EVENTS

Members Reports and Photos

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SUNDAY 1 SEPTEMBER  2013

PORTRANE-TURVEY

LEADERS: DECLAN DOOGUE

Earlier in the year there were reports of damage to the board walk at the south end of the Portrane Burrow where building has occurred close to the shoreline.  This visit to the north end revealed a rather different story. The old sand dunes on one side are leached and are heavily vegetated with Bracken. In between these dunes and the sea and Rogerstown Estuary there is a complex and dynamic system with both saltmarsh and newer dunes in various stages of development. Vegetation undergoes abrupt changes in community in some areas, e.g. from Festuca rubra dominated sward to salt marsh, with a metre or less.

Some of what is now saltmarsh was freshwater marsh a hundred years ago according to the G.H. Pethybridge survey. Why has this happened?  Is this a consequence of the local extraction of groundwater for domestic consumption or are there other causes?

Typical sand dune plants seen were Marram Ammophila arenaria, Lyme Grass Leymus arenarius, Elytrigia juncea and Carex arenaria all of which with their extensive root systems have varying degrees of capacity to bind sand together. Sea Rocket Cakile maritima, Sea Sandwort Honckenya peploides were plentiful. A small amount of Sea Holly Eryngium maritimum was seen. The saltmarsh/halophile  plants included the Sea Lavenders  Limonium binervis (upper part), L. humile (lower marsh), Sea Milk Glaux maritima, Sea Arrowgrass Triglochin maritimum , Sea Plantain Plantago maritima, Thrift Armeria maritima, Sea-purslane Atriplex (halimione) portulacoides, Sea Aster Aster tripolium. Seablite Suaeda maritima and Prickly Saltwort Salsola kali. Other plants on drier parts included Kidney Vetch Anthyllis vulneraria, Knotted Pearlwort  Sagina nodosa. Cordgrass Spartina sp., an introduced species in Ireland, was growing in some of the muddier areas

Slugs were scarce in Turvey due to the dry summer but a few Arion specimens were found under boards.  One plastic board revealed the long-legged ‘cellar’ spider Pholcus phalangioides familiar to some of us in the darker corner of our houses and another spider a member of the Salticidae (Jumping spider) was examined. Two small woodlice species were noted Trichoniscus pusillus (‘common pygmy”?) and Metponorthus (Porcellionides) pruinosus. – the former numerically one of the most common and the latter, described as a coloniser of synantropic sites was found in a typical ‘farmyard’ habitat.

Arable weeds included Veronica persica, Lamium amplexicaule and the Knotgrasses Polygonum maculosa (Redshank) and Polygonum lapathifolium, and Black Bindweed Fallopia (Bilderykia) convolvuus. Small tortoiseshell butterflies were nectaring on Sedum spectabile and a single Wall Brown was found in an atypical bare substrate – a log – and one migrant Painted Lady was briefly glimpsed. Birch Shieldbugs Elasmosthetus interstinctus (adults and nymphs) appeared on cue on a birch tree.

 

     

     

     

        

 

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