The alpine meadow ecosystem accounts for 27%of the total area of the Tibetan Plateau and is also one of the most important vegetation types.The Dangxiong alpine meadow ecosystem,located in the south-central part of th...The alpine meadow ecosystem accounts for 27%of the total area of the Tibetan Plateau and is also one of the most important vegetation types.The Dangxiong alpine meadow ecosystem,located in the south-central part of the Tibetan Plateau,is a typical example.To understand the carbon and water fluxes,water use efficiency(WUE),and their responses to future climate change for the alpine meadow ecosystem in the Dangxiong area,two parameter estimation methods,the Model-independent Parameter Estimation(PEST)and the Dynamic Dimensions Search(DDS),were used to optimize the Biome-BGC model.Then,the gross primary productivity(GPP)and evapotranspiration(ET)were simulated.The results show that the DDS parameter calibration method has a better performance.The annual GPP and ET show an increasing trend,while the WUE shows a decreasing trend.Meanwhile,ET and GPP reach their peaks in July and August,respectively,and WUE shows a“dual-peak”pattern,reaching peaks in May and November.Furthermore,according to the simulation results for the next nearly 100 years,the ensemble average GPP and ET exhibit a significant increasing trend,and the growth rate under the SSP5–8.5 scenario is greater than that under the SSP2–4.5 scenario.WUE shows an increasing trend under the SSP2–4.5 scenario and a significant increasing trend under the SSP5–8.5 scenario.This study has important scientific significance for carbon and water cycle prediction and vegetation ecological protection on the Tibetan Plateau.展开更多
Quantifying surface cracks in alpine meadows is a prerequisite and a key aspect in the study of grassland crack development.Crack characterization indices are crucial for the quantitative characterization of complex c...Quantifying surface cracks in alpine meadows is a prerequisite and a key aspect in the study of grassland crack development.Crack characterization indices are crucial for the quantitative characterization of complex cracks,serving as vital factors in assessing the degree of cracking and the development morphology.So far,research on evaluating the degree of grassland degradation through crack characterization indices is rare,especially the quantitative analysis of the development of surface cracks in alpine meadows is relatively scarce.Therefore,based on the phenomenon of surface cracking during the degradation of alpine meadows in some regions of the Qinghai-Tibet Plateau,we selected the alpine meadow in the Huangcheng Mongolian Township,Menyuan Hui Autonomous County,Qinghai Province,China as the study area,used unmanned aerial vehicle(UAV)sensing technology to acquire low-altitude images of alpine meadow surface cracks at different degrees of degradation(light,medium,and heavy degradation),and analyzed the representative metrics characterizing the degree of crack development by interpreting the crack length,length density,branch angle,and burrow(rat hole)distribution density and combining them with in situ crack width and depth measurements.Finally,the correlations between the crack characterization indices and the soil and root parameters of sample plots at different degrees of degradation in the study area were analyzed using the grey relation analysis.The results revealed that with the increase of degradation,the physical and chemical properties of soil and the mechanical properties of root-soil composite changed significantly,the vegetation coverage reduced,and the root system aggregated in the surface layer of alpine meadow.As the degree of degradation increased,the fracture morphology developed from"linear"to"dendritic",and eventually to a complex and irregular"polygonal"pattern.The crack length,width,depth,and length density were identified as the crack characterization indices via analysis of variance.The results of grey relation analysis also revealed that the crack length,width,depth,and length density were all highly correlated with root length density,and as the degradation of alpine meadows intensified,the underground biomass increased dramatically,forming a dense layer of grass felt,which has a significant impact on the formation and expansion of cracks.展开更多
In the Alpine Corsica(France),the Santa Lucia Nappe represents a peculiar unit preserving the unique relicts of Paleozoic lower to medium continental crust.It consists of composite basement affected by Permian granuli...In the Alpine Corsica(France),the Santa Lucia Nappe represents a peculiar unit preserving the unique relicts of Paleozoic lower to medium continental crust.It consists of composite basement affected by Permian granulite facies metamorphic conditions unconformably covered by a Late Cretaceous clastic sequence(Tomboni Conglomerate and Tralonca Flysch)affected by polyphase deformation and low-grade-metamorphism.In this work,we present a new reconstruction of the deformation events registered by the Tralonca Flysch during the Alpine orogeny.The D1 phase was testified by rare isoclinal folds.The D2 phase produced a continuous foliation and a map-scale sheath-fold with a top-to-W sense of shear.The D3 phase produced E-verging non-cylindrical folds and S3 crenulation cleavage that is not associated to metamorphic blastesis.We present the first temperature-pressure-deformation(P-T-d)path for the Tralonca Flysch,demonstrating that the Santa Lucia Nappe underwent accretion and then first stage exhumation in the Alpine wedge during the D1 phase with pressure and temperature peaks both occurred under blueschist metamorphic conditions.The D2 phase occurred at lower pressure-temperature conditions during a second stage exhumation.This pressure-temperaturedeformation path is comparable with those of the Lower Units(i.e.,the subducted continental units of Alpine Corsica)suggesting a common geodynamic history.展开更多
Ongoing encroachment is driving recent alpine shrubline dynamics globally,but the role of shrub-shrub interactions in shaping shrublines and their relationships with stem density changes remain poorly understood.Here,...Ongoing encroachment is driving recent alpine shrubline dynamics globally,but the role of shrub-shrub interactions in shaping shrublines and their relationships with stem density changes remain poorly understood.Here,the size and age of shrubs from 26 Salix shrubline populations along a 900-km latitudinal gradient(30°-38°N)were measured and mapped across the eastern Tibetan Plateau.Point pattern analyses were used to quantify the spatial distribution patterns of juveniles and adults,and to assess spatial associations between them.Mean intensity of univariate and bivariate spatial patterns was related to biotic and abiotic variables.Bivariate mark correlation functions with a quantitative mark(shrub height,basal stem diameter,crown width)were also employed to investigate the spatial relationships between shrub traits of juveniles and adults.Structural equation models were used to explore the relationships among conspecific interactions,patterns,shrub traits and recruitment dynamics under climate change.Most shrublines showed clustered patterns,suggesting the existence of conspecific facilitation.Clustered patterns of juveniles and conspecific interactions(potentially facilitation)tended to intensify with increasing soil moisture stress.Summer warming before 2010 triggered positive effects on population interactions and spatial patterns via increased shrub recruitment.However,summer warming after2010 triggered negative effects on interactions through reduced shrub recruitment.Therefore,shrub recruitment shifts under rapid climate change could impact spatial patterns,alter conspecific interactions and modify the direction and degree of shrublines responses to climate.These changes would have profound implications for the stability of alpine woody ecosystems.展开更多
