Article originally published in the Newsletter of the Natural History Section of the Leicester Literary and Philosophical Society during September 2013
Walks on the Wilder Side : Glenleraig to Ardvar Ian Evans
Pat and I enjoy two regular walks along the single track roads near our house at Nedd, on the north coast of Assynt, West Sutherland. The longer one starts at a disused fank (sheepfold) at the top of the steep hill out of Gleann Leireag, whose river runs into Loch Nedd. The road continues east, then north-east, to a point overlooking another sheltered inlet of the sea, Loch Ardbhair. There and back is about 4km. The road rises in the first kilometre from 80m a.s.l. to 130m at a watershed just east of a zig-zag through an old walled sheiling (Bad an Dioboirich – the thicket of the parting, probably cultivated until the early 19th century).
Thence it carries on for another kilometre at about the same height, passing two small lochs, the larger being Loch nan Claidhmhnean (loch of the sword, as in ‘claymore’).
The walk takes something over an hour, depending on what we find along its route. We like it because it affords good exercise in all weathers, with splendid views of the impressive ramparts of Quinag to the south-east and over the islands in Eddrachillis Bay to the north.
On a clear day, we can even see the northern tip of Lewis, in the Outer Isles, some 50 km to the west, albeit as a smudge on the horizon. It also provides a seasonal snapshot of the wildlife of the moorland, studded with rocky outcrops, cut by burns and with a liberal scattering of lochs, that typifies much of Assynt (which has over 680 lochs). The notes that follow will, hopefully, give you something of the flavour of the area it traverses. I would like to thank my brother, Manfred, for help in formatting the illustrations. The walk was once mainly a winter pastime, but we now enjoy it all the year round. We also drive along the road, by day and night, on our way in and out of Assynt, so get further glimpses of its wildlife in passing.
The roadside outcrops are Lewisian gneiss, formed over 2700 million years ago, cut by intrusive dykes of somewhat younger age. Much of the rock of both is mineral-rich, and its ‘bare’ surfaces support a colourful variety of lichens. As an example, some relatively recently-exposed faces (rusty-red with oxidised iron) are being colonised by small circular pinkish-grey thalli of a lichen called Placopsis gelida, which we had walked past for some years before noticing them. It is an upland species, ‘often associated with heavy-metal mine sites’, but here in its natural element.
Weathered debris from the gneiss, and the glacial till which fills its interstices on steep slopes above the road along the first part of the walk, support a colourful flora in June, with wild thyme Thymus polytrichus, bird’s-foot trefoil Lotus corniculatus, fairy flax Linum catharticum and occasional clumps of mountain everlasting Antennaria dioica.
On a sunny day, these and other flowers attract a variety of insects, including small pearl-bordered and dark-green fritillaries, common blues, striking argent and sable moths, and a little gem, the beautiful yellow underwing, whose larvae feed on heather.
Covering most level, and often waterlogged, parts of the adjacent ground is a layer of peat, a metre or more thick, laid down since the retreat of glaciers from this area some 10,000 years ago, and exposed when the road was built in the 19th century. This peat was cut for fuel by local people every year up to WW2 and occasionally since. Exposed peat has a particular lichen flora, including some of the ‘pixie cup’ species of the genus Cladonia. The abandoned peat cuttings have been recolonised by the flora of the surrounding moorland, with purple-flowered bell heather Erica cinerea on drier banks and yellow bog asphodel Narthecium ossifragum and common cotton-grass Eriophorum angustifolium in the wetter hollows. These and many other plants mark the passing of the seasons in the landscape, with the first neat single heads of hare’s–tail cotton-grass Eriophorum vaginatum in March, through to the foxy red of the dying stems of deer-grass Trichophorum germanicum in September, with the pinks and purples of the three heathers in between.
