SAC 000448 Fortwilliam Turlough
SITE NAME: Fortwilliam Turlough
SITE CODE: 000448
Fortwilliam Turlough is situated close to the eastern shore of Lough Ree, 6 km south of Lanesborough, in County Longford. The surrounding countryside is flat, with a thin cover of drift. The floor of the basin is at two levels, a lower central area with several lakes and ponds and a higher surrounding area of till with scattered rocks, extending north-westwards into flat fields and woodland. There is a little surface flow into the basin and floodwater appears to be strongly calcareous.
The central part of the turlough is marly and contains Shoreweed (Littorella uniflora), Various-leaved Pondweed (Potamogeton gramineus), Broad-leaved Pondweed (Potamogeton natans) and the moss, Scorpidium scorpioides, in the wetter parts, together with Lesser Water-plantain (Baldellia ranunculoides), Sedges (including Carex serotina) and Jointed Rush (Juncus articulatus).
At the southern end, the wettest areas support stands of Common Club-rush (Scirpus lacustris), with Greater Spearwort (Ranunculus lingua) and Mare's-tail (Hippuris vulgaris), and occasional patches of Amphibious Bistort (Polygonum amphibium). Slightly drier areas support a community dominated by Common Sedge (Carex nigra), Creeping Cinquefoil (Potentilla reptans) and abundant Adder's-tongue (Ophioglossum vulgatum).
Towards the turlough margin is a broad band of heath in the south and west. A calcareous influence is evident in the presence of Black Bog-rush (Schoenus nigricans), with Eyebright (Euphrasia micrantha), Tormentil (Potentilla erecta), Creeping Cinquefoil (Potentilla reptans) and Sneezewort (Achillea ptarmica). Tall herbs occur in places, including Meadowsweet (Filipendula ulmaria), Tall Fescue (Festuca arundinacea), Agrimony (Agrimonia eupatorium) and Vetches (Vicia cracca and Lathyrus pratensis). This community merges into a Blackthorn (Prunus spinosa) and Hawthorn (Crataegus monogyna) scrub, which has adjacent woodland consisting of Ash (Fraxinus excelsior) and Elder (Sambucus nigra).
Snipe and Mallard nest in the area.
Threats to turloughs stem mainly from drainage and agricultural improvement. Fortwilliam seems largely unaffected by drainage, and standing water may persist throughout the summer. It is an oligotrophic site, which indicates that it has escaped significant nutrient input but renders it sensitive to damage should this occur. The turlough is grazed by cattle and sheep, but is undivided.
Fortwilliam is the only extant large turlough in Longford and one of only two east of the Shannon. It has a high diversity caused by a semi-permanent waterbody, abundant marl precipitation, a relative lack of grazing and small outcrops of limestone, so it is a very representative example of the habitat. The turlough basin seems intact, its basin and hydrology largely unmodified. Its oligotrophic status is valuable, as this feature is becoming rarer in the context of modern agriculture. Due to these factors, Fortwilliam Turlough is a site of considerable ecological value.