Kilroosky Lough ASSI

The chemical composition of water in this lake reflects the underlying limestone bedrock and is highly base rich. This, along with calcium carbonate deposits, or marl, and high water quality and clarity, are characteristic of marl lakes. Kilroosky Lough is one of the best examples of such a lough in Northern Ireland.

The lough exhibits the natural succession from open water to terrestrial vegetation types and includes a number of scarce plant communities and species. The aquatic vegetation is dominated by an extensive bed of stoneworts including the regionally rare rugged stonewort and smooth stonewort.

The fringe of the lough is dominated by common club rush, backed by a tall swamp of common reed. Behind the fringe the shallow waters support species rich stands of calcareous fen vegetation dominated by lesser tussock sedge and associated plants such as marsh pennywort, marsh cinquefoil and marsh arrowgrass.

In addition to the rare plant communities the lough is also noted for its invertebrate populations. The lough supports a population of Atlantic stream or white-clawed crayfish, a species that is becoming increasingly rare throughout its range. In addition there are a number of rare waterbeetles.