Vol 8, No 3 (2017)

The absence of capacity for sexual reproduction does not hinder the rapid expansion of the invasive range of the alien species Veronica filiformis J.E. Smith (Plantaginaceae). Lawn mowing or raking causes the fragmentation of shoots and accelerates vegetative reproduction of V. filiformis. The clone diameter of this species was shown to increase up to 25 times during the growing season, whereas the number of internodes increased by a factor of 1000–2000. Slender speedwell expanded from the site of initial introduction (Moscow, Russia) at the speed of 4 km/year in the northern direction and at a speed of 10 km/year in the southern direction. Illumination of the site had a more pronounced effect on the regenerative capacity of the species than the age of root-forming shoots. Invasion of meadow and forest fringe communities by this species was registered in recent decades. The high speed of expansion of the secondary distribution range, the displacement of native species, and the direct damage to lawns caused by this plant allow for the assignment of an invasive species status to V. filiformis and justify the control over the dispersal of this species.

We analyzed samples of land mollusks of the genus Xeropicta collected on the Northern Black Sea Coast and others regions of Ukraine between 1990 and 2015. The findings indicate that the range of X. derbentina and X. krynickii has expanded as a result of human activities. Now the distribution of X. krynickii on the Northern Black Sea Coast is mainly limited to coastal territories. X. derbentina spreads much deeper into the mainland. Isolated colonies of this species were even recorded in the forest-steppe zone of Ukraine and in Zakarpattia oblast.

The paper contains information about findings of four new species of gastropods previously unreported in the Barents Sea and adjacent waters. Information on the place of the find, depth, date, pictures, and a brief description of the gastropods are given. Possible causes of the appearance of this species in the Barents Sea are analyzed.

Harpacticoid Mesochra rostrata Gurney, 1927 was found in Sivash Bay (Sea of Azov) for the first time in 2013. In 2015, it became the most common and abundant species of Harpacticoida in the bay. The morphological characteristics of males and females of M. rostrata found in the Sivash accord with the species description given in earlier publications. The bay population comprised adult males and females, naupliar and copepodite stages. Adult male size varied from 0.30 to 0.40 mm, and adult female size varied from 0.38 to 0.45 mm. Since 2014, a substantial increase in salinity has been observed in Sivash Bay. In August 2015, seven species of Harpacticoida were registered in the bay in total; M. rostrata dominated and was abundant in benthos (up to 56000 ind./m²), in the floating mats of filamentous green algae (up to 336 400 ind./m²), and in plankton (up to 580 ind./m³) at water salinity of 60–75 g/L. Earlier, this species was registered in the Sinai Peninsula at the water salinity not exceeding 45 g/L. M. rostrata can be considered a new invader in the Azov-Black Sea Region; the resting stage of this crustacean was brought here by wind or birds. However, it can be assumed also that the species is an aboriginal one for the Azov-Black Sea Region from times of the Tethys Ocean. In the Black and Mediterranean seas, there are some relicts of Tethys. In normal conditions, this species is rare and, possibly, can succeed only in destabilized biotopes, such as Sivash Bay nowadays during the period of a sharp increase in the water salinity.

The successful invasion of the Baikalian amphipod Gmelinoides fasciatus in the littoral zone of Lake Onega changed significantly the structure of the food resources of fish. High abundance and biomass of these amphipods in macrozoobenthos are the reasons why one of the mass species of littoral fish, perch Perca fluviatilis, turned to active feeding on these crustaceans. In some lake shallow water habitats, the share of this amphipod in the weight of stomach content and occurrence frequency are not less than 50%. Active spread of the amphipod and the dynamics of population indices of this invasive species in Lake Onega indicate the necessity for further studies on the role that G. fasciatus plays in the diet of littoral fish species in the seasonal aspect.

The distribution of Heracleum sosnowskyi in Bryansk oblast is assessed. Characteristic features of flowering and seed-based reproduction are considered, and a list of insects found on hogweed inflorescences is given. The mechanism of hogweed invasion into natural communities is addressed. Penetration into natural communities is related to anthropochorous dispersal and damage to the vegetative cover. High seed productivity, the formation of a large seed pool, the presence of dormant plants, and rapid development during the spring period enable the rapid dispersal of Heracleum sosnowskyi in the secondary range. Communities of the association Urtico dioicae–Heracleetum sosnowskyi Panasenko et al., 2014 are common in the region. Tree communities that include Heracleum sosnowskyi (Heracleum sosnowskyi–Salix fragilis, Heracleum sosnowskyi–Betula pendula) are scarce in Bryansk oblast.

Changes in distribution of six mammal species, viz. Procyon lotor, Nyctereutes procyonoides, Neovison vison, Cervus nippon, Dama dama, Ovis aries musimon in SW Poland (42000 km²), since their introduction till 2008, have been analyzed. A rough estimate of their numbers is also provided for seven regions in SW Poland (Silesia). Detailed maps of distribution of the American mink and fallow deer in SW Poland during 2004–2008 are also presented. The alien ungulates, as long-established species in SW Poland, are not considered as particularly destructive to indigenous flora and fauna. They are not invasive, and have never been regarded as such. On the other hand, the alien carnivores are regarded in SW Poland as destructive to the indigenous fauna. Counter-measures for the rapidly increasing carnivores are proposed.