Russian Journal of Biological Invasions

2014, issue № 3

CONTENTS

Faunistic revision of alien fish species in the Black Sea - Boltachev A.R, Karpova E.P. - According to the results of original and literary data for the period of 1998 to 2013, it was reliably established the findings of 25 alien marine species in the Black Sea, 16 of which were registered for the first time, and nine, previously known at single specimens, were found in new areas of the coastal zone of the sea. The greatest number of these new species (21) was found near the Black Sea coast of Crimea. Naturalization is assumed to 13 species, six species are assigned to the group of facultative fish, and six – to random species. The main vectors of introduction and reasons for the increase of registrations of allochthonous fish are considered for the last fifteen years.

Evaluation of tree-shrub forage of Eurasian beaver (Castor fiber L.) and changes in foraging strategy after forage depletion - Goryainova Z.I., Katsman E.A., Zavyalov N.A., Khlyap L.A., Petrosyan V.G. - The results of comparative analysis of tree-shrub beaver forage quantitative characteristics for active and abandoned beaver settlements in the basin of Tadenka River, Prioksko-Terrasny Nature Reserve, where beavers inhabit for more than 60 years, are presented. Using one-way ANOVA analysis with the settlement type (active or abandoned) as a factor, it was shown that long-term foraging of beavers in the settlements leads to a decrease in species richness (P = 0.068). Different hypotheses of the impact of beaver selective foraging on the forest layers (forest stand, undergrowth) were presented. The factors leading to thinning and changes in the age structure of the forest stand and undergrowth were discussed. The changes in the species composition were observed, which were accompanied by an increase of proportion of minor and uneaten species by beaver. The conclusion was made that while during the first time habitat utilization the foraging zone does not exceed 50 m, when the habitat is utilized repeatedly the foraging extends up to 165 meters in the absence of predators. This conclusion was confirmed using Fisher's exact test (P = 0.005), Yates' chi-squared test (P = 0.002), Likelihood ratio test (P = 0.0002). In case of beaver’s repeated utilization of the Tadenka basin settlements with not recovered food resources, a distant zone within 50 to 165 m from the bank becomes the main zone for tree-shrub foraging.

Consequences of introduction of teleut Sciurus vulgaris exalbidus in Omsk oblast - Kassal B.Yu. - In Omsk oblast the Sciurus vulgaris is represented by three chorological groups with different geographic and demographic characteristics. The first one lives in the southern taiga subzone, northern mixed and deciduous forests and represents an indigenous group of S. v. martensi. The second one formed in the southern subzone of mixed forests as a result of the introduction in 1957–1960 of S. v. exalbidus into the territory of habitation of S. v. martensi and represents a hybrid group different from the aboriginal one by the ratio of native color morphs and population dynamics and density. The third one formed in the central forest-steppe in artificial pine plantations as a result of the introduction in 1976–1984 of S. v. exalbidus into the free area, it is small with sparse density and a characteristic ratio of color morphs.

Threshold concentrations of cations in external environment required for ionic balance maintenance between organism of invader Elodea canadensis Michaux and fresh water - Martemyanov V.I. - The content of sodium, potassium, calcium, magnesium in invader pondweed Elodea canadensis in field conditions constituted 14.5±0.7, 56.2±0.9, 241.5±15.2, 26.4±0.2 mmol/kg wet mass, respectively; and content of various fractions of water was as followed: general 80.3±0.7%, free 77.5±0.8%, connected 2.73±0.14%. Threshold concentrations of sodium, potassium, calcium, magnesium in the water, necessary for maintenance of ionic balance between organism of plants and medium were 0.0014–0.0021, 0.00014–0.00024, 0.11–0.16, 0.0056–0.0075 mmol/l, respectively. Reduction of water mineralization was accompanied by essential drop of levels of sodium, calcium, magnesium in plants and augmentation of concentration gradients of cations between organism and medium, enhancing load on systems for maintenance of water-salt exchange. At that, the portion of dry substance in plants lowered, and the portion of water increased. Under such intense conditions the power expenses for maintenance of vital activity of organism prevail above the processes of accumulation of organic substances. On the basis of the data of threshold cation concentrations in the medium, the comparative analysis for ability of various species of aquatic organisms to master low mineralized freshwater reservoirs is given.

Propagation of invasive Harlequin ladybird Harmonia axyridis (Pallas, 1773) (Coleoptera, Coccinellidae) in the Caucasus and possible sources of invasion - Orlova-Bienkowskaja M.Ja. - Invasive Harlequin ladybird (Harmonia axyridis) has become a dominant ladybird species in the Black Sea coast of Krasnodar Region, in the part of the Black Sea coast of Abkhazia and in the southern and northern foothills of the Greater Caucasus. Both light and dark specimens (form succinea and form spectabilis, respectively) occur in Ciscaucasia. But there were no dark specimens among 220 beetles, collected in Transcaucasia. This dramatic difference between the populations points to their different origin. Probably, Transcaucasian population appeared as a result of the intentional introduction in 1980s. And the Ciscaucasian populations appeared as а result of some later releases of beetles or as а result of spontaneous expansion of European invasive range. Propagation of this alien predator can cause declines of native Caucasian ladybirds and some butterflies. Besides, H. аxyridis can become a serious pest of Caucasian fruit and wine production.

Parasites of introduced rotan Perccottus glenii (Actinopterygii: Odontobutidae) at the northern border of host range - Sokolov S.G., Protasova E.N. - The water bodies of the city of Mirny and its environs (Arkhangelsk oblast, Russian Federation) are the most northern sites of record for introduced rotan. The first data on rotan parasite fauna in this region are presented; the species Trichodina mutabilis, Goussia sp., Spironucleus sp. and larvae of Nematoda gen. sp. were found during the investigation.