Indicator value of oribatid mites in determining past permafrost dynamics in northern European sub‐Arctic peatlands

Abstract

Permafrost dynamics play an important role in the surface hydrology and carbon balance of northern peatlands. Plant macrofossil analysis with radiocarbon dating has been widely used in detecting past permafrost dynamics in peatlands; however, there is a lack of permafrost‐specific plant indicator species, which makes it challenging to determine the exact timing of historical permafrost aggradation. We investigated the indicator value of oribatid mites in determining past permafrost dynamics in sub‐Arctic peatlands. Analyses of subfossil oribatid mite assemblages of Holocene peat profiles from two mires, one in northern Finland and one in northeastern European Russia, were carried out and interpreted using modern calibration data from the same study areas. The results were compared with previously published reconstructions of permafrost history based on plant macrofossil analyses from the same locations. The results suggest that the oribatid mites Carabodes labyrinthicus, Chamobates borealis and Neoribates aurantiacus are promising indicator species to detect past permafrost occurrence in peatlands. In addition, N. aurantiacus is clearly associated with the presence of lichens, which is particularly useful because lichen remains are rarely preserved in peat deposits. Results are in accordance with earlier studies showing that oribatid mites are useful indicators of past environmental change.

Subfossil oribatid mite communities indicate Holocene permafrost dynamics in Canadian mires

“…Carabodes labyrinthicus , previously identified as permafrost indicator species in northern European palsa mires (Markkula et al . 2018), is abundant at 6 cm depth. A similar succession from a community of hygrophilous species to a dominance of C. labyrinthicus and T. velatus after palsa development has been recorded from a mire in northern Finland (Markkula et al .…”

“…A similar succession from a community of hygrophilous species to a dominance of C. labyrinthicus and T. velatus after palsa development has been recorded from a mire in northern Finland (Markkula et al . 2018).…”

“…Results from a previous study on permafrost peatlands in northern Europe (Markkula et al . 2018) had suggested that in order to obtain high enough counts significantly larger volumes of material are needed for subfossil oribatid mite analysis than for plant macrofossil analysis. Samples from McClintock peat plateau core were analyzed at 2–8 cm interval.…”

“…2017; Markkula et al . 2018) and volcanic areas (Klinger et al . 1990) have been used to reconstruct past ecosystems and detect ecosystem change.…”

“…In a recent study, we found that three oribatid species, Carabodes labyrinthicus , Neoribates aurantiacus and Chamobates borealis , are promising bioindicators to detect past permafrost occurrence in northern European peatlands (Markkula et al . 2018). However, no studies have so far been conducted on the indicator potential of oribatid mites in Canadian permafrost mires.…”