Warming hiatus and evergreen conifers in Altay-Sayan Region,Siberia

"Warming hiatus" occurred in the AltaySayan Mountain Region, Siberia in c. 1997–2014. We analyzed evergreen conifer(EGC) stands area(satellite data) and trees(Siberian pine, Pinus sibirica Du Tour, Siberian fir, Abies sibirica Ledeb.) growth increment(dendrochronology data) response to climate variables before and during the hiatus. During the hiatus, EGC area increased in the highlands(1000 m)(+30%), whereas at low and middle elevations(1000 m. a.s.l.) the EGC area decreased(-7%). The EGC area increase was observed on the rain-ward northwest slopes mainly. In highlands, EGC area increase mainly correlated with summer air temperature, whereas at low and middle elevations EGC area decrease correlated with drought index SPEI and vapor pressure deficit(VPD). EGC mortality(fir and Siberian pine) in lowland was caused by the synergy of water stress(inciting factor) and barkbeetle attacks(contributing factor). Tree growth increment(GI) dynamics differs with respect to elevation. At high elevation(1700 m) GI permanently increased since warming onset, whereas at the middle(900 m) and low elevations(450 m) GI increased until c. 1983 yr. with followed depression. That GI "breakpoint" occurred about a decade before hiatus onset. In spite of growth depression, during hiatus GI was higher than that in pre-warming period. At high elevation, GI positively responded to elevated June temperatures and negatively to moisture increase(precipitation, root zone moisture content, VPD, and SPEI). At low elevation GI negatively responded to June temperatures and positively to moisture increase. For both, low and high elevation, these patterns persisted throughout the study period(1967–2014). On the contrary, at middle elevations GI dependence on climate variables switch after breakpoint year(1983). Before breakpoint, June air temperature(positive correlation) and moisture(negative correlations) controlled GI. Further temperature increase leads GI depression and switched correlation signs to opposite(from positive to negative with temperature, and from negative to positive with moisture variables).     

Topographic controls on alpine treeline patterns on Changbai Mountain,China

The control mechanisms of topography on alpine treeline pattern are critical to understanding treeline dynamics and future changes. These mechanisms have not been understood quite well enough because of increasing human disturbance and low data resolution. In this study, the relationship between the treeline pattern and topography was analyzed based on high spatial resolution remote sensing data and a digital elevation model in an area in Changbai Mountain with little human disturbance. Future treeline patterns were also predicted. The results showed that(a) aspects with high solar radiation and low snow cover have a high coverage rate of trees,(b) the peak coverage rate of trees switches from low slopes(5°) to medium slopes(5°~25°) as the elevation rises because of the extreme environment,(c) the coverage rate of trees is a function that depends on environmental factors controlled by topography,(d) the future treeline pattern is controlled by new temperature mechanisms, new environmental factors and the reallocation effect of topography. Our research implies that topography controls the treeline pattern and changes in the treeline pattern associated with global warming, due to the effect of global warming on environmental factors. This study may well explain the causes of heterogeneous changes in the treeline pattern in the horizontal direction as well as differences in treeline response to climate warming.     

Ectomycorrhiza of Larix sibirica Ledeb. along the gradients of main ecological factors and elevation at the Northern and Subpolar Urals

Siberian larch(Larix sibirica Ledeb.) forests cover the largest areas in the Eurasian boreal zone, but there are insufficient data on its root system including the structure and functional traits of ectomycorrhizas(EM). The aim of this research is to find out if the morphological parameters of Larix sibirica EMs responded to the changes in elevation and main ecological factors(soil humidity, soil richness, soil acidity and habitat illumination). Using light microscopy, we studied EM diameter, root diameter, mantle width, and mantle volume share, share of tannin cells layers, EM density and EM length of Larix sibirica in two main types of plant communities along the elevation gradient at the Northern and Subpolar Urals. Differences in the environment were traced using phytoindication approach and the Ellenberg ecological scales. All the studied traits depend on the elevation and studied ecological factors. The diversity of fungal mantles is low, and the proportion of unstructured and pseudoparenchymatous mantles is high in response to the deterioration of the humidity, soil nitrogen content and acidity at higher-altitude habitats. Results of EM quantitative parameters measurements confirmed this pattern. We found a decline in the EM linear dimensions accompanied by a compensatory growth of the EM density with the raised elevation and the deterioration of environmental conditions.     

