Indicator species reveal the physical and biological singularity of esker ecosystems

•Biodiversity in lakes associated to esker geological formations is poorly known.•Half of the esker lakes sampled were fishless.•The waterbird species, common goldeneye (Bucephala clangula), was associated with esker lakes, preferring fishless lakes.•The Perlidae -benthic macro-invertebrate- was associated with esker lakes, most likely linked with higher dissolved oxygen concentration.•Biological diversity is lower in esker lakes but also that these waterbodies host valuable indicator species.