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The goal of this work was to study the resistance of three amphipod species to the influence of humus substances solutions. European species G.tigrinus and C.ischnus, from Lake Mugulsee (Germay), and also species E.cyaneus, from Lake Baikal, (Russia) were used in the experiments. Amphipods were exposed to solutions of humic substance, whereupon the level of peroxidase activity was measured; for E.cyaneus, the level of lipid peroxidation was estimated. The experiments showed that the exposure of amphipods to solutions of humus substances caused death of European species, and increased the peroxidase activity level in all the species. Lipid peroxidation level increased also in E.cyaneus. This means an increase of production of reactive oxygen forms. The highest resistance to the influence of humus substances was shown by the Baikalian endemic E.cyaneus. A hypothesis of evolutionary causes of the high resistance of the Baikalian species is put forward.

For two annual periods

Infection of preimaginal stages of the taiga tick Ixodes persulcatus and background species of small mammals by the agents of ixodoid tick-born borrelioses in the south of West Siberia was studied. Seasonal changes of infection of reservoir hosts and ticks parasiting on them by spirochete of the Borrelia burgdorferi sensu lato complex are discussed.

On the basis of a series of observations of the time course of numbers of conifer-gnawing insects and cyclic changes of solar activity (1920

On the basis of long-term studies of the economically important problem associated with periodically repeating bursts of mass reproduction of webworm, ecological peculiarities of this species that make it possible for it to develop successfully at the limit of conditions meeting its ecological standard are considered. A new approach to control of this pest is proposed. The first positive results of insecticide treatment against its imaginal stage have been obtained.

Based on censuses carried out with the help of 50-m long grooves and fences with five trapping cylinders, the non-uniformity of amphibian community of all landscape zones of West Siberia was analyzed, latitudinal variations of population density and of species abundance on the whole and by the zones, subzones and landscape groups are described, and the spatial-typological structure of communities is elucidated.

A regional system of protection and rational management of bird communities of the northern taiga of West Siberia is developed which has the priority task of conservation of water fowl, circumaquatic birds and birds of prey, especially those of rare and disappearing species, maintenance and recovery of the numbers of commercial hunting birds, conservation of biological diversity of ornithocomplexes in especially protected natural territories. Taking into account the biosphere damage caused to the bird population by the influence of the oil and gas complex, it is necessary to double the area of the especially protected territory with heightening of its protection grade. The bird cadastre and monitoring system of Hypoarctic birds must serve as the scientific and practical basis for implementation of protection and rational management of bird communities.

A multidimensional factor analysis of bird censuses in 31 habitats of the Middle Urals (from Primary fir-spruce forests to urban residential areas) was carried out. By the results of studies, graphs of spatial typological structure of bird population for the 1st and the 2nd half of summer and winter were drawn, and a multiple estimation of the force of constraint between the ornithocomplexes and the environmental factors was carried out. A comparison of the graphs demonstrated that in all the seasons the spatial non-uniformity of bird population was due to changes of the environment with respect to forestation, building, increase of influence of the surrounding landscape concomitant with simplification of architectonics, to decrease of food resources of the habitats and increase of man-caused activities on the whole. In summer, a considerable role is played by water content, heightening of temperature in water body, and in the first half also by the increase of industrial influence. The spatial organization of ornithocomplexes in the 1st half of summer is accounted for at 90 % by 27 natural

Winter feeding of northern pika of the Aldan highland within the stony biotopes situated in various taiga phytocenoses typical for this species was studied. In 1998 and 2000

Natural halogenated macrolides, tetracyclines and quinones comprise three small groups of natural antibiotics which were isolated from microorganisms, plants, fungi and marine organisms. The structures of about 86 compounds are considered and the data on their biological activity are described.