Climate warming and atmospheric nitrogen(N)deposition have profound influences on the terrestrial biosphere.However,how these two global change drivers affect phytoplankton which are important primary producers in wet...Climate warming and atmospheric nitrogen(N)deposition have profound influences on the terrestrial biosphere.However,how these two global change drivers affect phytoplankton which are important primary producers in wetlands with large carbon stocks and complex hydrological fluctuations remain largely unclear.As part of a two-year field experiment in a freshwater wetland,this study was conducted to investigate the effects of nighttime warming and N addition on phytoplankton biomass in the North China Plain.The results showed that neither nighttime warming nor N addition influenced the Shannon-Wiener index of phytoplankton community.Nighttime warming did not change phytoplankton biomass,likely due to the different warming impacts on dominant phyla and in different seasons.Decreased phytoplankton biomass in spring because of the increased water pH and submerged plant coverage was compensated by the enhanced biomass in autumn due to the reduced dissolved oxygen and submerged plant coverage,leading to the neutral change of phytoplankton biomass under warming.Nitrogen addition elevated phytoplankton biomass by 11.6%,which could be attributed to the enhanced nutrient availability and reduced submerged plant coverage.Positive relationships of methane(CH4)emission rates at the water-air interface with phytoplankton biomass indicated the potentially crucial role of phytoplankton in mediating wetland CH4 cycling through photosynthesis-driven metabolisms.The findings suggested the seasonal variation of phytoplankton and their potential responses to nighttime warming and N deposition,which may provide a more accurate basis for assessing the global change-carbon feedback in wetland ecosystems.展开更多
Background The temperate grasslands are facing numerous pressures from global change.Despite their essential ecological and economic role,how their microbial communities react to multiple varying factors remain obscur...Background The temperate grasslands are facing numerous pressures from global change.Despite their essential ecological and economic role,how their microbial communities react to multiple varying factors remain obscure.In this study,we simulated three global change drivers,i.e.,nitrogen deposition(ambient N vs.elevated N,a N vs.e N),precipitation increase(ambient precipitation vs.elevated precipitation,a P vs.e P),and mowing,represented experimentally by clipping(unclipped vs.clipped,u C vs.CL),together in all possible combinations in a temperate semi-arid grassland ecosystem.Results Nitrogen addition had negative effects on the richness of bacterial and fungal communties,significantly changed their structures(P<0.05)and increased their dissimilarities(P<0.05),while water addition had positive effects on fungal and protist communities and significantly stimulated theα-diversity of protist communities under N addition without clipping,which was in contrast to the effect in clipped plots.Clipping had a marginal effect on fungal communities and significantly affected protist communities(P<0.05).A notable interactive effect of N and precipitation on the structure of bacterial communities and a significant interactive effect of clipping and precipitation on protists were found.Combination effects of N with precipitation or clipping on module aggregation of metanetworks were also observed between u C and CL,as well as a P and e P meta-networks.Bacterial,fungal,and protist communities varied in their assembly mechanisms,and their assembly processes differed in response to the three global change factors.Conclusions Overall,N,water addition,and clipping individually and/or interactively,in distinct degrees,altered soil microbial interaction,community structure,and the potential function in a semi-arid steppe.These findings enhance our understanding of soil microbial community assembly and provide a scientific basis for managing temperate grasslands,particularly in the context of global change's impact on ecosystem function and stability.展开更多
Changes in micro-climate are important drivers influencing carbon cycles in natural ecosystems.However,due to the complexity of thermal conduction among air,water,and sediment and the difficulty of accurately characte...Changes in micro-climate are important drivers influencing carbon cycles in natural ecosystems.However,due to the complexity of thermal conduction among air,water,and sediment and the difficulty of accurately characterizing microclimatic impacts,the responses of wetland carbon cycles to microclimate under global change remain largely unexplored.In this study,based on a two-year field manipulative experiment from 2022 to 2023 in a freshwater wetland in the North China Plain,we investigated the effects of simulated nighttime warming and atmospheric nitrogen deposition on the temperatures of shallow water,deep water,and sediment,and also explored the potential influence of microclimate on wetland carbon cycles.The results showed that nighttime warming increased the daily mean temperatures of the shallow-water,deep-water,and sediment layers by 0.71,0.73 and 0.64℃,respectively.additionally,the diurnal temperature range of the deep-water layer decreased by 0.17℃.Nitrogen addition have no significant effect on the aforementioned temperature parameters.However,its influence could be observed in the seasonal fluctuations of these layers to some extent.Moreover,the warming effect on these thermal regimes were primarily influenced by solar radiation and water turbidity.Submerged plant cover exerted a cooling effect at various vertical levels.Therefore,future increases in wetland temperatures may enhance the rate of microbial metabolism,likely resulting in elevated carbon emissions.This study provides empirical evidence of temperature changes across vertical layers in freshwater wetlands under climate warming.Our findings highlighted the need to incorporate shallow-water,deep-water,and sediment temperature data into wetland carbon cycling to better predict the responses of wetland carbon cycle to global change.展开更多
Aims Quantifying changes in plant growth and interspecific interactions,both of which can alter dominance of plant species,will facilitate explanation and projection of the shifts in species composition and community ...Aims Quantifying changes in plant growth and interspecific interactions,both of which can alter dominance of plant species,will facilitate explanation and projection of the shifts in species composition and community structure in terrestrial biomes expected under global warming.We used an experimental warming treatment to examine the potential influence of global warming on plant growth and interspecific interactions in a temperate steppe in northern China.Materials and methods Six dominant plant species were grown in monoculture and all 15 two-species mixtures for one growing season under ambient and elevated temperatures in the field.Temperature was manipulated with infrared radiators.Important findings Total biomass of all the six plant species was increased by 34–63%in monocultures and 20–76%in mixtures.The magnitude of the warming effect on biomass was modified by plant interactions.Experimental warming changed the hierarchies of both competitive response and competitive effect.The competitive ability(in terms of response and effect)of one C4 grass(Pennisetum centrasiaticum)was suppressed,while the competitive abilities of one C3 forb(Artemisia capillaris)and one C3 grass(Stipa krylovii)were enhanced by experimental warming.The demonstrated alterations in growth and plant interactions may lead to changes in community structure and biodiversity in the temperate steppe in a warmer world in the future.展开更多
