Groundwater-Dependent Ecosystems (or GDEs) are ecosystems that rely on groundwater for their continued existence.
Groundwater is water that has seeped down beneath Earth’s surface and has come to reside within the pore spaces in soil and fractures in rock, this process can create water tables and aquifers, which are large storehouses for groundwater.
An ecosystem is a community of living organisms interacting with the nonliving aspects of their environment (such as air, soil, water, and even groundwater).
Twenty-one ecosystems on the Irish Water Framework Directive Register of Protected Areas (Annex I habitats under the Habitats Directive) were identified by Irish National Parks and Wildlife Service (NPWS) as directly dependent on groundwater.
Of these, 11 terrestrial habitat types that are considered to be the most groundwater dependent, namely:
1. Alkaline fens (Natura 2000 code 7230);
2. Species-rich Cladium fen (7210);
3. Petrifying springs (7220);
4. Transition mire (quaking bog) (7140);
5. Active raised bog (7110);
6. Turloughs (3180);
7. Flushes in blanket bog (7130);
8. Wet heath (4010);
9. Alluvial forests (91EO);
10. Machair (21AO);
11. Humid dune slacks (2190).
Image Source – By T.C. Winter, J.W. Harvey, O.L. Franke, and W.M. Alley – Ground Water And Surface Water A Single Resource. U.S. Geological Survey Circular 1139, Figure 3., Public Domain