Nitrogen deposition and water tables are important factors to control soil microbial community structure.However,the specific effects and mechanisms of nitrogen deposition and water tables coupling on bacterial divers...Nitrogen deposition and water tables are important factors to control soil microbial community structure.However,the specific effects and mechanisms of nitrogen deposition and water tables coupling on bacterial diversity,abundance,and community structure in arid alpine wetlands remain unclear.The nitrogen deposition(0,10,and 20 kg N/(hm^(2)•a))experiments were conducted in the Bayinbulak alpine wetland with different water tables(perennial flooding,seasonal waterlogging,and perennial drying).The 16S rRNA(ribosomal ribonucleic acid)gene sequencing technology was employed to analyze the changes in bacterial community diversity,network structure,and function in the soil.Results indicated that bacterial diversity was the highest under seasonal waterlogging condition.However,nitrogen deposition only affected the bacterial Chao1 and beta diversity indices under seasonal waterlogging condition.The abundance of bacterial communities under different water tables showed significant differences at the phylum and genus levels.The dominant phylum,Proteobacteria,was sensitive to soil moisture and its abundance decreased with decreasing water tables.Although nitrogen deposition led to changes in bacterial abundance,such changes were small compared with the effects of water tables.Nitrogen deposition with 10 kg N/(hm^(2)•a)decreased bacterial edge number,average path length,and robustness.However,perennial flooding and drying conditions could simply resist environmental changes caused by 20 kg N/(hm^(2)•a)nitrogen deposition and their network structure remain unchanged.The sulfur cycle function was dominant under perennial flooding condition,and carbon and nitrogen cycle functions were dominant under seasonal waterlogging and perennial drying conditions.Nitrogen application increased the potential function of part of nitrogen cycle and decreased the potential function of sulfur cycle in bacterial community.In summary,composition of bacterial community in the arid alpine wetland was determined by water tables,and diversity of bacterial community was inhibited by a lower water table.Effect of nitrogen deposition on bacterial community structure and function depended on water tables.展开更多
In the restoration of degraded wetlands,fertilization can improve the vegetation-soil-microorganisms complex,thereby affecting the organic carbon content.However,it is currently unclear whether these effects are susta...In the restoration of degraded wetlands,fertilization can improve the vegetation-soil-microorganisms complex,thereby affecting the organic carbon content.However,it is currently unclear whether these effects are sustainable.This study employed Biolog-Eco surveys to investigate the changes in vegetation characteristics,soil physicochemical properties,and soil microbial functional diversity in degraded alpine wetlands of the source region of the Yellow River at 3 and 15 months after the application of nitrogen,phosphorus,and organic mixed fertilizer.The following results were obtained:The addition of nitrogen fertilizer and organic compost significantly affects the soil organic carbon content in degraded wetlands.Three months after fertilization,nitrogen addition increases soil organic carbon in both lightly and severely degraded wetlands,whereas after 15 months,organic compost enhanced the soil organic carbon level in severely degraded wetlands.Structural equation modeling indicates that fertilization decreases the soil pH and directly or indirectly influences the soil organic carbon levels through variations in the soil water content and the aboveground biomass of vegetation.Three months after fertilization,nitrogen fertilizer showed a direct positive effect on soil organic carbon.However,organic mixed fertilizer indirectly reduced soil organic carbon by increasing biomass and decreasing soil moisture.After 15 months,none of the fertilizers significantly affected the soil organic carbon level.In summary,it can be inferred that the addition of nitrogen fertilizer lacks sustainability in positively influencing the organic carbon content.展开更多
Climate warming profoundly affects plant biodiversity, community productivity, and soil properties in alpine and subalpine grassland ecosystems. However, these effects are poorly understood across elevational gradient...Climate warming profoundly affects plant biodiversity, community productivity, and soil properties in alpine and subalpine grassland ecosystems. However, these effects are poorly understood across elevational gradients in subalpine meadow ecosystems. To reveal the elevational patterns of warming effects on plant biodiversity, community structure, productivity, and soil properties, we conducted a warming experiment using open-top chambers from August 2019 to August 2022 at high(2764 m a. s. l.), medium(2631 m a. s. l.), and low(2544 m a. s. l.) elevational gradients on a subalpine meadow slope of Mount Wutai, Northern China. Our results showed that three years of warming significantly increased topsoil temperature but significantly decreased topsoil moisture at all elevations(P<0.05), and the percentage of increasing temperature and decreasing moisture both gradually raised with elevation lifting. Warming-induced decreasing proportions of soil organic carbon(SOC, by 19.24%), and total nitrogen(TN, by 24.56%) were the greatest at high elevational gradients. Experimental warming did not affect topsoil C: N, p H, NO_(3)^(-)-N, or NH_(4)^(+)-N at the three elevational gradients. Warming significantly increased species richness(P<0.01) and Shannon-Weiner index(P<0.05) at low elevational gradients but significantly decreased belowground biomass(P<0.05) at a depth of 0–10 cm at three elevational gradients. Warming caused significant increases in the aboveground biomass in the three elevational plots. Warming significantly increased the aboveground biomass of graminoids in medium(by 92.47%) and low(by 98.25%) elevational gradients, that of sedges in high(by 72.44%) and medium(by 57.16%) elevational plots, and that of forbs in high(by 75.88%), medium(by 34.38%), and low(by 74.95%) elevational plots. Species richness had significant linear correlations with SOC, TN, and C: N(P<0.05), but significant nonlinear responses to soil temperature and soil moisture in the warmed treatment(P<0.05). The warmed aboveground biomass had a significant nonlinear response to soil temperature and significant linear responses to soil moisture(P<0.05). This study provided evidence that altitude is a factor in sensitivity to climate warming, and these different parameters(e.g., plant species richness, Shannon-Weiner index, soil temperature, soil moisture, SOC, and TN) can be used to measure this sensitivity.展开更多
Artificial vegetation restoration is the main measure for vegetation restoration and soil and water conservation in alpine mine dumps on the Qinghai-Tibet Plateau,China.However,there are few reports on the dynamic cha...Artificial vegetation restoration is the main measure for vegetation restoration and soil and water conservation in alpine mine dumps on the Qinghai-Tibet Plateau,China.However,there are few reports on the dynamic changes and the influencing factors of the soil reinforcement effect of plant species after artificial vegetation restoration under different recovery periods.We selected dump areas of the Delni Copper Mine in Qinghai Province,China to study the relationship between the shear strength and the peak displacement of the root-soil composite on the slope during the recovery period,and the influence of the root traits and soil physical properties on the shear resistance characteristics of the root-soil composite via in situ direct shear tests.The results indicate that the shear strength and peak displacement of the rooted soil initially decreased and then increased with the increase of the recovery period.The shear strength of the rooted soil and the recovery period exhibited a quadratic function relationship.There is no significant function relationship between the peak displacement and the recovery period.Significant positive correlations(P<0.05)exists between the shear strength of the root-soil composite and the root biomass density,root volume density,and root area ratio,and they show significant linear correlations(P<0.05).There are no significant correlations(P>0.05)between the shear strength of the root-soil composite and the root length density,and the root volume ratio of the coarse roots to the fine roots.A significant negative linear correlation(P<0.05)exists between the peak displacement of the rooted soil and the coarse-grain content,but no significant correlations(P>0.05)with the root traits,other soil physical property indices(the moisture content and dry density of the soil),and slope gradient.The coarse-grain content is the main factor controlling the peak displacement of the rooted soil.展开更多