Aims The balance between leaf photosynthesis and respiration of terrestrial plants determines the net carbon(C)gain by vegetation and consequently is important to climate–C cycle feedback.This study is to reveal the ...Aims The balance between leaf photosynthesis and respiration of terrestrial plants determines the net carbon(C)gain by vegetation and consequently is important to climate–C cycle feedback.This study is to reveal the global patterns of the responses of leaf-level net photosynthesis and dark respiration to elevated temperature.Methods Data for leaf-level net photosynthesis rate(P_(n))and dark respiration rate(R_(d))in natural terrestrial plant species with standard deviation(or standard error or confidence interval)and sample size were collected from searched literatures on Web of Science.Then a metaanalysis was conducted to estimate the effects of experimental warming on leaf-level P_(n) and R_(d) of terrestrial plants.Important findings Across all the plants included in the analysis,warming enhanced P_(n) and R_(d) significantly by 6.13 and 33.14%,respectively.However,the responses were plant functional type(PFT)specific.Specifically,photosynthesis of C_(4) herbs responded to experimental warming positively but that of C_(3) herbs did not,whereas their respiratory responses were similar,suggesting C_(4) plants would benefit more from warming.The photosynthetic response declined linearly with increasing ambient temperature.The respiratory responses linearly enhanced with the increase in warming magnitude.In addition,a thermal acclimation of R_(d),instead of P_(n),was observed.Although greater proportion of fixed C was consumed(greater R_(d)/P_(n) ratio),warming significantly enhanced the daily net C balance at the leaf level.This provides an important mechanism for the positive responses of plant biomass and net primary productivity to warming.Overall,the findings,including the contrastive responses of different PFTs and the enhancement in daily leaf net C balance,are important for improving model projection of the climate–C cycle feedback.展开更多
Aims Climate change largely impacts ecosystem carbon and water cycles by changing plant gas exchange,which may further cause positive or negative feedback to global climate change.However,long-term global change manip...Aims Climate change largely impacts ecosystem carbon and water cycles by changing plant gas exchange,which may further cause positive or negative feedback to global climate change.However,long-term global change manipulative experiments are seldom conducted to reveal plant ecophysiological responses to climatic warming and altered precipitation regimes.Methods An 8-year field experiment with both warming and increased precipitation was conducted in a temperate grassland in northern China.We measured leaf gas exchange rates(including plant photosynthesis,transpiration and instantaneous water use efficiency[WUE])of two dominant plant species(Stipa sareptana var.krylovii and Agropyron cristatum)from 2005 to 2012(except 2006 and 2010)and those of other six species from 2011 to 2012.Important Findings Increased precipitation significantly stimulated plant photosynthetic rates(A)by 29.5%and 19.9%and transpiration rates(E)by 42.2%and 51.2%for both dominant species S.sareptana var.krylovii and A.cristatum,respectively,across the 8 years.Similarly,A and E of the six plant functional types were all stimulated by increased precipitation in 2011 and 2012.As the balance of A and E,the instantaneous WUEs of different plant species had species-specific responses to increased precipitation.In contrast,neither warming nor its interaction with increased precipitation significantly affected plant leaf gas exchange rates.Furthermore,A and E of the two dominant species and their response magnitudes to water treatments positively correlated with rainfall amount in July across years.We did not find any significant difference between the short-term versus long-term responses of plant photosynthesis,suggesting the flexibility of leaf gas exchange under climate change.The results suggest that changing precipitation rather than global warming plays a prominent role in determining production of this grassland in the context of climate change.展开更多
Arbuscular mycorrhizal(AM) fungi form mutualistic symbioses with most plant species and play important roles in ecosystems.Knowledge of the response of AM fungi to temperature change will improve our understanding of ...Arbuscular mycorrhizal(AM) fungi form mutualistic symbioses with most plant species and play important roles in ecosystems.Knowledge of the response of AM fungi to temperature change will improve our understanding of the function of AM fungal community under global climate change scenarios in ecosystems.The effects of constant warming on AM fungal communities have been investigated previously,but responses to asymmetrical warming over 24-h periods have never been documented in natural ecosystems.In this study,we examined AM fungal communities in a full factorial design including day-time and night-time warming in a semiarid steppe in northern China.Day-time and 24-h warming,but not night-time warming,significantly increased AM fungal spore density.In contrast,none of the three warming regimes had a significant effect on AM fungal extra radical hyphal density.Atotal of 161 operational taxonomic units(OTUs) of AM fungi were recovered by 454 pyrosequencing of 18 S r DNA.Day-time,night-time,and 24-h warming all significantly increased AM fungal OTU richness.Some AM fungal OTUs showed a significant bias toward day-time,night-time or24-h warming.The AM fungal community composition was significantly affected by night-time warming,but not by day-time and 24-h warming.Our finding highlighted different responses of AM fungal spore density and community composition to asymmetrical warming.This study might improve our understanding of ecosystem functioning of AM fungal community under global climate change scenarios in a semiarid steppe ecosystem.展开更多
To most people,the Qinghai-Tibetan Plateau is a place full of mystery.It is also mysterious to many ecologists.The vast central Asian plateau lies at an average elevation>4000 m and covers about 370 million km2.Spa...To most people,the Qinghai-Tibetan Plateau is a place full of mystery.It is also mysterious to many ecologists.The vast central Asian plateau lies at an average elevation>4000 m and covers about 370 million km2.Spanning the highest range of elevations of any ecosystem in the world makes the plateau unique even among alpine ecosystems due to the presence of extreme abiotic environments:the lowest atmospheric pressure and thus,the lowest partial pressures of CO_(2) and O_(2),low temperatures and high levels of radiation,including high ultraviolet radiation.展开更多
