Vol 8, No 4 (2017)

This article considers two invasive species of sap beetles, Epuraea ocularis Fairmaire, 1849, and Stelidota geminata (Say, 1825), which were previously recorded in the Caucasus. Epuraea ocularis is indicated for the fauna of Russia for the first time.

We present the results of analyses of meadow partial flora and vegetation concerning invasive species in the Republic of Karelia. A total of 10 out of 390 vascular plant species occurring currently on Karelian grasslands are listed as invasive by different authors. However, most of those species are represented by single samples in single geographical locations. Only two of them (Festuca elatior and Thlaspi caerulescens) can integrate into meadow communities but do not transform them significantly.

Data on the first record of the species of the Mytilidae family Arcuatula senhousia (Benson, 1842) in the Russian part of the Azov-Black Sea basin are presented. Two live specimens of the species were found in the benthic samples collected at a depth of 2 m in the central part of the Kerch Strait near Tuzla Island. That was the second record of A. senhousia in the Azov-Black Sea basin. Specimens of this species were first recorded on the western shelf near the coast of Romania in 2002; afterwards, there were no data on its development in the Black Sea.

The results of analysis on Sosnowsky’s hogweed (Heracleum sosnowskyi Manden) invasion using long-term monitoring data in the valleys of 14 large and medium rivers of the East European Plain performed in 2008–2016 by the Complex Expedition for the Study of Historical Waterways were presented. A schematic map of the distribution of H. sosnowskyi in the valleys of big and medium rivers with georegistration and landscape description of each point of detection was created. General characteristics of spatial distribution were formulated; the vectors of invasion (anthropochoria, hydrochoria) and the most important factors determining the penetration of H. sosnowskyi into river valleys were identified. The data on H. sosnowskyi confinement to certain structural elements of the landscape of river valleys with definite geomorphological and soil characteristics were presented. It was shown that phytocenotic association of invasive species in natural and anthropogenic communities was associated with towpaths and basic banks in valleys of large and medium rivers. It was established that the banks of rivers formed by rocks with a high content of solid detrital material were most favorable for H. sosnowskyi invasion, and raw floodplains and abrasion sandy banks were unfavorable. The results obtained expand significantly the understanding of the invasive habitat and the confinement of plants to the floodplain sites and can be used in forecasting, preventing the spread of H. sosnowskyi, and developing the measures to control the hogweed.

The distribution, plant size and biomass allocation, leaf traits, and seed production of the invasive Bidens frondosa L. plant in the Middle Urals were studied. This species was found in disturbed riverside habitats in the upper stream of the Iset’ River in habitats extending approximately 100 km (from the city of Aramil’ to the city of Kamensk-Ural’sky). Comparative analysis showed that the B. frondosa plant was 35% taller than the native species of the genus Bidens. The dry mass of the B. frondosa plant exceeded the biomass of B. tripartita and B. radiata by 1.5 and 4.9 times, respectively. The large size and biomass of B. frondosa indicated a higher competitive ability of this species than the native species of the genus Bidens. Given the same leaf thickness in the three studied species, the smaller leaf density (LD) of B. frondosa determined a lower (by 1.2 times) dry leaf mass per unit area (LMA) than that of B. tripartita and B. radiata. These structural features of B. frondosa leaves contributed to the optimization of gas exchange processes within a leaf and made it possible to develop a greater assimilation area per unit plant weight (the leaf area ratio (LAR)), which should provide a high growth rate of this species. Analysis of seed production parameters showed that the number of capitula per plant increased in the series B. radiata–B. tripartita–B. frondosa; however, the number of achenes per capitulum and per plant decreased in this sequence. The mass of 100 achenes was 1.6 and 2.3 times higher in B. frondosa than in B. tripartita and B. radiata, respectively. On the whole, the frequent occurrence of B. frondosa in the extended area (approximately 100 km) in the upper stream of the Iset’ River and the values of production parameters (the size and weight of plants and the mass and number of seeds) indicate a successful naturalization of this species in the Middle Urals.

An invader leech species Archaeobdella esmonti (Clitellata: Hirudinida) was found during hydrobiological research in 2016 in the Volga and Volga-Kama reaches of the Kuybyshev Reservoir. This indicates the continuing process of spreading of this alien leech species in the Kuybyshev Reservoir and the colonization of new habitats on a considerable area of the upstream part of the reservoir. The article describes the occurrence and quantitative abundance of A. esmonti in the studied water area.

The technology of seawater decontamination from single-celled organisms with the use of ultraviolet (UV) radiation was investigated to prevent the introduction of alien organisms into local aquatic ecosystems with ballast water (BW) of ships. Experiments were carried out on the effects of low-pressure (LPL) and medium-pressure (MPL) mercury arc lamps on single-celled green algae, halophilic alga Dunaliella terricola and euryhaline alga Asteromonas gracilis, and also on the salt-resistant bacterium Nocardia sp. Doses of UV irradiation were determined for a tenfold decrease in the number of mobile algal cells and colony-forming units of the bacterium. For the first time, differences in the degree of damage with irradiation of LPL and MPL were found by example of the phytoplankton representatives. It was found that, during MPL irradiation, in contrast to LPL, except the cross-linking of the nitrogenous bases of DNA, other mechanisms are involved in the inactivation of microorganisms.