Implications of tree species–environment relationships for the responsiveness of Himalayan krummholz treelines to climate change

Climate warming is expected to advance treelines to higher elevations. However, empirical studies in diverse mountain ranges give evidence of both advancing alpine treelines as well as rather insignificant responses. In this context, we aim at investigating the sensitivity and responsiveness of the near-natural treeline ecotone in Rolwaling Himal, Nepal, to climate warming. We analysed population densities of tree species along the treeline ecotone from closed forest stands via the krummholz belt to alpine dwarf shrub heaths (3700-4200 m) at 50 plots in 2013 and 2014. We quantified species - environment relationships, i.e. the change of environmental conditions (e.g., nutrient and thermal deficits, plant interactions) across the ecotone by means of redundancy analyses, variation partitioning and distance-based Moran's eigenvector maps. In particular, we focus on explaining the high competitiveness of Rhododendron campanulatum forming a dense krummholz belt and on the implications for the responsiveness of Himalayan krummholz treelines to climate change. Results indicate that treeline trees in the ecotone show species-specific responses to the influence of environmental parameters, and that juvenile and adult tree responses are modulated by environmental constraints in differing intensity. Moreover, the species - environment relationships suggest that the investigated krummholz belt will largely prevent the upward migration of other tree species and thus constrain the future response of Himalayan krummholz treelines to climate warming.     

Tree wave migration across an elevation gradient in the Altai Mountains,Siberia

The phenomenon of tree waves(hedges and ribbons) formation within the alpine ecotone in Altai Mountains and its response to observed air temperature increase was considered. At the upper limit of tree growth Siberian pine(Pinus sibirica) forms hedges on windward slopes and ribbons on the leeward ones. Hedges were formed by prevailing winds and oriented along winds direction. Ribbons were formed by snow blowing and accumulating on the leeward slope and perpendicular to the prevailing winds, as well as to the elevation gradient. Hedges were always linked with microtopography features, whereas ribbons were not. Trees are migrating upward by waves and new ribbons and hedges are forming at or near tree line, whereas at lower elevations ribbons and hedges are being transformed into closed forests. Time series of high-resolution satellite scenes(from 1968 to 2010) indicated an upslope shift in the position ribbons averaged 155±26 m(or 3.7 m yr~(-1)) and crown closure increased(about 35%–90%). The hedges advance was limited by poor regeneration establishment and was negligible. Regeneration within the ribbon zone was approximately 2.5 times(5060 vs 2120 ha~(-1)) higherthen within the hedges zone. During the last four decades, Siberian pine in both hedges and ribbons strongly increased its growth increment, and recent tree growth rate for 50 year-old trees was about twice higher than those recorded for similarly-aged trees at the beginning of the 20~(th) century. Hedges and ribbons are phenomena that are widespread within the southern and northern Siberian Mountains.     

Assessment of alpine summit flora in Kashmir Himalaya and its implications for long-term monitoring of climate change impacts

In an era of climate change,the availability of empirical data on alpine summit vegetation in the Himalaya is still scarce.Here we report the assessment of alpine summit flora in Gulmarg Wildlife Sanctuary,Kashmir Himalaya.We employed a globally standardized Multi-Summit Approach and four spatially isolated summits spanning an elevation gradient of 210 m(between 3530-3740 m a.s.l.) from natural treeline to nival zone were studied.Sampling of the summits was carried out in the year 2018 to collect floristic data together with records of soil temperature.A total of 142 vascular plant species were recorded in the sampled summits.Majority of the species were of herbaceous growth form and with perennial life span.Based on Raunkiaer's life form,hemicryptophytes were the most dominant followed by therophytes and phanerophytes.The summit flora showed the predominance of narrow-endemic species,with broad-and non-endemics declining with elevation.A significant relationship between growth form,Raunkiaer's life form,and the degree of endemism with elevation was observed.Both species diversity and soil temperature showed a monotonic decrease with increasing elevation.Interestingly,soil temperature clearly determined the magnitude of species diversity on the summits.Furthermore,based on floristic composition,the lowest summit had the highest dissimilarity with the rest of the summits.The present study employed globally standardized protocol to scientifically assess the patterns of plant diversity on the alpine mountain summits of Kashmir Himalaya,which in turn has wide implications towards long-term monitoring of climate change impact on alpine biodiversity in the rapidly warming Himalaya.     

