No abstract

Viviparus viviparus L. is the most numerous alien species of the Novosibirsk reservoir. In some parts of the reservoir V. viviparus creates settlements with a very high density. After the death of mollusks in the bottom sediments and on the banks of the reservoir, large areas of accumulation of empty shells are formed. Due to their strong structure, the shells are poorly decomposed and can serve as a generalized indicator of the state of the mollusk population over a long time. We analyzed the size and age characteristics of the V. viviparus shells in thanatocenoses of the Novosibirsk reservoir coast. Empty shells of river snails were collected on the shores of the middle (near the village of Chingis, Ordynskoye and in the Karakansky Bay) and the lower (near the village of Borovoye, Bystrovka, Leninsky and in the Berdsky Bay) parts of the Novosibirsk Reservoir in May, 24–26, 2018. Shells height and width were measured with an electronic caliper with an accuracy of 0.1 mm. Age of mollusks was determined by the marks of a winter growth stop on the shell. It is shown that in the thanatocenoses of the middle part and in the bays of the reservoir, shells of young mollusks (the second and third years of life) prevailed. In the lower part of the reservoir, the coastal thanatocoenosis contained larger shells of adult mollusks (fourth and fifth years of life). In general, the most of V. viviparus individuals in the Novosibirsk reservoir die before they reach the age limit. It is suggested that the premature death of most river snails can be caused by significant seasonal fluctuations in the water level of the reservoir, during which the littoral is drained.

Анализ стабильных изотопов углерода и азота широко используется в экологических исследованиях для изучения структуры трофических сетей, оценки роли различных ресурсов в питании отдельных особей, определении трофического уровня консументов. Раковина у моллюсков постепенно формируется в течение всей жизни и отражает особенности питания особей в разном возрасте. Проведены исследования стабильных изотопов углерода и азота раковин чужеродных моллюсков Viviparus viviparus (Linnaeus, 1758), собранных в Новосибирском водохранилище. Отмечены статистически значимые различия изотопного состава фрагментов раковин, соответствующих годичному приросту разных лет. Высказано предположение о значимой роли межгодовых различий трофических условий в водохранилище в формировании изотопной подписи раковин моллюсков. Результаты работы могут быть использованы в экологических и палеолимнологических исследованиях питания моллюсков, при реконструкции долговременных изменений экологических условий водоемов.

The role of natural self-purification processes aimed at restoring water original properties and composition increases in conditions of high anthropogenic pressure on freshwater ecosystems. A significant contribution to these processes is made by filter-feeding hydrobionts, which can deposit suspended particles from water column. A main part of the research in this area is devoted to filter-feeding mollusks – bivalves and gastropods, but gastropods are less studied. The data obtained during the experimental study of the filtration activity effect of the river Viviparus viviparus (L.) on the change in the optical density of the suspension of the unicellular algae Chlorella sp. are presented in this pa-per. The results showed that the average value of optical density of Сhlorella suspension in the presence of the mol-lusk decreased by 2 times, from (0.151 ± 0.0090) to (0.068 ± 0.0400) B. Various changes in optical density in each of the experimental glasses are associated primarily with the unequal physiological state of the mollusks. It was sug-gested that numerous populations formed as a result of V. viviparus invasion into the Novosibirsk Reservoir are able to change water quality, potentially affecting the functioning of the reservoir ecosystem.

Successful experiments on olfactory enrichment of clove oil in Russian zoos have been carried out. Olfactory enrichment with clove oil reduced or eliminated stereotypical behavior (pacing) in most Amur tigers, African lions, and some Canadian and Red wolves. The behavior of the Far Eastern leopard and the Snow leopard behavior has not changed significantly under the influence of clove essential oil. Olfactory enrichment of clove essential oil is more successful for young animals.