The growth,survival,and mortality of conifer species in response to the hydrothermal regime have received considerable attention.It is expected that the highest sensitivity of trees to the warming-drying climate will ...The growth,survival,and mortality of conifer species in response to the hydrothermal regime have received considerable attention.It is expected that the highest sensitivity of trees to the warming-drying climate will occur mainly at the edges of the species ranges.We focused on the responses to climate change of the drought-resistant larch(Larix sibirica)and the moisture-sensitive Siberian pine(Pinus sibirica)along the elevation gradient in the Tannu-Ola Ridge,the southern margin where those two species coexist in Siberia by using satellite data(MODIS,Landsat,and microwave),the indexes of gross(GPP)and net(NPP)primary productivity,and tree radial growth index(GI).We found that since the warming restart in the 2000s,the area of larch-dominated forests increased by~150%while the area of pine-dominated forests decreased by~10%.The Siberian pine has retreated at low elevations(<1800 m)and increased its area at higher ones.In contrast,the area of larch stands increased in both the uphill and downhill directions.Birch(Betula spp.)also increased its area at low elevations(about+120%).Since 2001,the forested area increased by~5%.A shrubification,i.e.,an increase in the area of shrubs,was observed at high elevations.The uphill rate of timberline and shrubline migration was about 0.3 m/a.Since the 2000s,vegetation NPP has increased by 13%.A notable correlation between NPP and the GI of larch and pine was found(r=0.5-0.7).At lower elevations,NPP positively correlated with precipitation and soil moisture,while air temperature and VPD(vapor pressure deficit)increase inhibited productivity.At high elevations,the effects of these variables on productivity reversed.The continuous decline of the Siberian pine forest indicates an inevitable retreat of this species at low elevations and its replacement by larch and birch.展开更多
Poyang Lake,China's largest freshwater lake,is a critical wintering ground for most of the global Siberian Grane(Grus leucogeranus)population.However,increasingly prolonged dry seasons have degraded the natural we...Poyang Lake,China's largest freshwater lake,is a critical wintering ground for most of the global Siberian Grane(Grus leucogeranus)population.However,increasingly prolonged dry seasons have degraded the natural wetlands of Poyang Lake,forcing Siberian Cranes to shift to artificial habitats.From 2015 to 2023,field surveys revealed a substantial increase in the number of Siberian Cranes in artificial habitats,with peak counts reaching 3000individuals,accounting for up to 53%of the species'global population.Satellite telemetry of 13 individuals further confirmed the spatial use of these habitats,highlighting their consistent reliance on artificial sites over multiple years.Seven high-use hotspots were identified outside of Poyang Lake,including two artificial provisioning sites that supported dense foraging flocks for extended periods.Satellite telemetry confirmed this trend,with artificial habitats making up to 64.2%of the occurrence sites in some years.This reliance on artificial habitats was closely linked to the reduced tuber biomass in natural wetlands and low winter water levels in Poyang Lake,which collectively explained 83%of the variance in crane abundance in artificial habitats.Artificial habitat use peaked in December and January,indicating marked seasonal variation.Siberian Cranes also exhibited a pronounced circadian rhythm,foraging in artificial habitats during the day and returning to natural wetlands to roost at night.Despite the shift toward artificial habitats,natural wetlands remain critical for nighttime refuge.The continued dependence on artificial habitats raises concerns about disease transmission owing to dense congregations.Conservation strategies should prioritize both the careful management of artificial provisioning sites and the restoration of natural wetlands to improve food and habitat availability within natural ecosystems,ultimately enabling the return of Siberian Cranes to their traditional natural habitats.展开更多
Food abundance and availability constitute fundamental determinants of foraging habitat quality for waterbirds, with high-quality foraging habitats playing a crucial role in supporting the survival and annual life cyc...Food abundance and availability constitute fundamental determinants of foraging habitat quality for waterbirds, with high-quality foraging habitats playing a crucial role in supporting the survival and annual life cycle of wintering populations. The ongoing degradation and loss of optimal habitats have forced wintering waterbirds to increasingly rely on alternative foraging sites and modify their behavioral adaptation strategies to cope with food scarcity. The Siberian Crane (Leucogeranus leucogeranus), a large-bodied endangered waterbird species characterized by specialized dietary preferences, demonstrates particular sensitivity to environmental alterations. Faced with diminishing suitable habitats and declining natural food resources, this species has progressively adapted to utilizing artificial habitats, including agricultural landscapes such as paddy fields and lotus ponds, as supplementary wintering foraging grounds to fulfill their energetic requirements. This study examines the hypothesis that Siberian Cranes adapt their foraging behavior through plastic behavioral strategies in artificial habitats under conditions of limited food availability, thereby enhancing population fitness. A comparative analysis of crane foraging behaviors was conducted between mudflats and lotus ponds throughout the 2023–2024 wintering period. This investigation focused on three critical environmental factors: food abundance, food burial depth, and sediment penetrability, examining their influence on foraging patterns across these distinct habitats. The results revealed significant inter-habitat differences: foraging success rates were substantially higher (p < 0.05) and food handling times markedly longer in lotus ponds compared to mudflats, whereas foraging effort and attempt frequency were significantly elevated in mudflat habitats. The superior food availability in lotus ponds facilitated enhanced foraging success rates, enabling cranes to accumulate essential energy reserves for winter survival. However, the deeper burial depth of lotus roots in these habitats required more intensive processing behaviors, including prolonged digging, breaking, and swallowing activities, which consequently increased handling time by approximately 40% and reduced foraging attempts by 25–30% compared to mudflat conditions. These behavioral trade-offs suggest that while lotus ponds provide adequate food resources, their structural characteristics may impose physiological constraints that limit their effectiveness as optimal foraging grounds for Siberian Cranes. These findings offer valuable insights into the behavioral plasticity of wintering Siberian Cranes response to spatial variations in food resource distribution, while contributing to our understanding of the ecological value of lotus roots as alternative winter food sources in artificial wetland ecosystems.展开更多
Poyang Lake (PYL) and the Yellow River Delta (YRD) are two critical wintering areas for the Siberian Crane (Leucogeranus leucogeranus) along the East Asian–Australasian Flyway in China. Based on nearly two decades of...Poyang Lake (PYL) and the Yellow River Delta (YRD) are two critical wintering areas for the Siberian Crane (Leucogeranus leucogeranus) along the East Asian–Australasian Flyway in China. Based on nearly two decades of remote sensing and environmental data, this study used the MaxEnt model to assess wintering habitat suitability in Poyang Lake (PYL) and the Yellow River Delta (YRD). Landscape pattern and ecological network (EN) analyses were integrated to examine habitat changes and their impact on Siberian Crane distribution. In PYL, land use/land cover (LULC) change was driven primarily by water level fluctuations, leading to transitions among natural habitat types. In contrast, LULC change in YRD was dominated by anthropogenic activities, with widespread conversion of natural habitats into artificial habitats. In both regions, Siberian Cranes favored wetlands that are food-rich, flat, and minimally disturbed. In PYL, ecological sources were mainly found in sub-lakes of nature reserves and nearby moist areas, averaging 87.42 km^(2). In the YRD, sources were distributed across tidal flats, paddy land, and grasslands, with a larger mean area of 198.37 km^(2). Mann–Kendall tests showed significant trends in PYL, including increased patch density and decreased EN cumulative resilience. The maximum habitat suitability in the YRD significantly declined. Comparative analysis revealed that PYL had significantly higher habitat suitability and EN cumulative resilience, whereas the YRD had larger but more fragmented habitats. By introducing key stepping-stone nodes to optimize the ENs, the connectivity and resilience of PYL's EN were notably enhanced. Although improvements in the YRD were less marked, the optimization scheme still improved the security of the crane migration network. Based on the findings, it is recommended to implement refined water level management in PYL to maintain the stability of sub-lakes and adjacent wetlands, and to strengthen the protection of natural wetlands in the YRD by limiting the expansion of artificial land use, in order to mitigate habitat fragmentation.展开更多
