Loch Beannach: a visit to the largest island
Wooded islands occur in a number of the 680 lochs shown on the 1:50,000 O.S. map of Assynt. The exceptional interest of those in Loch Beannach (NC1426), on Little Assynt, has been recognised since they were first visited by the Scottish botanist Donald McVean in the mid-1950s. They were notified as an S.S.S.I. in 1963 and now form part of the larger Assynt Lochs S.P.A.
Loch Beannach’s largest island lies just off-shore, at the eastern end of the loch (NC143265). It is underlain by Lewisian gneiss, cut by a mafic dyke on its south-western side, and is covered with trees. There is a good view of it from the highest point on Ken’s Path (photos 1-2).
Three members of the Field Club visited the island on 5th September 2020, during a relaxation in pandemic rules. Gwen had been there previously, with Claire Belshaw, on 26th July 2003, but Bill and Ian never before. We had the use of one of the Assynt Angling Club boats, which are chained up in a bay about half a kilometre south-west of the island (photo 3). It took us half an hour to row over to its western shore, allowing for the differing skill levels of the two oarsmen (photo 4).
The tree cover on the island is mainly downy birch, including some huge examples. Two in particular caught our attention, both nearly a metre in diameter at the base. One was horizontal, with large vertical branches, and the other leaning over, but both still very much alive (photos 5-6).
There were scattered rowans and a loch-side fringe of alder. We came across a single large holly, and from the highest point could see a solitary oak on the southern half (photo 7). The northern part of the island contains a number of glades (photo 8), but elsewhere the ground vegetation is dominated by dense, high bracken, through which we had to fight our way. As a result, we were quite unable to reach the oak tree. McVean records it as a sessile oak Quercus petraea, but we suspect that it may be one of the hybrid swarm to which most Assynt oaks belong.
A conspicuous feature of the ground vegetation was a number of large stands of hay-scented buckler-fern Dryopteris aemula, mostly on or adjacent to crags (photo 9). It forms single crown ‘shuttlecock’ plants, with triangular fronds (photo 10), to quote James Merryweather’s excellent field guide. Moreover, its pinnules are curled up at the edge, giving the fronds a singular crinkly appearance (photo 11). This must be one of the best sites for this species in the parish, and one that was not mapped in the Flora of Assynt.
McVean describes the flora of the island as ‘more closely resembling oakwood than Highland birchwood’ and of the species he mentions we found bluebell Hyacinthoides non-scriptus, common sorrel Rumex acetosa, herb-robertGeranium robertianum and wild angelica Angelica sylvestris. There was also a small stand of common figwortScrophularia nodosa.
However, one of the specialities of the island eluded us. This is white climbing fumitory Ceratocapnos claviculata, a rare plant in Assynt, known from a couple of loch islands, and woodlands in the Nedd-Drumbeg area. It is not a showy plant, with cream flowers less than 1cm long. Gwen and Claire had found it in 2003, but we were unable to re-locate it, despite an extensive search.
Frustrated, we turned our attention to the wave-lapped rocky margins of the island, beneath the alders along its northern edge. Here, in half an hour, we added at least a dozen species not seen elsewhere, such as great wood-rush Luzula sylvatica, devil’s-bit scabious Succisa pratensis and common valerian Valeriana officinalis. Best find was a couple of plants of remote sedge Carex remota, with well spaced fruiting heads. It is known only from two other woodland sites in Assynt (see photo 12 of voucher specimen; it is difficult to photograph in situ). Our total haul was 56 species.
Our notes on organisms other than higher plants were fairly miscellaneous. Bryophytes and lichens abound, but require specialist skills to name them. We found an old birch with two of the lungwort lichens Lobaria pulmonaria and L. scrobiculata. Insect life was represented by the commonest of the blue-black dung-beetles hereabouts Anoplotrupes stercorosus, a caterpillar of the knotgrass moth (photo 13) and a few midges in sheltered situations.
Galls included one caused by the mite Eriophyes laevis on alder, another by the gall midge Dasineura pustulans on meadowsweet and some witches brooms on the downy birch (causative organism still disputed). Plants of slender St John’s-wort Hypericum pulchrum had curiously-distorted pouches at the ends of the stems, which may have been the galls of the midge Dasineura serotina, not before noted in Assynt. Unfortunately they lacked larvae, so that will remain just a possibility.
Vertebrates were represented by a frog, a robin, a scatter of woodpigeon feathers on a plucking site, most likely that of a sparrowhawk (photo 14), a single buzzard feather and occasional red deer dung.
We greatly enjoyed our three hours spent on the island (allowing for a leisurely lunch break on the highest point, at 85m.). We rowed back round the north and east sides, watching out for rocky shallows, with the inaccessible oak tree clearly visible (photo 15). We also kept an eye open for any marginal plants of dwarf juniper Juniperus communis nana; it occurs on neighbouring islands, whose geology is slightly different, but we saw none.
Previous visits to the island
Apart from those mentioned above, we have recently learned that Claire Belshaw, Chris Ferreira, Terry Keating and Alex Scott of SNH visited three of the islands, including the largest one, on 27th June 2003, when Chris listed the higher plants. Alex has kindly made available a transcript of the list for the largest island and some general notes on the visits.
They found some 61 species, including 13 not our list. We had 10 not on theirs, so honours are more or less even. They did rather better on sedges, but also failed to find the fumitory. Gwen and Claire were successful a month later, but the crowning glory of their visit was the discovery, in deep water in a bay west of the northernmost island (NC142268), of the floating yellow flowers of least water-lily Nuphar pumila. This was a ‘first’ for both Assynt and West Sutherland as a whole.
We are grateful to Stephen Peters, of Bill’s extended family, for his splendid panorama of the islands, taken, coincidentally, a week later. Thanks also to Alex Scott for his detailed notes on the earlier visit.
Ian M. Evans, Gwen Richards and Bill Badger