Figure 1 from: Gutjahr S, Schmidt S, Hahn H (2014) A proposal for a groundwater habitat classification at local scale. Subterranean Biology 14: 25-49. https://doi.org/10.3897/subtbiol.14.5429

Figure 1 - Map of the study area (from Hahn 2006, modified). All sites were equipped with 4–5 trans-sectional groundwater wells. Boxes: The respective natural regions [Pfälzerwald Mountains = Central Uplands; Haardtrand and the Upper Rhine Plateau = South-Western Uplands (according to Stein et al. 2012)]. Abbreviations on overview map: A = Austria, B = Belgium, CH = Switzerland, CZ = Czech Republic, D = Germany, DK = Denmark, F = France, L = Luxembourg, NL = Netherlands, PL = Poland.