Dynamic normals of temperature, wind speed, relative humidity, and cloud cover have been computed employ- ing a multiyear trend cubic model on the basis of observation data collected at the Minsk Meteorological Station for the period of 1985–2019. The results for most seasons differ substantially from the forecast obtained previously on the basis of data for 1985–2015 and the quadratic trend model. The conclusion is drawn about the inadequacy of the trend model used in earlier calculations. The possibilities and methods of constructing a satisfactory trend model, role of statistical significance estimation in model  selection, and prognostic capabilities of the dynamic climate normal are discussed.

The recurrence of soil droughts on the territory of the Belarusian Polesia was estimated with the involvement  of all areas where soil moisture was determined according to the data of the points of the state network of hydrometeorological observations. An assessment of the duration and the recurrence of years with severe soil droughts under the conditions of modern  climate change (1989–2018) is given. Comparative data on the frequency of occurrence of soil for the modern period of warming  and before the warming are presented. The cyclical nature of changes in the number of severe soil droughts on the territory of the  Belarusian Polesiа e with a period of 9–12 years was noted.

The study presents an assessment of the moistening regime over territory of Belarus in warm season and as resulting parameter – surface streamflow during low-flow season. The tendencies of monthly precipitation, maximal daily totals and duration of rainfall were detected; streamflow characteristics, such as the lowest discharges for the low-flow season and highest discharges of rain floods were estimated. The Standard Precipitation Index and Standard Streamflow Index were calculated  to estimate the drying conditions over territory of Belarus. Despite the insignificant change of the annual precipitation during the  period of 1989–2018, the intensification of rain falling has increased over territory of Belarus but at the same time the number  of meteorological droughts growth in May-September. The streamflow rate didn’t change significant but the highest rain floods  discharges and/or the lowest discharges during low-flow season has growth (except the Neman River basin) while hydrological  droughts repeatability also has increased in all river basins of the study region.

The article provides a brief geochemical characteristic of the ultrabasic-basic rocks of the argelovschinsky complex  of the crystalline basement of the central part of Belarus, the conditions of their formation are determined. Rocks of the complex are characterized by normal alkalinity, high magnesium content, low alumina content and total iron content. The microelement composition of the rocks is characterized by enrichment in Cr, Ni and Co. Their characteristic feature is negative Zr-Hf  and Ta-Nb anomalies, which suggests crustal contamination. The formation conditions of the rocks are similar to the geodynamic  settings of the formation of tholeiitic basalts of island arcs.

The paper presents the results of a palaeoichthyological study of core samples from the Bykhov 1 and Korma 1 boreholes drilled in eastern Belarus. Based on the ichthyofaunal, lithological and geophysical data, a detailed stratigraphic division of the Upper Emsian-Eifelian deposits exposed in the studied boreholes has been performed. Their detailed description is provided. Vertebrate evidences were used to compare these deposits with the similar age formations developed within the adjacent territories of Ukraine, Russia and the Baltic States. The ichthyofauna data were used to clarify the stratigraphic distribution of some taxa in the Upper Emsian-Eifelian deposits of Belarus, to supplement their systematic composition within the studied territory, and also to complement the palaeontological characteristics of the regional stratigraphic units of the actual Stratigraphic Chart of the Devonian Deposits of Belarus (2010). The presented results should be taken into account in the future when performing large-scale geological surveys within the studied area.

As a result of the revision of the MSK-L collection, lichens of 11 localities of maritime and continental Antarctic, diverse in species composition, were revealed. The collection includes three ecological groups of lichens. The material for this article was the lichen samples stored in the MSK-L collection in the amount of about 600 herbarium packages collected during 1 CAE, 5 SAE, 63 Russian Antarctic expeditions and 2, 3, 4, 6, 11, 12 Belarusian Antarctic expeditions. 82 species of lichens from 54 genera were identified. Most of the identified species were found in maritime Antarctic. 16 species of lichens were common to maritime and continental Antarctic. Most of the species are classified as bipolar lichens. Thin layer chromatography of genus Lepraria lichens was carried out. It has been shown that usnic acid and zeorin are present only in the Antarctic endemic L. straminea.

The taxonomic diversity, spatial distribution of zooplankton and zoobenthos in Barkovschina lake with clear division of water column by temperature and complete absence of oxygen in hypolimnion and presence of hydrogen sulfide toxic for aquatic fauna here was studied. The diversity and quantitative characteristics of both communities are maximal at shallow depths, where favourable conditions for life activity are created, and decrease sharply with increasing depth, and reach their minimum in the oxygen-free and hydrogen sulphide-free zone. The spatial structure is formed depending on oxygen concentration and presence of hydrogen sulfide. Lack of oxygen and presence of hydrogen sulfide significantly impoverish aquatic fauna, which is more clearly manifested in benthic animals.

