Нижнее Поволжье

During four field seasons (2013–2016.) conducted a study of the structure of morphological variability and vitality. 38 populations of Tulipa gesneriana in several areas of the Lower Volga region and adjacent territories. The significant variability in the vitality structure of the populations as on the interpopulation level, and year. It is revealed that years of observation in General, most populations of the species were quite pronounced tendency for a gradual reduction of vitality. from 2013 to 2015 and significantly improve the plants in them in 2016.

Key to the subfamilies of chironomids (Chironominae) based on the morphology of the male genitalia includes 16 genus and 45 species found in the Volga river floodplain lakes (Saratov region). For the six species of the four genera of the tribe Chironomini (Einfeldia sp.1, Chironomus sp. (Lobochironomus), Dicrotendipes sp.1, Dicrotendipes sp.2, Parachironomus sp., Polypedilum sp.) described morphological differences from the known and the most directly comparable species. 

The estimation size of individual plots the American mink on the res- ervoirs in Saratov region in the period from 2000 to 2014. The average plot size of males – 30.6 hectares, females – 27.8 hectares. During the cold period on most waters plot sizes are increased almost two- fold. Found that females go farther from the center of the rivers and streams than males (females – 203.8 m; males – 166.7 m). American mink is more inclined to the rivers with wide floodplain (χ2 = 26.2; p = 0.01). River with a narrow floodplain populated predator with lower density (χ2 = 15.3; p = 0.04).