The Atlantic heaths

In western Scotland there is a series of oceanic heaths which have a very interesting moss and liverwort flora.  These bryophyte-rich heaths are usually limited to steep and rocky slopes on the north or north-east side of the hills, with heather dominant on the lower slopes and blueberry becoming more frequent higher up.  Under the dwarf shrubs is a thick mat of bryophytes in which species of Sphagnum are common.  But it is the large, leafy liverworts that provide the interest, often forming swelling cushions of brown, orange and red.

Disjunct distributions of liverworts of the Atlantic heaths

 

Species Distribution outside Scotland

Lindenberg’s featherwort

Adelanthus lindenbergianus
W. Ireland, E. Africa, Madagascar, Central and S. America, Antarctica

Alpine notchwort
Anastrophyllum alpinum
E. Himalaya, W. China, Aleutian Islands

Donn’s notchwort
Anastrophyllum donnianum

Faroes, S.W. Norway, Tatra, W. Tibet, Himalaya, W. China, Alaska, W. Canada

Joergensen’s notchwort
Anastrophyllum joergensenii
S.W. Norway, W. China

Arch-leaved whipwort
Bazzania pearsonii
W. Ireland, E. and S.E. Asia, N.W. America

Northern prongwort
Herbertus borealis
S.W. Norway

Wood’s whipwort
Mastigophora woodsii
W. Ireland, Faroes, N.W. America, Himalaya, W. China, Taiwan

Carrington’s featherwort
Plagiochila carringtonii
W. Ireland, Faroes, E. Himalaya, W. China

Cloud earwort
Scapania nimbosa
W. Ireland, Himalaya, W. China

Bird’s-foot earwort
Scapania ornithopodioides
England, Wales, W. Ireland, Norway, Faroes, Himalaya, W. China, Japan, Taiwan, Philippines, Hawaii

 

There are a number of uncommon species here which have an extraordinary world distribution in a number of disjunct (widely separated) localities.

The best stands of this heath are in the north-west with good examples on the remote Sutherland hills and the mountains of Torridon, where Beinn Eighe has the only British population of Northern prongwort Herbertus borealis.   What all these sites have in common is a climate in which long, dry spells are rare and frost is infrequent and there has been little disturbance in recent times.  The protection given by the cover of heather or blaeberry seems to be critical and without it these plants are limited to areas of block scree or moderate snow-lie.

Recent survey work in the Hebrides has also revealed that an endemic species of Sphagnum also regularly occurs in this community.  Skye bog-moss Sphagnum skyense was first described from Skye but it is also frequent on Rum and in the Harris hills.  It often occurs with another near-endemic species Silky swan-neck moss Campylopus setifolius which, outside western Britain and Ireland, is only known from one site in north-west Spain.

In European terms, extensive stands of this oceanic heath community are limited to the west of Britain and Ireland, with the greatest extent on the mountains of the north-west of Scotland.  We have a particular responsibility for it, though it has been overlooked in conservation terms.