South-central Siberia Research Articles

Extended phylogeny of Aquilegia: the biogeographical and ecological patterns of two simultaneous but contrasting radiations

Studies of the North American columbines (Aquilegia, Ranunculaceae) have supported the view that adaptive radiations in animal-pollinated plants proceed through pollinator specialisation and floral differentiation. However, although the diversity of pollinators and floral morphology is much lower in Europe and Asia than in North America, the number of columbine species is similar in the three continents. This supports the hypothesis that habitat and pollinator specialisation have contributed differently to the radiation of columbines in different continents. To establish the basic background to test this hypothesis, we expanded the molecular phylogeny of the genus to include a representative set of species from each continent. Our results suggest that the diversity of the genus is the result of two independent events of radiation, one involving Asiatic and North American species and the other involving Asiatic and European species. The ancestors of both lineages probably occupied the mountains of south-central Siberia. North American and European columbines are monophyletic within their respective lineages. The genus originated between 6.18 and 6.57 million years (Myr) ago, with the main pulses of diversification starting around 3 Myr ago both in Europe (1.25–3.96 Myr ago) and North America (1.42–5.01 Myr ago). The type of habitat occupied shifted more often in the Euroasiatic lineage, while pollination vectors shifted more often in the Asiatic-North American lineage. Moreover, while allopatric speciation predominated in the European lineage, sympatric speciation acted in the North American one. In conclusion, the radiation of columbines in Europe and North America involved similar rates of diversification and took place simultaneously and independently. However, the ecological drivers of radiation were different: geographic isolation and shifts in habitat use were more important in Europe while reproductive isolation linked to shifts in pollinator specialisation additionally acted in North America.

Hunter–gatherer dispersals in the mammoth-steppe: technological provisioning and land-use in the Enisei River valley, south-central Siberia

Late Pleistocene Siberia was characterized by a unique mammoth-steppe biome. Two prevailing hypotheses exist to explain modern human dispersals in the Siberian mammoth-steppe. Upper Paleolithic human populations were either maintained continuously throughout the late Pleistocene or the peopling of this region resulted from multiple dispersal events. Past attempts at explaining the colonization process have resulted in culture-historical interpretations. This article uses lithic technological data from middle and late Upper Paleolithic sites in the Enisei River valley of south-central Siberia to explain human dispersals from a behavioral perspective. Technological provisioning and land-use strategies are reconstructed to help explain dispersal processes. Results of the study demonstrate that hunter–gatherers were using different adaptive strategies before and after the Last Glacial Maximum, indicating that multiple dispersal events shaped the peopling of Siberia.

Comments on Graf, Journal of Archaeological Science 36, 2009 “ “The Good, the Bad, and the Ugly”: evaluating the radiocarbon chronology of the middle and late Upper Paleolithic in the Enisei River valley, south-central Siberia”

Here I present a critical evaluation of the analysis conducted by Graf [Graf, K.E., 2009. “The Good, the Bad, and the Ugly”: Evaluating the radiocarbon chronology of the middle and late Upper Paleolithic in the Enisei River valley, south-central Siberia. Journal of Archaeological Science 36, 694–707] of the Paleolithic radiocarbon ( 14C) dataset for the Upper Paleolithic sites in the Yenisei River basin of Central Siberia. Graf applied a rating system to the corpus of existing 14C data for the region, and announced some new 14C dates. The results obtained, however, are highly biased due to several factors, including prejudice concerning the higher accuracy of the AMS technique in 14C dating and that 14C dates from the same cultural component should overlap with plus–minus two sigmas; ambiguities with the subdivision of the Lateglacial period; artificially high sample selection criteria; incomplete factual material; and unjustifiable and misleading statements on the 14C dating of fossil bones and the issue of Last Glacial Maximum human presence in Siberia. As a result, the conclusions made by Graf [Graf, K.E., 2009. “The Good, the Bad, and the Ugly”: Evaluating the radiocarbon chronology of the middle and late Upper Paleolithic in the Enisei River valley, south-central Siberia. Journal of Archaeological Science 36, 694–707] are unconvincing. New analysis is necessary in order to improve the quality of treatment of the original data for the Upper Paleolithic 14C chronology in the Yenisei River basin.

