Préférences écologiques des coléoptères saproxyliques emblématiques de Suisse

Abstract

Ecological preferences of Switzerland's emblematic saproxylic beetles Swiss forests are home to nearly 1500 species of saproxylic Coleoptera. 414 of these are considered emblematic of specific microhabitats and may be used to evaluate the biological quality of different types of forests and wooded areas in Switzerland. This article provides a summary of the ecological requirements of these beetles based on information gathered from entomological collections and the literature. 77% of emblematic saproxylic beetles live at low altitude and 64% depend on warmth and high insolation. Oak (Quercus spp.), beech (Fagus sylvatica) and pine (particularly Pinus sylvestris) are the trees most often exploited by these beetles. 46% of saproxylic Coleoptera depend on decaying wood and 12% on heavily decomposed wood. 12% develop only in cavities in wood and 13% only in wood-decomposing fungi. We propose measures to promote saproxylic Coleoptera, namely by increasing the total amount of dead wood available (namely tree trunks and large branches) throughout Switzerland to at least 20m3/ha in the Jura, on the Plateau and the southern foothills of the Alps and 25 m3/ha in the Alps and Prealps. We also recommend the conservation of old trees that provide unique treemicrohabitats for saproxylic beetles.