Aims Fire and atmospheric nitrogen(N)deposition have the potential to influence growth and productivity of forest canopy.However,their impacts on photosynthesis and growth traits of understory plants in forests remain...Aims Fire and atmospheric nitrogen(N)deposition have the potential to influence growth and productivity of forest canopy.However,their impacts on photosynthesis and growth traits of understory plants in forests remain largely unexplored.This study was conducted to examine the effects of burning and N addition on foliar N content,net photosynthesis and growth traits of three dominant shrub species(Vitex negundo,Lindera glauca and Symplocos chinensis)in a temperate forest in Central China.Methods The experiment used a pair-nested design,with four treatments(control,burning,N addition and burning plus N addition)and five replicates.Leaf mass area(LMA),area-based concentrations of foliar N and chlorophyll(N_(area) and Chl_(area)),net photosynthesis(A_(n)),stomatal conductance(g_(s)),maximum photosynthetic rate(A_(max))and maximal carboxylation rate(V_(cmax)),basal diameter,height and branch length(BL)of the three species were measured.Important Findings Across the three species,burning stimulated LMA,N_(area),Chl_(area),A_(n),g_(s),A_(max) and V_(cmax),and consequently enhanced basal diam-eter,height and BL.Nitrogen addition increased A_(n) and gs but did not affect LMA,N_(area),Chl_(area),A_(max),V_(cmax),basal diameter,height or BL.However,N addition strengthened the positive effects of burning on g_(s),V_(cmax),A_(n) and BL.The findings indicate the primary role of light resources in determining plant photosynthesis and growth of understory shrub species after fire and highlight that understory plants should be considered in projection of biomass accumulation and productivity of forests under environmental perturbations.展开更多
Aim Grasslands are dominant vegetation of China,support outstanding biodiversity and sequester bulk amount of atmospheric CO_(2).These grasslands are highly degraded and fragmented due to remarkable anthropogenic and ...Aim Grasslands are dominant vegetation of China,support outstanding biodiversity and sequester bulk amount of atmospheric CO_(2).These grasslands are highly degraded and fragmented due to remarkable anthropogenic and grazing loads.Chinese Government has made great attempt to restore by grazing exclusion.The relations of carbon fluxes with species composition and diversity in the communities sensitive to grazing by large herbivores are needed to be analysed under the global climate change scenario.The objective of present study was to comprehend the effects of grazing and fencing on the ecosystem structure and function of the typical steppe grassland.Methods To meet the objectives,overgrazed and fenced(since year 2001)sys-tems were selected in typical steppe grassland at the Duolun Restoration Ecology Research Station,Inner Mogolia,China.Within each system,three dominant communities with three replicates were selected.In each replicate community,three 1×1 m plots,were randomly located.Each plot was divided into four 50×50 cm quadrats.A total of 216,50×50 cm quadrats were sampled.From each quadrat,number of individuals and above-ground herbaceous biomass for each species,soil respiration(SR),ecosystem respira-tion(ER),net(NEE)as well as gross(GEE)ecosystem CO_(2) exchanges were recorded in June 2015.Data were well analysed using statistical software.Canonical correspondence analysis showed dif-ferential responses of communities to the structure and function of the typical steppe grassland.Important Findings Across the communities,fencing reduced the soil tempera-ture by 12%and at the same time increased the soil moisture by 44.30%,thus,increased the species richness by 28%,evenness by 21%,above-ground biomass by 19%and plant carbon by 20%.Interestingly,fencing increased NEE by 128%,GEE by 77%,SR by 65%and ER by 39%.Under fencing,species composition partially governed the CO_(2) exchange processes.Conclusions Fencing reduces soil temperature and thereby improves species diversity and more efficient CO_(2) sequestration and long-term and in-depth study is desirable for a better understanding of the relation-ship between species diversity and ecosystem carbon uptake.展开更多
Aims Precipitation is predicted to increase in arid and semiarid regions under climate change,with greater changes in intra-and interannual distribution in the future.As a major limiting factor in these regions,change...Aims Precipitation is predicted to increase in arid and semiarid regions under climate change,with greater changes in intra-and interannual distribution in the future.As a major limiting factor in these regions,changes in precipitation undoubtedly influence plant growth and productivity.However,how the temporal shifts in pre-cipitation will impact plant populations are uncertain.Methods A 3-year field experiment and a greenhouse experiment were conducted in a temperate grassland in northern China to examine the impacts of seasonal(spring and summer)increased precipitation on offspring performance of a common species,Potentilla tanacetifolia.Important Findings Our results showed that the amounts and timing of increased precipitation both played important roles in regulating offspring performance of P.tanacetifolia in the temperate steppe ecosystem.Increased precipitation in spring at maternal stage stimulated seed production,germination percentage and seedling biomass,whereas increased precipitation in summer at maternal stage stimulated seedling biomass.The timing of increased precipitation influenced seed attributes,whereas the amount of increased precipitation influenced offspring seedling biomass.Our results indicate that population development of P.tanacetifolia may be underestimated under future increased precipitation regime,if the transgenerational effect is not taken into account.展开更多
Ten years ago,the Botanical Society of China together with the Institute of Botany of the Chinese Academy of Sciences decided to launch the new international Journal of Plant Ecology,or in short JPE,to introduce the w...Ten years ago,the Botanical Society of China together with the Institute of Botany of the Chinese Academy of Sciences decided to launch the new international Journal of Plant Ecology,or in short JPE,to introduce the works of Chinese ecologists to the international community and promote ecological research in China.The new journal,which could be considered as an off-spring of the corresponding Chinese-language journal,offers authors from all over the world,but also specifically from China,a platform to publish peer-reviewed original research and reviews in the broad field of plant ecology.During initial discussions in the editorial board and with Oxford University Press,we decided that it would be best if the authors with their submissions are allowed to define the scope of the journal,because in this way we could gain a unique profile with least overlap with other international journals.The prime goal was to publish good and relevant science,which would produce long-term impact as a secondary result.展开更多
