How many species of centipedes coexist in temperate forests? Estimating local species richness of Chilopoda in soil coenoses of the South-Eastern Prealps

Centipedes (Chilopoda) are widespread and abundant predators in temperate forest soils, but reliable estimates of the actual number of species living in syntopy and interacting with each other are virtually nil. We estimated the local species richness of 10 centipede communities in the South-Eastern Prealps by sampling within small (ca. 1800 m2) and uniform forest sites, employing complementary methods (pitfall traps and hand extraction of centipedes from standard volumes of soil) throughout two consecutive years and applying non-parametric statistical methods (Chao-1 and Abundance-based Coverage Estimator) to account for incomplete species detection. We recorded a maximum of 26 syntopic species of centipedes and estimated that up to 27–28 species may coexist in a single site. By comparing the communities investigated, we found that species richness is not strictly associated with species composition, it does not strongly correlate with average density of centipedes, and communities with the same species richness may differ significantly in functional richness. Additionally, our results suggest that temperate forests of the South-Eastern Prealps, along with those in the Northern Dinarides, harbour the richest known communities of centipedes in the world.