Wetlands and Rivers

The Mourne Mountains catch the wet south-westerly winds resulting in high rainfall on all but the north-eastern side. 

• Nineteen rivers rise in the Mourne Mountains - some feeding five large mountain reservoirs. 
• The River Bann rises on the western flanks of Slieve Muck and flows into Lough Neagh, while the River Lagan rises on the flanks of Slieve Croob and flows to Belfast Lough.
• Thirteen fast flowing rivers susceptible to high water and flooding tumble down the steep eastern flanks of the Mournes.
• Dippers hunt these rivers for underwater larvae and typically nest in holes in banks or under bridges.
• Open water such as ponds, lakes and streams are important for dragonflies. 
• Kingfishers and otters are present on most rivers. Otters are commonly seen at the mouth of the Shimna river and the gentler rivers flowing into Dundrum Inner Bay. 
• Eighteen lakes in the lowland are trapped in inter-drumlin hollows, and many have plant rich fringing fens and marshes in which rare insects like the Irish damselfly are found.

Atlantic salmon
This large and impressive fish is able to swim against strong currents and leap waterfalls on its migration up many of Mourne’s rivers when returning to spawning grounds. Footstick Bridge in Tollymore Forest Park is a great place to see the leaping salmon. Growing from egg to smolt before it leaves the river, it matures in the sea whilst travelling as far as Greenland before returning to detect the waters from its river of birth. Mourne’s mountain rivers support sea trout, which also return to their native river from the sea each year to spawn.

This tall grass, up to 2m high, is commonly found on all types of ungrazed waterlogged soils, streams and ditches, but forms extensive reed beds on lake shores where the water is moderately nutrient rich. Wetland birds such as swans, grebes and ducks nest in its shelter, as do sedge warblers. Swallows and starlings use thick reed beds for autumn roosts. Over time its dead stems build up fen peat, which fills lakes and forms fens. 

Biodiversity Biodiversity Map Some of the most accessible areas designated for the quality of their biodiversity include:
  1. Carlingford Lough - Ramsar, SPA, ASSI
  2. Castlewellan Lake - ASSI
  3. Eastern Mournes - SAC, ASSI
  4. Murlough dunes - SAC, ASSI, NNR
  5. Rostrevor Wood - SAC, ASSI, NNR
  6. Slieve Croob - SLNCI
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