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Vegetation cover variation in the Qilian Mountains and its response to climate change in 2000–2011

An understanding 0f variati0ns in vegetati0n c0ver in resp0nse t0 climate change is critical f0r predicting and managing future terrestrial ec0system dynamics. Because scientists anticipate that m0untain ec0systems will be m0re sensitive t0 future climate change c0mpared t0 0thers, 0ur 0bjectives were t0 investigate the impacts 0f climate change 0n variati0n in vegetati0n c0ver in the Qilian M0untains （QLM）, China, between 2000 and 2011. T0 acc0mplish this, we used linear regressi0n techniques 0n 250-m MODIS N0rmalized Difference Vegetati0n Index （NDVI） datasets and mete0r0l0gical rec0rds t0 determine spati0temp0ral variability in vegetati0n c0ver and climatic fact0rs （i.e. temperature and precipitati0n）. Our results sh0wed that temperatures and precipitati0n have increased in this regi0n during 0ur study peri0d. In additi0n, we f0und that gr0wing seas0n mean NDVI was mainly distributed in the vertical z0ne fr0m 2,700 m t0 3,600 m in elevati0n. In the study regi0n, we 0bserved significant p0sitive and negative trends in vegetati0n c0ver in 26.71% and 2.27% 0f the vegetated areas. C0rrelati0n analyses indicated that rising precipitati0n fr0m May t0 August was resp0nsible f0r increased vegetati0n c0ver in areas with p0sitive trends in gr0wing seas0n mean NDVI. H0wever, there was n0 similar significant c0rrelati0n between gr0wing seas0n mean NDVI and precipitati0n in regi0ns where vegetati0n c0ver declined thr0ugh0ut 0ur study peri0d. Using spatial statistics, we f0und that veeetati0n c0ver freauentlvdeclined in areas within the 2,500-3,100 m vertical z0ne, where it has steep sl0pe, and is 0n the sunny side 0f m0untains. Here, the p0sitive influences 0f increasing precipitati0n c0uld n0t 0ffset the drier c0nditi0ns that 0ccurred thr0ugh warming trends. In c0ntrast, in higher elevati0n z0nes （3,900-4,500 m） 0n the shaded side 0f the m0untains, rising temperatures and increasing precipitati0n impr0ved c0nditi0ns f0r vegetati0n gr0wth. Increased precipitati0n als0 facilitated vegetati0n gr0wth in areas experiencing warming trends at l0wer elevati0ns （2,000-2,400 m） and 0n l0wer sl0pes where water was m0re easily c0nserved. We suggest that spatial differences in variati0n in vegetati0n as the result 0f climate change depend 0n l0cal m0isture and thermal c0nditi0ns, which are mainly c0ntr0lled by t0p0graphy （e.g. elevati0n, aspect, and sl0pe）, and 0ther fact0rs, such as l0cal hydr0l0gy.     

