- Freshwater habitats refer to naturally occurring water bodies that have a very low dissolved salt content. They include both flowing & standing waters.
- Standing open waters, which include lakes & ponds, are one of the most extensive natural habitats in Northern Ireland. There are more than 1,600 lakes, ranging in size from small ponds to the largest freshwater lake in the British Isles: Lough Neagh.
- Northern Ireland’s lakes can be classified into: oligotrophic (low nutrient levels), mesotrophic (moderate nutrient levels) & eutrophic (high nutrient levels). The latter type is a Priority Habitat included in this audit.
- Wetland habitats refer to areas of land that are transitional between terrestrial & aquatic systems. They are usually fringing standing open water & are regularly wet or flooded by surface or groundwater. Most of the lakes in NI are fringed by fen, marsh & swamp. However, wetland can also occur in low-lying wet ground or poorly drained marginal grassland.
- Fen, Marsh & Swamp includes wetlands that are fed by ground or river waters rather than directly by rainfall. The peaty or mineral soils are permanently, seasonally or periodically wet with vegetation dominated by herbs, sedges & rushes. This broad habitat covers 47,000 ha (3.3% of land area) in NI (NICS, 2007)
[Further information: Countryside Survey Results 2007 Chapter 7]
- Priority (wetland) Habitats included in this audit are as follows:
– Purple Moor-grass & Rush Pasture
- Freshwater & wetland habitats in NI support a diverse range of plants & animals. These include fish, birds, mammals (e.g. otter), a reptile (viviparous lizard) & amphibian (smooth newt). Invertebrates, such as insects, spiders, crustaceans, worms & snails, often use freshwater at various stages in their lifecycle. Northern Ireland’s fens are of particular importance for invertebrates & support several which are absent or threatened in Great Britain such as the Irish damselfly , marsh fritillary butterfly & whirlgig beetle.