[Extinction of large herbivore mammals: niche characteristics of musk ox Ovibos moschatus and reindeer Rangifer tarandus coexisting in isolation].

The extinction of large northern herbivores is a puzzle for many biologists. It is long debated whether climate change or human activity was the main factor of the extinction. The survival of the weak trophic competitors should reject the climatic hypothesis. Extant species of Pleistocene communities allow testing this explicitly. Up to date, reindeer and musk ox coexist in the Arctic territory. Their island populations provide a unique natural experiment to assess the role of competition. On Wrangel Island, their population sizes show the opposite trends and the same situation recurs on other Arctic islands--the reindeer population size decreases with the muskoxen population increasing. We have shown that the trends are defined by food-web structure. Niche overlap between species is found to .be considerable and cannot be facilitated by habitat partitioning. The number of plant species in the muskoxen diet was higher than in the reindeer. The exclusive part of the muskoxen diet was higher as well. Food webs in all of the habitat types showed the same relation. However, the changes in herbivores distribution during the Pleistocene demonstrate the opposite pattern. Therefore, the competitive advantage could not save the Palaearctic musk ox, and the extinction seems to be a result of selective overkill. Conclusively, the human activity may be considered as the main factor of the Late Pleistocene herbivore extinctions, and the musk ox reintroducing should be coupled with extensive conservational measures.

[Polymorphism of a short fragment of the mitochondrial genome control region (D-loop) in the Siberian roe deer Capreolus pygargus Pallas, 1771 (Artiodactyla, Cervidae) from the Russian Far East].

Genetic diversity of Siberian roe deer Capreolus pygargus, 1771 from the Russian Far East was studied based on polymorphism analysis of a mtDNA control region fragment (390 bp). Three phylogenetic lines were found in the animals examined. The trend for change of haplotypes of different phylogroups was shown to occur from north to south in Sikhote-Alin. The haplotype distribution of Siberian roe deer in the Russian Far East correlated with data on morphologiocal variability.

[Circulation of Seoul hantavirus in populations of synanthropic rodents and its significance in the incidence of hemorrhagic fever with renal syndrome in the Primorye territory]. / Tsirkuliatsiia khantavirusa Seul v populiatsiikh sinantropnykh gryzunov i ego znachenie v zabolevaemosti gemorragicheskoi likhoradkoi s pochechnym sindromom v Primorskom krae.

The prevalence of Seoul virus in the Primorie territory is presented and its significance in the morbidity structure with regard to hemorrhagic fever with the renal syndrome (HLPS) is discussed. Epidemiological and clinical manifestations of HLPS caused by Seoul virus are described. The authors conclude that in the urban foci of HLPS it is associated mainly with Seoul virus, while in the rural foci, with Hantaan virus.