A commentary on our recent article on Journal of Plant Ecology(Liang et al.2013)by Smith(2014)argues that it is not appro-priate to lump data from different experiments together to demonstrate the thermal acclimation ...A commentary on our recent article on Journal of Plant Ecology(Liang et al.2013)by Smith(2014)argues that it is not appro-priate to lump data from different experiments together to demonstrate the thermal acclimation of leaf dark respiration.We agree that many factors,as listed by Smith(2014),would impact the responses of leaf carbon exchanges to warming and the consequent thermal acclimation.Although not all factors were included,we discussed in the article that light and vapor pressure deficit(VPD)could have affected our conclusions(Liang et al.2013).The“acclimation”in our paper did not exactly accord with the physiological definition(Atkin and Tjoelker 2003;Smith and Dukes 2013).It is hard to make the environ-mental factors as well as warming magnitude coherent in a syn-thesis study because the data were from different experiments.Therefore,the“acclimation”in our meta-analysis was more like an apparent one rather than the physiologically intrinsic one as defined by Atkin et al.展开更多
Land use management affects plant carbon(C)supply and soil environments and hence alters soil nitrogen(N)dynamics,with consequent feedbacks to terrestrial ecosystem productivity.The objective of this study was to bett...Land use management affects plant carbon(C)supply and soil environments and hence alters soil nitrogen(N)dynamics,with consequent feedbacks to terrestrial ecosystem productivity.The objective of this study was to better identify mechanisms by which land-use management(clipping and shading)regulates soil N in a tallgrass prairie,OK,USA.Methods We conducted 1-year clipping and shading experiment to investigate the effects of changes in land-use management(soil microclimates,plant C substrate supply and microbial activity)on soil inorganic N(NH_(4)^(+)-N and NO_(3)^(-)-N),net N mineralization and nitrification in a tallgrass prairie.Important Findings Land-use management through clipping and/or shading significantly increased annual mean inorganic N,possibly due to lowered plant N uptake and decreased microbial N immobilization into biomass growth.Shading significantly increased annual mean mineralization rates(P<0.05).Clipping slightly decreased annual mean N nitrification rates whereas shading significantly increased annual mean N nitrification rates.Soil microclimate significantly explained 36%of the variation in NO_(3)^(-)-N concentrations(P=0.004).However,soil respiration,a predictor of plant C substrate supply and microbial activity,was negatively correlated with NH_(4)^(+)-N concentrations(P=0.0009),net N mineralization(P=0.0037)and nitrification rates(P=0.0028)across treatments.Our results suggest that change in C substrate supply andmicrobial activity under clipping and/or shading is a critical control on NH_(4)^(+)-N,net N mineralization and nitrification rates,whereas clipping and shading-induced soil microclimate change can be important for NO_(3)^(-)-N variation in the tallgrass prairie.展开更多
Launched by the Oxford University Press on behalf of the Botanical Society of China and the Institute of Botany of Chinese Academy of Sciences,the new Journal of Plant Ecology(JPE)publishes original research articles,...Launched by the Oxford University Press on behalf of the Botanical Society of China and the Institute of Botany of Chinese Academy of Sciences,the new Journal of Plant Ecology(JPE)publishes original research articles,reviews and forum pieces covering the entire field of plant ecology.We feel there is a great need for this journal in a time when many other journals are only able to publish a small amount of suitable manuscripts,often those for which they expect the highest impact in terms of citations.To achieve this,these journals focus on concepts and novelty.However,science,in particular the science of ecology,does not simply advance by accumulating concepts and novelty.In the long run,it is the sound results obtained in well-designed studies with sufficient replication and careful measurement and analysis which increase the base of knowledge on which interpretation,understanding and eventually the advancement of science depend.A key criterion by which sound scientific results can be judged is repeatability(a contrast to novelty!).One of the greatest threats to scientific advancement is nonpublication and exclusion of results from subsequent synthesis.By publishing sound scientific results,JPE aims to contribute to the advancement of plant ecology beyond concepts and novelty.展开更多
Background Soil erosion affects the stability of terrestrial ecosystems and ecosystem services by directly or indirectly impacting the cycling of soil materials and energy and reducing the fertility of grassland soils...Background Soil erosion affects the stability of terrestrial ecosystems and ecosystem services by directly or indirectly impacting the cycling of soil materials and energy and reducing the fertility of grassland soils.However,research on microbial adaptation to grazing and soil erosion is limited,particularly in relation to grassland ecosystem restora-tion.Here,we assess microbial communities subjected to simulated soil erosion and grazing in a semi-arid grassland of Inner Mongolia,China.Results No significant change was observed in soil variables.However,the structure of the soil microbial commu-nity underwent significant changes as a result of soil erosion and soil erosion plus grazing,leading to a significant increase in the relative abundance of Cyanobacteria(116.80%vs 116.38%).Wind erosion and deposition contributed to an increase in the network complexity of soil bacterial and fungal communities.However,much of this effect was alleviated by grazing.Simultaneously,aeolian processes and grazing regulate soil microbial community assembly,leading to inconsistent patterns of change in bacterial and fungal communities.Under wind erosion and deposi-tion,the relative contribution of deterministic processes(4.44%vs 31.11%)in bacterial communities increased,while the relative contribution of stochastic processes(2.23%vs 20%)in fungal communities reduced.Grazing resulted in a decrease in the relative contribution of deterministic processes(8.89%)in the bacterial community and an increase in the relative contribution of stochastic processes(8.89%)in the fungal community.Conclusion This study presents a comprehensive investigation of the response of soil microbial communities to aeolian erosion–deposition and grazing in a semi-arid grassland.Our findings indicate that microbial communities in the semi-arid grassland show resistance to external disturbances and that light grazing mitigates the effects of aeo-lian erosion–deposition on microbial communities,which is essential for maintaining the stability and biodiversity of grassland ecosystems.展开更多
基金supported by the Science and Technology Project of Hebei Education Department(No.QN2023028)the Natural Science Foundation of Hebei Province(No.C2022201042)+1 种基金the High-level Talent Research Funding Project of Hebei University(Nos.521000981405 and 521000981186)the Collaborative Innovation Center for Baiyangdian Basin Ecological Protection and Beijing-Tianjin-Hebei Sustainable Development.
