Coastal shingle

Shingle is familiar to most people as the deposits of rounded pebbles that line many shores in the UK. Churning by wave action causes the pebbles to rub against each other, making active shingle a most inhospitable environment for plants and animals. On more sheltered coasts, the shingle may be stable enough, at least over the summer months, to provide a viable habitat. Even here, however, deep shingle may have so little soil or other material to provide nutrients and retain moisture that large expanses may appear devoid of life. Only where sand or other fine material is mixed with the shingle, or where seaweed or other organic material provide nutrients, do plants become established. Undisturbed shingle can support a very rich lichen flora.

Shingle distribution

Scotland is not so well furnished with shingle coastline as England or Wales, but significant shingle coastlines occur in the Solway and Moray Firths, and on the Isle of Arran, with scattered sites elsewhere. The place-name mol is the Gaelic for shingle, while the term 'Ayre' is Old Norse for a shingle spit. Much of Scotland's shingle is so mobile that vegetation is absent or restricted to a summer strandline, or is on raised shorelines, now beyond true maritime influence. These more inland 'fossil' features may extend far inland, and support grassland or even woodland. Sometimes there are local shingle-filled depressions that are too deep and devoid of smaller material to provide a growing medium for plants, and the alternation of these with vegetated ridges can be spectacular, as at Spey Bay.

Restoring shingle habitat

One of the problems facing shingle is that nearby trees, often from plantations, deposit litter (fallen dead plant material) that provides a moisture-holding growing medium for new tree growth, which then provides more litter and so the process continues. Scottish Natural Heritage has been working with the Forestry Commission to attempt to reverse this process on some of its land holdings, notably at Spey Bay.