Definition of Machair

The following characteristics of the machair are used to help define machair:

1. a base of blown sand which has a significant percentage of shell-derived materials;
2. lime rich soils with pH1 values normally greater than 7.0;
3. a level or low angle smooth surface at a mature stage of geomorphological evolution;
4. a sandy grassland type vegetation with long dune grasses and other key dune species having been eliminated. Core plants are Festuca rubra, Lotus corniculatus, Trifolium repens, Achillea millefolium, Galium verum, Plantago lanceolata, Euphrasia officinotis, Bellis perennis and the moss Rhytidiadelphus squarrosus;
5. biotic interference such as is caused by heavy grazing, sporadic cultivation, trampling and sometimes artificial drainage should be a detectable influence within the recent historical period;
6. an oceanic location with a moist, cool climatic regime (Ritchie 1976).

References

Ritchie, W. 1976. The meaning and definition of Machair. Transactions of the Botanical Society of Edinburgh, 42., 431-440.