Critical zone(CZ)plays a vital role in sustaining biodiversity and humanity.However,flux quantification within CZ,particularly in terms of subsurface hydrological partitioning,remains a significant challenge.This stud...Critical zone(CZ)plays a vital role in sustaining biodiversity and humanity.However,flux quantification within CZ,particularly in terms of subsurface hydrological partitioning,remains a significant challenge.This study focused on quantifying subsurface hydrological partitioning,specifically in an alpine mountainous area,and highlighted the important role of lateral flow during this process.Precipitation was usually classified as two parts into the soil:increased soil water content(SWC)and lateral flow out of the soil pit.It was found that 65%–88%precipitation contributed to lateral flow.The second common partitioning class showed an increase in SWC caused by both precipitation and lateral flow into the soil pit.In this case,lateral flow contributed to the SWC increase ranging from 43%to 74%,which was notably larger than the SWC increase caused by precipitation.On alpine meadows,lateral flow from the soil pit occurred when the shallow soil was wetter than the field capacity.This result highlighted the need for three-dimensional simulation between soil layers in Earth system models(ESMs).During evapotranspiration process,significant differences were observed in the classification of subsurface hydrological partitioning among different vegetation types.Due to tangled and aggregated fine roots in the surface soil on alpine meadows,the majority of subsurface responses involved lateral flow,which provided 98%–100%of evapotranspiration(ET).On grassland,there was a high probability(0.87),which ET was entirely provided by lateral flow.The main reason for underestimating transpiration through soil water dynamics in previous research was the neglect of lateral root water uptake.Furthermore,there was a probability of 0.12,which ET was entirely provided by SWC decrease on grassland.In this case,there was a high probability(0.98)that soil water responses only occurred at layer 2(10–20 cm),because grass roots mainly distributed in this soil layer,and grasses often used their deep roots for water uptake during ET.To improve the estimation of soil water dynamics and ET,we established a random forest(RF)model to simulate lateral flow and then corrected the community land model(CLM).RF model demonstrated good performance and led to significant improvements in CLM simulation.These findings enhance our understanding of subsurface hydrological partitioning and emphasize the importance of considering lateral flow in ESMs and hydrological research.展开更多
Soil microbial communities are pivotal in permafrost biogeochemical cycles,yet the variations of abundant and rare microbial taxa and their impacts on greenhouse gas emissions in different seasons,remain elusive,espec...Soil microbial communities are pivotal in permafrost biogeochemical cycles,yet the variations of abundant and rare microbial taxa and their impacts on greenhouse gas emissions in different seasons,remain elusive,especially in the case of soil archaea.Here,we conducted a study on soil abundant and rare archaeal taxa during the growing and non-growing seasons in the active layer of alpine permafrost in the Qinghai-Tibetan Plateau.The results suggested that,for the archaeal communities in the sub-layer,abundant taxa exhibited higher diversity,while rare taxa maintained a more stable composition from the growing to non-growing season.Water soluble organic carbon and soil porosity were the most significant environmental variables affecting the compositions of abundant and rare taxa,respectively.Stochastic and deterministic processes dominated the assemblies of rare and abundant taxa,respectively.The archaeal ecological network influenced N_(2)O flux through different modules.Rare taxa performed an essential role in stabilizing the network and exerting important effects on N_(2)O flux.Our study provides a pioneering and comprehensive investigation aimed at unravelling the mechanisms by which archaea or other microorganisms influence greenhouse gas emissions in the alpine permafrost.展开更多
Grazing exclusion is one of the primary management practices used to restore degraded grasslands on the Tibetan Plateau.However,to date,the effects of long-term grazing exclusion measures on the process of restoring d...Grazing exclusion is one of the primary management practices used to restore degraded grasslands on the Tibetan Plateau.However,to date,the effects of long-term grazing exclusion measures on the process of restoring degraded alpine meadows have not been evaluated.In this study,moderately degraded plots,in which the vegetation coverage was approximately 65%and the dominant plant species was Potentilla anserina L,with grazing exclusion for 2 to 23 years,were selected in alpine meadows of Haibei in Qinghai-Tibet Plateau.Plant coverage,plant height,biomass,soil bulk density,saturated water content,soil organic carbon(SOC)and total nitrogen(TN)were evaluated.The results were as follows:(1)With aboveground biomass and total saturated water content at 0-40 cm depth,the average SOC and TN contents in moderately degraded alpine meadows increased as a power function,and the plant height increased as a log function.(2)The average soil bulk density at 0-40 cm depth first decreased and then increased with increasing grazing exclusion duration,and the minimum value of 0.90 g·cm^(-3) was reached at 15.23 years.The plant coverage,total belowground biomass at 0-40 cm depth,total aboveground and belowground biomass first increased and then decreased,their maximum values(80.49%,2452.92g·m^(-2),2891.06 g·m^(-2))were reached at 9.41,9.46 and 10.25 years,respectively.Long-term grazing exclusion is apparently harmful for the sustainable restoration of degraded alpine meadows.The optimal duration of grazing exclusion for the restoration of moderately degraded alpine meadows was 10 years.This research suggests that moderate disturbance should be allowed in moderately degraded alpine meadows after 10years of grazing exclusion.展开更多
The response of vegetation productivity to precipitation is becoming a worldwide concern.Most reports on responses of vegetation to precipitation trends are based on the growth season.In the soil freeze/thaw process,t...The response of vegetation productivity to precipitation is becoming a worldwide concern.Most reports on responses of vegetation to precipitation trends are based on the growth season.In the soil freeze/thaw process,the soil water phase and heat transport change can affect root growth,especially during the thawing process in early spring.A field experiment with increased precipitation(control,increased 25%and increased 50%)was conducted to measure the effects of soil water in early spring on above-and below-ground productivity in an alpine steppe over two growing seasons from June 2017 to September 2018.The increased 50%treatment significantly increased the soil moisture at the 10 cm depth,there was no difference in soil moisture between the increased 25%treatment and the control in the growing season,which was not consistent in the freeze/thaw process.Increased soil moisture during the non-growing season retarded root growth.Increased precipitation in the freezing-thawing period can partially offset the difference between the control and increased precipitation plots in both above-and below-ground biomass.展开更多
Alpine wetland is one of the typical underlying surfaces on the Qinghai–Tibet Plateau.It plays a crucial role in runoff regulation.Investigations on the mechanisms of water and heat exchanges are necessary to underst...Alpine wetland is one of the typical underlying surfaces on the Qinghai–Tibet Plateau.It plays a crucial role in runoff regulation.Investigations on the mechanisms of water and heat exchanges are necessary to understand the land surface processes over the alpine wetland.This study explores the characteristics of hydro-meteorological factors with in situ observations and uses the Community Land Model 5 to identify the main factors controlling water and heat exchanges.Latent heat flux and thermal roughness length were found to be greater in the warm season(June–August)than in the cold season(December–February),with a frozen depth of 20–40 cm over the alpine wetland.The transfers of heat fluxes were mainly controlled by longwave radiation and air temperature and affected by root distribution.Air pressure and stomatal conductance were also important to latent heat flux,and soil solid water content was important to sensible heat flux.Soil temperature was dominated by longwave radiation and air temperature,with crucial surface parameters of initial soil liquid water content and total water content.The atmospheric control factors transitioned to precipitation and air temperature for soil moisture,especially at the shallow layer(5 cm).Meanwhile,the more influential surface parameters were root distribution and stomatal conductance in the warm season and initial soil liquid water content and total water content in the cold season.This work contributes to the research on the land surface processes over the alpine wetland and is helpful to wetland protection.展开更多