Lower crustal intrusions beneath the southern Baikal Rift Zone: Evidence from full-waveform modelling of wide-angle seismic data

The Cenozoic Baikal Rift Zone (BRZ) is situated in south-central Siberia in the suture between the Precambrian Siberian Platform and the Amurian plate. This more than 2000-km long rift zone is composed of several individual basement depressions and half-grabens with the deep Lake Baikal at its centre. The BEST (Baikal Explosion Seismic Transect) project acquired a 360-km long, deep seismic, refraction/wide-angle reflection profile in 2002 across southern Lake Baikal. The data from this project is used for identification of large-scale crustal structures and modelling of the seismic velocities of the crust and uppermost mantle. Previous interpretation and velocity modelling of P-wave arrivals in the BEST data has revealed a multi layered crust with smooth variation in Moho depth between the Siberian Platform (41 km) and the Sayan-Baikal fold belt (46 km). The lower crust exhibits normal seismic velocities around the rift structure, except for beneath the rift axis where a distinct 50–80-km wide high-velocity anomaly (7.4–7.6 ± 0.2 km/s) is observed. Reverberant or “ringing” reflections with strong amplitude and low frequency originate from this zone, whereas the lower crust is non-reflective outside the rift zone. Synthetic full-waveform reflectivity modelling of the high-velocity anomaly suggests the presence of a layered sequence with a typical layer thickness of 300–500 m coinciding with the velocity anomaly. The P-wave velocity of the individual layers is modelled to range between 7.4 km/s and 7.9 km/s. We interpret this feature as resulting from mafic to ultra-mafic intrusions in the form of sills. Petrological interpretation of the velocity values suggests that the intrusions are sorted by fractional crystallization into plagioclase-rich low-velocity layers and pyroxene- and olivine-rich high-velocity layers. The mafic intrusions were probably intruded into the ductile lower crust during the main rift phase in the Late Pliocene. As such, the intrusive material has thickened the lower crust during rifting, which may explain the lack of Moho uplift across southern BRZ.

Estimating Siberian timber volume using MODIS and ICESat/GLAS

Geosciences Laser Altimeter System (GLAS) space LiDAR data are used to attribute a MODerate resolution Imaging Spectrometer (MODIS) 500 m land cover classification of a 10° latitude by 12° longitude study area in south-central Siberia. Timber volume estimates are generated for 16 forest classes, i.e., four forest cover types × four canopy density classes, across this 811,414 km 2 area and compared with a ground-based regional volume estimate. Two regional GLAS/MODIS timber volume products, one considering only those pulses falling on slopes ≤ 10° and one utilizing all GLAS pulses regardless of slope, are generated. Using a two-phase(GLAS-ground plot) sampling design, GLAS/MODIS volumes average 163.4 ± 11.8 m 3/ha across all 16 forest classes based on GLAS pulses on slopes ≤ 10° and 171.9 ± 12.4 m 3/ha considering GLAS shots on all slopes. The increase in regional GLAS volume per-hectare estimates as a function of increasing slope most likely illustrate the effects of vertical waveform expansion due to the convolution of topography with the forest canopy response. A comparable, independent, ground-based estimate is 146 m 3/ha [Shepashenko, D., Shvidenko, A., and Nilsson, S. (1998). Phytomass (live biomass) and carbon of Siberian forests. Biomass and Bioenergy, 14, 21–31], a difference of 11.9% and 17.7% for GLAS shots on slopes ≤ 10° and all GLAS shots regardless of slope, respectively. A ground-based estimate of total volume for the entire study area, 7.46 × 10 9 m 3, is derived using Shepashenko et al.'s per-hectare volume estimate in conjunction with forest area derived from a 1990 forest map [Grasia, M.G. (ed.). (1990). Forest Map of USSR. Soyuzgiproleskhoz, Moscow, RU. Scale: 1:2,500,000]. The comparable GLAS/MODIS estimate is 7.38 × 10 9 m 3, a difference of less than 1.1%. Results indicate that GLAS data can be used to attribute digital land cover maps to estimate forest resources over subcontinental areas encompassing hundreds of thousands of square kilometers.

