Was this shrub in­tro­duced from north of Spain?

Bray People - - LIFESTYLE -

MACKAY’S HEATH is an in­ter­est­ing wild plant. It is a heather-like, bushy shrub that dis­plays masses of small, bright pink flow­ers in late sum­mer. It is na­tive to and is only found in four prov­inces in the coastal Cantabrian re­gion of north-west Spain. The only other place in the world where it oc­curs is along the western seaboard of Ire­land.

It grows at six sites, one in each of coun­ties Kerry and Done­gal and two in each of coun­ties Galway and Mayo. Its dis­tri­bu­tion is very lo­cal and dis­junc­tive in deep peat in the drier fringes of wet blan­ket bogs near the sea.

Even though its pollen is fer­tile, for some un­known rea­son, the plant does not set seed in Ire­land. It spreads by lay­er­ing and does so freely, pos­si­bly aided by turf cut­ting.

Mackay’s Heath is re­garded as na­tive to Ire­land but how it got here is not un­der­stood. It is gen­er­ally be­lieved that the in­tense cold and the ice sheets of the last ice age wiped out all of the wild plants that grew here at that time.

If so, Mackay’s Heath must have colonised Ire­land by spread­ing north from Spain when the ice melted and the cli­mate im­proved some 13,000 years ago. But how could it get here?

It is be­lieved that Ire­land be­came an is­land about 7,500 years ago when melt­wa­ter from the ice caused sea level to rise cut­ting off our land links with Bri­tain and main­land Europe.

An­other pos­si­bil­ity is that Mackay’s Heath sur­vived the last ice age in Ire­land. How­ever, since it is es­sen­tially a Mediter­ranean plant, that seems un­likely when there is no ev­i­dence to sug­gest that much hardier species were able to sur­vive be­ing locked in the chilly em­brace of the pro­longed Arc­tic cold.

In­trigu­ingly, re­search for a re­cent study by botanists from Galway univer­sity re­ported in the cur­rent is­sue of the New Jour­nal of Botany notes that in Ire­land Mackay’s Heath al­ways grows within 1km of tracks and roads near sandy bays. Does that sug­gest that Span­ish traders us­ing these track­ways might have in­tro­duced the species to Ire­land from Cantabria, Gali­cia or As­turias?

It is known that heathers and heaths were used in the past as pack­ing ma­te­rial around im­ported goods and ge­netic stud­ies sug­gest that Ir­ish spec­i­mens of Mackay’s Heath are more closely re­lated to those in Spain that to other Ir­ish plants sug­gest­ing re­peated in­tro­duc­tions.

The present sta­tus of Mackay’s Heath as a na­tive Ir­ish plant is com­ing un­der in­creas­ing doubt.

As they fade, the pink flow­ers of Mackay’s Heath turn bright or­ange.

Newspapers in English

Newspapers from Ireland

© PressReader. All rights reserved.