Exploring Quinag: Coire Riabhach
The large burn that runs under the old bridge at Doire Cuilinn (NC207258) has two sources. The lower one is the Allt na Doire Cuilinn, which drains Lochan Duibhe, and runs parallel to the old track below the holly woodland from which the area gets its name. The other descends the higher flanks of Quinag from an area called Coire RIabhach, but does not now seem to have a name in its own right.
Coire Riabhach is translated by Gemma Smith as the ‘brown or brindled corrie’, but it is more of a shelf than a corrie, running west-east above the loch with a similar name. We had not previously recorded the 1km square (NC2126) containing this feature (map, photo 1) and set out to do so on 5th July 2022.
Up the burn
We parked at the old quarry, admired a huge stand (60+ spikes) of heath fragrant orchid on the west side of the burn, noted large heath and meadow brown butterflies, and then set up its western side (photo 2, taken earlier in the year).
This ground is noticeably base-rich in places, as in a stony flush just above the old track (NC209258). Amongst indicator tussocks of black bog-rush, there were scattered plants of broad-leaved cottongrass, tawny sedge, and sprawling well-concealed stems of the much rarer rough horsetail (photo 3). We had been logging individual plants of lesser butterfly-orchid all the way up from the quarry, and continued to do so, since it was at peak flowering and very obvious.
We worked our way uphill through quite demanding heather-covered bouldery slopes with large detached blocks of Torridonian sandstone (photo 4, taken earlier in the year). Our efforts were rewarded by two stands of the cotton-felted leaves of melancholy thistle, with a splendid flowering head (NC210259, photo 5). Scattered hollies, some large, were protected from browsing by the broken ground.
A little higher, there were more signs of base-richness in the form of the leaves of globeflower with, nearby, a small pearl-bordered fritillary. We had a breather in this area, by a fast-flowing section of the burn (photo 6), looking back down the slope to the road far below (photo 7).
Coire Riabhaich
After just over an hour, we reached the western end of the ‘corrie’ (photo 8), our target for the day, and started recording in earnest. There was a small waterfall, providing some scenic interest (photos 9-10), after which the burn levelled out again, running along the southern edge of boggy ground dominated by purple moor-grass. Such vegetation is not known for its botanical diversity, but a runnel feeding the burn from the north provided evidence of a little base-flushing, with black bog-rush, lesser clubmoss and the bronzy rosettes of pale butterwort.
Along the northern side of the ‘corrie’ there was a series of small Torridonian sandstone crags, some drier, with plants such as goldenrod and mountain fern, others with water splashing down them (photo 11), which added a few more species. We lunched at the base of one crag (NC215260) and noted, on another nearby, the only rowan seen in the corrie, and a solitary holly. The scarcity of trees is noteworthy. The area may be too high and exposed to support many; browsing, formerly by livestock, more recently by deer, is the more likely reason.
Botanically, the area was quite hard work, but the variety of small animal life was some compensation. There were nymphs of the meadow grasshopper, three species of orb-web spiders – Araneus diadematus, the heavyweight A. quadratus and Larinioides cornutus, a smoky wave moth and more large heaths (photo 12).
Further to the east, the burn continued to provide interest. In one place water was, curiously, upwelling from underground (photo 13). Not far away, it was deep enough to provide habitat for water voles, a four-spotted chaser dragonfly and a couple of frogs. A fox scat found on a mossy boulder nearby (photo 14) contained the remains of a field vole, beetles and the eggshell and foot of a small bird, probably meadow pipit.
We left the target square at this point, about 100m from the origin, to the north, of the burn we had been following. Looking up the hill at this point (photo 15), the junction is apparent between the Torridonian sandstones we were on and the Cambrian quartzites above them.
Loch a’ Choire Riabhaich
We then dropped down south to the eastern end of Loch a’Choire Riabhaich (NC219259, photo 16). At this end a rather poorly-defined exit burn flows east into another larger burn, which originates up the hill to the north (photo 17) and eventually flows south into Lochan Duibhe. This boggy area provided another large heath butterfly and a common blue damselfly.
We had a look along the southern edge of the loch (photo 18), but added very little to the species list for the day. Gwen surveyed this loch on 1st August 2010 as part of her Quinag Lochs Project. She found it to be quite acid (pH 5.4) and rather lacking aquatic vegetation, apart from bulbous rush, common cottongrass, water lobelia and a bladderwort.
However, the outflow area supported a good variety of animal life, including palmate newt tadpoles, five species of dragonflies and damselflies, and a variety of caddis flies, waterbugs and other aquatic invertebrates.
Allt na Doire Cuilinn
We left the loch about half way along, and then dropped quite steeply downhill to a point above the western end of Lochan Duibhe (NC217256). Here we had a tea break, with sightings of yet another large heath butterfly and a black-throated diver flying high overhead towards Loch Assynt. We then picked up the old track, which runs westwards on the north side of the Allt na Doire Cuilinn.
This burn is fed by a series of stony flushes (photo 19), with many signs of base-enrichment. Black bog-rush was frequent, with scattered plants of broad-leaved cottongrass, with its characteristic yellowish spear-shaped leaves (photo 20). We also found two forms of the early marsh-orchid Dactylorhiza incarnata subspecies incarnata and pulchella, and more lesser butterfly-orchids than we have ever seen on one day, in at least eight places.
Another good find, in one of the flushes, was a tuft of cruet collar-moss Splachnum ampullaceum with its striking yellow capsules (photo 21); this is much the rarer of the two species that occur locally on deer dung. More large heaths were also noted and, just off the track, the skeleton of a raven.
We followed a familiar route along the old track below the wooded crag from which Allt na Doire Cuilinn gets its name, and then dropped down to our starting point in the old quarry.
Results
In over six hours we had covered about 3km in three separate 1km squares. The parts of the target square in Coire Riabhaich (NC2126) that we reached proved quite dour, apart from occasional diversity provided by base-flushed areas, Torridonian crags and, as is usually the case, the banks of the burn. It yielded just 61 species, but the other two squares made up for any deficiencies with the large numbers of orchids. And views throughout the day were magnificent, as always.
So far as we know, no-one has ever botanised the steep slopes above Coire Riabhach, but the exposed Cambrian quartzites which there cap the Torridonian sandstones are unlikely to yield many surprises.
Ian M. Evans and Gwen Richards