“The Good, the Bad, and the Ugly”: evaluating the radiocarbon chronology of the middle and late Upper Paleolithic in the Enisei River valley, south-central Siberia

The 14C record for the Upper Paleolithic in Siberia has remained largely unevaluated and includes good, bad, and ugly dates. Too often researchers accept either all published dates or only those dates that tend to support proposed chronological hypotheses, regardless of sample quality and association. This article systematically evaluates all published 14C dates (including several newly obtained AMS dates) from middle and late Upper Paleolithic sites in the Enisei River valley of south-central Siberia to establish a reliable chronology for the region and address the tempo of modern human dispersals in Siberia during late Pleistocene times. The revised chronology indicates humans were present before and after the Last Glacial Maximum, but absent during this climatic event. Results also suggest that human population in the region may have increased during the Oldest Dryas.

A Holocene molluscan succession from floodplain sediments of the upper Lena River (Lake Baikal region), Siberia

Floodplain sediments of the upper Lena River near Basovo in south-central Siberia have yielded the most detailed Holocene molluscan succession yet reported from the entire eastern Palaearctic. Over 72,500 shells from at least 28 species of terrestrial and 23 species of freshwater mollusc have been recovered, an abundance and diversity far higher than previously reported from the region. The molluscan assemblages are dominated by land snails, especially members of the genus Vallonia, represented by five species including Vallonia tenuilabris and two poorly known species Vallonia kamtschatica and Vallonia cf. chinensis. Other noteworthy species recovered include Gastrocopta theeli, Carychium pessimum, Vertigo extima (southernmost record), Vertigo microsphaera and the first Asian records of three other taxa ( Vertigo geyeri, Vertigo genesii and Vertigo parcedentata). Illustrations are provided for the critical species, since opinions differ about the status of various taxa and the correct names that should be used. The molluscan assemblages show clear successional trends during the early to mid-Holocene, reflecting episodes of dryness/wetness on the floodplain. Drier conditions at ca 6350 14C yr BP coincide with major changes in the archaeological record seen at other sites in the region but it remains unclear whether the two are linked. A prominent charcoal-rich horizon dated to ca 2800 14C yr BP marks a burning event in the catchment, which resulted in a two-fold increase in sediment accumulation rate. Remains of small mammals occurred throughout the sequence including a tooth of Microtus cf. maximowiczii, possibly the first occurrence of Ungar vole west of Lake Baikal. The faunal analyses have been integrated with a detailed pedological study of the sedimentary profile and a chronology was obtained by means of 12 AMS radiocarbon dates. This study provides the first detailed palaeoecological information relating to Holocene molluscan assemblages from the Cis-Baikal region and lays the foundation for future work in the eastern Palaearctic.

