Arkady Savinetsky

Genetics, prehistory and the colonisation of the Aleutian Islands

The 1800 km-long Aleutian archipelago represents a model ecosystem to track human–environmental interactions across space and through time. Defining the southern margin of Beringia across which much of the early peopling of the Americas occurred, the Aleutians present a 9000 year record of human occupation in the eastern part of the island chain, and more than 3000 years in the west. Molecular evidence demonstrates: (1) that Aleuts shared common ancestry with Chukchi and Siberian Eskimos of Chukotka; (2) the original patterns of migration into the Aleutian islands were from the Alaskan peninsula in a westward direction with no evidence for island-hopping from Kamchatka; and (3) a highly significant statistical relationship between geography and genetics, based on mtDNA sequences, was observed despite previous population disruption. Historically, the Aleutian region is a rich ecotone, with ocean fisheries, abundant populations of large marine mammals, thick kelp forests, complex near-shore ecosystems and intertidal zones, spawning streams, and a highly diverse avian fauna. Each of these environments and resources has been pivotal in shaping the adaptive strategies of human occupants of the island chain since the initial colonisation of the Aleutians from the Alaskan Peninsula. In turn, Holocene human immigration, prehistoric cultural adaptations and subsequent historic events have had reciprocal impacts on the natural systems of the Aleutians.

Ecology of the Ringed Seal (Pusa hispida) from the Bering Strait in the Late Holocene

The combined use of analysis of stable isotopes and archeozoological methods with respect to osteological material from an ancient Eskimo settlement (2370-810 yr BP) made it possible to reveal the main distinguishing features of ringed seal in the past. On the basis of the data obtained, we suppose that in the late Holocene in the Bering Strait, there were seals of two different ecotopes: those reproducing on fast ice and those on pack ice differing not only in habitats, but also in the proportion of various food items in the diet. The ringed seals caught by ancient Eskimos during their life had a mixed diet consisting of crustaceans and fish, but in most individuals, a shift towards fish eating was observed. No significant changes in the feeding related to individual age were recorded. The influence of feeding type on body size was shown: bigger, mature individuals occupied higher trophic positions.

Architectonics of the hair of sled dogs of Chukotka

Architectonics of guard hairs from dogs of recent breeds, mongrel sled dogs, and fossil dogs from ancient settlements of Chukotka have been investigated using scanning electron microscopy. Distinct features of hair structure important for adaptation, including the adaptation to harness in sled dogs, were identified. Hairs of Chukchi sled dogs were most similar to those of the fossil dogs.

Vegetation and Climate Reconstruction for the Bale Mountains (Ethiopia) in the Holocene According to the Pollen Analysis and Radiocarbon Dating of Zoogenic Deposits

The vegetation and climate history of the Bale Mountains remains poorly studied. Only several stud� ies dealt with the reconstruction of plant communities and climatic conditions of the Bale highlands in the Late Pleistocene-Holocene (3, 4). The cause lies largely in the fact that the objects suitable for recon� struction of the centurylong dynamics of this ecosys� tem are scanty or absent in this area. Only a small amount of suitable lake deposits (3) can be found here; poor peatland preservation (4) does not facilitate a research of the regional vegetation and climate history. Since the classic objects of palynological analysis are rare in this region, zoogenic deposits from the caves and rock niches provide the most promising informa� tion necessary for reconstruction of the ecosystem his� tory. Therefore, this type of deposits was used to reconstruct the ecosystem history of the Sanetti pla� teau and adjacent areas. The goal of this study was to reconstruct the vegetation and climate of the Bale Mountains in Holocene using the spore-pollen anal� ysis and radiocarbon dating of zoogenic deposits.

Nitrogen Isotope Composition of Peat Samples as a Proxy for Determining Human Colonization of Islands

The Aleutian Islands comprise a unique ecosystem, providing nesting grounds and habitat for more than ten million seabirds. No doubt their numbers were even larger prior to the introduction of foxes and rats, invasive species that have shaped the current population sizes and distributions of bird-breeding colonies. Here we present evidence that the peopling of the Aleutian Islands had the same dramatic effect on seabird populations. Analyses of nitrogen stable isotopes in Shemya Island peat deposits revealed significant 15N enrichment of layers formed cal. 4,700–2,800 yrs BP suggesting high seabird guano input at that time. Following this period there was a sharp decline in δ15N that coincides with the first appearance of human settlement and reflects drastic reduction in seabird abundance. The isotope signature of marine-derived nitrogen vectored by seabirds is specific only for coastal peat deposits; neither 15N enrichment nor decline was detected in inland peat deposits.