Arctic climate changes have profoundly influenced the polar environmental changes in recent years.The Arctic Oscillation(AO),as a key component of the Arctic climate system’s internal variability,affects the source t...Arctic climate changes have profoundly influenced the polar environmental changes in recent years.The Arctic Oscillation(AO),as a key component of the Arctic climate system’s internal variability,affects the source to sink processes and interactions across the multilayer Arctic system by regulating the land,ocean,sea ice,and atmospheric processes.The East Siberian Arctic Shelf(ESAS)has experienced significant changes in the input,transport,and burial of sedimentary organic carbon(OC)due to climate warming and shifts in the AO phase in recent decades.This study analyzes grain size,total organic carbon(TOC),total nitrogen(TN),and stable carbon isotope(δ^(13)C)in two sediment cores from the ESAS to reconstruct the burial record of OC over the past few decades and examine the response mechanism of sedimentary OC records to regional-scale climate forcing.The results show that the OC in the two sediment cores originates from mixed sources with a dominant terrestrial contribution.In the LV83-28 core from the Laptev Sea,the TOC and TN contents have increased at an accelerated rate since the 1990s,with a noticeable rise in the contribution of terrestrial OC.This trend is linked to an increase in terrigenous input caused by the positive AO phase.Core LV83-39 in the East Siberian Sea could have accumulated more terrestrial OC transported along the continental shelf during the positive AO.This implies that,under the interannual regulation of the AO regime,the input and crossshelf transport of terrigenous OC in the ESAS showed consistent sedimentary responses.This finding could enhance the understanding of the burial mechanism of sedimentary OC and its environmental response to regional climate change.展开更多
By using the monthly average dataset of NCEP/NCAR reanalysis and the monthly average ocean temperature data of NOAA satellite center,we analyzed and probed into the relationship between Siberian high anomaly and SSTA,...By using the monthly average dataset of NCEP/NCAR reanalysis and the monthly average ocean temperature data of NOAA satellite center,we analyzed and probed into the relationship between Siberian high anomaly and SSTA,and found that the sea area anomaly is a bigger area,which have greater effect on the variation of Siberian high.The results indicated that there was a wonderful contemporaneously correlation between the area and intensity index of Siberian high and ocean temperature.The correlation type of the synchronous correlative areas between the central intensity index of Siberian high and ocean temperature have structural similarities with the correlative field's structure of area index,but the positive correlative regions expanded,and the intensity of negative correlative regions weakened significantly.The correlation among the area index of Siberian high and the central intensity index,as well as the ocean temperature anomaly of the North Atlantic during spring,autumn and summer of the same year was remarkable.The area index and the central intensity index of Siberian high anomaly have obvious correlation with the ocean temperature anomaly of Southwest Atlantic Ocean during spring,summer and autumn,however,they have apparent seasonal differences with the prominent negative correlative areas of subtropical South Indian Ocean and tropical South Pacific Ocean as well as Southwest Atlantic Ocean.The correlative index of area anomaly is greater than those of intensity anomaly.Larger impact on the variability of Siberian high anomaly are the SSTA of subtropical South Indian Ocean,mid and high latitudes of North Pacific Ocean,North Atlantic,tropical South Pacific Ocean,Southwest Atlantic Ocean,etc.several areas.展开更多
Using the NCEP/ NCAR reanalysis dataset covering a 40-year period from January 1958 to December 1997, sea surface temperature (1950-1992), and monthly sea-ice concentration dataset for the period from 1953 to 1995, we...Using the NCEP/ NCAR reanalysis dataset covering a 40-year period from January 1958 to December 1997, sea surface temperature (1950-1992), and monthly sea-ice concentration dataset for the period from 1953 to 1995, we investigate connections between winter Arctic Oscillation (AO) and Siberian high (SH), the East Asian winter monsoon (EAWM), and winter sea-ice extent in the Barents Sea. The results indicate that winter AO not only influences climate variations in the Arctic and the North Atlantic sector, but also shows possible effects on winter SH, and further influences EAWM, When winter AO is in its positive phase, both of winter SH and the EAWM are weaker than normal, and air temperature from near the surface to the middle troposphere is about 0.5-2degreesC higher than normal in the southeastern Siberia and the East Asian coast, including eastern China, Korea, and Japan. When AO reaches its negative phase, an opposite scenario can be observed. The results also indicate that winter SH has no significant effects on climate variations in Arctic and the North Atlantic sector. Its influence intensity and extent are obviously weaker than AO, exhibiting a 'local, feature in contrast to AO. This study further reveals the possible mechanism of how the winter AO is related to winter SH. It is found that winter SH variation is closely related to both dynamic processes and air temperature variations from the surface to the middle troposphere. The western SH variation mainly depends on dynamic processes, while its eastern part is more closely related to air temperature variation. The maintaining of winter SH mainly depends on downward motion of airflow of the nearly entire troposphere. The airflow originates from the North Atlantic sector, whose variation is influenced by the AO. When AO is in its positive (negative) phase, downward motion remarkably weakened (strengthened), which further influences winter SH. In addition, winter AO exhibits significant influences on the simultaneous sea-ice extent in the Barents Sea.展开更多
During 1979–2015, the intensity of the Siberian high(SH) in November and December–January(DJ) is frequently shown to have an out-of-phase relationship, which is accompanied by opposite surface air temperature and ci...During 1979–2015, the intensity of the Siberian high(SH) in November and December–January(DJ) is frequently shown to have an out-of-phase relationship, which is accompanied by opposite surface air temperature and circulation anomalies.Further analyses indicate that the autumn Arctic sea ice is important for the phase reversal of the SH. There is a significantly positive(negative) correlation between the November(DJ) SH and the September sea ice area(SIA) anomalies. It is suggested that the reduction of autumn SIA induces anomalous upward surface turbulent heat flux(SHF), which can persist into November, especially over the Barents Sea. Consequently, the enhanced eddy energy and wave activity flux are transported to mid and high latitudes. This will then benefit the development of the storm track in northeastern Europe. Conversely, when downward SHF anomalies prevail in DJ, the decreased heat flux and suppressed eddy energy hinder the growth of the storm track during DJ over the Barents Sea and Europe. Through the eddy–mean flow interaction, the strengthened(weakened)storm track activities induce decreased(increased) Ural blockings and accelerated(decelerated) westerlies, which makes the cold air from the Arctic inhibited(transported) over the Siberian area. Therefore, a weaker(stronger) SH in November(DJ) occurs downstream. Moreover, anomalously large snowfall may intensify the SH in DJ rather than in November. The ensemble-mean results from the CMIP5 historical simulations further confirm these connections. The different responses to Arctic sea ice anomalies in early and middle winter set this study apart from earlier ones.展开更多
In recent decades the Arctic surface air temperature(SAT) in autumn has been increasing steadily. In winter, however, instead of a linear trend, the Arctic SAT shows an abrupt change that occurred in 2004. During the ...In recent decades the Arctic surface air temperature(SAT) in autumn has been increasing steadily. In winter, however, instead of a linear trend, the Arctic SAT shows an abrupt change that occurred in 2004. During the years from 1979 to 2003, the first principle component(PC1) of winter Arctic SAT remains stable, and no significant increasing trend is detected. However, the PC1 changes abruptly from negative to positive phase in the winter of 2004. The enhanced Siberian high may have contributed to this abrupt change because the temporal evolution of Arctic temperature correlates significantly with sea level pressure variation in the northern Eurasian continent, and the atmospheric circulation anomaly related to the Siberian high from 2004 to 2013 favors a warmer Arctic. With the help of the meridional wind anomaly around the Siberian high, warmer air is transported to the high latitudes and therefore increases the Arctic temperature.展开更多
