Salix arbuscula

Tracheophyta MagnoliopsidaSalicaceaeSalixSalix arbuscula

Ecology

A low shrub of base-rich substrates on mountains, occurring in moist or wet habitats, mostly in flushes, on gravelly soil near burns and on damp ledges of calcareous rock. From 460 m (Ben Lui, Mid Perth) to 870 m (Carn Gorm in Glen Lyon, Mid Perth) but rarely below 600 m.

Status

Native

World Distribution

European Arctic-montane element; absent from mountains of C. Europe.

Broad Habitats

Light (Ellenberg): 8

Moisture (Ellenberg): 5

Reaction (Ellenberg): 7

Nitrogen (Ellenberg): 2

0

Salt Tolerance (Ellenberg): 0

January Mean Temperature (Celsius): 0

July Mean Temperature (Celsius): 11.5

Annual Precipitation (mm): 1965

Life form information

Height (cm): 70

Perennation - primary

Perennial

Life Form - primary

Nanophanerophyte

Woodiness

Woody

Clonality - primary

Little or no vegetative spread

Count of 10km squares in Great Britain: 48

Count of 10km squares in Ireland: 0

Count of 10km squares in the Channel Isles: 0

Atlas Change Index: -0.12

Distribution information

JNCC Designations

NBNSYS0000003882

Scarce Atlas Account

Scarce Atlas Account: 

Salix arbuscula L.  

Mountain willow

Status: scarce

 

This low shrub grows on base-rich mountains. It is found in moist or wet conditions such as flushes, in gravelly soil inundated by mountain burns, or on damp ledges on calcareous rock. Its main associates are Alchemilla glabra, Saxifraga aizoides and S. oppositifolia. Other patterns of association depend on grazing pressure, and on ungrazed ledges it often grows with a wide range of calcicolous tall herbs. It occurs at altitudes ranging from 460 metres on Ben Lui to 870 metres on Carn Gorm in Glen Lyon.

Seed is produced in quantity in dense colonies, and must be the main means of reproduction. The discrete form of most bushes indicates that vegetative spread is not a significant factor in reproduction. As seedlings require predominantly bare soil and freedom from competition in order to establish (Stace 1975), few will develop under stable conditions. It is likely that the landslips and rockfalls occurring in montane habitats are necessary in order to create the conditions for significant seedling establishment.

In the Southern Uplands S. arbuscula has not been recorded since 1934. There are insufficient data to show any changes in its distribution in the Scottish Highlands. Grazing, and the habitat changes resulting from it, have undoubtedly affected its distribution by destroying plants or parts of plants, thereby reducing seed production and preventing regeneration. However, some dense stands of procumbent plants, surviving heavy sheep-grazing, suggest that mature S. arbuscula may be more tolerant of grazing than most other montane willows. Scattered or isolated individuals may represent occasional colonists but are more probably survivors of once more numerous populations.

It is an arctic-alpine, Eurasiatic species, found in Scotland, Scandinavia, arctic Russia and the Urals, to Siberia and central Asia. Its European distribution is mapped by Jalas & Suominen (1976). Records from mountain ranges further south in Europe are based on misidentifications of other members of the S. arbuscula group (Meikle 1984). 

Its distribution in Britain, especially at the edges of its range, is somewhat unclear because of confusion with small-leaved plants of S. myrsinifolia, S. myrsinites, S. phylicifolia and with large plants of S. herbacea.

 

D. K. Mardon

PLANTATT - Attributes of British and Irish plants. (.zip 1455KB) This dataset was compiled and published in 2004, and last updated in November 2008. Download includes an Excel spreadsheet of the attributes, and a PDF explaining the background and nomenclature. Note that the PDF version is the booklet as published, whereas the Excel spreadsheet incorporates subsequent corrections. A hardcopy can be purchased from the Centre for Ecology and Hydrology.

Atlas text references

Atlas (191b)
Hultén E, Fries M
1986.  Atlas of north European vascular plants north of the Tropic of Cancer. 3 vols.
Jalas & Suominen (1976)
Mardon DK
1990.  Conservation of montane willow scrub in Scotland. Transactions of the Botanical Society of Edinburgh. 45:427-436.
Meikle RD
1984.  Willows and poplars of Great Britain and Ireland. Botanical Society of the British Isles Handbook no. 4.
Stewart A, Pearman DA, Preston CD
1994.  Scarce plants in Britain.