Members Reports and Photos
Saturday 14 JUNE 2014
derryadd bog & Lakes
LEADERS: fiona devery
Derryadd is located in west Offaly, just to the north of Fivealley, on the N52 from Tullamore to Birr. The area contains several small, natural lakes on the edge of bogland, nestled between eskers and ridges. The outing was led by Fiona Devery, and the field club members met at the theatre in Birr to car-pool before setting off down the narrow roads leading to the site.
First of all we had a look at the old hedgerows which contained Hazel (Corylus avellana), Holly (Ilex aquifolium, Blackthorn (Prunus spinosa), Spindle (Euonymus europaeus) and Guelder Rose (Viburnum opulus). The hedges also had a number of species of rose, including the Dog Rose (Rosa canina), Sherard’s Downy Rose (Rosa sherardii) and the Small-leaved Sweetbriar (Rosa agrestis). We also found some examples of the Wild Madder (Rubia peregrina) climbing up through the shrubby species. This is one of only two known sites where it occurs in Co. Offaly.
The bogland area is comparatively small and lies just south of more extensive areas harvested by Bord na Mona. There is evidence of former turf cutting around the edges and the central area may also have been cutover in the past. The vegetation includes some fen-like elements, indicating more minerotrophic conditions, around the edges and adjacent to the lakes. The central area contained Sphagnum mosses, Heather (Calluna vulgaris), Cross-leaved Heath (Erica tetralix), the Common Cotton-grass (Eriophorum angustifolium), Round-leaved Sundew (Drosera rotundifolia), Bearded Lichen (Cladonia portentosa) and Bog Asphodel (Narthecium ossifragum) – although the Asphodel was not yet in flower.
The drier bog edges were dominated by Heather, Purple Moor-grass (Molinia caerulea) and Bog Myrtle (Myrica gale). Orchid species included the pinkish Heath Spotted Orchid (Dactylorhiza maculata), the deeper purple Early Marsh Orchid (Dactylorhiza incarnata) and the cream Lesser Butterfly orchid (Platanthera bifolia). We also found some fine examples of the Common Butterwort (Pinguicula vulgaris) in full flower.
The small lakes were interesting, with a floating vegetation mat on the margins which ‘quaked’, and was quite a challenge to anyone without wellies. The marginal vegetation at the first lake included the Bogbean (Menyanthes trifoliata), Marsh Cinquefoil (Comarum palustre), Water Mint (Mentha aquatica), the Bottle Sedge (Carex rostrata) and the Lesser Tussock Sedge (Carex diandra) as well as the Common Club-rush (Schoenoplectus lacustris).
The second lake also had Hemp Agrimony (Eupatorium cannabinum), Quaking Grass (Briza media) and considerable numbers of the Marsh Helleborine (Epipactis palustris) around the edges; with Bulrush or Reed Mace (Typha latifolia), the Lesser Water Parsnip (Berula erecta) and the Water Horsetail (Equisetum fluviatile) out in deeper water. Both lakes had numerous examples of the White Water Lily (Nymphaea alba) in full flower on the surface.
In order to reach the second lake we took a detour along the edge of a field which had unimproved grassland dominated by Sweet Vernal Grass (Anthoxanthum odoratum), Crested Dogstail (Cynosurus cristatus) and Yorkshire Fog (Holcus lanatus). Other species included Meadowsweet (Filipendula ulmaria) Silverweed (Potentilla anserina), Yellow Rattle (Rhinanthus minor) and the Carnation Sedge (Carex panicea).
Butterflies active on a dull but warm day included the Green Hairstreak (Callophrys rubi) on the peatland area; the Common Blue (Polyommatus icarus) resting on Briza media on the edge of the lane close to the hedge; the Marsh Fritillary (Euphydryas aurinia) on the fen area near the lake; and four Speckled Woods (Pararge aegeria) in shadier scrub and wooded areas. We also found a rather impressive looking Emperor Moth (Saturnia pavonia), whose larvae feed on Heather, but unfortunately its flying days were over!
Derryadd Lake Nymphaea alba Derryadd Bog
Dactylorhiza maculata Platanthera bifolia D.incarnata
Cladonia portentosa Speckled Wood Pinguicula vulgaris
Myrica gale Rubia peregrina
Photograph© © Charles Shier
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