Blooming date is an important trait in fruit tree species.Although several quantitative trait loci confirming blooming date were identified in Prunus spp.,the molecular mechanism underlying it remains unclear.Arising ...Blooming date is an important trait in fruit tree species.Although several quantitative trait loci confirming blooming date were identified in Prunus spp.,the molecular mechanism underlying it remains unclear.Arising from this,the transcriptomes of normal blooming and lateblooming Siberian apricot(P.sibirica L.)flower buds were analyzed using RNA-seq technology.A total of 68,855 unigenes were de novo assembled,among which 1204 were differentially expressed between normal and late blooming.Gene ontology enrichment analysis revealed that biological processes were enriched with metabolic processes.The catalytic-related gene transcripts between the two types of blooming were significantly changed in the molecular function.Kyoto Encyclopedia of Genes and Genomes pathway analysis showed that 156 genes were successfully annotated and 75 pathways enriched.Genes for gibberellin biosynthesis were up-regulated in normal blooming,whereas abscisic acid degradation-related genes were also up-regulated in normal blooming.Moreover,circadian rhythms related genes including EARLY FLOWERING 4,LATE ELONGATED HYPOCOTYL and CIRCANDIAN CLOCK ASSOCIATED1 were all up-regulated in normal blooming,indicating that circadian rhythms have a very important role in controlling blooming date.Furthermore,zinc finger protein CONSTANS-LIKE 12 was blasted onto the quantitative trait loci region on linkage group 4 in peach.However,changes in the abundance of key flowering genes such as SUPPRESSOR OF OVEREXPRESSION OF CONSTANS 1,FLOWERING LOCU T,LEAFY and FLOWERING LOCUS C were not significantly different,indicating that further investigation should explore the function of these genes on blooming date.The outcomes of this study will provide a valuable platform for further research on the molecular mechanism of blooming date in Prunus.展开更多
The annual cycle of the thickness and temperature of landfast sea ice in the East Siberian Sea has been examined using a one-dimensional thermodynamic model. The model was calibrated for the year August 2012-July 2013...The annual cycle of the thickness and temperature of landfast sea ice in the East Siberian Sea has been examined using a one-dimensional thermodynamic model. The model was calibrated for the year August 2012-July 2013, forced using the data of the Russian weather station Kotel＇ny Island and ECMWF reanalyses. Thermal growth and decay of ice were reproduced well, and the maximum annual ice thickness and breakup day became 1.64 m and the end of July. Oceanic heat flux was 2 W.m^-2 in winter and raised to 25 W.m^-2 in summer, albedo was 0.3-0.8 depending on the surface type （snow/ice and wet/dry）. The model outcome showed sensitivity to the albedo, air temperature and oceanic heat flux. The modelled snow cover was less than 10 cm having a small influence on the ice thickness. In situ sea ice thickness in the East Siberian Sea is rarely available in publications. This study provides a method for quantitative ice thickness estimation by modelling. The result can be used as a proxy to understand the sea ice conditions on the Eurasian Arctic coast, which is important for shipping and high-resolution Arctic climate modelling.展开更多
Wetlands worldwide have suffered from serious degradation and transformation,leading to waterbirds increasingly dependent on agricultural fields for feeding.Although gut microbiota is an essential component of host he...Wetlands worldwide have suffered from serious degradation and transformation,leading to waterbirds increasingly dependent on agricultural fields for feeding.Although gut microbiota is an essential component of host health,the impacts of agricultural feeding on gut microbial community and pathogen transmission remain poorly understood.To fill this knowledge gap,we used 16S rRNA sequencing to characterize the fecal bacterial community of the Siberian Crane(Grus leucogeranus),a Critically Endangered species,that recently has shifted its foraging from largely Vallisneria tubers in Poyang Lake natural wetlands to crops(i.e.,rice seeds and lotus rhizomes)in agricultural fields.We compared the bacterial communities between tuber foraging cranes and crop foraging cranes.Our results indicate that diet shift greatly modified the gut microbiota diversity,composition and function.Crop foraging cranes had higher microbiota diversity than tuber foraging cranes.The alteration in microbiota composition and function were correlated with change in food nutrition.Tuber(i.e.,high in fiber)foraging cranes were enriched in Clostridiaceae with fiber digestion ability,and crop(i.e.,high in carbohydrate)foraging cranes were enriched in bacterial taxa and functions related to carbohydrate metabolism.The flexibility of gut microbiota might enhance Siberian Cranes’ability to adapt to novel diet and environment.However,many enriched families in crop foraging cranes were pathogenic bacteria,which might increase the susceptibility of cranes to pathogenic infection.Special caution should be taken to agricultural feeding waterbirds in Asia,where the widespread poultry-keeping in over-harvested rice fields might increase the transmission probability of pathogenetic bacteria among wild birds,domestic poultry and humans.展开更多
Both the Siberian Crane(Leucogeranus leucogeranus) and Hooded Crane(Grus monacha) have limited population sizes and are considered endangered by domestic Chinese and international agencies.To document the current size...Both the Siberian Crane(Leucogeranus leucogeranus) and Hooded Crane(Grus monacha) have limited population sizes and are considered endangered by domestic Chinese and international agencies.To document the current size of their respective populations and characterize their groups,between October 2012 and April 2013 we undertook fieldwork at four nature reserve areas within the Poyang Lake wetlands.We divided Poyanghu National Nature Reserve(PYH) into the Wucheng(PWC) and Hengfeng areas(PHF),because each are each located in different counties.Our fieldwork showed that the Siberian Crane occurred mainly in PYH(364 in the PHF,158 in the PWC) and the Nanjishan Wetland National Nature Reserve(NJS,with 200 individuals).The Hooded Crane was mainly distributed in PYH(302 in the PHF and 154 in the PWC).Family groups accounted for more than 50% of the total number of groups among both species,with Hooded Cranes forming more family groups than Siberian Cranes.Typically,these groups were formed of two adults with one offspring(Siberian Crane),and two adults with two offspring(Hooded Crane),with the mean family group size of the Siberian Crane and Hooded Crane being respectively 2.65±0.53(n=43) and 3.09±0.86(n=47) individuals per group.The mean collective group size of the Siberian Crane and Hooded Crane included 28.09±24.94(n=23) and 28.94±27.97(n=16) individuals per group,respectively,with the proportion of juveniles among Hooded Cranes being more than double that seen among the Siberian Cranes.展开更多
The stable isotopic composition(δ13C andδ15N)and carbon/nitrogen ratio(C/N)of particulate organic matter(POM)in the Chukchi and East Siberian shelves from July to September,2016 were measured to evaluate the spatial...The stable isotopic composition(δ13C andδ15N)and carbon/nitrogen ratio(C/N)of particulate organic matter(POM)in the Chukchi and East Siberian shelves from July to September,2016 were measured to evaluate the spatial variability and origin of POM.Theδ13CPOC values were in the range of−29.5‰to−17.5‰with an average of−25.9‰±2.0‰,and theδ15NPN values ranged from 3.9‰to 13.1‰with an average of 8.0‰±1.6‰.The C/N ratios in the East Siberian shelf were generally higher than those in the Chukchi shelf,while theδ13C andδ15N values were just the opposite.Abnormally low C/N ratios(<4),lowδ13CPOC(almost−28‰)and highδ15NPN(>10‰)values were observed in the Wrangel Island polynya,which was attributed to the early bloom of small phytoplankton.The contributions of terrestrial POM,bloom-produced POM and non-bloom marine POM were estimated using a three end-member mixing model.The spatial distribution of terrestrial POM showed a high fraction in the East Siberian shelf and decreased eastward,indicating the influence of Russian rivers.The distribution of non-bloom marine POM showed a high fraction in the Chukchi shelf with the highest fraction occurring in the Bering Strait and decreased westward,suggesting the stimulation of biological production by the Pacific inflow in the Chukchi shelf.The fractions of bloom-produced POM were highest in the winter polynya and gradually decreased toward the periphery.A negative relationship between the bloom-produced POM and the sea ice meltwater inventory was observed,indicating that the net sea ice loss promotes early bloom in the polynya.Given the high fraction of bloom-produced POM,the early bloom of phytoplankton in the polynyas may play an important role on marine production and POM export in the Arctic shelves.展开更多
