Round Lough and Lough Fadda ASSI

Round Lough and Lough Fadda is of special scientific interest because of its wetland flora and fauna. It is a diverse site with two distinct, but hydrologically linked lowland loughs which together support areas of open water with a species-rich assemblage of aquatic plants together with fen communities of high scientific value within County Tyrone. A wide range of wetland plants are present, some of which are scarce. The area is also important for the overall diversity of its invertebrates including species which have a restricted distribution within the United Kingdom.

The open waters of Round Lough are of particular importance, representing a good example of a naturally eutrophic lowland lough with a predominantly peat substrate. Although Round Lough is set in a landscape surrounded by gently sloping improved grassland, it is comparatively un-enriched compared to other lowland lough types. It is therefore relatively sensitive to nutrient enrichment. The diverse aquatic vegetation is dominated by beds of long-stalked pondweed, floating stands of broad-leaved pondweed with curled pondweed also occurring. The floating and submerged vegetation includes yellow water-lily, white water-lily, unbranched bur-reed, Canadian waterweed, common duckweed, ivy-leaved duckweed and stoneworts. The lough is fringed by emergent swamp vegetation including common club-rush and bulrush with natural transitions to fen communities.

Around both loughs, fen communities are generally species-rich and quite extensive in places, particularly along the eastern and southern shores of Lough Fadda. The sedge component is frequently dominated by brown sedge and bottle sedge, with the notable lesser tussock-sedge also occurring. Associated higher plants with a widespread occurrence include bogbean, wild Angelica, marsh cinquefoil and common marsh-bedstraw. Additional species with a more localised occurrence include water mint, Devil’s-bit scabious, marsh marigold, meadowsweet and ragged-robin. A dense mat of brown mosses dominated by pointed spear-moss grows beneath the sedge and herb sward. Other mosses include tall thyme-moss and marsh bryum.

Along the eastern shore of Lough Fadda, the fen is fed by a series of calcareous flushes with localised stonewort beds. Yellow-sedge and lesser tussock-sedge are frequent with jointed rush, marsh arrowgrass and marsh horsetail growing over a thick moss carpet which is dominated by pointed spear-moss and locally frequent curled hook-moss. Associated species include tree-moss, marsh bryum and localised pockets of the more notable heart-leaved spear-moss.

Where the fen communities are more extensive and diverse at Lough Fadda, natural successional transitions from open water through marginal swamp communities to fen and in places, wet woodland, are well represented adding to the diversity of the area. The open waters of Lough Fadda support a range of aquatic plants including six species of pondweed. yellow water-lily and white water-lily are also common in the open waters. The swamp communities are also diverse with great fen-sedge, common reed, and bottle sedge swamps occurring. A range of associated herbs are found in the swamp communities including water-plantain, mare's-tail, common spike-rush, water horsetail and more notably cowbane. The wet woodland communities that are closely associated with the fen extend from the south-east to the south-west corners of the lough. The canopy varies in composition, but is characteristically comprised of alder, grey willow, goat willow and downy birch with occasional ash. The notable greater tussock-sedge occurs frequently along the transition between the fen and wet woodland. Pockets of bog woodland also occur where alder and birch grow over a thick moss carpet that is comprised of blunt-leaved bog-moss, flat-topped bog-moss and spiky bog-moss. Further woodland diversity is provided by drier areas of semi-natural woodland and Estate woodland comprising a mixture of native and exotic tree species.

Lough Fadda supports a rich wetland invertebrate community, largely because of the diversity of the fen communities and associated wetland habitats. The site is species rich across many invertebrate groups, especially water beetles, spiders, dragonflies and damselflies. Notable species include the water beetle, a relict fen species, and a sphagnum bug, both of which may be found in the moss layer of fens. Other species of note include the hairy dragonfly and the variable damselfly.

Site Related Documents

Site map (.PDF 788Kb), Citation document (.PDF 157Kb) and Views about Management document (.PDF 77Kb)