Bryophyte Survey in Glen Affric

Gordon Rothero examining bryophytes in the ravine of the Allt na Imrich stream in Glen Affric.

As part of our ongoing project to document the biological diversity of the Glen Affric National Nature Reserve (NNR), we commissioned Gordon Rothero to carry out a survey of bryophytes (ie mosses and liverworts) there this summer. Because of its more westerly location than most of the other Caledonian pinewood remnants, Affric has long been noted for its abundance of mosses, but surprisingly, no systematic studies had previously been carried out. The total number of bryophyte species known from the glen was just 83, whereas, for example, in the Abernethy NNR (another main pinewood remnant area, in the Cairngorms, and owned by the RSPB) there are records for 293 species.

Gordon is a botanist specialising in bryophytes and he made three trips to Affric between May and July, concentrating his survey on parts of the glen that we had identified as most likely to contain a wide diversity of mosses and liverworts. These were targeted more towards the woodland areas, but the survey also included some time on higher ground, above the trees, as a different suite of species occurs there. Time restrictions and budget limitations meant that a comprehensive survey of the entire NNR could not be undertaken, as that would have required weeks of surveying.

I accompanied Gordon on several days during his survey, when we scrambled up ravines on some of the streams in the glen and suffered the unwanted attention of multitudinous midges as we explored some bogs and mires. I was impressed by his knowledge and expertise about bryophytes, and I learned a lot just by being in his company as he worked. The miniature world of mosses and liverworts is indeed interesting and wondrous, although I, and probably most people, often overlook it.

By the end of the survey, Gordon had identified a total of 108 liverworts and 201 moss species in the glen. Of particular note is the diversity of Sphagnum mosses, with Glen Affric containing 23 different species, including olive bog-moss (Sphagnum majus), a rare Red Data Book species that only occurs at 10 localities in the UK. Altogether, there were 6 Nationally Rare species and 40 Nationally Scarce species recorded during the survey.

Another feature of note from the survey was the abundance of pendulous wing moss (Antitrichia curtipendula) on various broadleaved trees in the bigger ravines, where the enclosed space formed by the rocks maintains a high level of atmospheric humidity. In some cases the trees are festooned with this moss, giving them all the appearance of the temperate rainforests of the west coast of Scotland.

Combining the species identified by Gordon (309) with those known from previous work gives a total of 323 species now recorded for the Glen Affric NNR. This is almost four times the previous figure of 83 species, and also surpasses the known bryophyte diversity at Abernethy.

We are very grateful to Scottish Natural Heritage (SNH) and Forestry Commission Scotland for providing grant aid towards the costs of the survey, to Gordon Rothero for doing the work, and to Sandy Payne (formerly of SNH, and newly-appointed to the Trees for Life Board of Directors) for his help in identifying the sites where Sphagnum majus occurs.

Alan Watson Featherstone

Pages about Bryophytes on this site

• Bryophytes occurring in Glen Affric
• Bryophyte survey in Glen Affric 2006
• Bryophytes occurring on Dundreggan
• Bryophytes occurring on Aspens

Return to Biological Diversity in Glen Affric