文摘Climate warming and atmospheric nitrogen(N)deposition have profound influences on the terrestrial biosphere.However,how these two global change drivers affect phytoplankton which are important primary producers in wetlands with large carbon stocks and complex hydrological fluctuations remain largely unclear.As part of a two-year field experiment in a freshwater wetland,this study was conducted to investigate the effects of nighttime warming and N addition on phytoplankton biomass in the North China Plain.The results showed that neither nighttime warming nor N addition influenced the Shannon-Wiener index of phytoplankton community.Nighttime warming did not change phytoplankton biomass,likely due to the different warming impacts on dominant phyla and in different seasons.Decreased phytoplankton biomass in spring because of the increased water pH and submerged plant coverage was compensated by the enhanced biomass in autumn due to the reduced dissolved oxygen and submerged plant coverage,leading to the neutral change of phytoplankton biomass under warming.Nitrogen addition elevated phytoplankton biomass by 11.6%,which could be attributed to the enhanced nutrient availability and reduced submerged plant coverage.Positive relationships of methane(CH4)emission rates at the water-air interface with phytoplankton biomass indicated the potentially crucial role of phytoplankton in mediating wetland CH4 cycling through photosynthesis-driven metabolisms.The findings suggested the seasonal variation of phytoplankton and their potential responses to nighttime warming and N deposition,which may provide a more accurate basis for assessing the global change-carbon feedback in wetland ecosystems.
基金financially supported by grants from the National Natural Science Foundation of China (41930643 and 42273084)Natural Science Foundation of Henan Province (242300421039)Science and Technology Development Plan Project of Henan Province (242102110186)
文摘Background The temperate grasslands are facing numerous pressures from global change.Despite their essential ecological and economic role,how their microbial communities react to multiple varying factors remain obscure.In this study,we simulated three global change drivers,i.e.,nitrogen deposition(ambient N vs.elevated N,a N vs.e N),precipitation increase(ambient precipitation vs.elevated precipitation,a P vs.e P),and mowing,represented experimentally by clipping(unclipped vs.clipped,u C vs.CL),together in all possible combinations in a temperate semi-arid grassland ecosystem.Results Nitrogen addition had negative effects on the richness of bacterial and fungal communties,significantly changed their structures(P<0.05)and increased their dissimilarities(P<0.05),while water addition had positive effects on fungal and protist communities and significantly stimulated theα-diversity of protist communities under N addition without clipping,which was in contrast to the effect in clipped plots.Clipping had a marginal effect on fungal communities and significantly affected protist communities(P<0.05).A notable interactive effect of N and precipitation on the structure of bacterial communities and a significant interactive effect of clipping and precipitation on protists were found.Combination effects of N with precipitation or clipping on module aggregation of metanetworks were also observed between u C and CL,as well as a P and e P meta-networks.Bacterial,fungal,and protist communities varied in their assembly mechanisms,and their assembly processes differed in response to the three global change factors.Conclusions Overall,N,water addition,and clipping individually and/or interactively,in distinct degrees,altered soil microbial interaction,community structure,and the potential function in a semi-arid steppe.These findings enhance our understanding of soil microbial community assembly and provide a scientific basis for managing temperate grasslands,particularly in the context of global change's impact on ecosystem function and stability.
基金financially supported by the Hebei Natural Science Foundation(C2022201042)the High-level Talent Research Funding Project of Hebei University(521000981186 and 521000981405)+1 种基金the Science and Technology Project of Hebei Education Department(QN2023028)Collaborative Innovation Center for Baiyangdian Basin Ecological Protection and Beijing-Tianjin-Hebei Sustainable Development.C.W.received funding from the National Innovative Entrepreneurship Training Program for college students(S202310075047 and S202410075044).
文摘Changes in micro-climate are important drivers influencing carbon cycles in natural ecosystems.However,due to the complexity of thermal conduction among air,water,and sediment and the difficulty of accurately characterizing microclimatic impacts,the responses of wetland carbon cycles to microclimate under global change remain largely unexplored.In this study,based on a two-year field manipulative experiment from 2022 to 2023 in a freshwater wetland in the North China Plain,we investigated the effects of simulated nighttime warming and atmospheric nitrogen deposition on the temperatures of shallow water,deep water,and sediment,and also explored the potential influence of microclimate on wetland carbon cycles.The results showed that nighttime warming increased the daily mean temperatures of the shallow-water,deep-water,and sediment layers by 0.71,0.73 and 0.64℃,respectively.additionally,the diurnal temperature range of the deep-water layer decreased by 0.17℃.Nitrogen addition have no significant effect on the aforementioned temperature parameters.However,its influence could be observed in the seasonal fluctuations of these layers to some extent.Moreover,the warming effect on these thermal regimes were primarily influenced by solar radiation and water turbidity.Submerged plant cover exerted a cooling effect at various vertical levels.Therefore,future increases in wetland temperatures may enhance the rate of microbial metabolism,likely resulting in elevated carbon emissions.This study provides empirical evidence of temperature changes across vertical layers in freshwater wetlands under climate warming.Our findings highlighted the need to incorporate shallow-water,deep-water,and sediment temperature data into wetland carbon cycling to better predict the responses of wetland carbon cycle to global change.
