[Shell Variability of the Terrestrial Mollusk Chondrula tridens (Pulmonata, Enidae) in the Forest-Steppe Zone of the Volga Upland].

Shell variability of the steppe mollusk Chondrula tridens from 18 micropopulations in the forest-steppe zone of the Volga Upland was studied. It was found that larger specimens of Ch. tridens with well-developed teeth inhabit the central and eastern parts of the territory. Specimens in the northwestern part of the upland are characterized by small shells, the highest degree of roundness, and mostly reduced teeth in the mouth. The main factors that determine variability in the size and proportions of shells are the average daily temperatures increasing from the northwest to the south, the reduction in the total precipitation, the decrease in the soil moisture content, and, possibly, the increased content of carbonates in the soil.

[Impact of chemical weapon destruction on the structure of lake zoohydrobiont community].

Community structure of zoohydrobionts in the lake affected by chemical weapon destruction was studied for the first time. Low pH favored species specific to acidic water bodies as well as bidominant zooplankton community. The long-term effects of chemical pollution determined the stage of community succession, namely, the absence of the key predator (fishes), abundance of detritus consumers in the zoobenthic community (dipteran larvae), diversity of amphibiotic insects, and low species diversity in the zooplankton community with the prevalence of cladocerans and rotifers. Unbalanced composition of higher trophic levels results in an unstable functioning of the lake and accumulation of significant amounts of detritus, which is utilized by the abundant microzoobenthic component of the ecosystem.