INFLUENCE OF SMALL- AND LARGE-SCALE ECOLOGICAL FACTORS ON THE CENTIPEDE (CHILOPODA) ASSEMBLAGES OF ARMORICAN FORESTS (NW FRANCE)

International audience; Despite their high functional role as abundant predators, the drivers of centipede assemblages remain poorly known in forests, especially in France. Using replicated depletion quadrats, we sampled five forests distributed over the Armorican Massif. A total of 5209 individuals belonging to 20 species was collected between 2015 and 2017. Assemblage composition was surprisingly constant across parcels, with only different dominant species in the oldest parcel (Berce, Pays-de-Loire) and in the forest of Cerisy (Normandy). The latter hosted two exclusive species, likely because of both biogeographic and abiotic conditions, Geophilus truncorum and Lithobius aeruginosus. Species richness was overall close among sites and parcels, and therefore little influenced by tree age or dominant species. Individual densities varied between site pair-matched parcels, probably because of differences in temporal forest continuity rather than differences in tree ages. In quadrats, the presence of numerous ants strongly affected the number of centipedes, with global densities divided by an average factor of 7. Also at small spatial scale, we did not find a strong vertical stratification of centipede species in terms of presence-absence, with only 2 species exclusive of soil and none for litter, but with important differences in the relative abundance of dominant species. This study suggests that centipedes are important components of the forest soil and litter fauna, should be more frequently studied in French forests and have a potential of bio-indicators of local conditions in these habitats, as well as of temporal forest continuity.