Objective To study the effectiveness and feasibility of cryogenic disinfectants in different cold scenarios and analyze the key points of on-site cryogenic disinfection.Methods Qingdao and Suifenhe were selected as ap...Objective To study the effectiveness and feasibility of cryogenic disinfectants in different cold scenarios and analyze the key points of on-site cryogenic disinfection.Methods Qingdao and Suifenhe were selected as application sites for the manual or mechanical spraying of cryogenic disinfectants.The same amount of disinfectant(3,000 mg/L)was applied on cold chain food packaging,cold chain containers,transport vehicles,alpine environments,and article surfaces.The killing log value of the cryogenic disinfectant against the indicator microorganisms(Staphylococcus aureus and Escherichia coli)was used to evaluate the on-site disinfection effect.Results When using 3,000 mg/L with an action time of 10 min on the ground in alpine regions,the surface of frozen items,cold-chain containers,and cold chain food packaging in supermarkets,all external surfaces were successfully disinfected,with a pass rate of 100%.The disinfection pass rates for cold chain food packaging and cold chain transport vehicles of centralized supervised warehouses and food processing enterprises were 12.5%(15/120),81.67%(49/60),and 93.33%(14/15),respectively;yet,the surfaces were not fully sprayed.Conclusion Cryogenic disinfectants are effective in disinfecting alpine environments and the outer packaging of frozen items.The application of cryogenic disinfectants should be regulated to ensure that they cover all surfaces of the disinfected object,thus ensuring effective cryogenic disinfection.展开更多
At first,the ecological restoration technology of abandoned mines is summarized,and the paths and models of mine ecological restoration in Zoige grassland area under the background of carbon neutrality are analyzed.Mo...At first,the ecological restoration technology of abandoned mines is summarized,and the paths and models of mine ecological restoration in Zoige grassland area under the background of carbon neutrality are analyzed.Moreover,the problems and deficiencies in the current research on mine ecological restoration in Zoige grassland area are initially identified,and the future research trend is prospected to provide a reference for the path of carbon reduction by mine ecological restoration in Zoige grassland area and other alpine grassland areas in the future.展开更多
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 ...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 pH, 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 speeies. The most significant 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 mask Shifts in the Astareeeae （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.展开更多
[Objective] The study aimed to investigate the effects of temperature and nitrogen input on nitrogen mineralization in alpine soils on the Tibetan Plateau.[Method]An incubation experiment in the laboratory was conduct...[Objective] The study aimed to investigate the effects of temperature and nitrogen input on nitrogen mineralization in alpine soils on the Tibetan Plateau.[Method]An incubation experiment in the laboratory was conducted using three alpine soils.These soils were collected from the top 10 cm depth in three grassland types：alpine meadow in Haibei,alpine steppe in Naqu and alpine wetland in Dangxiong.[Result] Temperature significantly affected nitrogen mineralization in alpine soils of three grassland types.The mineralization rate in alpine steppe soil rose with the rise of temperature,while the mineralization rate in the alpine meadow soil and alpine wetland soil decreased with the rise of temperature.Nitrogen input had no significant effect on nitrogen mineralization in the alpine meadow soil,but significantly increased nitrogen mineralization in the alpine steppe soil and the alpine wetland soil.Grassland types significantly affected nitrogen mineralization in alpine grasslands.[Conclusion] The effects of temperature and nitrogen input on nitrogen mineralization in alpine soils on the Tibetan Plateau were significant.And those different effects depended on different types of grassland.展开更多
In August 2003, we investigated spatial pattern in soil carbon and nutrients in the Alpine tundra of Changbai Moun-tain, Jilin Province, China. The analytical results showed that the soil C concentrations at different...In August 2003, we investigated spatial pattern in soil carbon and nutrients in the Alpine tundra of Changbai Moun-tain, Jilin Province, China. The analytical results showed that the soil C concentrations at different depths were significantly (p<0.05) higher in Meadow alpine tundra vegetation than that in other vegetation types; the soil C (including inorganic carbon) concentrations at layer below 10 cm are significantly (p<0.05) higher than at layer of 1020 cm among the different vegetation types; the spatial distribution of soil N concentration at top surface of 0-10 cm depth was similar to that at 1020 cm; the soil P concentrations at different depths were significantly (p<0.05) lower at Lithic alpine tundra vegetation than that at other vegetation types; soil K concentration was significantly (p<0.05) higher in Felsenmeer alpine tundra vegetation and Lithic alpine tundra vegetation than that in Typical alpine tundra, Meadow alpine tundra, and Swamp alpine tundra vegetations.. However, the soil K had not significant change at different soil depths of each vegetation type. Soil S concentration was dramatically higher in Meadow alpine tundra vegetation than that in other vegetation types. For each vegetation type, the ratios of C: N, C: P, C: K and C: S generally decreased with soil depth. The ratio of C: N was significantly higher at 010 cm than that at 1020 cm for all vegetation types except at the top layer of the Swamp alpine tundra vegetation. Our study showed that soil C and nutrients storage were significantly spatial heterogeneity.展开更多
[Objective]The aim of this study is to explore the effects of grassland degradation on soil physical and chemical properties.[Method]The ratio of plant root to soil and soil texture on Alpine Meadow were investigated ...[Objective]The aim of this study is to explore the effects of grassland degradation on soil physical and chemical properties.[Method]The ratio of plant root to soil and soil texture on Alpine Meadow were investigated in this study,and soil available N,P,K,Cu,Zn,organic matter and pH value were also analyzed by routine analysis of soil nutrients in different degraded grasslands.[Result]With the intensification of degraded gradient and the soil depth,the ratio of plant root to soil was decreased gradually.The highest ratio of plant root to soil was in 0-10 cm depth of soil in grassland with different degraded gradients,while its ratio of plant root to soil changed from 0.001 to 0.040 with soil type of loam.Soil chemical characteristic changed in different degraded gradients.The content of available N,P,K reduced significantly with the soil depth and the intensification of degraded gradients.The content of Cu and Zn was relatively lack in degraded grassland.[Conclusion]There is no significant correlation between nutrition content or pH value and the succession degree of degraded grassland.展开更多
To understand the dynamics of added nitrogen (N) in alpine meadow and the role of alpine plants and soil microorganisms in the retention of deposited N, the fate of 15 N labeled nitrate and ammonium salts was...To understand the dynamics of added nitrogen (N) in alpine meadow and the role of alpine plants and soil microorganisms in the retention of deposited N, the fate of 15 N labeled nitrate and ammonium salts was determined in an alpine meadow for two months. Two weeks after 15 N application, total recovery of 15 N from NO - 3_ 15 N was 73.5% while it was 78% from NH + 4_ 15 N. More 15 N was recovered in plants than in soil organic matter or in microbial biomass, irrespective of forms of N added. After one month, 70.6% of added NO - 3_ 15 N and 57.4% of NH + 4_ 15 N were recovered in soils and plants. 15 N recovered in soil organic matter decreased greatly while that recovered in plants varied little, irrespective of the form N. Compared with the results of two weeks after 15 N application, more NO - 3_ 15 N than NH + 4_ 15 N was recovered in microbial biomass. Total recovery was 58.4% (six weeks) and 67% (eight weeks) from NO - 3_ 15 N, and 43.1% and 49% from NH + 4_ 15 N, respectively. Both plants and soil microorganism recovered more NO - 3_ 15 N than NH + 4_ 15 N. But plants recovered more 15 N than soil microorganisms. During the whole experiment plants retained more NO - 3_N and 15 N than soil microorganisms while 15 N recovered in inorganic N pool did not exceed 1% due to lower amount of inorganic N. This indicates that plants play more important roles in the retention of deposited N although microbial biomass can be an important sink for deposited N in early days after N application.展开更多
基金supported by the Second Comprehensive Scientific Research Survey on the Tibetan Plateau[grant number 2019QZKK0103]the National Natural Science Foundation of China[grant numbers 42375071 and 42230610].
