The Water Framework Directive's protection of groundwater-dependent terrestrial ecosystems

The Water Framework Directive protects groundwater-dependent terrestrial ecosystems, but its concepts and definitions remain unclear. This paper aims to clarify the margin of discretion for the Member States, by applying a cross-disciplinary legal and biological analysis. We conclude that description of the protected ecosystems must include at least key components and processes and be based on a number of well-known groundwater-dependent habitats, but not restricted to habitats fed entirely by groundwater. We argue that the potential harm to terrestrial ecosystems by lowering the groundwater table should include the impact of both water abstraction and drainage, and, despite the discretion regarding scale, we recommend basing assessments and protection at a landscape-scale that aligns with the scale of bodies of groundwater, which typically includes a range of habitats in various ecological conditions.