Response of biomass spatial pattern of alpine vegetation to climate change in permafrost region of the Qinghai-Tibet Plateau,China

Alpine ecosystems in permafrost region are extremely sensitive to climate changes.To determine spatial pattern variations in alpine meadow and alpine steppe biomass dynamics in the permafrost region of the Qinghai-Tibet Plateau,China,calibrated with historical datasets of above-ground biomass production within the permafrost region's two main ecosystems,an ecosystem-biomass model was developed by employing empirical spatialdistribution models of the study region's precipitation,air temperature and soil temperature.This model was then successfully used to simulate the spatio-temporal variations in annual alpine ecosystem biomass production under climate change.For a 0.44°C decade-1 rise in air temperature,the model predicted that the biomasses of alpine meadow and alpine steppe remained roughly the same if annual precipitation increased by 8 mm per decade-1,but the biomasses were decreased by 2.7% and 2.4%,respectively if precipitation was constant.For a 2.2°C decade-1 rise in air temperature coupled with a 12 mm decade-1 rise in precipitation,the model predicted that the biomass of alpine meadow was unchanged or slightly increased,while that of alpine steppe was increased by 5.2%.However,in the absence of any rise in precipitation,the model predicted 6.8% and 4.6% declines in alpine meadow and alpine steppe biomasses,respectively.The response of alpine steppe biomass to the rising air temperatures and precipitation was significantly lesser and greater,respectively than that of alpine meadow biomass.A better understanding of the difference in alpine ecosystem biomass production under climate change is greatly significant with respect to the influence of climate change on the carbon and water cycles in the permafrost regions of the Qinghai-Tibet Plateau.     

Contrasting changes in above- and below-ground biomass allocation across treeline ecotones in southeast Tibet

Under conditions of a warmer climate, the advance of the alpine treeline into alpine tundra has implications for carbon dynamics in mountain ecosystems. However, the above- and below-ground live biomass allocations among different vegetation types within the treeline ecotones are not well investigated. To determine the altitudinal patterns of above-/below-ground carbon allocation, we measured the root biomass and estimated the above-ground biomass (AGB) in a subalpine forest, treeline forest, alpine shrub, and alpine grassland along two elevational transects towards the alpine tundra in southeast Tibet. The AGB strongly declined with increasing elevation, which was associated with a decrease in the leaf area index and a consequent reduction in carbon gain. The fine root biomass (FRB) increased significantly more in the alpine shrub and grassland than in the treeline forest, whereas the coarse root biomass changed little with increasing altitudes, which led to a stable below-ground biomass (BGB) value across altitudes. Warm and infertile soil conditions might explain the large amount of FRB in alpine shrub and grassland. Consequently, the root to shoot biomass ratio increased sharply with altitude, which suggested a remarkable shift of biomass allocation to root systems near the alpine tundra. Our findings demonstrate contrasting changes in AGB and BGB allocations across treeline ecotones, which should be considered when estimating carbon dynamics with shifting treelines.     

Palynostratigraphy of Upper Cretaceous and boundary Paleogene deposits in West Siberian Plain

The article presents the results of many years of studies of the Upper Cretaceous and Paleogene sediments in the territory of West Siberian Plain. The heterogeneous structure of these sediments in different regions of the plain is shown. The lithological and palynological characteristics of a number of studied wells drilled in different years in Omsk and Kulunda Depressions, in Baraba Lowland and Bakchar Basin are given. The obtained palynological data allowed to substantiate the age of the deposits and to make suggestions concerning their depositional environment, and to clarify the subdivision of geological section into formations. The sections of the Upper Cretaceous and Paleogene deposits in different lithofacial regions of the Western Siberia differ from each other in completeness, genesis, and paleontological characteristics. The Upper Cretaceous sediments in Western Siberia are represented by formations of both marine(Pokur, Kuznetzovo, Ipatovo, Slavgorod and Gan'kino Formations) and continental genesis(Lenkovo and Sym formations). The Paleogene sediments, with the exception of Oligocene, mostly have a marine genesis-these are Talitsa-, Marsyat-, Lulinvor-, Tavda-and Yurki formations, but there are also continental sediments(Ostrovnoje Formation). A large stratigraphic break in the Upper Cretaceous and Paleogene boundary deposits, covering a significant part of the Maastrichtian, Paleocene, Ypresian, and Lutetian stages of the Eocene, was established in the sourheast of the West Siberian Plain(Bakchar Basin, Baraba Lowland and Kulunda Depression). The most complete sections are located in the Omsk Depression, where the Upper Cretaceous Gan'kino Formation is covered by Talitsa and Lulinvor Formations of Paleogene age. The most important events occurring at the boundary of the Cretaceous and Paleogene in Western Siberia can be traced currently in a few sections located in the Trans-Ural area, since there was no sedimentation in the rest of the territory at that time.     