文摘The alpine meadow ecosystem accounts for 27%of the total area of the Tibetan Plateau and is also one of the most important vegetation types.The Dangxiong alpine meadow ecosystem,located in the south-central part of the Tibetan Plateau,is a typical example.To understand the carbon and water fluxes,water use efficiency(WUE),and their responses to future climate change for the alpine meadow ecosystem in the Dangxiong area,two parameter estimation methods,the Model-independent Parameter Estimation(PEST)and the Dynamic Dimensions Search(DDS),were used to optimize the Biome-BGC model.Then,the gross primary productivity(GPP)and evapotranspiration(ET)were simulated.The results show that the DDS parameter calibration method has a better performance.The annual GPP and ET show an increasing trend,while the WUE shows a decreasing trend.Meanwhile,ET and GPP reach their peaks in July and August,respectively,and WUE shows a“dual-peak”pattern,reaching peaks in May and November.Furthermore,according to the simulation results for the next nearly 100 years,the ensemble average GPP and ET exhibit a significant increasing trend,and the growth rate under the SSP5–8.5 scenario is greater than that under the SSP2–4.5 scenario.WUE shows an increasing trend under the SSP2–4.5 scenario and a significant increasing trend under the SSP5–8.5 scenario.This study has important scientific significance for carbon and water cycle prediction and vegetation ecological protection on the Tibetan Plateau.
基金This study was funded by the National Natural Science Foundation of China(42062019,42002283)the Project of Qinghai Science&Technology Department(2021-ZJ-927).
文摘Quantifying surface cracks in alpine meadows is a prerequisite and a key aspect in the study of grassland crack development.Crack characterization indices are crucial for the quantitative characterization of complex cracks,serving as vital factors in assessing the degree of cracking and the development morphology.So far,research on evaluating the degree of grassland degradation through crack characterization indices is rare,especially the quantitative analysis of the development of surface cracks in alpine meadows is relatively scarce.Therefore,based on the phenomenon of surface cracking during the degradation of alpine meadows in some regions of the Qinghai-Tibet Plateau,we selected the alpine meadow in the Huangcheng Mongolian Township,Menyuan Hui Autonomous County,Qinghai Province,China as the study area,used unmanned aerial vehicle(UAV)sensing technology to acquire low-altitude images of alpine meadow surface cracks at different degrees of degradation(light,medium,and heavy degradation),and analyzed the representative metrics characterizing the degree of crack development by interpreting the crack length,length density,branch angle,and burrow(rat hole)distribution density and combining them with in situ crack width and depth measurements.Finally,the correlations between the crack characterization indices and the soil and root parameters of sample plots at different degrees of degradation in the study area were analyzed using the grey relation analysis.The results revealed that with the increase of degradation,the physical and chemical properties of soil and the mechanical properties of root-soil composite changed significantly,the vegetation coverage reduced,and the root system aggregated in the surface layer of alpine meadow.As the degree of degradation increased,the fracture morphology developed from"linear"to"dendritic",and eventually to a complex and irregular"polygonal"pattern.The crack length,width,depth,and length density were identified as the crack characterization indices via analysis of variance.The results of grey relation analysis also revealed that the crack length,width,depth,and length density were all highly correlated with root length density,and as the degradation of alpine meadows intensified,the underground biomass increased dramatically,forming a dense layer of grass felt,which has a significant impact on the formation and expansion of cracks.
基金supported by the PRIN 2020(P.I.M.Marroni)Fondi Ateneo Grant by The University of Pisa。
文摘In the Alpine Corsica(France),the Santa Lucia Nappe represents a peculiar unit preserving the unique relicts of Paleozoic lower to medium continental crust.It consists of composite basement affected by Permian granulite facies metamorphic conditions unconformably covered by a Late Cretaceous clastic sequence(Tomboni Conglomerate and Tralonca Flysch)affected by polyphase deformation and low-grade-metamorphism.In this work,we present a new reconstruction of the deformation events registered by the Tralonca Flysch during the Alpine orogeny.The D1 phase was testified by rare isoclinal folds.The D2 phase produced a continuous foliation and a map-scale sheath-fold with a top-to-W sense of shear.The D3 phase produced E-verging non-cylindrical folds and S3 crenulation cleavage that is not associated to metamorphic blastesis.We present the first temperature-pressure-deformation(P-T-d)path for the Tralonca Flysch,demonstrating that the Santa Lucia Nappe underwent accretion and then first stage exhumation in the Alpine wedge during the D1 phase with pressure and temperature peaks both occurred under blueschist metamorphic conditions.The D2 phase occurred at lower pressure-temperature conditions during a second stage exhumation.This pressure-temperaturedeformation path is comparable with those of the Lower Units(i.e.,the subducted continental units of Alpine Corsica)suggesting a common geodynamic history.
基金the National Natural Science Foundation of China(42271054)the Second Tibetan Plateau Scientific Expedition and Research Program(2019QZKK0301)。
文摘Ongoing encroachment is driving recent alpine shrubline dynamics globally,but the role of shrub-shrub interactions in shaping shrublines and their relationships with stem density changes remain poorly understood.Here,the size and age of shrubs from 26 Salix shrubline populations along a 900-km latitudinal gradient(30°-38°N)were measured and mapped across the eastern Tibetan Plateau.Point pattern analyses were used to quantify the spatial distribution patterns of juveniles and adults,and to assess spatial associations between them.Mean intensity of univariate and bivariate spatial patterns was related to biotic and abiotic variables.Bivariate mark correlation functions with a quantitative mark(shrub height,basal stem diameter,crown width)were also employed to investigate the spatial relationships between shrub traits of juveniles and adults.Structural equation models were used to explore the relationships among conspecific interactions,patterns,shrub traits and recruitment dynamics under climate change.Most shrublines showed clustered patterns,suggesting the existence of conspecific facilitation.Clustered patterns of juveniles and conspecific interactions(potentially facilitation)tended to intensify with increasing soil moisture stress.Summer warming before 2010 triggered positive effects on population interactions and spatial patterns via increased shrub recruitment.However,summer warming after2010 triggered negative effects on interactions through reduced shrub recruitment.Therefore,shrub recruitment shifts under rapid climate change could impact spatial patterns,alter conspecific interactions and modify the direction and degree of shrublines responses to climate.These changes would have profound implications for the stability of alpine woody ecosystems.
基金supported by the National Natural Science Foundation of China(31960258)the Graduate Research Innovation Project of Xinjiang Uygur Autonomous Region(XJ2023G119).
