Nature Notes from Skye
(and occasionally other places)
Sat 31 Jul 2004
A hot day in Skye - I think! Well, it was sweltering at 9 a.m. when I set off for the hills, and it was sweltering at 6.30 p.m when I was down again, so I imagine that during the day it got even hotter at low levels, but up on the Storr it was really chilly, even with the sun out and despite there being only a gentle breeze. A reminder of what a different world it is at that height, and why plants with names like Iceland Purslane thrive there.
Before ascending I explored the rocks at the foot of the cliffs that separate the lower eastern side of the Trotternish hills from the upper western side, and found two surprises. On the left, Downy Currant, in its usual situation among heaps of boulders, but unusually distant from the coast. The tops get nipped off by sheep but the main stems survive in the crannies to put forth new leaves. Close by were some plants of Field Forgetmenot, shown on the right with Wood Sage. I don't recall seeing this plant before in Skye in a natural as opposed to human-made habitat.
I went up the Bealach Beag gully to the top of the ridge and then headed for the Storr summit area. The Field Gentian is quite often found among the grazed sward on both the lower and upper side of the ridge. Towards the summit the vegetation becomes more alpine and extremely low-growing, with large bare patches. Found this beetle there, which appears to be Aphodius depressus. Thanks to Mike Denton for confirming this ID.
At summit level the Dwarf Willow is one of the dominant species. This extraordinary plant belongs to the same genus as lofty trees such as the White Willow that arches over southern rivers. In this mountain version the "trunks" are all underground, and tiny shoots a few cm high bear small rounded leaves and short catkins that produce the fruits, on the left, which open to release the feathery seeds, on the right. In many places on the mountain top, what looked like patches of sheep's wool on the ground were in fact concentrations of these seeds.
All Willow species seem to be frequent hosts to various kinds of galls, and the Dwarf Willow is not exempt. In fact the galls are not diminutive in proportion to the rest of the plant, but are as large as lowland leaf galls and so use up virtually the whole leaf in this species! The gall-causer is Pontania herbaceae.
Wet patches on the summit area have three very special plants. The rarest (nationally, though common here) is Iceland Purslane, above right. This plant was not known to exist in Britain until the 1930's, though it has been on the Storr summit since the end of the last Ice Age.
The other two specialities of the wet patches are Three-flowered Rush, above left, and Two-flowered Rush, on the right.
There are also many bare dryish patches up there, with a covering of gravel over damp but not wet soil. It's a mystery to me why they are not vegetated, when the ground around them has a complete green covering, consisting of unidentifiable grazed grasses, Dwarf Willow, Cyphel and suchlike. One theory that comes to mind is that these bare patches are where snow lies in winter, but I would not have thought the proportion of time spent under snow is long enough to prevent vegetation colonising, as much of the time during winter the tops are snow-free.
Sometimes minute plants of Iceland Purslane are dotted around in the bare patches, barely perceptible to the eye from head level. These may be seedlings that never grow to any size. I made a list of the species that occur as isolated single plants in the midst of the bare patches. After Iceland Purslane, the most frequent were: Wild Thyme, Viviparous Fescue, Dog Violet, Heath Bedstraw, Mountain Sorrel, Alpine Lady's Mantle and Heath Pearlwort. An interesting mix of ubiquitous plants and specialist upland ones.
The wetter parts are divided into sparsely and densely vegetated zones, just as the drier parts are. The sparsely vegetated wet areas are those we've looked at, containing Iceland Purslane (much larger plants than in the bare dry areas) and the 2- and 3-flowered Rushes, along with Blinks (Montia fontana) and Yellow Sedge (Carex viridula ssp oedocarpa). The more densely vegetated wet areas look like typical mountain flushes with a bright green carpet of moss and a variety of flowering plants growing up through it. These include two seaside species, Thrift (above left) and Common Scurvy-grass (right). The latter has been variously split into different species or subspecies, but there seems to be no general agreement, and for the present I'm content to treat them as an aggregate. There is a continuum of this aggregate from sea to alpine zone along the Lealt River and its tributaries, and it would be interesting to know at what point the experts would say one subspecies ends and another one takes over. Thrift, on the other hand, is not split even into varieties in the books; the alpine plant is the same as the sea one and yet it does not occur at all anywhere in between.
Other prominent flowers at this time of year in these wet flushes are: Lesser Spearwort, Meadow Buttercup, Daisy, Starry Saxifrage, Common Mouse-ear and occasionally Creeping Forgetmenot. Many differently-constituted flush communities occur a bit further down the slopes.
The Old Man of Storr may be a giant but he's dwarfed by the cliffs behind him. On the right, the view south from where the photo on the left was taken, with the Cuillins in the background, a bit of Portree Bay visible below them, and the Storr Lochs in front and to the left of that. A lonely hill tarn, Loch a'Bhealaich Bhig, is in the foreground. At this point the Trotternish Ridge is relatively low and its eastern slopes relatively gentle, so it is one of the few places along its 20-mile length where a walker can get from the bottom to the top with minimal use of hands.
All photos and other content copyright © Carl Farmer