Горная лесостепь Тувы

The paper deals with the two main types of forest-steppe landscape of Tuva (the South-Central Siberia), i. e. the moderately warm forest-steppe of Eastern Tuva (the hemiboreal-forest-steppe altitudinal belt) and the moderately cold medium-height mountain forest-step­pe of Western Tuva. The first type of the forest-steppe forms a disconti­nued belt at an altitude of 800 to 1200 m above sea level. Its vegetation cover is typical of South-Siberian mountain forest-steppe. Plain areas are covered with meadow steppes of the ass. Pulsatillo patentis—Carice­tum pediformis nov. subass. stipetosum which give way to steppes of the ass. Pulsatillo turczaninovii—Carice­tum pediformis nov. on steep southern slopes. Stony sites are occupied by steppes of the ass. Colurio-Carice­tum nov. subass. artemisietosum. All the steppe associa­tions belong to the order Helictotrichetalia schelliani of the Central-Asian steppe class Cleistogenetea squarro­sae. Larch forests of the ass. Anemono-Laricetum Ermakov 1995 subass. phleumetosum nov. and A.-L. subass. calamagrostietosum nov. (the class Rhytidio-Laricetea), surrounded by steppe meadows of the ass. Adenophoro-Caricetum nov., dominate the northern slopes. The second type, the moderately cold forest-steppe, is characteristic of the western regions of Tuva, more arid and continental, which lay in the rain shadow of the mountain systems Altai and Sayan. The conditions required for forest vegetation appear at an altitude of 1400 m above sea level and the forest-steppe landscapes are located within the altitudinal ranges of 1400 to 1700 m a. s. l., so the forest-steppe of Western Tuva is colder than that of Eastern Tuva. Its vegetation cover represents a combination of the transformed vegetation of the steppe and the typical forest-steppe belts in the southern and the northern slopes, respectively. The southern slopes are dominated by bunchgrass (ass. Colurio-Caricetum nov.) and stony (ass. Euphorbio-Elytrigietum nov., Androsaco-Elytrigietum nov.) step­pes; the latter association is exclusively typical of the type of forest-steppe discussed. Vegetation of the northern slopes is mainly composed of larch forests of Anemono-Laricetum subass. phleumetosum nov. and A.‑L. subass. rhododendretosum nov. The herba­ceous plant communities observed on the northern slopes are meadow steppes and steppe meadows of the associations Adenophoro-Caricetum, Pulsatillo-Carice­tum subass. potentilletosum, Aconogono-Caricetum nov. The latter two units are also restricted to the moderately cold forest-steppe, as well as Anemono-Laricetum rhododendretosum. The total syntaxonomic diversity of mountain forest-steppes of Tuva principally comprises 8 asso­ciations and 9 subassociations. All of them are des­cribed anew respectively.

The Peopling of the New World: Perspectives from Molecular Anthropology

▪ Abstract A number of important insights into the peopling of the New World have been gained through molecular genetic studies of Siberian and Native American populations. These data indicate that the initial migration of ancestral Amerindian originated in south-central Siberia and entered the New World between 20,000–14,000 calendar years before present (cal yr BP). These early immigrants probably followed a coastal route into the New World, where they expanded into all continental regions. A second migration that may have come from the same Siberian region entered the Americas somewhat later, possibly using an interior route, and genetically contributed to indigenous populations from North and Central America. In addition, Beringian populations moved into northern North America after the last glacial maximum (LGM) and gave rise to Aleuts, Eskimos, and Na-Dené Indians.

Climate change and the expansion of the Scythian culture after 850 BC: a hypothesis

In south-central Siberia archaeological evidence suggests an acceleration of cultural development and an increase in the density of nomadic populations around 850 BC. We hypothesize a relationship with an abrupt climatic shift towards increased humidity caused by a decline of solar activity. Areas that initially may have been hostile semi-deserts changed into attractive steppe landscapes with a high biomass production and high carrying capacity. Newly available steppe areas could be invaded by herbivores, making them attractive for nomadic tribes. The central Asian horse-riding Scythian culture expanded, and an increased population density was a stimulus for westward migration towards southeastern Europe.

Mitochondrial DNA and Y chromosome diversity and the peopling of the Americas: evolutionary and demographic evidence.

A number of important insights into the peopling of the New World have been gained through molecular genetic studies of Siberian and Native American populations. While there is no complete agreement on the interpretation of the mitochondrial DNA (mtDNA) and Y chromosome (NRY) data from these groups, several generalizations can be made. To begin with, the primary migration of ancestral Asians expanded from south-central Siberia into the New World and gave rise to ancestral Amerindians. The initial migration seems to have occurred between 20,000-15,000 calendar years before present (cal BP), i.e., before the emergence of Clovis lithic sites (13,350-12,895 cal BP) in North America. Because an interior route through northern North America was unavailable for human passage until 12,550 cal BP, after the last glacial maximum (LGM), these ancestral groups must have used a coastal route to reach South America by 14,675 cal BP, the date of the Monte Verde site in southern Chile. The initial migration appears to have brought mtDNA haplogroups A-D and NRY haplogroups P-M45a and Q-242/Q-M3 to the New World, with these genetic lineages becoming widespread in the Americas. A second expansion that perhaps coincided with the opening of the ice-free corridor probably brought mtDNA haplogroup X and NRY haplogroups P-M45b, C-M130, and R1a1-M17 to North and Central America. Finally, populations that formerly inhabited Beringia expanded into northern North America after the LGM, and gave rise to Eskimo-Aleuts and Na-Dené Indians.