文摘Nitrogen deposition and water tables are important factors to control soil microbial community structure.However,the specific effects and mechanisms of nitrogen deposition and water tables coupling on bacterial diversity,abundance,and community structure in arid alpine wetlands remain unclear.The nitrogen deposition(0,10,and 20 kg N/(hm^(2)•a))experiments were conducted in the Bayinbulak alpine wetland with different water tables(perennial flooding,seasonal waterlogging,and perennial drying).The 16S rRNA(ribosomal ribonucleic acid)gene sequencing technology was employed to analyze the changes in bacterial community diversity,network structure,and function in the soil.Results indicated that bacterial diversity was the highest under seasonal waterlogging condition.However,nitrogen deposition only affected the bacterial Chao1 and beta diversity indices under seasonal waterlogging condition.The abundance of bacterial communities under different water tables showed significant differences at the phylum and genus levels.The dominant phylum,Proteobacteria,was sensitive to soil moisture and its abundance decreased with decreasing water tables.Although nitrogen deposition led to changes in bacterial abundance,such changes were small compared with the effects of water tables.Nitrogen deposition with 10 kg N/(hm^(2)•a)decreased bacterial edge number,average path length,and robustness.However,perennial flooding and drying conditions could simply resist environmental changes caused by 20 kg N/(hm^(2)•a)nitrogen deposition and their network structure remain unchanged.The sulfur cycle function was dominant under perennial flooding condition,and carbon and nitrogen cycle functions were dominant under seasonal waterlogging and perennial drying conditions.Nitrogen application increased the potential function of part of nitrogen cycle and decreased the potential function of sulfur cycle in bacterial community.In summary,composition of bacterial community in the arid alpine wetland was determined by water tables,and diversity of bacterial community was inhibited by a lower water table.Effect of nitrogen deposition on bacterial community structure and function depended on water tables.
基金supported by the National Nature Science Foundations of China(32160269)the International Science and Technology Cooperation Project of Qinghai province of China(2022-HZ-817).
文摘In the restoration of degraded wetlands,fertilization can improve the vegetation-soil-microorganisms complex,thereby affecting the organic carbon content.However,it is currently unclear whether these effects are sustainable.This study employed Biolog-Eco surveys to investigate the changes in vegetation characteristics,soil physicochemical properties,and soil microbial functional diversity in degraded alpine wetlands of the source region of the Yellow River at 3 and 15 months after the application of nitrogen,phosphorus,and organic mixed fertilizer.The following results were obtained:The addition of nitrogen fertilizer and organic compost significantly affects the soil organic carbon content in degraded wetlands.Three months after fertilization,nitrogen addition increases soil organic carbon in both lightly and severely degraded wetlands,whereas after 15 months,organic compost enhanced the soil organic carbon level in severely degraded wetlands.Structural equation modeling indicates that fertilization decreases the soil pH and directly or indirectly influences the soil organic carbon levels through variations in the soil water content and the aboveground biomass of vegetation.Three months after fertilization,nitrogen fertilizer showed a direct positive effect on soil organic carbon.However,organic mixed fertilizer indirectly reduced soil organic carbon by increasing biomass and decreasing soil moisture.After 15 months,none of the fertilizers significantly affected the soil organic carbon level.In summary,it can be inferred that the addition of nitrogen fertilizer lacks sustainability in positively influencing the organic carbon content.
基金carried out in the framework of the 1331 Project of Cultural Ecology Collaborative Innovation Center in Wutai Mountain (00000342)co-financed by Program for the Philosophy and Social Sciences Research of Higher Learning Institutions of Shanxi (2022J027)+1 种基金Applied Basic Research Project of Shanxi Province (202203021221225)Basic Research Project of Xinzhou Science and Technology Bureau (20230501)。
文摘Climate warming profoundly affects plant biodiversity, community productivity, and soil properties in alpine and subalpine grassland ecosystems. However, these effects are poorly understood across elevational gradients in subalpine meadow ecosystems. To reveal the elevational patterns of warming effects on plant biodiversity, community structure, productivity, and soil properties, we conducted a warming experiment using open-top chambers from August 2019 to August 2022 at high(2764 m a. s. l.), medium(2631 m a. s. l.), and low(2544 m a. s. l.) elevational gradients on a subalpine meadow slope of Mount Wutai, Northern China. Our results showed that three years of warming significantly increased topsoil temperature but significantly decreased topsoil moisture at all elevations(P<0.05), and the percentage of increasing temperature and decreasing moisture both gradually raised with elevation lifting. Warming-induced decreasing proportions of soil organic carbon(SOC, by 19.24%), and total nitrogen(TN, by 24.56%) were the greatest at high elevational gradients. Experimental warming did not affect topsoil C: N, p H, NO_(3)^(-)-N, or NH_(4)^(+)-N at the three elevational gradients. Warming significantly increased species richness(P<0.01) and Shannon-Weiner index(P<0.05) at low elevational gradients but significantly decreased belowground biomass(P<0.05) at a depth of 0–10 cm at three elevational gradients. Warming caused significant increases in the aboveground biomass in the three elevational plots. Warming significantly increased the aboveground biomass of graminoids in medium(by 92.47%) and low(by 98.25%) elevational gradients, that of sedges in high(by 72.44%) and medium(by 57.16%) elevational plots, and that of forbs in high(by 75.88%), medium(by 34.38%), and low(by 74.95%) elevational plots. Species richness had significant linear correlations with SOC, TN, and C: N(P<0.05), but significant nonlinear responses to soil temperature and soil moisture in the warmed treatment(P<0.05). The warmed aboveground biomass had a significant nonlinear response to soil temperature and significant linear responses to soil moisture(P<0.05). This study provided evidence that altitude is a factor in sensitivity to climate warming, and these different parameters(e.g., plant species richness, Shannon-Weiner index, soil temperature, soil moisture, SOC, and TN) can be used to measure this sensitivity.
基金supported by the Project of Qinghai Science&Technology Department(Grant No.2021-ZJ-956Q).
文摘Artificial vegetation restoration is the main measure for vegetation restoration and soil and water conservation in alpine mine dumps on the Qinghai-Tibet Plateau,China.However,there are few reports on the dynamic changes and the influencing factors of the soil reinforcement effect of plant species after artificial vegetation restoration under different recovery periods.We selected dump areas of the Delni Copper Mine in Qinghai Province,China to study the relationship between the shear strength and the peak displacement of the root-soil composite on the slope during the recovery period,and the influence of the root traits and soil physical properties on the shear resistance characteristics of the root-soil composite via in situ direct shear tests.The results indicate that the shear strength and peak displacement of the rooted soil initially decreased and then increased with the increase of the recovery period.The shear strength of the rooted soil and the recovery period exhibited a quadratic function relationship.There is no significant function relationship between the peak displacement and the recovery period.Significant positive correlations(P<0.05)exists between the shear strength of the root-soil composite and the root biomass density,root volume density,and root area ratio,and they show significant linear correlations(P<0.05).There are no significant correlations(P>0.05)between the shear strength of the root-soil composite and the root length density,and the root volume ratio of the coarse roots to the fine roots.A significant negative linear correlation(P<0.05)exists between the peak displacement of the rooted soil and the coarse-grain content,but no significant correlations(P>0.05)with the root traits,other soil physical property indices(the moisture content and dry density of the soil),and slope gradient.The coarse-grain content is the main factor controlling the peak displacement of the rooted soil.
基金funded by the National Natural Science Foundation of China(42371022,42030501,41877148).
