Succession of beetles (genus Cis) and oribatid mites (genus Carabodes) in dead sporocarps of the red-banded polypore fungus Fomitopsis pinicola

Abstract

Dead sporocarps contribute to forest biodiversity by supporting a specialised decomposer fauna. However, detailed succession studies are few and microarthropods are rarely included. In a spruce-dominated forest reserve near Oslo in southern Norway, sporocarps of Fomitopsis pinicola with known age since death (0–5 years) were sampled and invertebrates extracted by Tullgren funnel. While living sporocarps of this species were rarely attacked by tunnelling invertebrates, dead sporocarps were rapidly colonised by a diverse fauna. The youngest pore layers were consumed first, and after five years, the remaining parts were strongly fragmented. Among 16 beetle species, Cis glabratus and Cis quadridens dominated. Another abundant group in dead sporocarps was oribatid mites belonging to the genus Carabodes, with a total of 10 species. Seven of these colonised during less than one year. While there were few significant changes in the density of adult Cis specimens during decomposition, and C. glabratus dominated all years, the Carabodes community underwent considerable changes. Carabodes femoralis dominated during the three first years, after which Carabodes areolatus and Carabodes reticulatus took over the dominance. These three Carabodes species are rare in Norwegian coniferous forest soil. Dead sporocarps of various polypore fungi may represent important microhabitats for sustaining the diversity of Carabodes mites in Fennoscandian coniferous forests.