Succession of oribatid fauna (Acari, Oribatida) in fallen spruce trees: Deadwood promotes species and functional diversity

Abstract

The purpose of this study was to contribute to our understanding of oribatid mites inhabiting fallen logs, and to studysuccessional patterns in Oribatida associated with deadwood. This research was carried out in the spruce forest in theBabia G‘ora National Park, Carpathian Mountains. Per season, five samples of decaying wood were taken from fivedowned spruce logs of similar size. Forty soil and litter samples were additionally collected around logs. Overall 55,723specimens of oribatid mites belonging to 131 species were collected in 140 samples. Spruce deadwood is settled by arich mite fauna. It becomes a more rewarding food resource for mites as they tend to increase with log age, althoughthe maximum density was observed in log IV (i.e., the last but one decay class). It was both surprising and interestingto find that oribatid mite fauna in deadwood is not depauperated in comparison with forest soil. For oribatid miteslogs are a separate habitat rather than simply an extension of the forest floor. Some mite species may specialize ondeadwood, because 55 species (of 131 in total) were obligate members of the intra-log community. The structuringforces that influence the oribatid communities in their successional stages of decaying wood were variable anddependent on the stage of wood decay. Against our expectations wood feeders did not prefer deadwood over soilhabitat, whereas eurytopic and parthenogenetic species did not constitute a major part of the oribatid community inpioneer stages of wood decay.