Exposed riverine sediments (ERS) occur within river systems at the juncture of the aquatic and terrestrial, and consist of poorly vegetated alluvial deposits of silts, sands and gravels, which are habitat for a wide range of rare and highly specialised beetles. The fidelity scores used in Pantheon originate from Bates 2005 (see link below) who worked in collaboration with Adrian Fowles, who had developed a previous set of scores.
The criteria for the inclusion as a fidelity 1 or 2 species were designed to include both species fairly fastidiously associated with ERS, and bare ground species for which ERS are very important habitats.Species with fidelity scores of 1 are more closely associated with ERS habitat than species with a fidelity of 2.
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Fidelity score 1 = species dependent for at least some stage in their life cycle on bare or sparsely vegetated sediments on the banks of rivers. Some of these species may also inhabit exposed lacustrine sediments, particularly where wave action forms banks of sediment on lake shores, as these features are in many ways ecologically similar to riverine shoals.
- Fidelity score 2 = species strongly associated with exposed riverine sediments for at least some stage of their life cycle, but also occurring in a wider range of habitat types, such as flushes, seepages, pond margins, etc., where the presence of bare sediment is of fundamental importance for some stage of their life cycle.
Species that are commonly found (sometimes in abundance) on ERS, but which are also often found in less open habitats, or in bare ground habitats well away from water, are not included because they could easily reflect the quality of adjoining habitats rather than ERS itself.
For more information see: Bates, A.J. 2005. The ecology and conservation of beetles (Coleoptera) living on exposed riverine sediments. PhD thesis, University of Birmingham.