Siberian silkmoth(SSM,Dendrolimus sibiricus Tschetv.)is the most important defoliator of Siberian pine(Pinus sibirica Du Tour)and fir(Abies sibirica Ledeb.)stands.Warming-induced SSM outbreaks are one of the major dri...Siberian silkmoth(SSM,Dendrolimus sibiricus Tschetv.)is the most important defoliator of Siberian pine(Pinus sibirica Du Tour)and fir(Abies sibirica Ledeb.)stands.Warming-induced SSM outbreaks are one of the major driving factors of successions within the taiga zone.It is suggested that climate change impacted the SSM range and life cycle.We analyzed the migration of alpine and northerly SSM outbreak boundaries in Siberia and the impact of the climate variables and topography on the outbreak dynamics.We used time-series scenes(multispectral data,and vegetation indexes EVI and NDII)in combination with field studies,climate variables,and GIS techniques.We found that SSM outbreaks in the area of alpine boundary shifted about 370 m uphill since the mid of 1950.The outbreak onset was promoted by increased dryness and active temperatures and decreased root zone moisture content in the spring-early summer period.The terrain topography strongly affected SSM outbreak onset and dynamics.Initially,the outbreak was located at the middle elevations on the gentle concave southeastern slopes,which are the favorable insect habitats between outbreaks.Then the outbreak expanded uphill and downhill,to steeper slopes,and both concave and convex terrains.Alongside with elevation range expansion,SSM surpassed its northern historical outbreak boundary:the potential outbreaks’boundary moved about 300 km northward.Climate warming contributes to SSM migration into former outbreak free conifer stands located in highlands and at northern latitudes.展开更多
Birch(Betula tortuosa)is one of the treeline forming species within the Siberian Mountains.We analysed the area dynamics of birch stands and the upslope climb of birch treeline based on the Landsat time series scenes ...Birch(Betula tortuosa)is one of the treeline forming species within the Siberian Mountains.We analysed the area dynamics of birch stands and the upslope climb of birch treeline based on the Landsat time series scenes and on-ground data.We found that since the warming onset(1970th)birch area increased by 10%,birch stands and treeline boundary were moving upslope with a rate of 1.4 m/yr and 4.0 m/yr.Birch upslope shift correlated with air temperatures at the beginning(May-June)and the end(August-October)of the growth period.Meanwhile,no correlation was found between birch upslope migration and precipitation.Winds negatively influenced both birch area growth and birch upslope climb during spring,fall,and wintertime.In the windy habitats,birch,together with larch and Siberian pine,formed clusters(hedges)which mitigated the influence of adverse winds.These clusters are the adaptive pattern for trees’upslope climb within windward slopes.The other adaptation to the harsh alpine ecotone habitat is non-leaf(bark)photosynthesis which supports tree survival.Thereby,Betula tortuosa upslope climb depends on the wind impact and warming in spring and fall that extended growth period.With ongoing warming and observed wind speed decrease on the background of sufficient precipitation,it is expected to further birch advance into alpine tundra in the Siberian Mountains.展开更多
Most of forest birds have the characteristics for habitat selection. The purpose of this study is to clarify the vegetation structure in breeding area of Siberian rubythroat (Luscinia calliope). In Daecheongbong peak,...Most of forest birds have the characteristics for habitat selection. The purpose of this study is to clarify the vegetation structure in breeding area of Siberian rubythroat (Luscinia calliope). In Daecheongbong peak, Mt. Seoraksan national park, South Korea from May to August, 2001, breeding population of Siberian rubythroat and the dominant species in breeding area of Siberian rubythroat (Luscinia calliope) were surveyed by line transect method along the ridge in the Daecheongbong peak area. Number of individuals and location of song posts were observed and recorded. According to the survey results, the study area was classified into high, middle and low density areas. Those birds selected the forest area of dominant species for Ermans birch and dwarf Siberian pine as habitat and preferred the shrubs area with the lower height and higher coverage.展开更多
Unusual reliefs on the Earth’s surface were found in aerial photographs of Eastern Siberia in the late 20</span><sup><span style="font-family:Verdana;">th</span></sup><span ...Unusual reliefs on the Earth’s surface were found in aerial photographs of Eastern Siberia in the late 20</span><sup><span style="font-family:Verdana;">th</span></sup><span style="font-family:Verdana;"> century. The facts justifying the connection are given by Siberian Fan Reliefs and the Tunguska Cosmic Body. It is most natural to assume that we are dealing with the falling of numerous fragments of a collapsed comet. The more likely version is that the comet is captured by the Earth-Moon system and remains in Earth orbit for some time.展开更多
Unusual reliefs on the Earth’s surface were found in aerial photographs of Eastern Siberia in the late 20<sup>th</sup> century. These reliefs consist of several tens (up to hundreds) of stripes that have ...Unusual reliefs on the Earth’s surface were found in aerial photographs of Eastern Siberia in the late 20<sup>th</sup> century. These reliefs consist of several tens (up to hundreds) of stripes that have arisen as a result of the destruction of vegetation and the surface layer of the ground. Structures of stripes are extended, ranging in size from 6 km to ≥20 km, with a width of several kilometers. Every strip (scratch on the ground) is roughly estimated to be up to 50 m wide and ≥500 m long. The stripes start from one edge of the relief and stretch at inter-vals to the other, slightly diverging symmetrically from the central axis. It was determined that these reliefs are not associated with the movement of soil (avalanches, mudflows) or with the impact of air currents (hurricanes, storm, tornado). Geographically, these struc-tures of stripes are located within a circle with a radius of 770 km, described around the epicenter of the Tunguska catastrophe.展开更多
In this paper,I report SHRIMP zircon U-Pb ages of Paleoproterozoic high-grade metasedimentary rocks from southwestern part of the Siberian Craton.Early Precambrian high-grade complex including garnet -biotite,hypersth...In this paper,I report SHRIMP zircon U-Pb ages of Paleoproterozoic high-grade metasedimentary rocks from southwestern part of the Siberian Craton.Early Precambrian high-grade complex including garnet -biotite,hypersthene-biotite and cordierite-bearing gneisses compose the Irkut terrane of the Sharyzhalgay Uplift.Protoliths of studied展开更多
基金supported by the Tomsk State University Development Program(《Priority-2030》)the Basic Project of the Federal Research Center of the Scientific Center,no.FWES-2024-0023the Russian Science Foundation(project No.23-14-20015)。
文摘The growth,survival,and mortality of conifer species in response to the hydrothermal regime have received considerable attention.It is expected that the highest sensitivity of trees to the warming-drying climate will occur mainly at the edges of the species ranges.We focused on the responses to climate change of the drought-resistant larch(Larix sibirica)and the moisture-sensitive Siberian pine(Pinus sibirica)along the elevation gradient in the Tannu-Ola Ridge,the southern margin where those two species coexist in Siberia by using satellite data(MODIS,Landsat,and microwave),the indexes of gross(GPP)and net(NPP)primary productivity,and tree radial growth index(GI).We found that since the warming restart in the 2000s,the area of larch-dominated forests increased by~150%while the area of pine-dominated forests decreased by~10%.The Siberian pine has retreated at low elevations(<1800 m)and increased its area at higher ones.In contrast,the area of larch stands increased in both the uphill and downhill directions.Birch(Betula spp.)also increased its area at low elevations(about+120%).Since 2001,the forested area increased by~5%.A shrubification,i.e.,an increase in the area of shrubs,was observed at high elevations.The uphill rate of timberline and shrubline migration was about 0.3 m/a.Since the 2000s,vegetation NPP has increased by 13%.A notable correlation between NPP and the GI of larch and pine was found(r=0.5-0.7).At lower elevations,NPP positively correlated with precipitation and soil moisture,while air temperature and VPD(vapor pressure deficit)increase inhibited productivity.At high elevations,the effects of these variables on productivity reversed.The continuous decline of the Siberian pine forest indicates an inevitable retreat of this species at low elevations and its replacement by larch and birch.
