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Amachair (Scottish Gaelic pronunciation:[ˈmaxɪɾʲ]; sometimesmachar in English) is a fertile low-lying grassyplain found on part of the northwesterncoastlines ofIreland andScotland, particularly theOuter Hebrides. The best examples are found onNorth andSouth Uist,Harris andLewis.[1] Machairs in Ireland are listed as priority habitats, receiving the highest level of protection, in the EUHabitats Directive.
Machair is a Gaelic word meaning "fertile plain", but the word is now also used in scientific literature to describe the dune grasslands unique to western Scotland and northwest Ireland.[2] It had been used by naturalists since 1926, but the term was not adopted by scientists until the 1940s.[3] The word is used in a number of Irish, Scottish and Manx place names to refer to low-lying fertile ground or fields, even in areas not on duneland.[3] In Scotland, some Gaelic speakers usemachair as a general term for the entire dune system, including the dune ridge, while others restrict its use to the extensive flat grasslands inland of the dune ridge.[3] In Ireland, the word has only been used in place names, and the existence of the habitat there was onlyconfirmed in 2013.[3] In Manx Gaelic, 'magher' is a common term for a field.
In 1976, an attempt was made to strictly definemachair,[4] although a number of systems still evade classification.[3] This proved difficult when the habitat was listed on Annex I of theHabitats Directive in 1992, leading to the distinction between "machair grassland" and the "machair system".[3]
Machair differs from thelinks on the east coast of Scotland in having a lower mineral content, whereas the links are high insilica.[5] Machair plains are highlycalcareous, withcalcium carbonate concentrations ranging from 20% to 80% on the beaches, and decreasing further away from the coast.[5] ThepH of a machair is typically greater than 7, i.e. it isalkaline.[3]
The inside of a machair is often wet or marshy, and may contain lochs.[3][6]
The modern theory of machair formation was first put forward byWilliam MacGillivray in 1830.[5] He worked out that shell fragments are rolled by waves towards the shore, where they are further broken up. The small shell fragments are blown up the beach to form mounds, which are then blown inland.[5]
Human activity has played an important role in the creation of the machair. Archaeological evidence suggests that some trees were cleared for agriculture as early as 6000 BC, but there was still some woodland on the coast ofSouth Uist as late as 1549.[5] Seaweed deposited by early farmers provided a protective cover and added nutrients to the soil.[5] The grass is kept short bycattle andsheep, which also trample and add texture to thesward, forming tussocks that favour a number of bird species.[5]
Thesoil is low in a number of keynutrients, including trace elements such ascopper,cobalt andmanganese, requiring cattle to be fed supplements or taken to summer pastures elsewhere.[5] The sandy soil does not hold nutrients well, making artificial fertilisers ineffective and limiting the crops that can be grown to certain varieties ofoats andrye, andbere barley.[5]
Machairs have received considerableecological andconservational attention, chiefly because of their uniqueecosystems.
Kelp in the sea next to the machair softens the impact of waves, reducing erosion, and when it is washed ashore by storms, forms a protective barrier on the beach.[5] As the kelp decays, it provides a home for local sand flies, which in turn provide food for flocks ofstarlings and otherpasserines, winteringwaders,gulls and others.[5] When covered with sand, kelp will compost to form a fertile bed in which annual coastal flowers andmarram grass will thrive.[5]
They can houserarecarpet flowers, includingorchids such asIrish lady's tresses and theHebridean spotted orchid and other plants such as theyellow rattle.
Bird species including thecorn crake,twite,dunlin,common redshank andringed plover, as well as rare insects such as thenorthern colletes bee, the great yellow bumblebee (Bombus distinguendus) and the moss carder bee (Bombus muscorum), are found there.
Arable and fallow machair is threatened by changes in land management, where the original system ofcrofts is under threat from a reduction in the number of crofters and the use of "modern" techniques.[7] Changes in theCommon Agricultural Policy, which decoupled production fromsubsidies, reduced the amount of grazing taking place in many crofting areas, and led to some areas being undergrazed or abandoned.[7][8][9] A lack of native seed increases the need for fertiliser and herbicides.[7]
Rising sea levels, a consequence ofglobal warming, also pose a threat to low-lying coastal areas, leading to increasederosion.[5][10][11] In January 1993, the storm which ranMVBraer aground offShetland eroded 3 metres (9.8 feet) of machair along the entire length of Uist and Barra.[5] On11/12 January2005, a storm blew consistently in excess ofhurricane force 12, destroying hectares of machair.[5]
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