Communities of Soil Microarthropods (Acari, Collembola) at Ash Dumps of a Combined Heat and Power Plant at Different Degrees of Conservation

The features of the composition and structure of soil microarthropod communities that are formed at ash dumps of a combined heat and power plant (CHPP) at the initial stages of their self-restoration at different degrees of conservation are studied. The research was carried out in 2017 in Novosibirsk (55°00′ N, 83°04′ E) at the ash dump of CHPP no. 5 consisting of two sections: the nonreclaimed section (S1) and the section reclaimed by covering ash and slag with potentially fertile soil (S2). A plot in a birch forest adjacent to the ash dump was used as a control. The material was collected in ash-dump zones differing in degrees of moisture (three plots in both S1 and S2) and in the control (in total, seven plots). Microarthropod communities included mites (Mesostigmata, Oribatida, and Prostigmata) and springtails (Collembola). The microarthropod abundance was significantly lower at both sections of the ash dump than in the control, while no significant differences were found between the ash-dump sections. The effect of reclamation was revealed only for mites. Among them, representatives of Oribatida proved to be most sensitive. There were no significant differences in the proportion of different groups of the community at S1. In turn, Oribatida were dominant at S2 and in the control. Based on the example of Oribatida and Mesostigmata model groups, it is shown that mite communities formed at the ash dump were species-poor and consisted of widespread species with a high degree of dominance of some of them. Oribatida can serve as a good bioindicator for assessing the soil state during restoration successions at ash dumps of CHP plants.