基金supported by the National Natural Science Foundation of China(No.32260275)Fundamental Research Funds of CAF(CAFYBB2024ZA033)。
文摘Poyang Lake,China's largest freshwater lake,is a critical wintering ground for most of the global Siberian Grane(Grus leucogeranus)population.However,increasingly prolonged dry seasons have degraded the natural wetlands of Poyang Lake,forcing Siberian Cranes to shift to artificial habitats.From 2015 to 2023,field surveys revealed a substantial increase in the number of Siberian Cranes in artificial habitats,with peak counts reaching 3000individuals,accounting for up to 53%of the species'global population.Satellite telemetry of 13 individuals further confirmed the spatial use of these habitats,highlighting their consistent reliance on artificial sites over multiple years.Seven high-use hotspots were identified outside of Poyang Lake,including two artificial provisioning sites that supported dense foraging flocks for extended periods.Satellite telemetry confirmed this trend,with artificial habitats making up to 64.2%of the occurrence sites in some years.This reliance on artificial habitats was closely linked to the reduced tuber biomass in natural wetlands and low winter water levels in Poyang Lake,which collectively explained 83%of the variance in crane abundance in artificial habitats.Artificial habitat use peaked in December and January,indicating marked seasonal variation.Siberian Cranes also exhibited a pronounced circadian rhythm,foraging in artificial habitats during the day and returning to natural wetlands to roost at night.Despite the shift toward artificial habitats,natural wetlands remain critical for nighttime refuge.The continued dependence on artificial habitats raises concerns about disease transmission owing to dense congregations.Conservation strategies should prioritize both the careful management of artificial provisioning sites and the restoration of natural wetlands to improve food and habitat availability within natural ecosystems,ultimately enabling the return of Siberian Cranes to their traditional natural habitats.
基金funded by the National Natural Science Foundation of China(No.32470553).
文摘Food abundance and availability constitute fundamental determinants of foraging habitat quality for waterbirds, with high-quality foraging habitats playing a crucial role in supporting the survival and annual life cycle of wintering populations. The ongoing degradation and loss of optimal habitats have forced wintering waterbirds to increasingly rely on alternative foraging sites and modify their behavioral adaptation strategies to cope with food scarcity. The Siberian Crane (Leucogeranus leucogeranus), a large-bodied endangered waterbird species characterized by specialized dietary preferences, demonstrates particular sensitivity to environmental alterations. Faced with diminishing suitable habitats and declining natural food resources, this species has progressively adapted to utilizing artificial habitats, including agricultural landscapes such as paddy fields and lotus ponds, as supplementary wintering foraging grounds to fulfill their energetic requirements. This study examines the hypothesis that Siberian Cranes adapt their foraging behavior through plastic behavioral strategies in artificial habitats under conditions of limited food availability, thereby enhancing population fitness. A comparative analysis of crane foraging behaviors was conducted between mudflats and lotus ponds throughout the 2023–2024 wintering period. This investigation focused on three critical environmental factors: food abundance, food burial depth, and sediment penetrability, examining their influence on foraging patterns across these distinct habitats. The results revealed significant inter-habitat differences: foraging success rates were substantially higher (p < 0.05) and food handling times markedly longer in lotus ponds compared to mudflats, whereas foraging effort and attempt frequency were significantly elevated in mudflat habitats. The superior food availability in lotus ponds facilitated enhanced foraging success rates, enabling cranes to accumulate essential energy reserves for winter survival. However, the deeper burial depth of lotus roots in these habitats required more intensive processing behaviors, including prolonged digging, breaking, and swallowing activities, which consequently increased handling time by approximately 40% and reduced foraging attempts by 25–30% compared to mudflat conditions. These behavioral trade-offs suggest that while lotus ponds provide adequate food resources, their structural characteristics may impose physiological constraints that limit their effectiveness as optimal foraging grounds for Siberian Cranes. These findings offer valuable insights into the behavioral plasticity of wintering Siberian Cranes response to spatial variations in food resource distribution, while contributing to our understanding of the ecological value of lotus roots as alternative winter food sources in artificial wetland ecosystems.
基金supported by the National Natural Science Foundation of China(Grant No.32360142).
文摘Poyang Lake (PYL) and the Yellow River Delta (YRD) are two critical wintering areas for the Siberian Crane (Leucogeranus leucogeranus) along the East Asian–Australasian Flyway in China. Based on nearly two decades of remote sensing and environmental data, this study used the MaxEnt model to assess wintering habitat suitability in Poyang Lake (PYL) and the Yellow River Delta (YRD). Landscape pattern and ecological network (EN) analyses were integrated to examine habitat changes and their impact on Siberian Crane distribution. In PYL, land use/land cover (LULC) change was driven primarily by water level fluctuations, leading to transitions among natural habitat types. In contrast, LULC change in YRD was dominated by anthropogenic activities, with widespread conversion of natural habitats into artificial habitats. In both regions, Siberian Cranes favored wetlands that are food-rich, flat, and minimally disturbed. In PYL, ecological sources were mainly found in sub-lakes of nature reserves and nearby moist areas, averaging 87.42 km^(2). In the YRD, sources were distributed across tidal flats, paddy land, and grasslands, with a larger mean area of 198.37 km^(2). Mann–Kendall tests showed significant trends in PYL, including increased patch density and decreased EN cumulative resilience. The maximum habitat suitability in the YRD significantly declined. Comparative analysis revealed that PYL had significantly higher habitat suitability and EN cumulative resilience, whereas the YRD had larger but more fragmented habitats. By introducing key stepping-stone nodes to optimize the ENs, the connectivity and resilience of PYL's EN were notably enhanced. Although improvements in the YRD were less marked, the optimization scheme still improved the security of the crane migration network. Based on the findings, it is recommended to implement refined water level management in PYL to maintain the stability of sub-lakes and adjacent wetlands, and to strengthen the protection of natural wetlands in the YRD by limiting the expansion of artificial land use, in order to mitigate habitat fragmentation.