基金supported by the National Natural Science Foundation of China(90511006)Chinese Academy of Sciences(Hundred Talents Program).
文摘Aims Quantifying changes in plant growth and interspecific interactions,both of which can alter dominance of plant species,will facilitate explanation and projection of the shifts in species composition and community structure in terrestrial biomes expected under global warming.We used an experimental warming treatment to examine the potential influence of global warming on plant growth and interspecific interactions in a temperate steppe in northern China.Materials and methods Six dominant plant species were grown in monoculture and all 15 two-species mixtures for one growing season under ambient and elevated temperatures in the field.Temperature was manipulated with infrared radiators.Important findings Total biomass of all the six plant species was increased by 34–63%in monocultures and 20–76%in mixtures.The magnitude of the warming effect on biomass was modified by plant interactions.Experimental warming changed the hierarchies of both competitive response and competitive effect.The competitive ability(in terms of response and effect)of one C4 grass(Pennisetum centrasiaticum)was suppressed,while the competitive abilities of one C3 forb(Artemisia capillaris)and one C3 grass(Stipa krylovii)were enhanced by experimental warming.The demonstrated alterations in growth and plant interactions may lead to changes in community structure and biodiversity in the temperate steppe in a warmer world in the future.
基金National Natural Science Foundation of China(41030104/D0308,30925009)the Ministry of Science and Technology of China(2013CB956300).
文摘Aims The balance between leaf photosynthesis and respiration of terrestrial plants determines the net carbon(C)gain by vegetation and consequently is important to climate–C cycle feedback.This study is to reveal the global patterns of the responses of leaf-level net photosynthesis and dark respiration to elevated temperature.Methods Data for leaf-level net photosynthesis rate(P_(n))and dark respiration rate(R_(d))in natural terrestrial plant species with standard deviation(or standard error or confidence interval)and sample size were collected from searched literatures on Web of Science.Then a metaanalysis was conducted to estimate the effects of experimental warming on leaf-level P_(n) and R_(d) of terrestrial plants.Important findings Across all the plants included in the analysis,warming enhanced P_(n) and R_(d) significantly by 6.13 and 33.14%,respectively.However,the responses were plant functional type(PFT)specific.Specifically,photosynthesis of C_(4) herbs responded to experimental warming positively but that of C_(3) herbs did not,whereas their respiratory responses were similar,suggesting C_(4) plants would benefit more from warming.The photosynthetic response declined linearly with increasing ambient temperature.The respiratory responses linearly enhanced with the increase in warming magnitude.In addition,a thermal acclimation of R_(d),instead of P_(n),was observed.Although greater proportion of fixed C was consumed(greater R_(d)/P_(n) ratio),warming significantly enhanced the daily net C balance at the leaf level.This provides an important mechanism for the positive responses of plant biomass and net primary productivity to warming.Overall,the findings,including the contrastive responses of different PFTs and the enhancement in daily leaf net C balance,are important for improving model projection of the climate–C cycle feedback.
基金National Natural Science Foundation of China(31000227)Ministry of Science and Technology of China(2013CB956300).
文摘Aims Climate change largely impacts ecosystem carbon and water cycles by changing plant gas exchange,which may further cause positive or negative feedback to global climate change.However,long-term global change manipulative experiments are seldom conducted to reveal plant ecophysiological responses to climatic warming and altered precipitation regimes.Methods An 8-year field experiment with both warming and increased precipitation was conducted in a temperate grassland in northern China.We measured leaf gas exchange rates(including plant photosynthesis,transpiration and instantaneous water use efficiency[WUE])of two dominant plant species(Stipa sareptana var.krylovii and Agropyron cristatum)from 2005 to 2012(except 2006 and 2010)and those of other six species from 2011 to 2012.Important Findings Increased precipitation significantly stimulated plant photosynthetic rates(A)by 29.5%and 19.9%and transpiration rates(E)by 42.2%and 51.2%for both dominant species S.sareptana var.krylovii and A.cristatum,respectively,across the 8 years.Similarly,A and E of the six plant functional types were all stimulated by increased precipitation in 2011 and 2012.As the balance of A and E,the instantaneous WUEs of different plant species had species-specific responses to increased precipitation.In contrast,neither warming nor its interaction with increased precipitation significantly affected plant leaf gas exchange rates.Furthermore,A and E of the two dominant species and their response magnitudes to water treatments positively correlated with rainfall amount in July across years.We did not find any significant difference between the short-term versus long-term responses of plant photosynthesis,suggesting the flexibility of leaf gas exchange under climate change.The results suggest that changing precipitation rather than global warming plays a prominent role in determining production of this grassland in the context of climate change.
基金supported by the National Natural Science Foundation of China(31070434,30592005)the Knowledge Innovation Program of the Chinese Academy of Sciences(KSCX2-EW-J-6)
文摘Arbuscular mycorrhizal(AM) fungi form mutualistic symbioses with most plant species and play important roles in ecosystems.Knowledge of the response of AM fungi to temperature change will improve our understanding of the function of AM fungal community under global climate change scenarios in ecosystems.The effects of constant warming on AM fungal communities have been investigated previously,but responses to asymmetrical warming over 24-h periods have never been documented in natural ecosystems.In this study,we examined AM fungal communities in a full factorial design including day-time and night-time warming in a semiarid steppe in northern China.Day-time and 24-h warming,but not night-time warming,significantly increased AM fungal spore density.In contrast,none of the three warming regimes had a significant effect on AM fungal extra radical hyphal density.Atotal of 161 operational taxonomic units(OTUs) of AM fungi were recovered by 454 pyrosequencing of 18 S r DNA.Day-time,night-time,and 24-h warming all significantly increased AM fungal OTU richness.Some AM fungal OTUs showed a significant bias toward day-time,night-time or24-h warming.The AM fungal community composition was significantly affected by night-time warming,but not by day-time and 24-h warming.Our finding highlighted different responses of AM fungal spore density and community composition to asymmetrical warming.This study might improve our understanding of ecosystem functioning of AM fungal community under global climate change scenarios in a semiarid steppe ecosystem.
