Litter quality indirectly influences community composition, reproductive mode and trophic structure of oribatid mite communities: a microcosm experiment.

Abstract

Our knowledge of the assembly processes of species-rich oribatid mite communities is fairly limited. Also, very little information is available on the effects of habitat factors on these processes. In this paper, the role of litter quality in pattern formation was investigated in a microcosm experiment using the "home-field advantage" approach. Native (home) and foreign (away) types of microarthropod assemblages were extracted from three types of litter samples (Turkey oak, Scots pine and black locust tree), and transferred alive into 'home' and 'away' samples, which have been defaunated and reinoculated with microorganisms to form microcosms. Microarthropods were extracted from the microcosms after incubation for 3-12 months. In addition to species identification and abundance records, some chemical properties of the litter were measured. We hypothesized that oribatid mite communities deteriorate, the proportion of parthenogenetic individuals decreases and the proportion of omnivorous individuals increases in 'away' microcosms in contrast to 'home' systems. Pine and oak litter were favourable for all the three types of oribatid communities since their community traits in these types of litter were found to be similar to 'home' litter. Black locust litter was favourable only for its native oribatid community in the long run. The proportion of parthenogenetic individuals partly supported our hypothesis, mainly in black locust litter. The relative abundance of omnivorous individuals did not differ significantly between treatments. Litter quality is likely to influence oribatid mite assemblages only indirectly.