This landscape is not obviously rich in vertebrates. Red deer are frequently seen from the car at night, but tend to stay away from the road during the day (often spotted silhouetted on nearby ridges, where they can escape the attentions of midges and klegs). Foxes pass along the road, leaving scats as markers. One such scat yielded the jaws of field voles (the commonest small mammal hereabouts), an elytron of the large ground beetle Carabus problematicus and some bird bones. Lower down the glen, in more wooded areas, pine martens leave their markers on the verges and badgers may be seen in the gloaming trotting along the tarmac. At night, we sometimes glimpse wood mice darting across the road; moles raise their tumps in the fertile soil of the old sheiling and the remains of pygmy and common shrews have been found in discarded drinks cans (of which more later).
Birds are relatively scarce. Along the lower parts of the walk, downy birch and sallows along an adjacent burn provide food and shelter for great tits, lesser redpolls and chaffinches, and tall heather almost anywhere harbours wrens. Stonechats were seen regularly at the sheiling prior to the hard winter of 2011 and may well return. However, the moorland in the second half of the walk has few resident species. In the summer meadow pipits are present in numbers, sometimes seen actively pursuing cuckoos, and several skylarks may be heard at any one time singing on territory. Common snipe are heard drumming in May and one was seen, from the car, perched on a glacial erratic. Small numbers of red grouse are present, but flighty. The numbers are made up by predators: ravens perform their acrobatics in the spring, kestrels hover above nearby ridges and buzzards soar effortlessly over. Just once, a golden eagle, probably from an eyrie a few miles up Gleann Leireag, flew low over our heads as we drove through the area. Otherwise, there are occasional fieldfares and mistle thrushes and, in spring and autumn, large skeins of greylag and pink-footed geese passing over high.
I have twice come across slow-worms on the more fertile ground in the first half of the walk, and adders certainly occur in sheltered spots along Gleann Leireag; common lizards are also seen, albeit fleetingly. We have recent sightings of all our three local amphibians. On 16th March this year, for example, there was frog-spawn in roadside ditches near the larger loch (and probably in the loch as well) and on 13th August recently metamorphosed toads along the road in the same area, having presumably bred in the loch. On the same day, I was focussing my camera onto the fruiting body of a waxcap fungus, when a juvenile palmate newt crawled into view.
I have not given the roadside invertebrates the attention they are due. However, as an example, on 16th June this year, clumps of soft rush along the road by the larger loch were providing shelter from a blustery wind for large red damselflies Pyrrhosoma nymphula, common blue damselflies Enallagma cyathigerum and two magnificent golden-ringed dragonflies Cordulegaster boltonii. In webs in the same rush clumps were two orb-web spiders, the so-called garden spider Araneus diadematus and the almost ubiquitous Larinioides cornutus; the nursery webs of the last are frequently spun up in drawn-together heads of purple moor-grass. Other species noted on the same day were our only local grasshopper Chorthippus parallelus, an adult green tiger beetle Cicindela campestris, a fox moth flying fast and erratically across the moorland, and large hairy caterpillars of its larger relative, the northern eggar. The last is the unfortunate host for larvae of a fearsome, large, spiky, black tachinid fly Tachina grossa, which has been noted in numbers along this road, and elsewhere locally, in recent years.
This stretch of road has its share of soft drink cans, bottles and other litter tossed out of passing cars, but these, though ugly, can be quite productive when examined (and removed for more environmentally-friendly disposal). On 16th March this year, I found, embedded in grass at the edge of the sheiling, a rusty Stella Artois can, which contained a veritable beetle graveyard. Amongst the larger (and more readily identifiable) species were three Carabus glabratus, eight Abax parallelipipedus and eighteen Pterostichus niger, all ground beetles. There were also two species of carrion or burying beetles Thanatophilus rugosus (the ‘wrinkled death-lover’) and orange-banded Nicrophorus species, and, no doubt, many other smaller beetles. Such discards often trap small mammals such as shrews, whose dead bodies then attract beetles, but in this case the beetles seem to have followed one another.
On 7th August, the same area of grassland and bracken afforded Pat a glimpse of a more attractive insect, a male scotch argus, a butterfly which has lately been spreading into Assynt.