基金The National Natural Science Foundation of China under contract Nos 42130412 and 42376068the Fundamental Research Funds for the Central Universities under contract No.202241001+2 种基金the Ocean Negative Carbon Emissions Program and the Taishan Scholar Program under contract No.TSQN20182117the Russian Scientific Foundation under contract No.21-77-30001the Ministry of Science and Higher Education of the Russian Federation under contract Nos 124022100083-1 and 124022100084-8.
文摘Arctic climate changes have profoundly influenced the polar environmental changes in recent years.The Arctic Oscillation(AO),as a key component of the Arctic climate system’s internal variability,affects the source to sink processes and interactions across the multilayer Arctic system by regulating the land,ocean,sea ice,and atmospheric processes.The East Siberian Arctic Shelf(ESAS)has experienced significant changes in the input,transport,and burial of sedimentary organic carbon(OC)due to climate warming and shifts in the AO phase in recent decades.This study analyzes grain size,total organic carbon(TOC),total nitrogen(TN),and stable carbon isotope(δ^(13)C)in two sediment cores from the ESAS to reconstruct the burial record of OC over the past few decades and examine the response mechanism of sedimentary OC records to regional-scale climate forcing.The results show that the OC in the two sediment cores originates from mixed sources with a dominant terrestrial contribution.In the LV83-28 core from the Laptev Sea,the TOC and TN contents have increased at an accelerated rate since the 1990s,with a noticeable rise in the contribution of terrestrial OC.This trend is linked to an increase in terrigenous input caused by the positive AO phase.Core LV83-39 in the East Siberian Sea could have accumulated more terrestrial OC transported along the continental shelf during the positive AO.This implies that,under the interannual regulation of the AO regime,the input and crossshelf transport of terrigenous OC in the ESAS showed consistent sedimentary responses.This finding could enhance the understanding of the burial mechanism of sedimentary OC and its environmental response to regional climate change.
文摘By using the monthly average dataset of NCEP/NCAR reanalysis and the monthly average ocean temperature data of NOAA satellite center,we analyzed and probed into the relationship between Siberian high anomaly and SSTA,and found that the sea area anomaly is a bigger area,which have greater effect on the variation of Siberian high.The results indicated that there was a wonderful contemporaneously correlation between the area and intensity index of Siberian high and ocean temperature.The correlation type of the synchronous correlative areas between the central intensity index of Siberian high and ocean temperature have structural similarities with the correlative field's structure of area index,but the positive correlative regions expanded,and the intensity of negative correlative regions weakened significantly.The correlation among the area index of Siberian high and the central intensity index,as well as the ocean temperature anomaly of the North Atlantic during spring,autumn and summer of the same year was remarkable.The area index and the central intensity index of Siberian high anomaly have obvious correlation with the ocean temperature anomaly of Southwest Atlantic Ocean during spring,summer and autumn,however,they have apparent seasonal differences with the prominent negative correlative areas of subtropical South Indian Ocean and tropical South Pacific Ocean as well as Southwest Atlantic Ocean.The correlative index of area anomaly is greater than those of intensity anomaly.Larger impact on the variability of Siberian high anomaly are the SSTA of subtropical South Indian Ocean,mid and high latitudes of North Pacific Ocean,North Atlantic,tropical South Pacific Ocean,Southwest Atlantic Ocean,etc.several areas.
基金the National Key Basic Research Program (Grant No.G 1998040900), the Frontier Research System for Global Change of Japan and the
文摘Using the NCEP/ NCAR reanalysis dataset covering a 40-year period from January 1958 to December 1997, sea surface temperature (1950-1992), and monthly sea-ice concentration dataset for the period from 1953 to 1995, we investigate connections between winter Arctic Oscillation (AO) and Siberian high (SH), the East Asian winter monsoon (EAWM), and winter sea-ice extent in the Barents Sea. The results indicate that winter AO not only influences climate variations in the Arctic and the North Atlantic sector, but also shows possible effects on winter SH, and further influences EAWM, When winter AO is in its positive phase, both of winter SH and the EAWM are weaker than normal, and air temperature from near the surface to the middle troposphere is about 0.5-2degreesC higher than normal in the southeastern Siberia and the East Asian coast, including eastern China, Korea, and Japan. When AO reaches its negative phase, an opposite scenario can be observed. The results also indicate that winter SH has no significant effects on climate variations in Arctic and the North Atlantic sector. Its influence intensity and extent are obviously weaker than AO, exhibiting a 'local, feature in contrast to AO. This study further reveals the possible mechanism of how the winter AO is related to winter SH. It is found that winter SH variation is closely related to both dynamic processes and air temperature variations from the surface to the middle troposphere. The western SH variation mainly depends on dynamic processes, while its eastern part is more closely related to air temperature variation. The maintaining of winter SH mainly depends on downward motion of airflow of the nearly entire troposphere. The airflow originates from the North Atlantic sector, whose variation is influenced by the AO. When AO is in its positive (negative) phase, downward motion remarkably weakened (strengthened), which further influences winter SH. In addition, winter AO exhibits significant influences on the simultaneous sea-ice extent in the Barents Sea.
基金supported by the National Key R&D Program of China (Grant No.2016YFA0600703)the National Natural Science Foundation of China (Grant Nos.41505073 and 41605059)+1 种基金the Research Council of Norway–supported project SNOWGLACE (Grant No.244166/E10)and the Young Talent Support Program of the China Association for Science and Technology (Grant No.2016QNRC001)
文摘During 1979–2015, the intensity of the Siberian high(SH) in November and December–January(DJ) is frequently shown to have an out-of-phase relationship, which is accompanied by opposite surface air temperature and circulation anomalies.Further analyses indicate that the autumn Arctic sea ice is important for the phase reversal of the SH. There is a significantly positive(negative) correlation between the November(DJ) SH and the September sea ice area(SIA) anomalies. It is suggested that the reduction of autumn SIA induces anomalous upward surface turbulent heat flux(SHF), which can persist into November, especially over the Barents Sea. Consequently, the enhanced eddy energy and wave activity flux are transported to mid and high latitudes. This will then benefit the development of the storm track in northeastern Europe. Conversely, when downward SHF anomalies prevail in DJ, the decreased heat flux and suppressed eddy energy hinder the growth of the storm track during DJ over the Barents Sea and Europe. Through the eddy–mean flow interaction, the strengthened(weakened)storm track activities induce decreased(increased) Ural blockings and accelerated(decelerated) westerlies, which makes the cold air from the Arctic inhibited(transported) over the Siberian area. Therefore, a weaker(stronger) SH in November(DJ) occurs downstream. Moreover, anomalously large snowfall may intensify the SH in DJ rather than in November. The ensemble-mean results from the CMIP5 historical simulations further confirm these connections. The different responses to Arctic sea ice anomalies in early and middle winter set this study apart from earlier ones.