文摘To most people,the Qinghai-Tibetan Plateau is a place full of mystery.It is also mysterious to many ecologists.The vast central Asian plateau lies at an average elevation>4000 m and covers about 370 million km2.Spanning the highest range of elevations of any ecosystem in the world makes the plateau unique even among alpine ecosystems due to the presence of extreme abiotic environments:the lowest atmospheric pressure and thus,the lowest partial pressures of CO_(2) and O_(2),low temperatures and high levels of radiation,including high ultraviolet radiation.
基金This work was financially supported by the National Natural Science Foundation of China(31430015).
文摘Aims Fire and atmospheric nitrogen(N)deposition have the potential to influence growth and productivity of forest canopy.However,their impacts on photosynthesis and growth traits of understory plants in forests remain largely unexplored.This study was conducted to examine the effects of burning and N addition on foliar N content,net photosynthesis and growth traits of three dominant shrub species(Vitex negundo,Lindera glauca and Symplocos chinensis)in a temperate forest in Central China.Methods The experiment used a pair-nested design,with four treatments(control,burning,N addition and burning plus N addition)and five replicates.Leaf mass area(LMA),area-based concentrations of foliar N and chlorophyll(N_(area) and Chl_(area)),net photosynthesis(A_(n)),stomatal conductance(g_(s)),maximum photosynthetic rate(A_(max))and maximal carboxylation rate(V_(cmax)),basal diameter,height and branch length(BL)of the three species were measured.Important Findings Across the three species,burning stimulated LMA,N_(area),Chl_(area),A_(n),g_(s),A_(max) and V_(cmax),and consequently enhanced basal diam-eter,height and BL.Nitrogen addition increased A_(n) and gs but did not affect LMA,N_(area),Chl_(area),A_(max),V_(cmax),basal diameter,height or BL.However,N addition strengthened the positive effects of burning on g_(s),V_(cmax),A_(n) and BL.The findings indicate the primary role of light resources in determining plant photosynthesis and growth of understory shrub species after fire and highlight that understory plants should be considered in projection of biomass accumulation and productivity of forests under environmental perturbations.
基金This study was supported by TWAS Fellowships for Research and Advanced Training,Italy to R.S.(FR number 3240281997)the National Natural Science Foundation of China(31430015,31270564).
文摘Aim Grasslands are dominant vegetation of China,support outstanding biodiversity and sequester bulk amount of atmospheric CO_(2).These grasslands are highly degraded and fragmented due to remarkable anthropogenic and grazing loads.Chinese Government has made great attempt to restore by grazing exclusion.The relations of carbon fluxes with species composition and diversity in the communities sensitive to grazing by large herbivores are needed to be analysed under the global climate change scenario.The objective of present study was to comprehend the effects of grazing and fencing on the ecosystem structure and function of the typical steppe grassland.Methods To meet the objectives,overgrazed and fenced(since year 2001)sys-tems were selected in typical steppe grassland at the Duolun Restoration Ecology Research Station,Inner Mogolia,China.Within each system,three dominant communities with three replicates were selected.In each replicate community,three 1×1 m plots,were randomly located.Each plot was divided into four 50×50 cm quadrats.A total of 216,50×50 cm quadrats were sampled.From each quadrat,number of individuals and above-ground herbaceous biomass for each species,soil respiration(SR),ecosystem respira-tion(ER),net(NEE)as well as gross(GEE)ecosystem CO_(2) exchanges were recorded in June 2015.Data were well analysed using statistical software.Canonical correspondence analysis showed dif-ferential responses of communities to the structure and function of the typical steppe grassland.Important Findings Across the communities,fencing reduced the soil tempera-ture by 12%and at the same time increased the soil moisture by 44.30%,thus,increased the species richness by 28%,evenness by 21%,above-ground biomass by 19%and plant carbon by 20%.Interestingly,fencing increased NEE by 128%,GEE by 77%,SR by 65%and ER by 39%.Under fencing,species composition partially governed the CO_(2) exchange processes.Conclusions Fencing reduces soil temperature and thereby improves species diversity and more efficient CO_(2) sequestration and long-term and in-depth study is desirable for a better understanding of the relation-ship between species diversity and ecosystem carbon uptake.
基金This study was supported by the National Natural Science Foundation of China(31500393,31500322,31601887)Science and Technology Program of the Shaanxi Academy of Sciences(2016K-55).
文摘Aims Precipitation is predicted to increase in arid and semiarid regions under climate change,with greater changes in intra-and interannual distribution in the future.As a major limiting factor in these regions,changes in precipitation undoubtedly influence plant growth and productivity.However,how the temporal shifts in pre-cipitation will impact plant populations are uncertain.Methods A 3-year field experiment and a greenhouse experiment were conducted in a temperate grassland in northern China to examine the impacts of seasonal(spring and summer)increased precipitation on offspring performance of a common species,Potentilla tanacetifolia.Important Findings Our results showed that the amounts and timing of increased precipitation both played important roles in regulating offspring performance of P.tanacetifolia in the temperate steppe ecosystem.Increased precipitation in spring at maternal stage stimulated seed production,germination percentage and seedling biomass,whereas increased precipitation in summer at maternal stage stimulated seedling biomass.The timing of increased precipitation influenced seed attributes,whereas the amount of increased precipitation influenced offspring seedling biomass.Our results indicate that population development of P.tanacetifolia may be underestimated under future increased precipitation regime,if the transgenerational effect is not taken into account.
