The Other Side of ‘Mother Nature’

It is said of my brother, that he loves Mother Nature, despite what she has done to him. And on this month’s trip we were to learn that Mother Nature is not always benign, indeed, she can be ‘Red in Tooth and Claw’.

The weather forecast for Saturday the 3rd of August (2013) was not terribly encouraging. The towering clouds, gusting wind and the occasional spit of rain felt quite ominous; but it all gave way to breezy sunshine – one of those ‘good to be alive’ days.

Off we went to Sheskinmore Nature Reserve. We parked close to the Bird Hide and made our way past the lake to the bridge, across flat Machaire plain to the dunes, over the dunes to Ballinreavey Strand, back to estuary, up the river, over the bridge and back to the cars. We hadn’t planned to stay out so long, or to walk that far but the weather was good, we had our lunch with us, and away we went; it was that kind of day.

Given the recent dry weather Sheskinmore lake was very low. There was a solitary Mute Swan but quite a crowd of Grey Herons and half a dozen Mallard in among the reeds.

Machaire is one of the rarest habitats in the world. It occurs only in Western Ireland, in the counties Donegal, Sligo, Mayo and Galway, and in the Western Isles of Scotland. In all only 30,000ha to 4,000ha exist, two thirds of this in Scotland and one third in Ireland.

The key to Machaire development is the nature of the sand that is brought ashore in the locality. The sand is a mix of various small particles of rocks, known as Silica Sand that is derived from quartz and other particles that are derived from the shells of sea creatures. Shell sand is rich in lime, otherwise known as Calcium Carbonate. Once it has been brought ashore the wind tends to transport the sand inland. The heavier Silica sand tends to accumulate in the sand dunes whilst the lighter, more flaky shell-sand gets carried further inland by the wind to form the flat calcareous plain of Machaire behind the dunes.

Machaire vegetation is rich in legume species

Machaire vegetation is rich in legume species

While Machaire may be rich in lime, it is low in minerals and organic matter, especially where conditions are free-draining. Nitrate is perhaps the most essential plant nutrient but it is also very soluble. In these free–draining conditions, any nitrate that is free in the soil is quickly washed away by the first shower of rain. This scenario presents relatively tough growing conditions for plants. As a result of this many of the species that grow on Machaire are members of the Pea Family, that is the Leguminosae (Bird’s-foot-trefoil, the vetches, clovers, medicks, etc.). The Leguminosae are extraordinary in that they can take Nitrogen from the atmosphere, which is useless to most plants, and convert it into the Nitrate which is essential for plant growth. This is a brilliant adaptation for such harsh growing conditions.

Other plants survive and thrive in the harsh conditions by being semiparasitic and stealing nutrients from nearby plants. The roots of plants, such as Yellow Rattle, Red Bartsia and Eyebrights, tap into the roots of nearby grasses and sedges and extract nutrients from their unfortunate hosts.

If you were a plant that managed to grow in these harsh conditions, the last thing you would want, after all the effort, would be to be eaten. Many plants produce poisons to deter grazers; for example Ragwort produces bitter, poisonous alkaloids and Bird’s-foot-trefoil produces a variety of cyanide containing compounds.

These poisons are effective deterrents for the vast majority of creature except for a few caterpillars. The bright green caterpillars of the Burnet Moth live on the leaves of Bird’s-foot-trefoil and accumulate cyanide from their food plant, in their bodies. As they develop to adulthood, the poison remains in their bodies; a fact they advertise with their vivid black and red markings. This deters most predators from eating Burnet Moths. Likewise with the Cinnabar Moth Caterpillars, they munch the leaves of Ragwort and accumulate the vile tasting, poisonous Alkaloids that deter more sensitive creature. Again the presence of the poisons within the flesh of caterpillars and adults is advertised with vivid colouration.

We noticed quite a lot of Burnet Rose growing in the Machaire. Burnet Rose is the only Rose where the ripened rose hips are black; all others are red. One of more unusual sightings on this outing was the large bulbous red galls growing on leaves of Burnet Rose. Galls are abnormal outgrowths of plant tissue and are caused by infestation by fungi, bacteria, mites or insects. Depending on the parasite and the host, very distinctive galls can be created. Galls provide shelter, and food for the growing parasite; good for the parasite, bad for the host; another of Mother Nature’s unfortunate arrangements. In this particular case the gall was caused by the Rose Gall Wasp Diplolepis spinosissimae.

Women will never say it out loud in the company of men but will readily admit it when they get together in their conspiratorial huddles – men can be mugs! Mother Nature has another nasty trick up her sleeve for the male bees that inhabit Sheskinmore. Growing on the reserve is an Orchid, the flowers of which look like, smell like and feel like a female bee, and naturally, its name is the Bee Orchid. Not being too bright, the male bee is quickly smitten by the charms of, what he thinks is his perfect woman. The male attempts to mate with the flower and gets covered in pollen. After a while he realises that the relationship isn’t going anywhere so he moves on to another Bee Orchid. Again its ‘picture and no sound’. Pollen from the first flower is passed to the second and so the cross-fertilisation of the flowers takes place. The flowers get what they want and the bee is just left with the feeling that he always chooses the wrong woman.

The birds we saw in the Machaire and dune region of the reserve included Chough, Hooded Crow, House Martin, Kestrel, Meadow Pipit, Raven, Reed Bunting, Sand Martin, Skylark, Swallow and a mixed flock of Twite and Linnet. Choughs are a national rarity but are quite common in Sheskinmore; likewise with Twite; we were treated to good views of both. There were a mixed flock of House Martin and Sand Martin zooming and skimming over a pool in the dunes. We were particularly pleased to discover the nesting burrows of the Sand Martins in an eroding dune along side the river.

When we crossed over onto Ballinreavey Strand, we saw some eider duck with flapping wings, ‘running’ across the surface of the water. We were not too sure what this type of behaviour was all about, but it seemed to be a bunch of males in eclipse plumage ‘throwing shapes’. There were a few Black Guillemots offshore and, on the strand, there were Ring Plover and Sanderling searching the shoreline for suitable food items.

The birds seen on this outing were, Black Guillemot, Chough, Eider Duck (in eclipse plumage), Grey Heron, Hooded Crow, House Martin, Kestrel, Meadow Pipit, Mute Swan, Raven, Reed Bunting, Ring Plover, Sand Martin, Sanderling, Skylark, Swallow and a mixed flock of Twite and Linnet.

Our next outing will be to Bell’s Isle on the 31st of August, meeting at Murvagh Beach Car Park at 10am.

Michael Cunningham

Plant seen included Autumn Gentian, Bird’s-foot-trefoil, Black Medick, Buttercup, Common Centuary, Crane’s-bills (Various), Daisy, Devil’s-bit-Scabious, Eyebrights, Grass of Parnassus, Kidney Vetch, Knapweed, Lady’s Bedstraw, Orchids (various), Ragwort, Red Bartsia, Red Fescue, Ribwort Plantain, Selfheal, Speedwells, Sticky Mouse-ear, Tuffed Vetch, White Clover, Wild Pansy, Wild Thyme, Yarrow and Yellow Rattle.

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