alpinum, Hylocomium splendens,
Rhytidiadelphus squarrosus, Racomitrium fasciculare and R. sudeticum. U4eA resembles the Festuca-Agrostis-
Alchemilla community CG11, but is less herb-rich and lacks Thymus polytrichus and other small calcicoles.
It is a grassland of steep, stony, well-drained soils, and is especially common on stabilised scree and on the
gravelly banks of stream gullies. It occurs quite widely in the study area at moderate to high altitudes.
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