In Belarus 16 species of phytophagous insects (Insecta: Rhynchota, Coleoptera, Lepidoptera, Diptera) damage dogwoods (Cornus s.l.) in green areas: Anoecia corni (F.), Aphis salicariae Koch, Lepidosaphes ulmi (L.), Parthenolecanium corni (Bouche), Pulvinaria vitis (L.), Stictocephala bisonia Kopp & Yonke, Phyllopertha horticola (L.), Phyllobius pyri (L.), Otiorhynchus smreczynskii Cmoluch, Coleophora anatipenella (Hübn.), Coleophora ahenella Heinemann, Antispila metallella (Den. & Schiff.), Acleris umbrana (Hübn.), Pandemis corylana (F.), Phytomyza agromyzina Mg. and Craneiobia corni (Giraud). Among them, at least the buffalo treehopper (S. bisonia) and a weevil O. smreczynskii Cmoluch are alien species in the fauna of Belarus. Most of phytophagous insects are open-living, polyphagous pests, belonging to the all-season phenological group, which skeletonize and perforate leaf blades. Coccids are xylem-sucking insects inhabiting bark of shoots and branches. S. bisonia damages both shoots and leaf blades. Larvae of case-bearing moths (Coleophoridae) live in the cases they made, larvae of leaf-miner fly P h .  a g  - romyzina create leaf mines, larvae of gall midges C. corni initiates the formation of leaf galls. The list of the most common and pestful phytophagous insects damaging dogwoods in green areas in Belarus includes 8 species: 3 species of Rhynchota, 2 species of Coleoptera, 2 species of Lepidoptera, and 1 species of Diptera.

even populations of noble crayfish Astacus astacus recorded during the survey of thirty-eight water bodies (33 lakes, 5 rivers) of Braslav territory. All the populations, except one in the lake Belyani, are in the poor state. The population of noble crayfish in the river Usveyka was recorded in 2013, but since 2017, no crayfish recorded in the river. The distribution of noble crayfish on Braslav region territory is highly fragmented. Narrow-clawed crayfish Pontastacus leptodactylus is recorded in the small number of lakes (8), three of which can be considered as promising commercial lakes – Rozhevo, Raukety, Bolta. Noble crayfish recorded in 18 % surveyed water bodies, narrow-clawed crayfish in 21 %. No crayfish recorded in 61 % of studied water bodies. The water bodies of Braslav region are promising places for the preservation of noble crayfish. The strategy for the preservation of noble crayfish in this region should be constant creation of new populations.

The article presents the results of experiments on growing seedlings of European spruce (Picea abies) in open ground, with their complex treatment with triterpene growth regulators Ecosil Mix and Ecosil Plus, which are obtained from Siberian fir (Abies sibirica) extract. To assess the effect of treatments on the growth of spruce, the length of the root and aerial part, the diameter of the root collar of the seedlings, as well as the mass of organic matter of plants (separately for needles, stems and roots) were measured. In order to determine the effect of drugs on plant cells, such biochemical parameters as the amount of lipid peroxidation products and the integrity of cell membranes, as well as the amount and ratio of photosynthetic pigments were determined. As a result, the most effective was the pre-sowing incrustation of seeds with the growth regulator Ecosil Mix and the fungicide Vincit Forte, which was proved not only by the enhancement of the growth of seedlings, but also by the normalization of physiological and biochemical processes in plant cells.

 As a result of a review of the works of the author and other researchers of the algal flora of various habitats (mainly aquatic) in Belarus, a general characteristic of the combined group “algae”, its structure, species and taxonomic representation of its divisions, the degree of dominance and prevalence of species and intraspecific taxa are given. About 3000 species, varieties and forms (more than 370 genera) have been identified in Belarus. On average, for all types of habitats (the originality of some of them is also noted), the most represented by the number of species are green algae, mainly chlorococcal, in second place, as a rule, are diatoms (and in the number of taxa, diatoms are in the first place, and green algae are second). The range of occur - rence of species is indicated. The review focuses on identifying new for science, rare, invasive, red books’ and other species that attract attention in the flora of the republic. Some of them are illustrated with light and electronic microscope photographs.

Green lacewing species, Ch. gibeauxi, was relatively recently restored as an independent species from the com- plex Ch. pallens (Rambur, 1838) sensu lato and is first indicated for the fauna of Belarus in this notes. The material was collected near Uza village of the Gomel district (June 2017) and the center of the city of Gomel (July 2019). Brief information on the species identification, distribution and ecology of this species is given.