Pleistocene climate change, natural environments and palaeolithic occupation of the upper Yenisei area, south-central Siberia

The upper Yenisei River area, near the geographical centre of Asia, is of major importance for mapping the Pleistocene climate evolution over Siberia. An extensive loess cover with a suite of buried palaeosols from the Northern Minusinsk Basin has provided one of the most complete, high resolution Late Quaternary palaeoclimatic archives currently described in north-central Asia. Coupled with the pollen evidence, the loess–palaeosol records indicate establishment of periglacial steppe–tundra during cold stadial intervals, replaced by parkland steppe and boreal forest during warm interstadial intervals. Zonal transformations of the Pleistocene environments due to marked climatic variations are reflected by the diversity of fossil faunal species, including non-analogue communities. Geoarchaeological records incorporated in the loess–palaeosol formations represent important palaeoenvironmental multi-proxy data complementing the fossil biotic and palaeopedological evidence. Abundant “pebble tool” assemblages provide explicit evidence of human occupation of the upper Yenisei area prior to the last interglacial (>130 ka BP). The morphological and technological variability of the palaeolithic industries displaying a differential degree of patination and aeolian abrasion attest to several stages of the initial peopling of the southern Siberian territory. The cultural finds associated with the Middle Pleistocene cold-adapted fossil fauna indicate that early humans were able to survive in local periglacial environments. Favourable climatic conditions during the last interglacial promoted expansion of the more advanced Mousterian (Levallois) tradition that persisted until the early last glacial stage (OIS 4). Warming during the mid-last glacial stage (OIS 3) accelerated formation of the Late Palaeolithic cultures dominated by developed blade reduction techniques. Intervals of significant climatic deterioration and onset of full glacial conditions are manifested by the absence of any archaeological record. The main focus of the current Quaternary investigations is to refine the established chronological framework and detail contextual settings of the cultural records within the larger study area.

Clay minerals in the sediments of Lake Baikal; a useful climate proxy

Lake Baikal, in south-central Siberia, has been the focus of an international effort (the Baikal Drilling Project; BDP) to obtain continuous long cores (upwards of 100 m) from this unique rift-valley lake and to interpret the paleoclimatic history from various proxy data. As part of this effort, the clay minerals were examined by two research teams. A consistent clay-mineral assemblage, containing illite, inter- stratified illite-smectite, chlorite, and kaolinite as the major minerals, characterizes much of the modern sediments. The relative abundance of these minerals changes with depth in both short piston cores from various parts of the lake and in 100-m-long cores taken from the distal toe of the Selenga Delta (BDP-93). Independent analyses of the abun- dance changes and correlation with other data from the cores show that the clays are responding to two influences: (1) climatic fluctua- tions, particularly in the upper 40 m of the sedimentary record, which show the relative amount of illite-smectite (and sometimes kaolinite) increasing during warmer climate episodes, and (2) source-area chang- es, which are most evident below 40 m in the BDP-93 cores and mark a shift from an eastern (Buguldeika River) to a western (Selenga River) source. The clay-mineral-based climate fluctuations are correlative with the marine oxygen-isotope record through stage 7, and provide a relatively simple and cost-effective tool for gaining insight into the pa- leoclimate of this interior continental site.

