Exploring Quinag: Loch an Leothaid
This article continues our accounts of exploring Quinag. On Saturday 24th September 2022 our target was in the upper part of Gleann Leireag, on the eastern shore of Loch an Leothaid (map, photo 1). We had hoped to ‘mop up’ the small area of land within the JMT boundary in NC1729 and then work up the valley to its east, where two parallel mafic dykes are marked on the geological map (sketched in pink on the O.S. map). In the event, it took us four hours to explore the former area and we had to postpone further surveys.
Path up Gleann Leireag
We left the road at 1045 hrs and, after a short coffee break by the conspicuous dead rowan in the middle of the old shieling at Ruigh Dorch (NC161307), continued up the glen. Walking was slowed by the considerable amount of water on and beside the path and, later, stops to scan the two lochs it skirts (photo 2). We were also diverted by a shallow boggy area on the path beside Loch Uidh na h’Iarna (NC 168306). It contained black bog-rush, indicating some basic flushing, but also a web of finely-branched stems of lesser bladderwort, with its spherical winter buds already formed.
We eventually reached the target square at 1235 hrs. and got out our sandwiches and flasks on a heathery tump above a small burn gorge (photo 3, NC178299). Burn courses are often the richest parts of the mosaic of dry and wet heath which dominates these moorland landscapes. This proved to be the case once more, with occasional small trees of downy birch, rowan and eared willow, and even a 1m tall holly, all protected by steep banks from browsing by red deer. Herbaceous plants tucked into grassy hollows on the banks included wild angelica, lady’s-smock, northern bedstraw, cat’s-ear, autumn hawkbit, bird’s-foot trefoil, primrose, meadow buttercup, common sorrel and wild thyme. This mix indicates a degree of base-enrichment from the gneiss bedrock, or more likely, the mafic dykes that the burn cuts through higher up.
Loch an Leothaid
After a productive wander down the burn (photo 4), we reached the shore of Loch an Leothaid (NC177298) at 1400 hrs. and then walked south along its rocky margins (photo 5) to a gravel beach towards the mouth of the river that drains Uidh an Leothaid. This shore is subject to vigorous wave action, and aquatics were few and predictable: water horsetail, jointed rush, shoreweed Littorella uniflora and lesser spearwort. The beach (photo 6) was much trodden by red deer, but its grassy banks had a fair variety of plants, including viviparous fescue, and more wild thyme, bearing the furry galls of the mite Aceria thomasi. We also found the graceful forked stems of fairy flax and sprawling reddish stems of yellow pimpernel, amongst others.
The mouth of the river had embedded pebbles with yellowish patches of the freshwater lichen Ionaspis lacustris (photo 7), amongst others. It was too deep to cross, so we walked up its northern bank (photo 8), with the deeply-fissured flanks of Sail Ghorm towering above us (photo 9). Gravelly patches on its loops bore richer marshy grassland than we had so far encountered, with isolated tussocks of greater woodrush, perhaps washed down from higher up, marsh thistle and marsh dandelion.
Grassland beside the river
The grassland also contained, to our surprise, several groups of mole hills (photo 10, foreground, NC178296), a sign of the fertility of the soil and local abundance of earthworms. They seemed a long way from any other ground inhabited by moles. However, when we checked, we found an isolated record from the west side of Loch an Leothaid (NC167299, 23rd June 1999) and another, by Andy Summers, from alongside the track a little further up the glen (NC182296, 19th February 2002). So, moles may occur in small patches of grassland on gravelly ground scattered across this landscape.
We also came across two splendid black-blotched frogs (photo 11), probably females, and flushed a common snipe. A little higher up the river, we spotted the divided leaves of marsh lousewort and also found those of water avens. On a bank nearby wild thyme was acting as host to the larvae of the gall midge Bayeriola thymicola. The large galls which result are much less common than the mite galls mentioned above.
Waterfall and crag
At this point, our attention became focussed on a waterfall with adjoining overflow channel and a small crag (photos 12-13). There were a few trees in the vicinity (noteworthy in this landscape). One of the largest, a downy birch, had apparently been browsed for decades, resulting in odd bushy re-growths (photo 14); others included a rowan, holly and a willow (probably of hybrid origin), with some scattered downy birch seedlings.
Boulder scree at the base of the crag provided cover for several additions to the plant list including beech fern, meadowsweet and wood sorrel. There was also a small drinker moth caterpillar on bog asphodel. A wet slab beside the waterfall provided alpine lady’s-mantle, together with an unfamiliar tiny crinkled lichen of which a small sample was collected. Tony Fletcher later identified this as Vahliella leucophaea, rare in Assynt.
A fruitful day
We had a leisurely tea break at the foot of the waterfall (photo 15) and then made our way north to the track, adding broad-leaved cottongrass from a basic flush and the hairy caterpillar of a ruby tiger moth (photo 16). The total for the relatively small area we had covered was 102 species, emphasising once again the significant local boost to biodiversity across much of Quinag provided by two features, watercourses and the mineralogy of the gneiss.
A small mossy waterfall just above the track tempted us to take a look, although in the adjoining square (NC1829), since it was right on the line of one of the mafic dykes. It produced more northern bedstraw, with its neat whorls of four leaves, and the first yellow saxifrage seen. We rounded off the visit with a quick list from a substantial gorge higher up the same burn we had been following earlier in the day (photo 17), which probably cuts right through the dyke. It is located in yet a third square (NC1830), and proved to be quite rich, yielding in a short time some 32 species, providing a starter for a more thorough listing of that and adjacent areas in the future.
We left the area at 1630 hrs and reached the car, after a long slog along the wet path, just after 1800 hrs. The total distance covered was only about 7.5 km, but given the state of the ground it felt rather more!
Ian Evans and Gwen Richards