Short-term intensive warming shifts predator communities (Parasitiformes: Mesostigmata) in boreal forest soils

Boreal forests are predicted to have drastically new temperature regimes due to climate change, as temperature increases will coincide with longer and more frequent short-term, extreme warming events (e.g., heat waves). Boreal forest soils contain a hyperdiverse array of microarthropods and nematodes where mesostigmatic mites (Parasitiformes: Mesostigmata) sit atop of the soil food web and connect energy channels (i.e., fungi and bacteria) to one another. Although extensive research exists on the effect of climate change on oribatid mite and collembolan communities, fewer studies have examined Mesostigmata communities. We tested the effect of short-term (three months), intensive warming (+8 °C) on Mesostigmata communities from the boreal forest using experimental mesocosms incubated at 12 °C and 20 °C. We then examined how warming impacted mesostigmatic mite community indices and community-level body mass, along with microarthropod (i.e., oribatid, astigmatid and prostigmatid mites, and collembolans) and nematode abundances. We counted 43,662 individuals of microarthropods and nematodes, of which 3,349 individuals (1,899 adults and 1,450 juveniles) were mesostigmatic mites, consisting of 14 species. Mesostigmatic abundances and community-level body mass increased under warming, which shifted their community composition. Changes to Mesostigmata communities were driven by the greater abundances of parthenogenetic species, particularly Veigaia mitis (Berlese), which has been shown in oribatid mite communities, but not mesostigmatic mite communities, before. Overall, we found that warming shifted predator communities, the mesostigmatic mites, in boreal forest soils, which has wide ranging implications for the soil food web.