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

Scottish Natural Heritage Commissioned Report No. 090 (ROAME No. F02LD01)
M4 Carex rostrata-Sphagnum fallax mire
These are mires with a lush grey-green sward of Carex rostrata, C. nigra, C. echinata and Eriophorum
angustifolium swaying above a wet carpet of Sphagnum fallax, S. palustre, S. denticulatum and Polytrichum
commune. There is a speckling of small plants such as Potentilla erecta, Viola palustris, Succisa pratensis
and Euphrasia officinalis. In slightly more nutrient-enriched examples there are species such as Parnassia
palustris, Ranunculus acris and Plagiomnium undulatum. M4 mires are widely though thinly distributed over
most of the study area. Almost all the examples are small. Typically they occupy ill-drained hollows within
patches of blanket mire. The largest examples are in lower Coire Giubhsachan, on wet level ground where
there may once have been a shallow lochan. There are also patches of M4 around Lochan Meall an
t-Suidhe, on the boggy flats in Coire an Eòin and An Coire Calma to the east of Aonach Beag, around the
lochans in lower Coire na Ceannain and in upper Glen Nevis.
M6a Carex echinata-Sphagnum fallax/denticulatum mire, Carex echinata sub-community
Carex echinata-Sphagnum mires are among the commonest small acid mires in the uplands, generally
occurring in patches on flushed lower slopes as they do throughout in the study area. This type of vegetation,
however, is unusually extensive on the floor of lower Coire Giubhsachan, in a mixture of mires which look
as if they are filling the bed of what was once a shallow lochan. M6a has a short, grey-green sward of
Carex echinata, interleaved with a little C. nigra, C. panicea and Eriophorum angustifolium and flecked
with Viola palustris, Potentilla erecta, Succisa pratensis, Leontodon autumnalis and Pinguicula vulgaris. These
plants grow in a green carpet of Sphagnum fallax, S. denticulatum, S. palustre and Polytrichum commune.
M6b Carex echinata-Sphagnum fallax/denticulatum mire, Carex nigra-Nardus stricta
sub-community
M6b is a more varied, heterogenous type of acid mire than M6a (see above), and can be intermediate
between a sedge mire and a wet grassland. The variegated green swards can be hard to pick out
from the surrounding mires and wet grasslands. They are made up of Carex echinata, C. nigra, C. panicea,
Eriophorum angustifolium, Nardus stricta, Molinia caerulea, Agrostis canina and Juncus squarrosus, growing
in uneven, tufted mixtures dotted with Succisa pratensis, Viola palustris, Galium saxatile, Leontodon
autumnalis and Potentilla erecta. The bryophyte layer is the familiar assemblage of Sphagnum fallax,
S. denticulatum, S. palustre and Polytrichum commune which is shared by all of the acid small-sedge mires
and rush-mires. M6b mires occur on flushed slopes at low to moderate altitudes and are probably the most
common type of soligenous sedge mire in the study area.
M6c Carex echinata-Sphagnum fallax/denticulatum mire, Juncus effusus sub-community
These tall mires of Juncus effusus form narrow bands along stream-courses and spread out to fill wet hollows
on the low ground. They are common in Glen Nevis and on the lower northern slopes of the Grey Corries.
They have a dense sward of Juncus effusus, growing with Carex echinata, C. nigra, Molinia caerulea,
Eriophorum angustifolium and Juncus bulbosus through a wet mat of Sphagnum denticulatum, S. fallax,
S. palustre and Polytrichum commune. Generally species-poor, they may be home to a speckling of small
mire plants such as Viola palustris, Succisa pratensis and Narthecium ossifragum.
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