The last six months studying bryophytes in Scotland have been fantastic. Not only am I improving my identifcation skills of these beautiful plants but I am learning so much about the Scottish environment. Just by being out in the field regularly I have been experiencing all manner of other Scottish wildlife from Golden Eagles to July Belles. The bryophytes tell me so much about the underlying geology such as whether the soil is base-enriched, or if the rocks are mainly composed of silica. When there is a mish-mash of species favouring both the conditions described above in a small area I know that there is something odd going on with the geology. Places like Arthur’s Seat in Edinburgh are a perfect example of this sort of situation. All becomes clear when it is known that (put simply) lava once burst through the overlying sandstone creating situations today where there is base-rich basalt and silica-rich sandstone very close to each other. In other areas the angle of dip determines whether leaching or enrichment is occurring on a hillside. The bryophyte composition reveals all.
The influence of climate on bryophytes is well documented. It has been great to see the Atlantic oceanic bryophyte communities of the western oakwoods and compare them to the species able to thrive in a more continental climate on the eastern coast. To find species with a main centre of distribution in the tropics in these western temperate rainforests not many miles from species associated with arctic conditions on the mountain tops is fascinating. Scotland really has a unique bryophyte flora.
During the recent BioBlitz in Holyrood Park I was accompanying an expert in search of rare Grimmias. One of the rarest species we were looking for was Grimmia anodon – a species that is very common in the deserts of Utah but is only known from this one location in Scotland. One reason may be that the dark basalt absorbs the heat of the sun effectively and then radiates heat slowly. Hence, these rocks are much warmer than the air temperature and they are also very dry. Perhaps these conditions conspire to enable G. anodon to survive there (as they resemble those approaching a desert). Moss is not just a piece of dark green fuzz on a rock – it has a really exciting story to tell.