The research was carried out on species diversity, density and similarity of Gastrotricha living on two species of macrophytes Myriophyllum spicatum L. and Elodea canadensis Michx. in a mesotrophic lake. Gastrotricha occurring on the studied macrophytes were represented by 23 species (21 on M. spicatum L. and 22 on E. canadensis Michx.). Species diversity (expressed by the Shannon index) for the Gastrotricha occurring on the two studied species of macrophytes amounted to 2.70 for M. spicatum L. and 2.81 for E. canadensis Michx., what suggests equal distribution of the gastrotrich species revealed in the studied species of macrophytes. The definite dominants inhabiting the two species of macrophytes were: Heterolepidoderma macrops Kisielewski, 1981, Heterolepidoderma ocellatum (Mečnikow, 1865), Lepidoderma squamata (Dujardin, 1841) and Aspidiophorus squamulosus Roszczak, 1936, and their inclusive percentage participation in the whole gastrotrich fauna for M. spicatum L. and E. canadensis Michx. was 41.8 and 40.3% respectively. The domination structure of the gastrotrich fauna of the two species of macrophytes was similar for each gastrotrich species (G-test, for all p > 0.05). Average density of Gastrotricha inhabiting M. spicatum L. amounted to 588.0 10³ indiv. m-2, and density of Gastrotricha occurring on E. canadensis Michx. amounted to 670.0 10³ indiv. m-2. Statistic analysis based on the Mann-Whitney test showed that differences of the gastrotrich densi-ty on the studied species of macrophytes: M. spicatum L. and E. canadensis Michx. (Z = -1.9282; p = 0.05) are statistically insignificant.

The recapitulation of the investigations on oribatid mite fauna carried out at various kinds of abandoned galena-calamine wastelands in the south of Poland is presented. Soil samples were collected at nine sites in three regions of zinc-lead mining. In total, 24267 oribatid individuals belonging to 160 species were analyzed. The sites differing in the period of ceasing exploitation, species composition of plants and their stage of succession were chosen. The abundance and species richness of oribatid mites were generally higher on afforested sites and sites of older origin. The abundance of oribatids noted on wastelands was generally lower than in most natural or semi-natural biotopes. Surprisingly, the species richness on afforested wastelands was higher than in many natural forest biotopes. With regard to species similarity, the oribatid communities have been grouped due to localities instead of been organized due to the type of wastelands or vegetation. Correspondence analysis (CA) indicated that certain species of Oribatida preferentially occurred in a certain type of wastelands. Species characteristic of afforested new and old or unforested wastelands were distinguished. The biodiversity of oribatid fauna on galena-calamine wastelands was high with many new species for the Polish fauna ( 15). Some of them were recorded only from a few localities in the world.

Nematoda, Tardigrada, Rotifera and Crustacea composition in different freshwater habitats on Spitsbergen (Arctic) and King George Island (Antarctic) was presented. In all surveyed groups more genera and species were recorded from Spitsbergen than from King George Island. Habitats richest in taxa were moss banks and thaw ponds, whereas streams were poorest in species. In all groups in both regions cosmopolitan species dominated, but higher number of endemic species was recorded on King George Island. Regarding species composition in surveyed groups it can be suggested that freshwater habitats on Spitsbergen are more similar to each other than those on King George Island.

To improve plant resistance to pests, we analysed the impact of various agronomic practices on the number and species diversity of pests in the crops of spring wheat varieties of foreign and Kazakhstan breeding in North- Eastern Kazakhstan.
The intensive development of agriculture, resulting in the new technological flow processes of wheat growing, the sowing of foreign varieties not previously cultivated under local conditions, and climate change contribute to the formation of new food chains in agrocenoses. These new food chains require the monitoring of plant-feeding species with the help of ecological approaches and techniques.
Efficient protection of crops with plant feeders requires constant updating on the phytosanitary in agrocenoses. Information on phytosanitary monitoring previously carried out in the region is not available, so it became necessary to collect data and analyse the number and species composition of wheat pests, considering new foreign varieties and cultivation technology practices.
The research was carried out in 2021 in typical agricultural organisations of the North-Eastern regions of Kazakhstan with different preceding crops. The vegetation period was characterised by high atmospheric temperatures and a lack of moisture in the soil in spring and summer, contributing to decreasing of plant turgor and damage resistance.
Early sowing of the ‘Triso’ wheat variety was affected by high temperatures and lack of soil moisture in the initial stage of development, which delayed its growth and made it more susceptible to pest damage. The other varieties were sown in optimal dates recommended by regional scientific institutions.