基金supported by the National Basic Research Program of China (2013CBA01804 and 2015CB453200)the National Natural Science Foundation of China (41475080 and 41221064)State Oceanic Administration Project (201205007)
文摘In recent decades the Arctic surface air temperature(SAT) in autumn has been increasing steadily. In winter, however, instead of a linear trend, the Arctic SAT shows an abrupt change that occurred in 2004. During the years from 1979 to 2003, the first principle component(PC1) of winter Arctic SAT remains stable, and no significant increasing trend is detected. However, the PC1 changes abruptly from negative to positive phase in the winter of 2004. The enhanced Siberian high may have contributed to this abrupt change because the temporal evolution of Arctic temperature correlates significantly with sea level pressure variation in the northern Eurasian continent, and the atmospheric circulation anomaly related to the Siberian high from 2004 to 2013 favors a warmer Arctic. With the help of the meridional wind anomaly around the Siberian high, warmer air is transported to the high latitudes and therefore increases the Arctic temperature.
基金funded by the Fundamental Research Funds for the Central Universities(BLYJ201517)the Program for New Century Excellent Talents in University by the Ministry of Education,China(NCET-10-0223)
文摘Blooming date is an important trait in fruit tree species.Although several quantitative trait loci confirming blooming date were identified in Prunus spp.,the molecular mechanism underlying it remains unclear.Arising from this,the transcriptomes of normal blooming and lateblooming Siberian apricot(P.sibirica L.)flower buds were analyzed using RNA-seq technology.A total of 68,855 unigenes were de novo assembled,among which 1204 were differentially expressed between normal and late blooming.Gene ontology enrichment analysis revealed that biological processes were enriched with metabolic processes.The catalytic-related gene transcripts between the two types of blooming were significantly changed in the molecular function.Kyoto Encyclopedia of Genes and Genomes pathway analysis showed that 156 genes were successfully annotated and 75 pathways enriched.Genes for gibberellin biosynthesis were up-regulated in normal blooming,whereas abscisic acid degradation-related genes were also up-regulated in normal blooming.Moreover,circadian rhythms related genes including EARLY FLOWERING 4,LATE ELONGATED HYPOCOTYL and CIRCANDIAN CLOCK ASSOCIATED1 were all up-regulated in normal blooming,indicating that circadian rhythms have a very important role in controlling blooming date.Furthermore,zinc finger protein CONSTANS-LIKE 12 was blasted onto the quantitative trait loci region on linkage group 4 in peach.However,changes in the abundance of key flowering genes such as SUPPRESSOR OF OVEREXPRESSION OF CONSTANS 1,FLOWERING LOCU T,LEAFY and FLOWERING LOCUS C were not significantly different,indicating that further investigation should explore the function of these genes on blooming date.The outcomes of this study will provide a valuable platform for further research on the molecular mechanism of blooming date in Prunus.
基金supported by research funding from the National Natural Science Foundation of China (Grant nos. 41428603, 41376186, 41476170)the EU FP7 Project Eu Ru CAS(European-Russian Centre for Cooperation in the Arctic and Sub-Arctic Environmental and Climate Research,Grant no.295068)+2 种基金Academy of Finland (Grant nos. 11409391, 259537)the Liaoning Educational Committee Foundation (Grant no. L2013497)the Ocean Public Welfare Scientific Research Project of China (Grant nos. 201205007, 201205007-2)
文摘The annual cycle of the thickness and temperature of landfast sea ice in the East Siberian Sea has been examined using a one-dimensional thermodynamic model. The model was calibrated for the year August 2012-July 2013, forced using the data of the Russian weather station Kotel＇ny Island and ECMWF reanalyses. Thermal growth and decay of ice were reproduced well, and the maximum annual ice thickness and breakup day became 1.64 m and the end of July. Oceanic heat flux was 2 W.m^-2 in winter and raised to 25 W.m^-2 in summer, albedo was 0.3-0.8 depending on the surface type （snow/ice and wet/dry）. The model outcome showed sensitivity to the albedo, air temperature and oceanic heat flux. The modelled snow cover was less than 10 cm having a small influence on the ice thickness. In situ sea ice thickness in the East Siberian Sea is rarely available in publications. This study provides a method for quantitative ice thickness estimation by modelling. The result can be used as a proxy to understand the sea ice conditions on the Eurasian Arctic coast, which is important for shipping and high-resolution Arctic climate modelling.
基金the National Natural Science Foundation of China(Grant No.32160132,31772480).
文摘Wetlands worldwide have suffered from serious degradation and transformation,leading to waterbirds increasingly dependent on agricultural fields for feeding.Although gut microbiota is an essential component of host health,the impacts of agricultural feeding on gut microbial community and pathogen transmission remain poorly understood.To fill this knowledge gap,we used 16S rRNA sequencing to characterize the fecal bacterial community of the Siberian Crane(Grus leucogeranus),a Critically Endangered species,that recently has shifted its foraging from largely Vallisneria tubers in Poyang Lake natural wetlands to crops(i.e.,rice seeds and lotus rhizomes)in agricultural fields.We compared the bacterial communities between tuber foraging cranes and crop foraging cranes.Our results indicate that diet shift greatly modified the gut microbiota diversity,composition and function.Crop foraging cranes had higher microbiota diversity than tuber foraging cranes.The alteration in microbiota composition and function were correlated with change in food nutrition.Tuber(i.e.,high in fiber)foraging cranes were enriched in Clostridiaceae with fiber digestion ability,and crop(i.e.,high in carbohydrate)foraging cranes were enriched in bacterial taxa and functions related to carbohydrate metabolism.The flexibility of gut microbiota might enhance Siberian Cranes’ability to adapt to novel diet and environment.However,many enriched families in crop foraging cranes were pathogenic bacteria,which might increase the susceptibility of cranes to pathogenic infection.Special caution should be taken to agricultural feeding waterbirds in Asia,where the widespread poultry-keeping in over-harvested rice fields might increase the transmission probability of pathogenetic bacteria among wild birds,domestic poultry and humans.
基金supported by the National Natural Science Foundation of China(3126051731101651)
文摘Both the Siberian Crane(Leucogeranus leucogeranus) and Hooded Crane(Grus monacha) have limited population sizes and are considered endangered by domestic Chinese and international agencies.To document the current size of their respective populations and characterize their groups,between October 2012 and April 2013 we undertook fieldwork at four nature reserve areas within the Poyang Lake wetlands.We divided Poyanghu National Nature Reserve(PYH) into the Wucheng(PWC) and Hengfeng areas(PHF),because each are each located in different counties.Our fieldwork showed that the Siberian Crane occurred mainly in PYH(364 in the PHF,158 in the PWC) and the Nanjishan Wetland National Nature Reserve(NJS,with 200 individuals).The Hooded Crane was mainly distributed in PYH(302 in the PHF and 154 in the PWC).Family groups accounted for more than 50% of the total number of groups among both species,with Hooded Cranes forming more family groups than Siberian Cranes.Typically,these groups were formed of two adults with one offspring(Siberian Crane),and two adults with two offspring(Hooded Crane),with the mean family group size of the Siberian Crane and Hooded Crane being respectively 2.65±0.53(n=43) and 3.09±0.86(n=47) individuals per group.The mean collective group size of the Siberian Crane and Hooded Crane included 28.09±24.94(n=23) and 28.94±27.97(n=16) individuals per group,respectively,with the proportion of juveniles among Hooded Cranes being more than double that seen among the Siberian Cranes.