Vascular plants distribution in relation to topography and environmental variables in alpine zone of Kedarnath Wild Life Sanctuary,West Himalaya

The present study was carried out in Tungnath alpine meadows of Kedarnath Wild Life Sanctuary, Western Himalaya from subalpine to upper alpine zone. A total of four summits were selected along an altitudinal gradient and sampled for detailed vegetation analysis using multi summit approach as per Global observation research initiative in alpine environments(GLORIA). Species richness, diversity, and evenness among four summits as well as the interaction between environmental variables with plant communities were assessed. Monthly mean soil temperature was calculated using data retrieved from geo-precision temperature logger in order to identify the trend of soil temperature among different season and altitudinal gradient and its implications to plant communities. Soil samples were analyzed fromeach summit by collecting randomized composite soil samples. The indirect non-metric multidimensional scaling(NMDS) and direct canonical correspondence analysis(CCA) tools of ordination techniques to determine the linkage between plant species from various sample summits and biotic/abiotic environmental gradients were used in the present study. The results of the study demonstrated increase in species richness as soil temperature increases, the ecotone representing summits were found most warm summits followed by highest species richness. Annual soil temperature increased by 1.43°C at timberline ecotone. Whereas, at upper alpine zone the soil temperature increased by 0.810 C from year 2015 to 2016. S?rensen's similarity index was found to be increased between subalpine and upper alpine zone with increase in the presence of subalpine plant species at upper alpine zone. Both the ordination tools separate the subalpine summit and their respective vegetation from summits representingtimberline ecotone and upper alpine zone. Soil p H, altitude, soil cation exchange capacity were found as the key abiotic drivers for distribution of plant species.     

Assessing adaptability and response of vegetation to glacier recession in the afro-alpine moorland terrestrial ecosystem of Rwenzori Mountains

The objective of this study was to explore vegetation adaptability in a changing afro-alpine moorland terrestrial ecosystem on Mt. Rwenzori and to determine whether there were any links with response of vegetation to glacier recession. We analyzed the composition and distribution of plant species in relation to soils, geomorphic processes, and landscape positions in the Alpine zone. To accomplish this objective, archival data sources and published reports for this ecosystem were reviewed. A field trip was conducted in 2010 to study in detail seven vegetation sampling plots that were systematically selected using GIS maps and a nested-quadrat sampling design framework along an altitudinal gradient in the lower and upper alpine zones. Using these sampling plots, 105 vegetation and 13 soil samples were assessed in the alpine zone. Soil samples were taken for laboratory testing and analysis. The results show statistically significant differences in p H, OM, N, P, Ca, Mg, and K pools between soils samples drawn from the lower and upper alpine sites(p 0.0033). Furthermore, we observed a significant vegetation formation with numerous structural forms, but there was a limited diversity of species. The mostsignificant forms included Alchemilla carpets, Bogs, Dendrosenecio woodland, and Scree slopes. The lower alpine area(3500–3900 masl) had a more diverse plant species than other areas, especially Alchemilla argyrophylla and Dendrosenecio adnivalis species that were evident due to well-drained deeper soils. The Alchemilla subnivalis were evident at a higher altitude of above 4000 masl. Shifts in the Astareceae(e.g. Senecio species) were particularly prominent even on recently deglaciated areas. The spatial variations of species distribution, structure, and composition suggest there are serious implications in terms of ecosystem adaptability, resilience, and stability that require further evaluation.     

