Vol 10, No 2 (2019)

On the basis of the analysis of the published data and materials of our studies on phytoplankton, the distribution of eight alien species of diatom algae in the Kama and Votkinsk reservoirs is considered. It is noted that only Actinocyclus normanii (Greg.) Hust. reaches considerable development. The diameter of the valve of A. normanii varies from 16.5 to 48.5 μm, and the size of the valves of this species decreases from the north to the south. The dynamics of the abundance and biomass of this species is considered during a long-term period (2004–2017); its distribution is studied over the water area of the reservoirs. A change in the size of A. normanii is observed depending on the mineralization and water temperature. It is shown that there is no correlation between the quantitative development of the species in the reservoirs of the Middle Kama and the changes in temperature and water content of a year, content of biogenic elements, water mineralization, proportion of cyanoprokaryota (cyanobacteria), and the total number of phytoplankton.

The invasion of common ragweed (Ambrosia artemisiifolia L.) into the landscapes of the southeastern Belarus has been studied. The locations of A. artemisiifolia populations are mainly confined to roadsides (82.4%). A formation of communities with the domination of A. artemisiifolia was registered at the southern outskirts of Gomel in 2013. Two types of communities have been identified: Ambrosia artemisiifolia–Artemisia vulgaris [Chenopodietea/Artemisietea] and Ambrosia artemisiifolia–Polygonum arenarium [Polygono arenastri-Poetea annuae]. Phytocoenoses containing A. artemisiifolia are observed in ecotopes characterized by a relatively wide range of nitrogen supply and acid-base conditions, but a narrow range of moisture and illumination conditions.

Data on the expansion of the range of an invasive beetle species, harlequin ladybird (Harmonia axyridis Pall.), in Armenia are presented. The species was first recorded in 2016 in the extreme northwest of Armenia; however, in 2018, the species was found in several localities of Central Armenia and in the basin of Lake Sevan and its mass outbreak was recorded in the extreme northeast of Armenia. It is assumed that the species penetrated into Armenia from Georgia as a result of self-colonization (in the northeast of Armenia) or owing to an unintentional introduction along the main roads of Armenia together with fruit and vegetable products.

Thladiantha dubia Bunge is a perennial herbaceous climbing liana from Cucurbitaceae family, which is found naturally in the Russian Far East (mainly in the south of Primorsky krai) and beyond in Northeastern China and on the Korean Peninsula. T. dubia is cultivated for decorative purposes, but owing to the ability to rapidly reproduce by underground tubers, it often turns into a dangerous weed. T. dubia is common in Russia, as well as in Japan, Europe, the United States, and Canada. We have found and studied large invasive populations of T. dubia in several villages of the Republic of Bashkortostan, in an area of 60 km north of the city of Ufa. In this area, it is known exclusively as a dangerous and hard-to-eradicate weed; it appeared here in the 1970s and continues to propagate rapidly by pieces of tubers during mechanical soil treatment. By artificial reproduction of T. dubia plants by small pieces of tubers in laboratory conditions, a very high capability of vegetative reproduction of this plant was revealed. Comparative RAPD and ISSR analyses of samples from the natural population of T. dubia from Primorsky krai of the Russian Federation and its invasive population from the Republic of Bashkortostan showed genetic differences between the analyzed populations, which can be a reflection of the formation of an aggressive form of this plant in the secondary range. From the data we have received and from the literature, it follows that T. dubia species needs to be classified as a weed with a high invasive potential, and therefore, during its cultivation, all necessary measures should be taken to exclude its distribution in natural biocoenoses and agroecosystems.

The data on infestation of muscles of alien fish species with metacercariae of trematode Opisthorchis felineus Rivolta, 1884 in the Middle Ob River basin are presented. It is shown that bleak and bream are susceptible to infestation with the larvae of cat liver fluke Opisthorchis felineus, but the rates of infestation are low even in the hotbed of opisthorchiasis.

Oriental shrimp (Palaemon macrodactylus Rathbun, 1902) was recorded for the first time in the waters of the European part of Russia in the Kerch Strait (Sea of Azov, Chushka Spit coast, Krasnodar krai, Russia) in July 2018. The species natural geographic range is located in the northwestern Pacific Ocean, while the invasion range includes the Atlantic coastal waters of Europe, the Pacific and Atlantic coasts of the United States, and the coast of Argentina. An egg-bearing female was caught, and it had some morphological differences in the armature and relative length of rostrum compared to the specimens collected in the marginal population of the natural distribution range (Peter the Great Bay, Sea of Japan). P. macrodactylus was first discovered in the Black Sea at the Romanian coast in 2002; since that time, its occurrence in the region has increased significantly. The invasion with the ballast waters is the most probable vector, although the dispersal of larvae with the sea currents cannot be excluded. In this case, established but still hidden populations are expected to be discovered in the coastal waters of Turkey and Georgia. P. macrodactylus is an active invader, colonizing transitional waters, where it should be monitored in order to forecast consequences for local species and ecosystems.