Ecology of Siberian Taimen Hucho taimen in the Lake Baikal Basin

Taimen Hucho taimen historically inhabited most tributaries and littoral areas of Lake Baikal, in south central Siberia, where they supported subsistence and commercial fisheries. Logging, pollution, and overfishing have caused dramatic population declines or local extinction of most stocks. Most of what is known about this species has been published in eastern journals and therefore is not readily available to western scientists. New data collected during the 1980s and 1990s have been combined with other reports to provide an overview of the biology and life history of this species. Taimen are long-lived fish and can reach ages of 29 years and sizes up to 60 kg. Populations can either be strictly riverine or anadromous. Adults from both life histories ascend rivers in spring to spawn and feed, and less extensive migrations occur in fall to prey on spawning omul ( Coregonus autumnalis migratorius). Principal food items for age 1 and 2 taimen are macroinvertebrates, but young taimen quickly become piscivorous at age 2 when they consume mainly black Baikal grayling ( Thymallus arcticus baicalensis), and sculpins ( Taracottus kneri, Cottus kesslerij). Males reach sexual maturity at ages 7 to 8 and later for females at ages 8 to 9. Average egg production per female was about 22,000 eggs. Parasite burdens are heavy but composed of few species and mediated by prey items consumed. This fish is a highly-specialized predator and plays an indispensable role in the structure of fish communities in mountains and foothills. Taimen conservation in the Baikal region is impossible without adoption and implementation of a dedicated rehabilitation program that includes the protection of remaining populations and habitat, and possibly introduction of hatchery-reared fish in selected areas where habitat remains, but parental stocks are low.

Chrysophyte cyst biogeographical and ecological distributions: a synthesis

The distributions of chrysophyte stomatocysts in the sediments of 221 lakes from four study areas located in British Columbia, Canada (two datasets), New York, U.S.A., and south central Siberia were examined. The combined lake set spanned a wide range of chemical and morphometric variables. Approximately 400 cyst morphotypes were identified, from which we selected sixty‐three common types for further analysis. Canonical ordination (detrended canonical correspondence analysis (DCCA) and constrained DCCA) showed that four environmental variables (pH, conductivity, depth and total phosphorus (TP) ) were significant (Monte Carlo permutation test, P=0.01 for all four variables) and independent determinants of the cyst distributions. Weighted averaging (WA) inference models were developed for each variable. The best models, in terms of their r2, were developed for pH and conductivity (r2=0.78 and 0.73, respectively). The models for depth and TP were less robust (r2=0.47 and 0.46, respectively). We discuss the relative importance of conductivity and salinity, lakewater acidity and metal concentrations, lake morphometry and trophic status as determinants of chrysophyte population distributions, and possible causal mechanisms for each variable. We identify assemblages of cysts that appear to be associated with six different groups of lakes: (1) very acidic (pH <6.5) lakes; (2) acidic (pH <7.0), softwater lakes; (3) circumneutral (pH 7–8), oligo‐ to mesotrophic lakes; (4) alkaline, hardwater, meso‐ to eutrophic lakes; (5) shallow, alkaline (pH 8–8.5), meso‐ to eutrophic lakes; and (6) shallow, very alkaline (pH >8.5) lakes, including sub‐ and hyposaline lakes. Finally, we suggest further possible avenues for research that will improve the usefulness of chrysophyte stomatocysts as paleolimnological indicators.

Lake Baikal Record of Continental Climate Response to Orbital Insolation During the Past 5 Million Years

The sedimentary record of biogenic silica from Lake Baikal in south-central Siberia suggests that this region of central Asia was impacted by two major cooling episodes at 2.8 to 2.6 and 1.8 to 1.6 million years ago. The spectral evolution of this continental interior site parallels the evolutionary frequency spectra for various marine oxygen isotope records. In the Baikal record, the 41,000-year obliquity cycle is particularly strong from 1.8 to 0.8 million years ago; variance in the 100,000-year eccentricity band increases during the past 0.8 million years. The expected precession frequency of 23,000 years is highest during the past 400,000 years. The modulation of the predicted 23,000- and 41,000-year insolation forcing by the 100,000- and 400,000-year eccentricity bands indicates that the transfer of variance from the precession and obliquity frequencies to the eccentricity part of the spectrum occurred in the Eurasian continental interior, as well as in tropical and high-latitude ocean sites.

Ecologically Sustainable Land Use Planning in the Russian Lake Baikal Region

Efforts at achieving sustainable forest management throughout the world often appear to pit global economic and development interests against those who seek preservation and environmental protection of the Faith's resources. Such conflicts, where they do arise, are often unmindful of the full range of land use parameters which must be taken into account when developing sustainable forest models on a regional, if not subconlinenlal scale the scale on which many multinational corporate entities now base their business planning. In fact, sustainable forest resource planning in the global marketplace must be integrated with regional sustainable land use, cultural, ecosystem and economic planning if the myriad forest attributes are to be maintained for future generations. The proposed paper would describe comprehensive sustainable land use planning being implemented in the Lake Baikal region of south central Siberia, Russia, which incorporates the full range of forest utilization from wild forest preserves to ecologically sustainable forest management for wood products. This paper describes similar projects being undertaken by Ecologically Sustainable Development, Inc. (ESD) in Mongolia, the Altai region of Russia, the Ussuri River Basin of Far Eastern Russia and China. Nicaragua and British Columbia, finally, the authors make recommendations key to achieving sustainable forest policy on the federal, state, regional and local levels.