Responses of Alpine Wetlands to Climate Changes on the Qinghai-Tibetan Plateau Based on Remote Sensing

The alpine wetlands in QTP(Qinghai-Tibetan Plateau) have been profoundly impacted along with global climate changes. We employ satellite datasets and climate data to explore the relationships between alpine wetlands and climate changes based on remote sensing data. Results show that: 1) the wetland NDVI(Normalized Difference Vegetation Index) and GPP(Gross Primary Production) were more sensitive to air temperature than to precipitation rate. The wetland ET(evapotranspiration) across alpine wetlands was greatly correlated with precipitation rate. 2) Alpine wetlands responses to climate changes varied spatially and temporally due to different geographic environments, variety of wetland formation and human disturbances. 3) The vegetation responses of the Zoige wetland was the most noticeable and related to the temperature, while the GPP and NDVI of the Qiangtang Plateau and Gyaring-Ngoring Lake were significantly correlated with both temperature and precipitation. 4) ET in the Zoige wetland showed a significantly positive trend, while ET in Maidika wetland and the Qiangtang plateau showed a negative trend, implying wetland degradation in those two wetland regions. The complexities of the impacts of climate changes on alpine wetlands indicate the necessity of further study to understand and conserve alpine wetland ecosystems.     

三江源区不同退化程度的高寒草甸光谱特征分析

 青海三江源区是长江、黄河、澜沧江3大河流的发源地。草地是该区域的主体生态系统,高寒草甸是其主要类型。近30年来,三江源地区草地发生了大面积的退化,不同退化程度的高寒草甸光谱特征是高寒草甸遥感分类和退化监测的重要依据。2009年8月作者在青海省三江源区对高山嵩草、矮嵩草和藏嵩草3种未退化高寒草甸,以及4种不同退化程度的高山嵩草草甸,进行了地面光谱测量和草地样方调查。同时对实测光谱曲线进行了比较,提取和分析了它们在557nm、675nm和760nm处反射率,以及"红边"斜率。结果表明,3种高寒草甸的光谱曲线,以及4种退化程度高寒草甸和未退化高寒草甸的光谱曲线在557nm处的反射率差异较小,在675nm和760nm处的反射率及"红边"斜率存在明显差异,能有效区分高寒草甸,可为高寒草甸遥感自动分类和退化监测提供依据。不同退化程度的高寒草甸地上生物量与其光谱曲线的"红边"斜率和归一化植被指数(NDVI)线性拟合的确定系数分别为0.93和0.87,其相关性较好,可用于高寒草甸地上生物量的估算。本文提取的光谱反射率的"红边"斜率不仅能有效区分3种典型高寒草甸和不同退化程度的高寒草甸,且与高寒草甸地上生物量的关系优于NDVI,对高寒草甸识别分类,退化监测和生物量估算有重要意义。     

Geodynamics and ore content of basite-ultrabasite complexes ofSiberian Platform southern framing rocks （Kodaro-Udokan and Muja zones of North Transbaikalye）

In southern framing of Siberian Platform, basite-ultrabasite intrusive complexes were forming over a long period of time (Early Proterozoic-Paleozoic Era) as a result of collisional and post-collisional processes. In Muja zone they formed mainly in island-arch geodynamic conditions, in Kodaro-Udokan zone-in continental. Most productive toward noble metals in Muja zones are basite-ultrabasites of the Dovyrensk complex‘, in Kodaro-Udokan basites of the Chiney complex. Gold in these formations has both mantle and crustal springs.     

Alpine taxa exhibit differing responses to climate warming in the Snowy Mountains of Australia

The phenologies of plants and animals in snow-covered landscapes are expected to accelerate with global warming. However, there are few studies that have examined a range of unrelated taxa in alpine environments to determine whether there is commonality in the proximate causes, synchrony in timing, or the direction of any changes. Records for five alpine animal species and two alpine plant species, chosen primarily for their visibility, were examined to determine their temporal response to regional climate warming. Over the 30-year period studied, they showed an array of different phenological responses. Plant flowering appeared linked to date of snow melt, whereas animal responses varied. Although having accelerated phenologies, two migratory bird species exhibited contrary changes; one to low-altitude warming regardless of snow conditions in the alpine zone (flame robin) and the other to state of the snowpack regardless of low-altitude temperatures (Richard’s pipit). By contrast, the migratory bogong moth arrived significantly later over the years with no apparent explanatory climatic cause. Although bogong moths are not responding to earlier snow melt, insectivorous predators on the ground are. This could lead to a serious mismatch in timing at different trophic levels, putting pressure on endangered vertebrates. Emergence of locally wintering insect species, March flies and Macleay’s swallowtails, were not significantly related to measured climatic parameters over the study period. A consequence of the disparate responses to climate warming recorded here is the questionable value of ‘indicator species’ to examine the impact of climate warming on alpine ecosystems.     

