Magheraveely Marl Loughs RAMSAR

Magheraveely Marl Loughs Special Area of Conservation (SAC), comprising of Knockballymore Lough ASSI, Kilroosky Lough ASSI, Summerhill Lough ASSI, Burdautien Lough ASSI, Annachullion Lough ASSI and Drumacrittin Lough ASSI has been selected as a Ramsar site because of its important wetland habitats.

The Magheraveely Marl Loughs comprises six low-lying loughs in the catchment of the River Finn. The site is situated in the south west of Northern Ireland approximately 22 miles from Enniskillen, with three of the loughs intersected by the border with the Republic of Ireland.

A combination of hard water and low nutrient status has produced loughs that approach the classic marl loughs condition. In addition they are surrounded by wetlands whose interest is also promoted by high calcium concentration. There are 23 loughs of this type in Northern Ireland of which these are the best examples.

The Ramsar site is a Wetland of International Importance. It qualifies under Criteria 1 and 2 because it is a representative example of a natural wetland type found within its biogeographic region, and it supports vulnerable, endangered or critically endangered species or threatened ecological communities.

The six loughs are characterised by the presence of calcium carbonate deposits, or marl, which are precipitated out of the calcium rich water to produce marl loughs, a relatively rare lake type in Northern Ireland.
Biological interest is related to the presence of vegetation, which reflects these calcareous conditions. This includes rich and extensive stonewort (Charophyte) communities including several rare and local species, including Chara aspera, Chara curta, Chara hispida and Chara pedunculata.

Chemical composition of the water reflects the underlying carboniferous lower limestone bedrock and the surface glacial till in this area and is highly base-rich. Marl deposition and high water quality, clarity and base-richness are characteristic features of marl loughs.

The loughs exhibit the natural succession from open water to terrestrial vegetation types and include a number of rare and unusual plant communities. The aquatic vegetation is dominated by submerged beds of stoneworts. Other open water species include white water lily, yellow water lily and pondweeds such as Potamogeton natans and Potamogeton lucens.

The loughs are surrounded by an inundation zone containing significant stands of alkaline fen vegetation. This is generally composed of a sward rich in sedges and herbs. Characteristic species include, the lesser tussock sedge, long stalked yellow sedge and glaucous sedge. Other frequent, yet scarce species in other parts of Northern Ireland, include marsh arrowgrass, quaking-grass and more notably, marsh helleborine, grass-of-Parnassus, knotted pearlwort and fen bedstraw. Calcareous fen containing great fen-sedge is also present within the site.

The clean unpolluted waters of the loughs support populations of white-clawed crayfish, a species which is becoming increasingly rare throughout its geographical range. Major threats to crayfish populations include the introduction of non-native species and crayfish plague. Four of the marl loughs have strong isolated populations of white clawed crayfish. This site is particularly important because of its hydrological isolation and the absence of crayfish plague from Northern Ireland.