基金The National Natural Science Foundation of China under contract No.41721005the China Ocean Mineral Resources R&D Association(COMRA)Program under contract No.DY135-E2-2-03+1 种基金the Marine S&T Fund of Shandong Province for Pilot National Laboratory for Marine Science and Technology under contract No.2018SDKJ0104-3the Ministry of Science and Education of Russia Project under contract No.АААА-А17-117030110033-0.
文摘The stable isotopic composition(δ13C andδ15N)and carbon/nitrogen ratio(C/N)of particulate organic matter(POM)in the Chukchi and East Siberian shelves from July to September,2016 were measured to evaluate the spatial variability and origin of POM.Theδ13CPOC values were in the range of−29.5‰to−17.5‰with an average of−25.9‰±2.0‰,and theδ15NPN values ranged from 3.9‰to 13.1‰with an average of 8.0‰±1.6‰.The C/N ratios in the East Siberian shelf were generally higher than those in the Chukchi shelf,while theδ13C andδ15N values were just the opposite.Abnormally low C/N ratios(<4),lowδ13CPOC(almost−28‰)and highδ15NPN(>10‰)values were observed in the Wrangel Island polynya,which was attributed to the early bloom of small phytoplankton.The contributions of terrestrial POM,bloom-produced POM and non-bloom marine POM were estimated using a three end-member mixing model.The spatial distribution of terrestrial POM showed a high fraction in the East Siberian shelf and decreased eastward,indicating the influence of Russian rivers.The distribution of non-bloom marine POM showed a high fraction in the Chukchi shelf with the highest fraction occurring in the Bering Strait and decreased westward,suggesting the stimulation of biological production by the Pacific inflow in the Chukchi shelf.The fractions of bloom-produced POM were highest in the winter polynya and gradually decreased toward the periphery.A negative relationship between the bloom-produced POM and the sea ice meltwater inventory was observed,indicating that the net sea ice loss promotes early bloom in the polynya.Given the high fraction of bloom-produced POM,the early bloom of phytoplankton in the polynyas may play an important role on marine production and POM export in the Arctic shelves.
基金supported by the Russian Foundation for Basic Research,project nos.18-45-240003 and 18-05-00432。
文摘Siberian silkmoth(SSM,Dendrolimus sibiricus Tschetv.)is the most important defoliator of Siberian pine(Pinus sibirica Du Tour)and fir(Abies sibirica Ledeb.)stands.Warming-induced SSM outbreaks are one of the major driving factors of successions within the taiga zone.It is suggested that climate change impacted the SSM range and life cycle.We analyzed the migration of alpine and northerly SSM outbreak boundaries in Siberia and the impact of the climate variables and topography on the outbreak dynamics.We used time-series scenes(multispectral data,and vegetation indexes EVI and NDII)in combination with field studies,climate variables,and GIS techniques.We found that SSM outbreaks in the area of alpine boundary shifted about 370 m uphill since the mid of 1950.The outbreak onset was promoted by increased dryness and active temperatures and decreased root zone moisture content in the spring-early summer period.The terrain topography strongly affected SSM outbreak onset and dynamics.Initially,the outbreak was located at the middle elevations on the gentle concave southeastern slopes,which are the favorable insect habitats between outbreaks.Then the outbreak expanded uphill and downhill,to steeper slopes,and both concave and convex terrains.Alongside with elevation range expansion,SSM surpassed its northern historical outbreak boundary:the potential outbreaks’boundary moved about 300 km northward.Climate warming contributes to SSM migration into former outbreak free conifer stands located in highlands and at northern latitudes.
基金The research was funded by Russian Foundation for Basic Research,Krasnoyarsk Territory and Krasnoyarsk Regional Fund of Science,project number 20-44-240007.
文摘Birch(Betula tortuosa)is one of the treeline forming species within the Siberian Mountains.We analysed the area dynamics of birch stands and the upslope climb of birch treeline based on the Landsat time series scenes and on-ground data.We found that since the warming onset(1970th)birch area increased by 10%,birch stands and treeline boundary were moving upslope with a rate of 1.4 m/yr and 4.0 m/yr.Birch upslope shift correlated with air temperatures at the beginning(May-June)and the end(August-October)of the growth period.Meanwhile,no correlation was found between birch upslope migration and precipitation.Winds negatively influenced both birch area growth and birch upslope climb during spring,fall,and wintertime.In the windy habitats,birch,together with larch and Siberian pine,formed clusters(hedges)which mitigated the influence of adverse winds.These clusters are the adaptive pattern for trees’upslope climb within windward slopes.The other adaptation to the harsh alpine ecotone habitat is non-leaf(bark)photosynthesis which supports tree survival.Thereby,Betula tortuosa upslope climb depends on the wind impact and warming in spring and fall that extended growth period.With ongoing warming and observed wind speed decrease on the background of sufficient precipitation,it is expected to further birch advance into alpine tundra in the Siberian Mountains.
基金This paper was supported by Korea Science and Engineering Foundation (KOSEF No. 2000-2-51300-002-3).
文摘Most of forest birds have the characteristics for habitat selection. The purpose of this study is to clarify the vegetation structure in breeding area of Siberian rubythroat (Luscinia calliope). In Daecheongbong peak, Mt. Seoraksan national park, South Korea from May to August, 2001, breeding population of Siberian rubythroat and the dominant species in breeding area of Siberian rubythroat (Luscinia calliope) were surveyed by line transect method along the ridge in the Daecheongbong peak area. Number of individuals and location of song posts were observed and recorded. According to the survey results, the study area was classified into high, middle and low density areas. Those birds selected the forest area of dominant species for Ermans birch and dwarf Siberian pine as habitat and preferred the shrubs area with the lower height and higher coverage.
文摘Unusual reliefs on the Earth’s surface were found in aerial photographs of Eastern Siberia in the late 20</span><sup><span style="font-family:Verdana;">th</span></sup><span style="font-family:Verdana;"> century. The facts justifying the connection are given by Siberian Fan Reliefs and the Tunguska Cosmic Body. It is most natural to assume that we are dealing with the falling of numerous fragments of a collapsed comet. The more likely version is that the comet is captured by the Earth-Moon system and remains in Earth orbit for some time.
文摘Unusual reliefs on the Earth’s surface were found in aerial photographs of Eastern Siberia in the late 20<sup>th</sup> century. These reliefs consist of several tens (up to hundreds) of stripes that have arisen as a result of the destruction of vegetation and the surface layer of the ground. Structures of stripes are extended, ranging in size from 6 km to ≥20 km, with a width of several kilometers. Every strip (scratch on the ground) is roughly estimated to be up to 50 m wide and ≥500 m long. The stripes start from one edge of the relief and stretch at inter-vals to the other, slightly diverging symmetrically from the central axis. It was determined that these reliefs are not associated with the movement of soil (avalanches, mudflows) or with the impact of air currents (hurricanes, storm, tornado). Geographically, these struc-tures of stripes are located within a circle with a radius of 770 km, described around the epicenter of the Tunguska catastrophe.
文摘In this paper,I report SHRIMP zircon U-Pb ages of Paleoproterozoic high-grade metasedimentary rocks from southwestern part of the Siberian Craton.Early Precambrian high-grade complex including garnet -biotite,hypersthene-biotite and cordierite-bearing gneisses compose the Irkut terrane of the Sharyzhalgay Uplift.Protoliths of studied