The influence of seasonal snow on soil thermal and water dynamics under different vegetation covers in a permafrost region

Seasonal snow is one of the most important influences on the development and distribution of permafrost and the hydrothermal regime in surface soil. Alpine meadow, which constitutes the main land type in permafrost regions of the Qinghai-Tibet Plateau, was selected to study the influence of seasonal snow on the temperature and moisture in active soil layers under different vegetation coverage. Monitoring sites for soil moisture and temperature were constructed to observe the hydrothermal processes in active soil layers under different vegetation cover with seasonal snow cover variation for three years from 2010 to 2012. Differences in soil temperature and moisture in areas of diverse vegetation coverage with varying levels of snow cover were analyzed using active soil layer water and temperature indices. The results indicated that snow cover greatly influenced the hydrothermal dynamics of the active soil layer in alpine meadows. In the snow manipulation experiment with a snow depth greater than 15 cm, the snow cover postponed both the freeze-fall and thawrise onset times of soil temperature and moisture in alpine LC （lower vegetation coverage） meadows and of soil moisture in alpine HC （higher vegetation coverage） meadows; however, the opposite response occurred for soil temperatures of alpine HC meadows,where the entire melting period was extended by advancing the thaw-rise and delaying the freeze-fall onset time of the soil temperature. Snow cover resulted in a decreased amplitude and rate of variation in soil temperature, for both alpine HC meadows and alpine LC meadows, whereas the distinct influence of snow cover on the amplitude and rate of soil moisture variation occurred at different soil layers with different vegetation coverages. Snow cover increased the soil moisture of alpine grasslands during thawing periods. The results confirmed that the annual hydrothermal dynamics of active layers in permafrost were subject to the synergistic actions of both snow cover and vegetation coverage.     

Geodynamics and ore content of basite-ultrabasite complexes of Siberian Platform southern framing rocks (Kodaro-Udokan and Muja zones of North Transbaikalye)

In southern framing of Siberian Platform, basite-ultrabasite intrusive complexes were forming over a long period of time (Early Proterozoic-Paleozoic Era) as a result of collisional and post-collisional processes. In Muja zone they formed mainly in island-arch geodynamic conditions, in Kodaro-Udokan zone-in continental. Most productive toward noble metals in Muja zones are basite-ultrabasites of the Dovyrensk complex, in Kodaro-Udokan basites of the Chiney complex. Gold in these formations has both mantle and crustal springs.     

Shrub Communities and Environmental Variables Responsible for Species Distribution Patterns in an Alpine Zone of the Qilian Mountains,Northwest China

Understanding the factors that drive variation in species distribution is a central theme of ecological research. Although several studies focused on alpine vegetation, few efforts have been made to identify the environmental factors that are responsible for the variations in species composition and richness of alpine shrublands using numericalmethods. In the present study, we investigated vegetation and associated environmental variables from 45 sample plots in the middle Qilian Mountains of the northwestern China to classify different community types and to elucidate the speciesenvironment relationships. We also estimated the relative contributions of topography and site conditions to spatial distribution patterns of the shrub communities using the variation partitioning. The results showed that four shrub community types were identified and striking differences in floristic composition were found among them. Species composition greatly depended on elevation, slope,shrub cover, soil p H and organic carbon. The important determinants of species richness were soil bulk density and slope. No significant differences in species richness were detected among the community types. Topography and site conditions had almost equal effects on compositional variation. Nonetheless,a large amount of the variation in species composition remained unexplained.