When Scotland emerged from its mantle of ice, it had been scoured bare, leaving rounded hills, jagged mountains, deep valleys, undulating lowlands, lakes and wetlands. All were ripe for colonisation by plants, and the group best equipped to move in quickly were the most ancient of the land plants, the bryophytes – mosses, liverworts and hornworts – pioneers of rock, soil and water, which are perfectly adapted for rapid dispersal by their vast numbers of tiny wind-borne spores. The diversity of Scotland’s geology and the cool, wet climate favoured rapid colonisation by a wide range of bryophytes, and as trees became increasingly dominant, so the bryophytes diversified further. The long history of man’s destructive activities has brought about loss of both mossy habitats and species, but has also produced new habitats and new incomers from overseas, right up to the present day.
As a result, bryophytes are amongst the most dominant and beautiful components of many of Scotland’s habitats, perhaps most spectacular and luxuriant in the oceanic ravines and oakwoods of the western seaboard (our own temperate rainforests) and in the unique liverwort heaths of the north-western mountains. They are also conspicuous components of many other habitats from raised mires to montane springs and flushes, coastal sand dunes and slacks with their esoteric rarities, to rich boulder screes and mossy cliff ledges throughout the uplands. On a global scale our bryophyte flora is truly outstanding in its wealth of species and luxuriance, and every corner of the country, from the wind-blasted cliffs of St Kilda to the summit of Ben Nevis, and to the warm sea-banks of the Black Isle and Berwickshire, has its own specialities.
Yet bryophytes for all their aesthetic appeal and ecological importance have often been ignored and neglected, new discoveries are still regularly made by careful field work and taxonomic research, and long-overdue measures to protect this unique heritage are at last being implemented. This new publication, by one of the country’s foremost bryologists, will surely help to increase awareness of the beauty and importance of this heritage, attract new converts to their study, promote exploration of parts of the country still unsurveyed, and encourage recognition of our responsibilities to protect our rich diversity of species and habitats.
Bryophytes, like their frequent consorts the lichens, are highly sensitive to air and water pollution, and many ‘indicator species’ found in Scotland demonstrate the high environmental cleanliness of our wild places. However, this sensitivity makes them very vulnerable to man-made changes such as eutrophication and climate change. We must be ever-vigilant in monitoring the tundra bryophytes of the Cairngorm snow-beds, carry out essential research such as study of the spectacular disjunct species found only in Scotland and the Himalayas or South America, and be diligent in opening the eyes of schoolchildren to the wonders of the secret world of bryophytes. Gordon Rothero and Scottish Natural Heritage have, in this book, made a splendid contribution to this process.Dr David G Long Bryologist, Royal Botanic Garden, Edinburgh