SATURDAY 23RD NOVEMBER 2013                                                         LAYTOWN  

Coastal Ecology and Visit to the Grounds of National Ecology Centre (Sonairte)

LEADER: DECLAN DOOGUE

We assembled at Sonairte and then moved to the mouth of the River Nanny on the outskirts of Laytown ( A SPA  - designated Special Protection  Area http://www.npws.ie/protectedsites/specialprotectionareasspa/rivernannyestuaryandshorespa/) and viewed the various estuarine zonation features resulting from deposition and scouring. The quantity of sea shells and other debris was quite extensive in places.  Lyme-grass Leymus arenarius was very much in evidence binding sand in the small embryonic  fore-dune system. This broad-leaved grass appears to be replacing  Marram Ammophila arenaria at the fore of developing system as has been noted elsewhere e.g. on the Merrion Dune system at Booterstown.  Marram Ammophila arenaria, with its narrower and more rolled leaves,  was plentiful further back in the older dunes. Other grasses observed included  Couch Grass Elytrigia repens,  Sea Couch E. atherica, Sand Couch E. juncea  and Red Fescue Festuca rubra.  Declan explained how these grasses, together with the Sand Sedge Carex arenaria,  play an essentialrole in dune formation by binding sand. Everyone had the opportunity to have a close look at the ‘key’ surface features of the leaves of these  grasses..

Other pioneer plants seen included Sea Sandwort Honckenya peploides  and Sea Rocket Cakile maritima. The latter was still in flower with some quite dark inflorescences. Rosettes of the yellow crucifer Sea Radish Raphanus raphanus subsp. maritimus were quite plentiful. One plant of the latter which was still in flower displayed its characteristic  fruits with  pods containing  one, two or three seeds in separate swollen compartments.  Bird’s Nest Fungus ?Cyathia sp.  – a ‘first’ for nearly everyone present -  was found on a log buried in the sand.  A large number of land snail shells were found – some in areas which had been burnt – the most obvious one being Theba pisana,  an alien of Mediterranean origin now known from dunes along the east coast of Ireland from the Bull Island northwards to Clogher Head.

Lunch was available in the very pleasant environs of the café at Sonairte. Afterwards we had a quick tour of the premises and headed through the gardens to the estuary where the path meets the ancient towards Julianstown and viewed the Nanny and its flood plain. Sea birds such as Oystercatchers, Widgeon, Teal, Mallard, Shelduck, Whimbrel, Redshank, and Godwit were visible along the estuary. A  Buzzard was seen overhead and a Pheasant roosting on Beech across the river. The biggest ‘bird’ seen was a microlite which passed overhead and followed the river inland.

Although late in the year, we were able to identify typical saltmarsh plants such as Sea-purslane Atriplex (Halimione)  portulacoides , Lax-flowered Sea-Lavender Limonium humile, Sea-milkwort Glaux maritima, Thrift Armeria maritima, Cord-grass Spartina sp.  – some infested with the highly toxic fungus Ergot (Claviceps  purpurea ?var. spartinae) once used in the synthesis of LSD  -  Common Reed Phragmites australis,  Common Saltmarsh-grass Puccinnellia maritima and Red Fescue Festuca rubra.  Prominent rushes were Saltmarsh Rush Juncus gerardii, Sea Rush Juncus maritimus and Sea Club-rush Bolboschoenus maritimus. We walked the saltmarsh and noted the sharp zonation of the vegetation which was directly related to small changes in elevation and observed the various channels through the marsh.

Laytown / Sonairte is clearly a very interesting area which merits visits at various times during the season.  

     

     

      

  

Photographs © P Lenihan. 

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