The article considers the characteristic plant communities with the description of the dominant forms, plant biomorphology, insect population of steppe and halophytic ecosystems in Orongoy depression. 2 profiles were establish and 54 descriptions of the vegetation cover were made, the distribution of plant communities in the basin depending on the steepness and exposure of the slope, the soil, moisture and salinity was shown. There were 86 species of insects belonging to 7 groups and 45 families. All of them are divided into key sections of the profiles. The most rich and diverse entomofauna of steppe and partly fallow areas - 76 species. The greatest values of biomass reach real grasshoppers (Gampsocleis sedakovii) and real locusts with the dominance of representatives of the genera Chorthippus and Bryodema. It is shown that the species richness of the animal population increases with increasing layering in steppe communities. Studied community referred by us to microecoton local level, which is characterized by the species and ecological diversity, dynamics of animal population. The formation of the steppe microecoton facilitated in spaces of deformations of relief in the form of natural deepening, erosion gullies, bedrock outcrops, bushes (all types of Caragana sp., Spiraea sp.) and trees (Úlmus sp., Hippóphae sp.) and water basins.

Yelayev Erdeni Nicolaevich, Doctor of Sciences (Biology), Professor, Buryat State University, 24а, Smolin str., Ulan-Ude, 670000, Russian Federation, tel.: (3012) 21–03–48, e-mail: elaev967@yandex.ru 

Pyzhikova Evgenia Mihailovna, Candidate of Sciences (Biology), Associate Professor, Buryat State University, 24а, Smolin str., Ulan-Ude, 670000, Russian Federation, tel.: (3012) 21–03–48, e-mail: gp777@yandex.ru 

Rudykh Sergey Gennadyevich, Candidate of Sciences (Biology), Research Scientist, Institute of General and Experimental Biology SB RAS, 6, Sakhyanova St., Ulan-Ude, 670037, Russian Federation, tel.: (3012) 43–32–47, E-mail: rudykh@list.ru 

Tsyrenova Marina Garmazhapovna, Candidate of Sciences (Biology), Senior Lecturer, Buryat State University, 24а, Smolin str., Ulan-Ude, 670000, Russian Federation, tel.: (3012) 21–03–48, e-mail: tsyrenova2000@mail.ru 

Byantuev Erdem Batorovich, Student, Buryat State University, 24а, Smolin str., Ulan-Ude, 670000, Russian Federation, tel.: (3012) 21–03–48, e-mail: erdem96bb@gmail.com

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