Again, what we used to call the ‘lower plants’ along the roadside have not received my critical attention. However, the closely-grazed verges (formerly by sheep, now just by deer), where not spoiled by re-profiling and soil-dumping, do approximate to ‘old grassland’, supporting a variety of waxcap fungi, including the conspicuous blackening waxcap Hygrocybe conica, and amongst their associates several species of black earthtongues, of which Geoglossum glutinosum and G. starbaeckii were named by our neighbour and friend the late John Blunt. A bryological curiosity, found under the galvanised crash barriers which protect unwary drivers from serious accidents along much of the road, is the heavy-metal-tolerant moss Bryum pallescens, identified by our friend Gordon Rothero.
It would probably be possible to list well over a hundred species of higher plants within 100m of the road, an exercise that we have not carried out, partly because the 2km stretch falls into three separate tetrads. Loch nan Claidhmhnean, for example, has a good range of the plants typical of our shallow peaty lochs, including white water-lily Nymphaea alba, broad-leaved pondweed Potamogeton natans and the bright-green narrow shoots of floating club-rush Eleogiton fluitans on the surface, interspersed with emergents such as bottle sedge Carex rostrata, bog-bean Menyanthes trifoliata and many-stalked spike-rush Eleocharis multicaulis. Mossy gulleys discharging into the loch have two of the sedge-relatives found in this area, black bog-rush Schoenus nigricans (indicative of some base-enrichment) and the less common white beak-sedge Rhynchospora alba. On a quick visit on 28th August to check the flora, we were diverted by numerous emerald damselflies Lestes sponsa, egg-laying in tandem.
However, the roadside itself has, over the years, provided some interesting plant records. The muddy floor of a former small quarry on the first stretch, much used for parking by walkers setting off up Gleann Leireag, is an example. This is one of two known localities in Assynt for slender rush Juncus tenuis, whose russet tussocks seem to survive an extraordinary amount of punishment from vehicles, on whose tyres the species probably arrived. This rush now extends sporadically over some 0.5 km along the road. Recently I have been taking a closer look at the roadside halophytes which thrive along our liberally salted and gritted roads. Sea plantain Plantago maritima is the most obvious on this stretch, as elsewhere, accompanied in silty depressions just off the tarmac by occasional fleshy, pink-flowered plants of lesser sea-spurrey Spergularia marina. However, on 13th August, we recorded the first inland occurrences for Assynt, in two places on our walk, of a tiny tide-line species chaffweed Anagallis minima. Since, at its most minimal, this annual can produce a single stem just 15mm tall, with perhaps three pairs of leaves and a single spherical fruiting capsule, I was well pleased to have spotted it.
We have recently been apprised of a simple classification of naturalists, into ‘stoopers’ i.e. botanists (and perhaps entomologists as well) and ‘gazers’ i.e. bird-watchers. Lest much of the above seems to characterize us as inveterate stoopers, I will end with two broader views of the local landscape, informed by fieldwork on other occasions. For most of the walk, the deeply-fissured crags of Quinag, our local ‘hill’, are clearly visible, stretching for some 4km to the south-east and rising to 808m at its highest point on Sail Gharbh (the rough heel). The summit ridges of this mass of red Torridonian sandstone house scattered populations of ptarmigan and mountain hare, and damp, shaded ledges on north-facing cliffs support an upland tall herb community containing species such as moss campion Silene acaulis, purple saxifrage Saxifraga oppositifolia and alpine saw-wort Saussurea alpine, amongst many others of interest.
From the far end of our walk we look down to Loch Ardbhair, with the tumbled remains of an Iron Age fort on a small tidal island.
Round the innermost margins of the loch, clearly visible from the road when the tide is out, is a bright orange band of fucoid seaweeds, which we discovered was a hitherto-unknown population of the curious detached form of knotted wrack Ascophyllum nodosum mackaii, known as wig wrack. Raising our eyes, we can see, on the northern horizon about ten miles away, the sea cliffs of Handa Island, a bird reserve with a population of nesting great and arctic skuas, amongst tens of thousands of other sea birds, which we visited as recently as 22nd August (albeit to list its plants).
So, our enjoyment of the immediate vicinity of the road is enhanced, on our walks, by memories of many other areas that we can see from it.
[For those with access to local O.S. maps Landranger 15 or Explorer 442 the grid refs. for the walk are NC153313-166323]