文摘Ten years ago,the Botanical Society of China together with the Institute of Botany of the Chinese Academy of Sciences decided to launch the new international Journal of Plant Ecology,or in short JPE,to introduce the works of Chinese ecologists to the international community and promote ecological research in China.The new journal,which could be considered as an off-spring of the corresponding Chinese-language journal,offers authors from all over the world,but also specifically from China,a platform to publish peer-reviewed original research and reviews in the broad field of plant ecology.During initial discussions in the editorial board and with Oxford University Press,we decided that it would be best if the authors with their submissions are allowed to define the scope of the journal,because in this way we could gain a unique profile with least overlap with other international journals.The prime goal was to publish good and relevant science,which would produce long-term impact as a secondary result.
文摘A commentary on our recent article on Journal of Plant Ecology(Liang et al.2013)by Smith(2014)argues that it is not appro-priate to lump data from different experiments together to demonstrate the thermal acclimation of leaf dark respiration.We agree that many factors,as listed by Smith(2014),would impact the responses of leaf carbon exchanges to warming and the consequent thermal acclimation.Although not all factors were included,we discussed in the article that light and vapor pressure deficit(VPD)could have affected our conclusions(Liang et al.2013).The“acclimation”in our paper did not exactly accord with the physiological definition(Atkin and Tjoelker 2003;Smith and Dukes 2013).It is hard to make the environ-mental factors as well as warming magnitude coherent in a syn-thesis study because the data were from different experiments.Therefore,the“acclimation”in our meta-analysis was more like an apparent one rather than the physiologically intrinsic one as defined by Atkin et al.
基金National Science Foundation(to DEB 0078325 and DEB 0743778).
文摘Land use management affects plant carbon(C)supply and soil environments and hence alters soil nitrogen(N)dynamics,with consequent feedbacks to terrestrial ecosystem productivity.The objective of this study was to better identify mechanisms by which land-use management(clipping and shading)regulates soil N in a tallgrass prairie,OK,USA.Methods We conducted 1-year clipping and shading experiment to investigate the effects of changes in land-use management(soil microclimates,plant C substrate supply and microbial activity)on soil inorganic N(NH_(4)^(+)-N and NO_(3)^(-)-N),net N mineralization and nitrification in a tallgrass prairie.Important Findings Land-use management through clipping and/or shading significantly increased annual mean inorganic N,possibly due to lowered plant N uptake and decreased microbial N immobilization into biomass growth.Shading significantly increased annual mean mineralization rates(P<0.05).Clipping slightly decreased annual mean N nitrification rates whereas shading significantly increased annual mean N nitrification rates.Soil microclimate significantly explained 36%of the variation in NO_(3)^(-)-N concentrations(P=0.004).However,soil respiration,a predictor of plant C substrate supply and microbial activity,was negatively correlated with NH_(4)^(+)-N concentrations(P=0.0009),net N mineralization(P=0.0037)and nitrification rates(P=0.0028)across treatments.Our results suggest that change in C substrate supply andmicrobial activity under clipping and/or shading is a critical control on NH_(4)^(+)-N,net N mineralization and nitrification rates,whereas clipping and shading-induced soil microclimate change can be important for NO_(3)^(-)-N variation in the tallgrass prairie.
文摘Launched by the Oxford University Press on behalf of the Botanical Society of China and the Institute of Botany of Chinese Academy of Sciences,the new Journal of Plant Ecology(JPE)publishes original research articles,reviews and forum pieces covering the entire field of plant ecology.We feel there is a great need for this journal in a time when many other journals are only able to publish a small amount of suitable manuscripts,often those for which they expect the highest impact in terms of citations.To achieve this,these journals focus on concepts and novelty.However,science,in particular the science of ecology,does not simply advance by accumulating concepts and novelty.In the long run,it is the sound results obtained in well-designed studies with sufficient replication and careful measurement and analysis which increase the base of knowledge on which interpretation,understanding and eventually the advancement of science depend.A key criterion by which sound scientific results can be judged is repeatability(a contrast to novelty!).One of the greatest threats to scientific advancement is nonpublication and exclusion of results from subsequent synthesis.By publishing sound scientific results,JPE aims to contribute to the advancement of plant ecology beyond concepts and novelty.
基金financially supported by grants from the National Natural Science Foundation of China(41930643,42273084,and 41673077)Key Scientific Research Projects of Henan Province(21B180011)
文摘Background Soil erosion affects the stability of terrestrial ecosystems and ecosystem services by directly or indirectly impacting the cycling of soil materials and energy and reducing the fertility of grassland soils.However,research on microbial adaptation to grazing and soil erosion is limited,particularly in relation to grassland ecosystem restora-tion.Here,we assess microbial communities subjected to simulated soil erosion and grazing in a semi-arid grassland of Inner Mongolia,China.Results No significant change was observed in soil variables.However,the structure of the soil microbial commu-nity underwent significant changes as a result of soil erosion and soil erosion plus grazing,leading to a significant increase in the relative abundance of Cyanobacteria(116.80%vs 116.38%).Wind erosion and deposition contributed to an increase in the network complexity of soil bacterial and fungal communities.However,much of this effect was alleviated by grazing.Simultaneously,aeolian processes and grazing regulate soil microbial community assembly,leading to inconsistent patterns of change in bacterial and fungal communities.Under wind erosion and deposi-tion,the relative contribution of deterministic processes(4.44%vs 31.11%)in bacterial communities increased,while the relative contribution of stochastic processes(2.23%vs 20%)in fungal communities reduced.Grazing resulted in a decrease in the relative contribution of deterministic processes(8.89%)in the bacterial community and an increase in the relative contribution of stochastic processes(8.89%)in the fungal community.Conclusion This study presents a comprehensive investigation of the response of soil microbial communities to aeolian erosion–deposition and grazing in a semi-arid grassland.Our findings indicate that microbial communities in the semi-arid grassland show resistance to external disturbances and that light grazing mitigates the effects of aeo-lian erosion–deposition on microbial communities,which is essential for maintaining the stability and biodiversity of grassland ecosystems.
