A low shrub of damp base-rich mountain rock ledges and crags in N.-facing corries, often in areas where snow lies late. It is usually on calcareous schist and rarely on limestone. From 620 m to 1035 m (Geal Charn, Westerness).
This species is now known from more 10-km squares than were mapped in the 1962 Atlas. However, numbers have declined due to increasing grazing pressure by deer and sheep. Some populations have been reduced to single plants, and others lost altogether. Fencing is being tried to arrest the decline at some sites.
Circumpolar Arctic-montane element; absent from mountains of C. Europe.
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Light (Ellenberg): 8
Moisture (Ellenberg): 6
Reaction (Ellenberg): 7
Nitrogen (Ellenberg): 3
Salt Tolerance (Ellenberg): 0
January Mean Temperature (Celsius): -0.8
July Mean Temperature (Celsius): 10.8
Annual Precipitation (mm): 1723
Height (cm): 100
Perennation - primary
Life Form - primary
Clonality - primary
Count of 10km squares in Great Britain: 15
Count of 10km squares in Ireland: 0
Count of 10km squares in the Channel Isles: 0
Atlas Change Index: 0.07
Plantatt Conservation Status
RDB Species Accounts
Salix lanata L. (Salicaceae)
Woolly willow, Seileach Clòimheach
Status in Britain: VULNERABLE.
Status in Europe: Not threatened.
S. lanata is a montane willow inhabiting damp situations on basic rocks (usually schists, or in one case, limestone) in north-facing corries. It is almost confined to ungrazed ledges and crags, and is often associated with late snow, some bushes emerging from under the snow as late as July. Although the altitude range is 620-1,036 metres, most populations are found between 700 and 900 metres. S. lanata often grows with other montane willows, especially S. lapponum. The habitat also supports herb-rich communities including Alchemilla alpina, Luzula sylvatica, Oxyria digyna, Saxifraga aizoides, S. oppositifolia, Sedum rosea, Vaccinium myrtillus, and Racomitrium and Sphagnum species.
It is a dioecious species pollinated by bumble-bees, and thus a population that becomes fragmented is likely to suffer reduced seed-set. The short-lived seeds are wind dispersed. The bushes, some of which may be up to a metre tall, are capable of horizontal growth, rooting in the mossy substrate. The tallest are found in Coire Fee at an altitude of 750-770 metres, whereas those at the highest altitudes (on Geal Charn) were only 20 cm high.
In Britain the species is confined to Scotland, where it was first recorded in Glen Callater in 1812 (Meikle 1984). It has always been very localised, but a new colony was found in Gleann na Ciche in 1991. In a survey in 1994 of fourteen known sites, five were considered to hold viable populations from 30 to almost 1,000 plants. Three other sites held populations of up to 30 plants and each were reckoned to be at risk, and at a further three sites only a single, and in each case female, bush remained. At the remaining three sites no sign of the species was found, which may be because of extinction, past misidentification or erroneous map references attached to old records.
The more intensive grazing by increasing numbers of deer and sheep threaten this species. Rockfall and unstable slopes pose a threat to individual bushes whilst at the same time providing sites for seedlings. The three sites where S. lanata is reduced to a single female plant are clearly doomed. At Coire Fee, one of the major sites for the species, the whole coire has been fenced against the larger grazing animals, and it will be interesting to see whether this and other species can spread naturally off the crags on to more accessible ground. However, if the total population and the number of localities continue to decline, then this species will become endangered in the near future.
S. lanata has an arctic and subarctic distribution, and is found from Iceland and the Faeroe Islands eastwards through Scandinavia and Finland, Russia and eastern Siberia. Related taxa (perhaps subspecies) occur in North America (Meikle 1984).
R. W. Marriot
Atlas text references
1980. Trees and shrubs hardy in the British Isles, edn 8, IV. Ri-Z.
1986. Atlas of north European vascular plants north of the Tropic of Cancer. 3 vols.
Jalas & Suominen (1976)
1990. Conservation of montane willow scrub in Scotland. Transactions of the Botanical Society of Edinburgh. 45:427-436.
1984. Willows and poplars of Great Britain and Ireland. Botanical Society of the British Isles Handbook no. 4.
1999. British Red Data Books. 1. Vascular plants, edn 3.