Evaluating field-based GIS for environmental characterization, modelling and decision support

ABSTRACT This paper examines the potential of using GIS (Geographical Information Systems) in the field for environmental characterization, modelling and decision support particularly in isolated areas where data collection is difficult. Observations are based on experiences gained during two Anglo-Russian expeditions to the Altai Mountains of south central Siberia aimed at evaluating proposals for a new national park in the Katunsky Ridge area of the Belukha Massif. The use of GIS together with GPS (Global Positioning Systems) for primary data collection and verification/update of existing data is described and the use of field-based systems for on-the-spot environmental modelling and decision support is evaluated.

Similar Patterns of Change in Stemwood Calcium Concentration in Red Spruce and Siberian Fir

Changes in stemwood calcium concentration ((Ca)) for the last 120 years occurred in a common pattern for two sample collections of red spruce (n = 33 and 20) froin the northeastern United States and for one sample collection of Siberian fir (tz = 20) from southcentral Siberia, Russia. The (Caj was measured for wood formed during the periods 1871-90, 1891-1910, 1911-30, 1931-50, 1951-70 and 1971- 90. For each core, the relative increase or decrease in (Ca) for adjacent periods of wood formation was recorded. The relative frequency of positive change in (Caj for each period of wood formation was calculated for the three sample collections. Previous research indicated that under equilibrium condi- tions, (Ca) in stemwood tended to decrease in more recently formed wood, due to declining numbers of Ca binding sites. Consequently, we expected a low frequency of positive changes in (Ca) in successively formed wood. Consistent with expectation, the relative frequency of positive change from the preceding period to the periods 1891-1910, 191 1-30, 1931- 50, and 1971-90 were low. Contrary to expectation, the frequency of positive increases in (Ca) more than dollbled in 1951-70 compared to 1931-50. The frequency of positive increases in the 1951-70 period relative to the preceding period was 48%, significantly greater than all other periods (P S 0.01). The frequencies of positive increases for all other periods were not significantly different from each other (over- all mean = 21 %, SD = 7). This anomaly in the frequency of positive change in (Ca) in wood formed in 1951-70 relative to wood formed in 1931-50 indicated a perturbation in the ion exchange chemistry of stemwood in two widely separated parts of the northern coniferous forest. This anomaly could be due to external or internal factors. Changes in sap chemistry that affected stem- wood chemistry could have been due to changes in the rooting zone. Such changes in rooting zone chemistry could result from the atmospheric deposition of ionic pollutants. Other external factors that could cause the observed anomaly include unusual climatic periods or environmental disturbances such as logging or fire. Internal factors that might produce an anomalously high frequency of positive change of (Caj in- clude heartwood formation, stemwood infection and a hyper- sensitive response of the tree against infection.

Sedimentary effects of cataclysmic late Pleistocene glacial outburst flooding, Altay Mountains, Siberia

Pleistocene glacial outburst floods were released from ice-dammed lakes of the Altay Mountains, south-central Siberia. The Kuray-Chuja lake system yielded peak floods in excess of 1 × 106 m3 s−1 and as great as 18 × 106 m3 s−1. The phenomenally high bed shear stresses and stream powers generated in these flows produced a main-channel, coarse-grained facies of coarse gravel in (1) foreset-bedded bars as much as 200 m high and several kilometers long, and (2) degradational, boulder-capped river terraces. Giant current ripples, 50 to 150 m in spacing, composed of pebble and cobble gravel, are locally abundant. The whole sedimentary assemblage is very similar to that of the Channeled Scabland, produced by the Pleistocene Missoula Floods of western North America.