文摘Critical zone(CZ)plays a vital role in sustaining biodiversity and humanity.However,flux quantification within CZ,particularly in terms of subsurface hydrological partitioning,remains a significant challenge.This study focused on quantifying subsurface hydrological partitioning,specifically in an alpine mountainous area,and highlighted the important role of lateral flow during this process.Precipitation was usually classified as two parts into the soil:increased soil water content(SWC)and lateral flow out of the soil pit.It was found that 65%–88%precipitation contributed to lateral flow.The second common partitioning class showed an increase in SWC caused by both precipitation and lateral flow into the soil pit.In this case,lateral flow contributed to the SWC increase ranging from 43%to 74%,which was notably larger than the SWC increase caused by precipitation.On alpine meadows,lateral flow from the soil pit occurred when the shallow soil was wetter than the field capacity.This result highlighted the need for three-dimensional simulation between soil layers in Earth system models(ESMs).During evapotranspiration process,significant differences were observed in the classification of subsurface hydrological partitioning among different vegetation types.Due to tangled and aggregated fine roots in the surface soil on alpine meadows,the majority of subsurface responses involved lateral flow,which provided 98%–100%of evapotranspiration(ET).On grassland,there was a high probability(0.87),which ET was entirely provided by lateral flow.The main reason for underestimating transpiration through soil water dynamics in previous research was the neglect of lateral root water uptake.Furthermore,there was a probability of 0.12,which ET was entirely provided by SWC decrease on grassland.In this case,there was a high probability(0.98)that soil water responses only occurred at layer 2(10–20 cm),because grass roots mainly distributed in this soil layer,and grasses often used their deep roots for water uptake during ET.To improve the estimation of soil water dynamics and ET,we established a random forest(RF)model to simulate lateral flow and then corrected the community land model(CLM).RF model demonstrated good performance and led to significant improvements in CLM simulation.These findings enhance our understanding of subsurface hydrological partitioning and emphasize the importance of considering lateral flow in ESMs and hydrological research.
基金This work was supported by Gansu Provincial Science and Technology Program(22ZD6FA005)"Light of the West"Cross-team Project of the Chinese Academy of Sciences(xbzgzdsys-202214)+1 种基金the National Natural Science Foundation of China(41871064)Qinghai Province High-level Innovative"Thousand Talents"Program.
文摘Soil microbial communities are pivotal in permafrost biogeochemical cycles,yet the variations of abundant and rare microbial taxa and their impacts on greenhouse gas emissions in different seasons,remain elusive,especially in the case of soil archaea.Here,we conducted a study on soil abundant and rare archaeal taxa during the growing and non-growing seasons in the active layer of alpine permafrost in the Qinghai-Tibetan Plateau.The results suggested that,for the archaeal communities in the sub-layer,abundant taxa exhibited higher diversity,while rare taxa maintained a more stable composition from the growing to non-growing season.Water soluble organic carbon and soil porosity were the most significant environmental variables affecting the compositions of abundant and rare taxa,respectively.Stochastic and deterministic processes dominated the assemblies of rare and abundant taxa,respectively.The archaeal ecological network influenced N_(2)O flux through different modules.Rare taxa performed an essential role in stabilizing the network and exerting important effects on N_(2)O flux.Our study provides a pioneering and comprehensive investigation aimed at unravelling the mechanisms by which archaea or other microorganisms influence greenhouse gas emissions in the alpine permafrost.
基金funded by the National Natural Science Foundation of China(32001149,U20A2006,31971507)Applied Basic Research Project of Qinghai Province(2022-ZJ-716)+3 种基金Youth Innovation Promotion Association CAS(2022436)Joint Grant from Chinese Academy of Sciences-People’s Government of Qinghai Province on Sanjiangyuan National Park(LHZX-2020-07)Chinese Academy of Science(CAS)"Light of West China"Program(2018)"The effect of grazing on grassland productivity in the basin of Qinghai Lake"。
文摘Grazing exclusion is one of the primary management practices used to restore degraded grasslands on the Tibetan Plateau.However,to date,the effects of long-term grazing exclusion measures on the process of restoring degraded alpine meadows have not been evaluated.In this study,moderately degraded plots,in which the vegetation coverage was approximately 65%and the dominant plant species was Potentilla anserina L,with grazing exclusion for 2 to 23 years,were selected in alpine meadows of Haibei in Qinghai-Tibet Plateau.Plant coverage,plant height,biomass,soil bulk density,saturated water content,soil organic carbon(SOC)and total nitrogen(TN)were evaluated.The results were as follows:(1)With aboveground biomass and total saturated water content at 0-40 cm depth,the average SOC and TN contents in moderately degraded alpine meadows increased as a power function,and the plant height increased as a log function.(2)The average soil bulk density at 0-40 cm depth first decreased and then increased with increasing grazing exclusion duration,and the minimum value of 0.90 g·cm^(-3) was reached at 15.23 years.The plant coverage,total belowground biomass at 0-40 cm depth,total aboveground and belowground biomass first increased and then decreased,their maximum values(80.49%,2452.92g·m^(-2),2891.06 g·m^(-2))were reached at 9.41,9.46 and 10.25 years,respectively.Long-term grazing exclusion is apparently harmful for the sustainable restoration of degraded alpine meadows.The optimal duration of grazing exclusion for the restoration of moderately degraded alpine meadows was 10 years.This research suggests that moderate disturbance should be allowed in moderately degraded alpine meadows after 10years of grazing exclusion.
基金funded by the Second Tibetan Plateau Scientific Explorationthe Strategic Priority Research Program of Chinese Academy of Sciences+1 种基金the National Natural Science Foundation,grant number 2019QZKK0404,XDA20020401,41977284by the Doctoral Science Foundation of Henan Polytechnic University(B2019-019)。
文摘The response of vegetation productivity to precipitation is becoming a worldwide concern.Most reports on responses of vegetation to precipitation trends are based on the growth season.In the soil freeze/thaw process,the soil water phase and heat transport change can affect root growth,especially during the thawing process in early spring.A field experiment with increased precipitation(control,increased 25%and increased 50%)was conducted to measure the effects of soil water in early spring on above-and below-ground productivity in an alpine steppe over two growing seasons from June 2017 to September 2018.The increased 50%treatment significantly increased the soil moisture at the 10 cm depth,there was no difference in soil moisture between the increased 25%treatment and the control in the growing season,which was not consistent in the freeze/thaw process.Increased soil moisture during the non-growing season retarded root growth.Increased precipitation in the freezing-thawing period can partially offset the difference between the control and increased precipitation plots in both above-and below-ground biomass.
基金supported by the National Natural Science Foundation of China(Grant Nos.42005075,41975130)Natural Science Foundation of Gansu Province(Grant No.21JR7RA047)+1 种基金Open Research Fund Program of Plateau Atmosphere and Environment Key Laboratory of Sichuan Province(Grant No.PAEKL-2022-K03)the State Key Laboratory of Cryospheric Science(Grant No.SKLCS-ZZ-2023,SKLCS-ZZ-2022).
文摘Alpine wetland is one of the typical underlying surfaces on the Qinghai–Tibet Plateau.It plays a crucial role in runoff regulation.Investigations on the mechanisms of water and heat exchanges are necessary to understand the land surface processes over the alpine wetland.This study explores the characteristics of hydro-meteorological factors with in situ observations and uses the Community Land Model 5 to identify the main factors controlling water and heat exchanges.Latent heat flux and thermal roughness length were found to be greater in the warm season(June–August)than in the cold season(December–February),with a frozen depth of 20–40 cm over the alpine wetland.The transfers of heat fluxes were mainly controlled by longwave radiation and air temperature and affected by root distribution.Air pressure and stomatal conductance were also important to latent heat flux,and soil solid water content was important to sensible heat flux.Soil temperature was dominated by longwave radiation and air temperature,with crucial surface parameters of initial soil liquid water content and total water content.The atmospheric control factors transitioned to precipitation and air temperature for soil moisture,especially at the shallow layer(5 cm).Meanwhile,the more influential surface parameters were root distribution and stomatal conductance in the warm season and initial soil liquid water content and total water content in the cold season.This work contributes to the research on the land surface processes over the alpine wetland and is helpful to wetland protection.
