Réponse des Coléoptères saproxyliques à l’hétérogénéité des subéraies dans le massif des Maures (France)

Abstract

Saproxylic beetles’ response to cork-oak forests heterogeneity in the Massif des Maures (France). — Cork-oak stands are a major component of the “Massif des Maures” forests (France, Var). Depending on fire frequency, soil conditions and human uses, these forests present different forms. Even if Mediterranean landscapes have been shaped for a long time by fire, such recurrent perturbation may affect several functional groups of organisms associated with old forests, such as saproxylics insects. Our aims were (i) to investigate species richness and composition of saproxylic beetle assemblages in different cork-oak stands, (ii) to estimate between stand complementarity and (iii) identify indicator species of each habitat. Three different types of cork-oak stands common in the “Massif des Maures”, representing an increasing gradient of canopy closing and ecosystem maturing, were investigated : a senescent stand associated with mature maquis, an adult stand with high maquis and an open adult stand with low maquis. Beetles were sampled from April to August in 2003 and 2004 using baited window traps. Our results showed that : (i) the three studied cork-oak stands can be considered as three different habitats regarding saproxylic beetle assemblages, (ii) the closed cork-oak stands support the highest cumulative species richness, (iii) abundances of ecological groups show significant betweenstands differences, (iv) each habitat supports remarkable species from a patrimonial point of view.