Exploring co-occurrence patterns in saproxylic beetle assemblages
Etude des patrons de co-occurence d'espèces dans les assemblages de coléoptères saproxyliques
Résumé
Understanding which mechanisms structure the community assembly has been a challenge for the last past decades. A main difficulty that emerges from the co-occurrence species study is to quantify the contribution of the habitat and the biotic interactions in non-random patterns. The present study consists in analyzing species co-occurrence of saproxylic beetles emerging from pieces of deadwood. We sampled 353 pieces of deadwood belonging to different tree species, decay stages and strata (downed woody debris, aerial woody debris, snags and stumps), ranging from 1cm up to 50 cm in diameter. Pieces come from several types of stands (clearcuts, mature stands…) throughout France. In total, we captured more than 17,000 individuals from nearly 600 species. Co-occurrences were examined for each pair of species. We used null model analysis based on a binary matrix (presence/absence) of the species to test for the significance of observed patterns. In order to separate the effect of biotic interactions and habitat preferences in the non-random patterns of co-occurrence, we compared two models, a ‘no-constrained’ and ‘habitat constrained’. The data analysis is ongoing.