Exploring Quinag: Allt Bad na Fearnaig (1)

February 1st 2021

Exploring Quinag: Allt Bad na Fearnaig (1)

Setting the scene

The south-west corner of the Quinag estate occupies the eastern half of the 1km square NC1926 (photo 1).  The estate boundary is marked by an old fence which follows the course of a substantial burn, the Allt Bad na Fearnaig.  This burn gets its name from a once-wooded ridge to the west of its lower reaches (bad na fearnaig = place of the alder, although there appear to be none there now).  It arises at over 250m altitude just south of the Bealach Leireag, the pass on the track running over into Gleann Leireag and, gathering water from small tributaries, flows south for some 2km down to the shores of Loch Assynt, at c.65m. The burn is crossed at NC196266 by the old track between Achmore and Tumore.  This track is a useful reference feature to the east, but to the west it disappears into dense tussocks of purple moor-grass and can be difficult to locate.

Records of the wildlife of this area appear to be sparse, so we spent two days of October exploring the ‘wilder’ parts, on the 2nd and 18th,  with a brief look, on 14th, at the flora of the verges of the A837.

First visit, 2nd October

Having parked at the Boat Bay (NC201260), we made our way west along the road, noting, in passing, a thin but extensive stand of common reed Phragmites communis in a wet area just north of the road (NC200260, photo 2). These hillside ‘reed-beds’ occur occasionally on the lower slopes of Quinag, a habitat quite different from that of the denser beds found in some lochs.

Having entered our target area, we plodded up a boggy hillside until we met the old track.  It was running, at this point, on rocky ground along the south side of a mafic dyke in the Lewisian gneiss, cannily avoiding steeper slopes above and wet ground below.  Turning west along the track, we came across a large angular boulder of Torridonian sandstone perched on smaller rocks (photo 3).  We could not decide whether this was a glacial erratic or a man-made feature, but in either case it was odd.

Pools

A fair-sized burn crosses the track alongside a conspicuous outcrop of dark dyke rock (photo 4, NC198265).  On it was mountain everlasting Antennaria dioica and wild thyme Thymus polytrichus, together with rock pocket-mossFissidens dubius (identified later by Gordon Rothero), all confirming a degree of base-enrichment.

We then turned up the burn into a flatter area with elongated boggy pools (photos 5 and 6), surrounded by tussocks of black bog-rush Schoenus nigricans.  There were good stands of the whip-like slender sedge Carex lasiocarpa and also bog-sedge C. limosa, which has creeping rhizomes with ascending shoots, giving it a curious ‘falling-about’ look (photo 7).  Submerged in the pools were conspicuous ‘bottle-brush’ stems of the largest of the local bladderworts, Nordic bladderwort Utricularia stygia (photo 8), with globular over-wintering buds forming at the ends of the stems.

These bladderwort stems are often plastered with minute green algae, so a few were collected and later processed for desmids.  From samples sent to him, David Williamson, a specialist in this group, identified some 18 species.  His drawings of a selection of these have been scanned (photo 9) to illustrate the variation of form in eight different genera; the species are listed below.  They are not all to the same precise scale.

Desmid drawings

Top row, left to right: Bambusina borreri, Closterium kuetzingii, Cosmarium brebissonii, Euastrum crassum.

Bottom row, left to right: Haplotaenium minitum, Penium cylindrus, Tetmemorus granulatus, Xanthidium armatum 

These pools seem to be relics of the former sinuous course of the burn, which now runs straight and deep just to their east.  It drains a largish lochan to the north-east, and appears to have been ‘ditched’ at some time in the past; to what end in such a boggy landscape it is difficult to guess, since the effort involved would seem to outweigh any possible benefits.

Lunch was taken in the sun on a peaty tump to the west, overlooking a much larger pool (NC198265, photo 10) covered in the leafy stems of bogbean Menyanthes trifoliata (photo 11), which must have been a delightful sight when flowering earlier in the year.  Skating about on the surface of the pool was a typically frenetic group of whirligig beetles Gyrinus sp., but since they are both difficult to catch and tricky to identify, we do not know precisely which species.

The main burn

About 150m to the north of the pool we dropped down into the shallow valley of the Allt Bad na Fearnaig, where it was sliding down water-smoothed sandstones in the lowest strata of the Torridonian (NC198267).  Bankside boulders sheltered a small grey willow Salix cinerea in a place safe from browsing by red deer, the historic enemy of tree establishment in this area.

A male stonechat was perched nearby on a post in the boundary fence, the only bird seen all day.  We noticed, some way above it, a large white object in the burn, and wondered if it might be a dead sheep, although that there are now none in this area.  So we walked up the side of the burn until it was revealed as a sizeable boulder, almost completely covered with a bright white lichen (photo 12).  A lichenologist friend suggests that a possible candidate is the crustose species Pertusaria lactea, common on siliceous rocks in upland areas.  It is UV positive, which might make it appear to shine on a sunny day; however a small specimen would be required for certain identification.  From the size of the thallus, it must have been colonising that boulder for decades, if not longer.

Torridonian crags

Further up the lower slopes of Quinag to our east we could see two crags in the Torridonian (photo 13), which we thought might provide some further variety, so we clambered up to them. The first was a fractured outcrop in a lower scarp (photo 14), which was sheltering a large holly (NC199268).  Closer to, this proved to be a well-berried female tree.  Birds such as thrushes, which had been feeding on the holly berries in former years, were presumably responsible for the single bush of himalayan cotoneaster C. simonsii in a crevice beneath the holly (photo 15).  Bushes of this species, which was indeed originally introduced into cultivation from the Himalayas, are not uncommon in the Assynt landscape.  There was also a rose Rosa sp., which had presumably arrived in the same way.

Some 100m further up the hill was a much more massive Torridonian crag (NC199269), providing niches, out of reach of deer, for a further three holly trees, together with some rowans (with seedlings below) and aspens (photo16).  Like so many other crags along the south side of Quinag, this one gives some idea of the potential for regeneration of woodland in the area, if the browsing pressure from red deer could be further reduced.  This crag did, in fact, also boost the plant list, with species such as flea sedge Carex pulicaris, goldenrod Solidago virgaurea and wood sage Teucrium scorodonia.

Downhill for home

Having reached the very corner of our target square, we then turned for home, following, thankfully, what appeared to be an old stalkers’ track.  There were two surprises soon after we started down the hill.  The first was a steeply sloping area of marshy grassland, perhaps spring-fed, just to the east of the lower crag (also on photo 13), which we had missed on the way up.  This contained a range of species unexpected in an otherwise fairly acid landscape, such as meadow buttercup Ranuculus acris, autumn hawkbit Scorzoneroides autumnalis, bog stitchwort Stellaria uliginosa and white clover Trifolim repens, together with a large plant of heath spotted orchid Dactylorhiza maculata.  Not far away on the track was a lump of jelly (photo 17), the discarded remains of a female frog that had been caught in the open by a mammal or bird predator.

It took us a further hour to reach the road, at first along the old track (photo 18), and then negotiating, with some care, steep rocky slopes covered with heather, and flatter wet areas thick with purple moor-grass tussocks (not our favourite terrain).  The number of higher plants listed for the day was a modest 83 species, with interesting contrasts between rather richer boggy areas on the Lewisian gneiss below and the dourer, but generally drier, heathland and crags on the Torridonian above.  It had been a good day out, gloriously sunny at times, and reasonably warm for the time of year, at about.8 degrees.

The exploration of this area continues here Exploring Quinag: Allt Bad na Fearnaig (2)

 

Ian M. Evans and Gwen Richards

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