Invasive Reynoutria taxa as a contaminant of soil. Does it reduce abundance and diversity of microarthropods and damage soil habitat?

Little is known about the impact of exotic invasive plant species on soil invertebrate communities. The influence of highly productive invader Reynoutria sachalinensis on the soil microarthropods was studied. Three sites, with different coverage of the invader, have been selected in the mixed forest in the Jura Krakowsko-Częstochowska. The lowest abundance of microarthropods and the lowest oribatid species richness were noted in the monospecific Reynoutria infestation stand. The reduction of abundance of saprophagous mites (Oribatida, Acaridida) and springtails were observed at the totally invaded site, whereas gamasid and actinedid mites reacted positively to the presence of Reynoutria. Observed abundances and species richness of microarthropods at studied sites were in accordance with theories on biodiversity. Antifungal activity of phenolic compounds present in leaves of R. sachalinensis may negatively influence on saprophagous representatives of microarthropods. On the other hand, predacious mites profited from the simplified vegetation structure.