Machair

Machairs are complex landscapes that support more or less extensive, short-turf dune grasslands in mosaics with calcareous lochs, saltmarshes, fens and other coastal habitats. In the National Vegetation Classification of the United Kingdom, twelve vegetation types have been mentioned belonging to the machair landscape. The grassland part is generally considered as ‘machair in the strict sense’ or ‘machair grassland’. The landscape always shows a long history of human intervention, especially through grazing, low-intensity systems of rotational cropping and fishery-related activities. Grazing may include cattle and/or sheep grazing, sometimes grazing by horses or goats is involved. Grazing by rabbits is an important natural phenomenon. The habitat type is found along the Atlantic coasts of Ireland and Scotland (where the largest and richest examples are found on the Outer Hebrides), characterised by a moist and cool climate, on calcareous sandy soils, that are blown inland from the shores by strong prevailing western winds, overlying peat or impermeable bedrock. The pH values are normally above 7.0. The dynamics of the system are enhanced by the digging and trampling activities of rabbits and domestic animals. The name machair is derived from the Irish word magh, meaning low-laying, fertile plain. A smooth surface is often considered an important criterion, like in the definition of Curtis: ‘systems in which the bulk of the area consists of a flat to gentle-sloping landform from which ridges are absent or very restricted and with a consequent restriction of the area of Ammophila’. The more or less humid sandy soils contain a significant proportion of shell fragments (up to 60 % of the soil or even more), producing lime-rich conditions. During winter, the low-lying parts of the system are flooded or at least waterlogged. The grasslands are dominated by rather generalist grasses including Poa pratensis and Festuca rubra, but a species- and flower-rich herb layer attracts many insects, whereas the complex landscape setting is important for breeding waders and other birds. As an example, at present, machairs support the healthiest western European population of the threatened Corncrake (Crex crex). On the European continent, to some extent, similar landscapes can be found, but not in the same complex landscape setting. In the Netherlands, for instance, low-lying, undulating plains with species-rich dry to humid dune grasslands do occur on old grazing grounds in the southwestern part of the country (vroongronden), but these sites are not dynamic and to a large extent decalcified. Calcareous, dynamic grasslands with a long history of human interference can be observed in the mainland dunes of Holland province (zeedorpenlandschap), but these are lacking the other landscape elements and wide-ranging grazing.

Indicators of good quality: 

The following characteristics can be considered as indicators of good quality:

• High richness in herb species
• Long-term, non-intensive human land-use, including grazing
• Complex landscape setting, with grasslands and small water bodies and other elements

Synthesis of Red List assessment

Confidence in the assessment

Pressures and threats