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

Scottish Natural Heritage Commissioned Report No. 090 (ROAME No. F02LD01)
M10a Carex dioica-Pinguicula vulgaris mire, Carex viridula ssp. oedocarpa-Juncus bulbosus/
kochii sub-community
These are the characteristic mires of places where moderately base-rich water emerges from the ground.
Although they are most common where the rocks are generally base-rich, such as on the eastern side of
Coire Giubhsachan and on Beinn na Socaich, they are also widespread on slopes where the rock is acid
or covered with peat or glacial drift, marking out small, localised areas of base-rich flushing. The mires can
be hard to see from a distance, and their appearance is not particularly distinguished. Often the most
noticeable thing about them is the strong sulphurous smell of decomposing vegetation. They have a short,
sparse sward of Carex panicea, C. viridula ssp. oedocarpa, C. dioica, C. pulicaris, C. hostiana,
Eriophorum angustifolium and Trichophorum cespitosum, growing on gravelly, muddy soils studded
with small species such as Pinguicula vulgaris with its lime-green rosettes of sticky leaves, Selaginella
selaginoides, Linum catharticum and Euphrasia officinalis. Saussurea alpina grows in this type of mire in
Coire Giubhsachan. There are thin wisps and wefts of bryophytes such as Drepanocladus revolvens,
Scorpidium scorpioides, Campylium stellatum, Ctenidium molluscum, Blindia acuta, Calliergon trifarium,
Hylocomium splendens, Breutelia chrysocoma and Aneura pinguis.
M11a Carex viridula ssp. oedocarpa-Saxifraga aizoides mire, Thalictrum alpinum-Juncus
triglumis sub-community
This is the more montane form of base-rich small-sedge mire. M11a mires are generally found at higher
altitudes than the Carex-Pinguicula type M10 (see above), on bare, stony, gravelly soils which are flushed
with base-rich water. Like the M10 mires, they have a thin, sparse sward of sedges and other small plants
such as Carex panicea, C. viridula ssp. oedocarpa, C. pulicaris, Thymus polytrichus, Pinguicula vulgaris,
Selaginella selaginoides, Leontodon autumnalis, Lotus corniculatus and Prunella vulgaris. They are, however,
distinguished from M10 by Saxifraga aizoides, which grows in clustering patches of fat, grey-green shoots
which are lit up by its cascades of yellow starry flowers in summer. Among the vascular plants are tufts and
shoots of bryophytes such as Blindia acuta, Campylium stellatum, Hylocomium splendens, Scorpidium
scorpioides and Drepanocladus revolvens. M11 mires tend to have more montane species than M10 mires,
and one of the most characteristic of these is Juncus triglumis, with its neat green stems topped by dark
brown, oval flowers. We were interested to note that this species is common in M11a mires on the
Grey Corries part of the study area, but rare on the hills further west. Other montane species include
Persicaria vivipara, Thalictrum alpinum, Tofieldia pusilla and Saxifraga oppositifolia. There are some
especially fine examples of M11a on the south-facing side of Sgurr a’ Bhuic, on the eastern side of
Coire an Eòin and in Coire a’ Mhadaidh and Coire Choimhlidh.
M11b Carex viridula ssp. oedocarpa-Saxifraga aizoides mire, Palustriella commutata-
Eleocharis quinqueflora sub-community
This is the less montane form of the Carex-Saxifraga mire. It occurs on the lower east-facing slopes of
Beinn na Socaich in Coire a’ Mhadaidh, where there is considerable and extensive flushing of base-rich
water. Most examples are fed by Palustriella-Festuca springs M37, and the flora of the two types
of vegetation has much in common. M11b has more sedges than M37. There is an open sward of
Carex panicea, C. viridula ssp. oedocarpa, C. dioica, Trichophorum cespitosum and Triglochin palustris,
entangled with Saxifraga aizoides and dotted with Pinguicula vulgaris. The wefts and mats of bryophytes
consist of species such as Palustriella commutata, Scorpidium scorpioides, Blindia acuta and Campylium
stellatum. Some of these mires in Coire a’ Mhadaidh are home to the rare horsetail Equisetum variegatum,
and the uncommon Eriophorum latifolium also grows in this type of vegetation here.
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