Populations of orchids at the northern limit of their distribution (Murmansk Oblast): Effect of climate

The effect of climatic conditions on the dynamics of 21 populations of 10 species of the family Orchidaceae at the northern limit of their range in Europe was studied between 1992 and 2004. The abundance of orchid populations proved to depend primarily on air temperature during the previous and current growing seasons.     

Carbon accumulation in lowland bog soils of fallow lands in Murmansk oblast

The dynamics of organic carbon accumulation in lowland bog soils of Murmansk oblast were assessed by analyzing soil samples from fields formerly sown with perennial grasses but withdrawn from agricultural use three, six, and eight years ago. Within three years, the organic carbon content in the topsoil (0–20 cm) increased by 0.07%, compared to that in cultivated soil. In six-and eight-year-old fallows, the increase in the soil carbon content averaged 0.2 and 0.46%, respectively. Experimental data were used for verifying calculations of carbon turnover in lowland bog soils of fallows in Murmansk oblast by the RothC model.     

Species diversity of spiders (Arachnida, Aranei) in agroecosystems of Moscow oblast and Krasnodar krai

A census of spiders has been taken in Moscow oblast and Krasnodar krai (the Kuban Plain) in fields under corn, vetch-oat mixture, and winter wheat (in the central and peripheral zones separately), as well as on their margins and in adjoinint areas of other biotopes. Spiders were collected using entomological sweeping and pitfall traps. On the whole, 286 species of 20 families and 146 genera have been found (205 species in Moscow oblast and 139 species in Krasnodar krai). The level of species diversity does not change significantly; a noticeable decrease in this parameter is observed only in the central zones of fields. In Moscow oblast, species diversity reaches a peak at field margins; in Krasnodar krai, no regular differences in this parameter between the forest strip, field margin, and the peripheral zone of a crop field has been revealed. Species diversity usually decreases toward the field center. However, changes in species diversity at a distance of more than 100 m from the margins are insignificant.     

State of the population of the European pearl mussel <Emphasis Type="Italic">Margaritifera margaritifera</Emphasis> (L.) (Mollusca,Margaritiferidae) at the northeastern boundary of its range (Solza River,White Sea Basin)

Only two river basins in which the European pearl mussel has survived to date are known in Arkhangelsk oblast. These are the Solza and Kozha basins. The northeastern boundary of the European range of this species passes along the watershed between the basins of the Solza and the Shirshema (the Onega Peninsula) and then along the Onega-Northern Dvina watershed. The population density and the proportion of juveniles widely vary in different parts of the Solza Basin, and, therefore, the previously conclusion concerning the ageing of the population in the Kazanka River (Bolotov and Semushin, 2003) applies only to certain parts of this river. The highest density of the pearl mussel in the Solza Basin is 68 ind./m². Fish cultivation contributes to the conservation of this pearl mussel population, as the release of Atlantic salmon juveniles ensures reproduction of the mollusk under conditions of regulated river flow.