基金supported by National Key R&D Program of China[grant number:2021YFC0863000]。
文摘Objective To study the effectiveness and feasibility of cryogenic disinfectants in different cold scenarios and analyze the key points of on-site cryogenic disinfection.Methods Qingdao and Suifenhe were selected as application sites for the manual or mechanical spraying of cryogenic disinfectants.The same amount of disinfectant(3,000 mg/L)was applied on cold chain food packaging,cold chain containers,transport vehicles,alpine environments,and article surfaces.The killing log value of the cryogenic disinfectant against the indicator microorganisms(Staphylococcus aureus and Escherichia coli)was used to evaluate the on-site disinfection effect.Results When using 3,000 mg/L with an action time of 10 min on the ground in alpine regions,the surface of frozen items,cold-chain containers,and cold chain food packaging in supermarkets,all external surfaces were successfully disinfected,with a pass rate of 100%.The disinfection pass rates for cold chain food packaging and cold chain transport vehicles of centralized supervised warehouses and food processing enterprises were 12.5%(15/120),81.67%(49/60),and 93.33%(14/15),respectively;yet,the surfaces were not fully sprayed.Conclusion Cryogenic disinfectants are effective in disinfecting alpine environments and the outer packaging of frozen items.The application of cryogenic disinfectants should be regulated to ensure that they cover all surfaces of the disinfected object,thus ensuring effective cryogenic disinfection.
基金Supported by the Financial Research Foundation of Sichuan Academy of Geological Survey(51000023Y000008287156).
文摘At first,the ecological restoration technology of abandoned mines is summarized,and the paths and models of mine ecological restoration in Zoige grassland area under the background of carbon neutrality are analyzed.Moreover,the problems and deficiencies in the current research on mine ecological restoration in Zoige grassland area are initially identified,and the future research trend is prospected to provide a reference for the path of carbon reduction by mine ecological restoration in Zoige grassland area and other alpine grassland areas in the future.
基金financial support from START International for funding the project activities(Makerere University and University of Tennessee at Memphis) provided us with the necessary support
文摘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 pH, 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 speeies. The most significant 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 mask Shifts in the Astareeeae （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.
基金Supported by Young Talents Project of Chinese Academy of Sciences (KZCX2-YW-QN302)the National Natural Science Found ofChina (41071209,30870424)~~
文摘[Objective] The study aimed to investigate the effects of temperature and nitrogen input on nitrogen mineralization in alpine soils on the Tibetan Plateau.[Method]An incubation experiment in the laboratory was conducted using three alpine soils.These soils were collected from the top 10 cm depth in three grassland types：alpine meadow in Haibei,alpine steppe in Naqu and alpine wetland in Dangxiong.[Result] Temperature significantly affected nitrogen mineralization in alpine soils of three grassland types.The mineralization rate in alpine steppe soil rose with the rise of temperature,while the mineralization rate in the alpine meadow soil and alpine wetland soil decreased with the rise of temperature.Nitrogen input had no significant effect on nitrogen mineralization in the alpine meadow soil,but significantly increased nitrogen mineralization in the alpine steppe soil and the alpine wetland soil.Grassland types significantly affected nitrogen mineralization in alpine grasslands.[Conclusion] The effects of temperature and nitrogen input on nitrogen mineralization in alpine soils on the Tibetan Plateau were significant.And those different effects depended on different types of grassland.
基金This research was supported by National Natural Science Foundation of China (40173033) and Important Direction Project of Knowl-edge Innovation of Chinese Academy of Sciences (KZCX3-SW-423).
文摘In August 2003, we investigated spatial pattern in soil carbon and nutrients in the Alpine tundra of Changbai Moun-tain, Jilin Province, China. The analytical results showed that the soil C concentrations at different depths were significantly (p<0.05) higher in Meadow alpine tundra vegetation than that in other vegetation types; the soil C (including inorganic carbon) concentrations at layer below 10 cm are significantly (p<0.05) higher than at layer of 1020 cm among the different vegetation types; the spatial distribution of soil N concentration at top surface of 0-10 cm depth was similar to that at 1020 cm; the soil P concentrations at different depths were significantly (p<0.05) lower at Lithic alpine tundra vegetation than that at other vegetation types; soil K concentration was significantly (p<0.05) higher in Felsenmeer alpine tundra vegetation and Lithic alpine tundra vegetation than that in Typical alpine tundra, Meadow alpine tundra, and Swamp alpine tundra vegetations.. However, the soil K had not significant change at different soil depths of each vegetation type. Soil S concentration was dramatically higher in Meadow alpine tundra vegetation than that in other vegetation types. For each vegetation type, the ratios of C: N, C: P, C: K and C: S generally decreased with soil depth. The ratio of C: N was significantly higher at 010 cm than that at 1020 cm for all vegetation types except at the top layer of the Swamp alpine tundra vegetation. Our study showed that soil C and nutrients storage were significantly spatial heterogeneity.
基金Supported by National Natural Science Foundation of China(30700563)the Middleaged Fund in Qinghai University(2009-QN-07)~~
文摘[Objective]The aim of this study is to explore the effects of grassland degradation on soil physical and chemical properties.[Method]The ratio of plant root to soil and soil texture on Alpine Meadow were investigated in this study,and soil available N,P,K,Cu,Zn,organic matter and pH value were also analyzed by routine analysis of soil nutrients in different degraded grasslands.[Result]With the intensification of degraded gradient and the soil depth,the ratio of plant root to soil was decreased gradually.The highest ratio of plant root to soil was in 0-10 cm depth of soil in grassland with different degraded gradients,while its ratio of plant root to soil changed from 0.001 to 0.040 with soil type of loam.Soil chemical characteristic changed in different degraded gradients.The content of available N,P,K reduced significantly with the soil depth and the intensification of degraded gradients.The content of Cu and Zn was relatively lack in degraded grassland.[Conclusion]There is no significant correlation between nutrition content or pH value and the succession degree of degraded grassland.
文摘To understand the dynamics of added nitrogen (N) in alpine meadow and the role of alpine plants and soil microorganisms in the retention of deposited N, the fate of 15 N labeled nitrate and ammonium salts was determined in an alpine meadow for two months. Two weeks after 15 N application, total recovery of 15 N from NO - 3_ 15 N was 73.5% while it was 78% from NH + 4_ 15 N. More 15 N was recovered in plants than in soil organic matter or in microbial biomass, irrespective of forms of N added. After one month, 70.6% of added NO - 3_ 15 N and 57.4% of NH + 4_ 15 N were recovered in soils and plants. 15 N recovered in soil organic matter decreased greatly while that recovered in plants varied little, irrespective of the form N. Compared with the results of two weeks after 15 N application, more NO - 3_ 15 N than NH + 4_ 15 N was recovered in microbial biomass. Total recovery was 58.4% (six weeks) and 67% (eight weeks) from NO - 3_ 15 N, and 43.1% and 49% from NH + 4_ 15 N, respectively. Both plants and soil microorganism recovered more NO - 3_ 15 N than NH + 4_ 15 N. But plants recovered more 15 N than soil microorganisms. During the whole experiment plants retained more NO - 3_N and 15 N than soil microorganisms while 15 N recovered in inorganic N pool did not exceed 1% due to lower amount of inorganic N. This indicates that plants play more important roles in the retention of deposited N although microbial biomass can be an important sink for deposited N in early days after N application.
