Some surprises along the Stoer Peat Track
One of the pleasures of being a naturalist is that relatively familiar landscapes can spring surprises. Such was the case on Saturday 14th March 2020, when bryologist friend Gordon Rothero was making his first visit of the year to Assynt. He has been coming up here regularly since 1992, and the routes of his visits are highlighted on a copy of the O.S. 1:50,000 map (photo 1). Since it was chilly, and the weather looked unreliable, we were searching for a readily accessible area not previously explored. The Stoer Peat Track, running eastwards from Loch End (NC040295) to Loch na h-Uidhe Doimhne, seemed a good candidate, and so it proved to be.
Gordon started recording at the edge of Loch a’ Mhi Runaich (NC041294), with me acting as scribe. He had notched up 30 species by the time we reached a small crag beside the track (NC042293), to which I had not previously paid much attention (photo 2). However it is plastered with lichens, mosses and liverworts (photo 3), indicating some degree of mineral-enrichment. Gordon added a further 16 species of bryophytes from this crag, including rock pocket-moss Fissidens dubius, a common species on the Assynt limestone, but only found sparingly elsewhere. He also spotted the tiny fronds of Wilson’s filmy-fern Hymenophyllum wilsonii, a new site, and a surprisingly exposed one for a plant usually found on mossy boulders in woodland. The local geology map (Sheet 107W. Point of Stoer), consulted later, shows this small crag to be the starting point of a base-rich mafic dyke running east-south-east through the Lewisian gneiss.
We continued along the track and then veered off south to a grassy area east of Loch nan Cullach, which houses the tumbledown remains of an ancient sheep fank, and is backed by a large crag (NC047293). The crag (photos 4-5), although well-vegetated in places, is composed of one of the dourer facies of the gneiss and was not very productive. However, Gordon did note on it cushions of the usually strictly maritime moss seaside grimmia Schistidium maritimum, a sign of the carrying power of salt-laden winds off The Minch. He also found a pellet, probably from a tawny owl, which later yielded the remains of three field voles and a common shrew.
Lunch was enjoyed out of the wind, in fitful sunshine, a further kilometre to the east, just before we reached a substantial 19th century sheep fank (NC059292). Shortly after lunch, two large mossy hummocks caught Gordon’s eye in a mire just to the south of the track (NC061291, photo 6). The nearer one contained the tight tobacco-brown heads of rusty bog-moss Sphagnum beothuk (formerly S. fuscum, photos 7-8), and the further one the compact orange heads of Austin’s bog-moss Sphagnum austinii (photo 9). Both species are indicators of undisturbed raised and blanket bogs and scarce in Assynt; neither had previously been recorded in this 10km square (NC02). Since the track was built to access peat deposits, this particular area must have been judged unsuitable for extraction.
We left the track a little later to explore the margins of two lochans to its south that I had never before seen, the larger one with an island bearing an old rowan white over with lichens. We eventually found our way to the southern narrows on Loch na h-Uidhe Doimhne (NC067286). We had logged several further sites for the two hummock-forming bog-mosses, and also, on drier ground, substantial areas of old peat banks.
As we approached the loch we began to notice bushes of prostrate juniper Juniperus communis nana, including some impressive old ones on its margins (photo 10). I had noted in the past occasional junipers on rock outcrops along the peat track, but did not know that it occurred in such quantity elsewhere in this area. Since this part of Assynt probably contains more prostrate juniper than the rest of West Sutherland put together, it would be very worthwhile to map its distribution in detail.
Shortly afterwards we turned for home, reaching the car an hour later. In some five hours bryologising, Gordon had recorded 80 mosses and 34 liverworts, and we had been reminded, once again, of the delightfully unpredictable nature of the Assynt landscape.
Ian M. Evans