Site prioritisation for the protection of rare subterranean species – the cases of two ostracods from south‐western France

SUMMARY 1. Delineation of protected areas for rare subterranean species is a key problem for groundwater biodiversity conservation, because of practical difficulties in implementation. Criteria for site selection are presented that are derived from studies on two remarkable Ostracoda, Dolekiella europaea Gido ´ , Artheau, Colin, Danielopol & Marmonier (Limnocytheridae) and Vestalenula carveli Artheau (Darwinulidae) discovered in south-western France. 2. Arguments for natural heritage value and protection of subterranean species are proposed and illustrated by using information on these two ostracod species. The proposed criteria are: (i) local and ⁄ or regional endemism; (ii) known occurrence of the species at a few localities only; (iii) representativeness for ancient phylogenetic lineages with wider geographical distributions in the past; and (iv) suitability for scientific study because of unique morphological or biological traits. 3. It is also proposed to prioritise the protection of subsurface sites using the following criteria: (i) type locality for newly described species; (ii) presence of other rare stygobiotic taxa; and (iii) high population densities of the primary target species. 4. Development and implementation of protection strategies at local scale are likely to benefit from collaboration between scientists, policy makers and stakeholders. The measures taken should complement existing national and ⁄ or international attempts at large-scale protection of groundwater biodiversity.