Holocene dynamics of invertebrate fauna in the littoral zone of Adak,the Aleutian Islands,according to archaeozoological data

Studies on invertebrate remains from the cultural layer of an ancient Aleut settlement on Adak Island have shown that the faunistic composition of invertebrates in the study area had not changed significantly during the Late Holocene. The traditional mode of natural resource use by the ancient Aleuts had no impact on the abundance of valuable species and biodiversity in general. Changes in the temperature regime were found to have taken place in the history of deposit formation. The period from the 8th to the mid-11th century was relatively cold. Climate warming took place between the mid-11th and the mid-12th centuries and between the mid-16th and the 19th centuries, with an intervening cooling period (from the mid-12th to the mid-16th century). This cooling was most distinct between the 15th and the mid-16th centuries.     

Structure and formation of conifer stands in the upper timberline ecotone on the North Chuya Ridge,Central Altai

The structure of Siberian stone pine (Pinus sibirica Du Tour.) and Siberian larch (Larix sibirica Ledeb.) stands and specific features of their formation have been studies in the forest-tundra ecotone on the North Chuya Ridge (2235–2475 m a.s.l.). Changes in the structure of these stands along the transition from the upper boundary of closed forests to the high-mountain tundra have proved to have an ambiguous pattern. Both tree species form mixed clusters of similar-aged trees in the lower part of the ecotone but grow singly, in scatters, in its upper part. The formation of conifer stands (tree clusters) in the lower part of the ecotone, on the slopes of the Aktru River valley, began during climate warming in the second half of the 19th century. The expansion of confers to its upper part took place markedly later, in the early 20th century (Siberian larch) or even in the 1930s (Siberian stone pine).     

Accumulation of Biophilic Elements in the Needles of Picea Species in Natural and Urbanized Ecosystems of Siberia and Central Asia in Relation to the Assessment of Environmental Quality

Variation in the content of N, P, K, Ca, Mg, Na, Cu, Zn, Mn, and Fe has been analyzed in the needles of 19 spruce species growing in the natural and urbanized ecosystems of Siberia and Central Asia. The results have shown that similarity in the content of biophilic elements in one-year-old needles of different species is conditioned by biochemical processes, which confirms the status of these species as passive bioindicators of environmental quality. The contents of trace elements in perennial needles, except color variations of chlorophyll, deserve further study as prospective indicators of environmental quality.     

Role of genetic factors in landscape-geographic variation of the water vole (Arvicola terrestris L.)

The geographic variation of the water vole Arvicola terrestris L. has been analyzed with respect to two linear combinations of craniometric characters with the highest additive heritability (h ² = 0.59 and h ² = 0.52). The greatest differences have been revealed between the territorially close montane and piedmont populations. The lowland and montane populations have proved to differ to the smallest extent, despite their spatial and altitudinal separation. Selection under extreme conditions that leads to similar phenotypic results may be based on the common genetic background of these populations, irrespective of considerable distances between them and different environmental conditions in their habitats.     

Species composition and quantitative representation of fishes in biotopes with the riffle minnow <Emphasis Type="Italic">Alburnoides bipunctatus</Emphasis>

Species composition of fishes was studied in rivers (capture sites) inhabited by the riffle minnow. In some localities, this species proved to occupy a leading position in the ichthyofauna, being obviously dominant. In small rivers, 16 species were caught together with it, including seven species regularly occurring in catches. The relative abundance of riffle minnow showed a moderate positive correlation with that of the gudgeon (0.568) and a nonsignificant negative correlation (?0.399) with that of the bleak. It is probable that the population dynamics of riffle minnow are determined mainly by natural intraspecific mechanisms rather than by water quality, which has changed only slightly in the rivers studied.     

Current state and long-term changes of the <Emphasis Type="Italic">Crenomytilus grayanus</Emphasis> community in Vostok Bay,Sea of Japan

The composition and structure of the Gray mussel (Crenomytilus grayanus) community in Vostok Bay of the Sea of Japan have been studied. A total of 165 species have been identified in the macrobenthos. Its species composition has changed insignificantly since the 1970s. The total biomass of the biocenosis has decreased, and the size-age composition of the C. grayanus population has changed due to poaching. The trophic structure of the community has also changed, with the Shannon indices of species diversity and equitability (E) becoming lower, due to intensive organic pollution of Vostok Bay resulting from increasing recreational activities and sewage discharge.