Sibbaldia procumbens
Ecology
This montane perennial herb has two main habitats. It is most abundant in areas of late snow-lie, in corries and hollows and especially under cornices along a ridge. Its other main habitat is on bare, stony surfaces of high plateaux, often in areas of severe wind-scour where permanent snow does not lie. From 425 m (Sgurr na Coinnich, Skye, N. Ebudes) to 1310 m (Ben Nevis, Westerness).
Status
Trends
S. procumbens is under-recorded in some areas, though the map is more complete than in the 1962 Atlas. It is probably still present in 10-km squares for which there are only pre-1987 records.
World Distribution
Circumpolar Arctic-montane element, with a disjunct distribution.
Broad Habitats
Light (Ellenberg): 8
Moisture (Ellenberg): 5
Reaction (Ellenberg): 4
Nitrogen (Ellenberg): 3
Salt Tolerance (Ellenberg): 0
January Mean Temperature (Celsius): 0.4
July Mean Temperature (Celsius): 11.3
Annual Precipitation (mm): 2109
Height (cm): 5
Perennation - primary
Life Form - primary
Woodiness
Clonality - primary
Count of 10km squares in Great Britain: 133
Count of 10km squares in Ireland: 0
Count of 10km squares in the Channel Isles: 0
Atlas Change Index: -0.75
JNCC Designations
Scarce Atlas Account
Sibbaldia procumbens L.
Sibbaldia
Status: scarce
S. procumbens is a montane plant of the Scottish Highlands, with two main habitats, both characterised by sparse and open vegetation. The first, where it is more abundant, is in situations where snow lies late into the spring, in high corries and hollows, and especially along the line of snow cornices under a ridge or plateau rim. The other main habitat is on the bare, stony ablation surfaces of high plateaux with fell-field terrain, where wind exposure is severe and the winter snow cover usually slight and ephemeral. It also grows in dwarf herb communities on intermittently flushed soils on high slopes, sometimes beneath cliffs.
S. procumbens tends to be calcicolous in the southern part of its range, but becomes indifferent to pH further north and grows on a wide range of parent rocks (McVean & Ratcliffe 1962). In areas of non-calcareous rock, associated species include Alchemilla alpina, Carex bigelowii, Deschampsia cespitosa, Festuca ovina, Galium saxatile, Gnaphalium supinum, Luzula spicata and Persicaria vivipara. Over calcareous substrates, Minuartia sedoides, Silene acaulis and Thymus polytrichus can also be found with it. S. procumbens ascends from 580 metres on Ben More Assynt to 1300 metres in the Cairngorms (Hadley 1985; Wilson 1956).
S. procumbens has a branched, woody, perennial stock with short stems bearing inconspicuous flowers. These, with their few stamens, appear to have little chance of insect pollination, but nectar is attractive to flies and it seems that insect pollination is the rule (Clapham, Tutin & Warburg 1962). Vegetative propagation also takes place from the branches.
There are few threats to this montane species. It is under-recorded in some areas and is almost certainly still present in most of the 10 km squares in which it has not been seen since 1970.
S. procumbens is an arctic-alpine plant. The typical form is mainly European, growing in the Alps, north to Scandinavia and the Kola peninsula, south to Spanish Sierra Nevada, and west to Scotland, Iceland and Greenland. In Siberia and North America, subspecies or closely related species complete the circumpolar distribution (Clapham, Tutin & Warburg 1962).
For a detailed account of this species, see Coker (1966).
A. Slack
Atlas text references
Atlas (123c)
.
1966. Biological Flora of the British Isles. No. 104. Sibbaldia procumbens L. Journal of Ecology. 54:823-831.
.
1986. Atlas of north European vascular plants north of the Tropic of Cancer. 3 vols.
.
1965. Vergleichende Chorologie der zentraleuropäischen Flora. Volume 1. 2 vols.
.
1994. Scarce plants in Britain.