Northern Ireland's Priority Species

Rubus chamaemorus – cloudberry

 

Distribution map

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Rubus chamaemorus L.
Family: Rosaceae

This blanket bog or heathland relative of the common bramble or blackberry is extremely rare in Ireland, being confined to just one mountain slope in the Sperrins, County Tyrone. When first discovered in 1826 it was described as 'plentiful', and in a later account as, 'very abundant and in flower'. It was not seen again until August 1892, when two extremely experienced and well-travelled field botanists rediscovered two small patches of the plant after several hours diligent search. They described it as occurring 'very sparingly', and, '...almost choked by Sphagnum and stunted Ling. The plants are thinly scattered, and usually show a single minute leaf about half an inch in diameter, whose petiole barely brings it to the light.' They also reported no trace of flower or fruit (Hart & Barrington, 1892). Cloudberry continued extremely rare and elusive to the extent that the eminent naturalist, R. Ll. Praeger (1950), declared it extinct. Subsequently, however, a colony of about 30 non-flowering shoots, plus a solitary shoot at some distance away, were rediscovered in June 1958, (Kertland, 1958). This Sperrin colony survives, but in 2003 just 19 shoots were counted at the site.

In brief

  • Cloudberry has been recorded to the west of Dart and Sawel on the north facing slopes of Mullaghclogha – the only site for the species anywhere in Ireland

  • It is believed to represent the last remnant of a much larger species population that would have occurred in Ireland in the distant past when a colder climate, more typical of the Arctic region prevailed

  • It is a very much more common plant in similar mountain situations in most of northern Great Britain to this day, where it grows in moist or somewhat drier blanket bog acid peat and in arctic-montane heaths

  • R. chamaemorus is almost unique among brambles in growing in Britain and Ireland at altitudes above 350m

  • Cloudberry is rare with only one site for the species in Ireland

  • The Irish colony may well consist of a single clone, possibly of a single sex (most likely male), ruling out seed production and the maintenance of genetic variation.

Species description
It is a much smaller plant than the blackberry, growing low against the ground, the stem only 5 to 20cm in height. The 1 to 3 leaves are undivided, but lobed like the palm of a hand, and are normally 2 to 5cm across and 3 to 7cm long. The solitary white flower, male or female, is 2 to 3cm in diameter. Unlike the blackberry, the fruit starts green, turns red, and then ripens orange-yellow in colour.

Life cycle
Cloudberry plants throughout the whole circumpolar range of the species rely principally on non-flowering vegetative reproduction by means of a shallow spreading underground stem or rhizome. This sends up short aerial shoots at intervals and tends to form a carpet of spreading growth. Male and female flowers are borne on separate plants, males often being strongly in the majority. For some reason the Irish plants are stunted and nowadays appear to produce neither flowers nor fruit. Sterility of this type has been noted in numerous other regions where cloudberry and other species of past climates, growing at the southern limit of their range in isolated localities under less than optimal conditions, fail to flower or to set seed. A detailed account of cloudberry biology and ecology in Britain is given by Taylor (1971).

Similar species
It is a much smaller plant than the blackberry, growing low against the ground, the stem only 5 to 20cm in height. Unlike the blackberry, the fruit starts green, turns red, and then ripens orange-yellow in colour.

How to see this species
Due to the vulnerability of the solitary population in Northern Ireland it is not recommended to visit it. Cloudberry is widespread, abundant and much better grown in upland Scotland and the English Pennines. It grows in moist or somewhat drier blanket bog acid peat and in arctic-montane heaths, especially where a depth of late-lying snow cover gives shoots protection from both severe winter and late-spring frosts (Taylor, 1971). It flowers from June to August. Relevant access permissions should always be sought prior to visiting any sites.

Current status
Cloudberry has been recorded to the west of Dart and Sawel on the north-facing slopes of Mullaghclogha – the only site for the species anywhere in Ireland. There is an unconfirmed 1952 report of the species seen in flower on the Dingle peninsula in County Kerry, made by the famous Scottish botanist, the late Miss McCallum Webster, who was very familiar with the plant in her area of Inverness and did not realise its Irish significance (Kertland, 1958). Hillwalkers are therefore advised that it might possibly be present on other Irish mountains. It is listed in Schedule 8, Parts 1 and 2 of the Wildlife (Northern Ireland) Order 1985.

Why is this species a priority in Northern Ireland?

  • It is extremely rare with only one site for the species in Ireland.

Threats/Causes of decline
The marked decline of this very small Sperrin colony when compared with dominant or co-dominant populations in Scottish sites, has probably been caused by a combination of unfortunate and damaging circumstances. The Irish colony may well consist of a single clone, possibly of a single sex (most likely male), ruling out seed production and the maintenance of genetic variation. It occurs on a gentle north-facing slope over very wet peat that showed in 1958, 'some evidence of previous bog flow'. The smaller than usual leaves are almost submerged in the close growth of associated plants. The blanket bog and montane heath is weathered, grazed, burnt, trampled and the shallow peat is seriously eroding. Climate change influencing plant competition during the whole 12,000 year period since the end of the Ice Age has so far failed to eliminate this relict species. Further global warming, however, may finish the job. Despite definite decline, the present population size seems remarkably stable, notwithstanding its vulnerable, endangered status.

Conservation of this species

Current action

  • Implementation of the Northern Ireland Habitat Action Plan for Montane Heath.

Proposed objectives/actions

  • Maintain the viability of the population of this species

What you can do
Records of new sites and estimates or counts of the sizes of populations are always valuable. Send information (including photographs, if obtained) to The Botanical Society of the British Isles – c/o Botany Department, National Museums Northern Ireland, 153 Bangor Road, Cultra, Co. Down, BT18 0EU or to CEDaR, National Museums Northern Ireland, 153 Bangor Road, Cultra, Co. Down, BT18 0EU, Tel: 028 9039 5256, cedar.info [at] magni.org.uk.

Further information

Links
http://www.ehsni.gov.uk/natural/country/29.shtml

http://www.mun.ca/biology/delta/arcticf/_ca/www/roruch.htm

http://en.wikipedia.org/wiki/Rubus_chamaemorus

http://www.chem.ucla.edu/~alice/explorations/churchill/cloudb.htm

http://linnaeus.nrm.se/flora/di/rosa/rubus/rubucha.html

Northern Ireland Habitat Action Plans

Literature
Hart, H.C. and Barrinton, R.M. (1892). The rediscovery of Rubus chamaemorus in Ireland. Irish Naturalist 1: 124.

Kertland, M.P.H. (1958). The Cloudberry, Rubus chamaemorus L., in County Tyrone. Irish Naturalists' Journal 12: 309-314 & Plate 10.

Praeger, R. Ll. (1950). Natural History of Ireland. Collins, London. p. 60.

Taylor, K. (1971). Rubus chamaemorus L. Biol. Flora of the British Isles No. 121. Journal of Ecology 59: 293-306.

Text written by:
Dr Ralph Forbes